The specific embodiment
Below, with Fig. 1 to Fig. 3, the air conditioner that relates to one embodiment of the invention is described.The air conditioner of present embodiment is routine explanation the as refrigerating plant.
At first, with reference to Fig. 1, all formations of the air conditioner 50 of present embodiment are described.Fig. 1 relates to the air conditioner formation figure of one embodiment of the invention.
Air conditioner 50 has: freeze cycle, and air-supply arrangement and control these control system and constitute.And this air conditioner 50 is the divergence type air conditioners that connect indoor set and off-premises station by refrigerant piping, electrical connecting wires, signal link etc.
Freeze cycle has: split-compressor 1, cross valve 2, outdoor heat exchanger the 3, the 1st decompressor 4, gas-liquid separator the 5, the 2nd decompressor 6, indoor side heat exchanger 7, injection control valve 9 constitute by connecting these by refrigerant piping.Indoor side heat exchanger 7 is placed in the indoor set, and split-compressor 1, cross valve 2, outdoor heat exchanger the 3, the 1st decompressor 4, gas-liquid separator the 5, the 2nd decompressor 6, injection control valve 9 are placed in the off-premises station.
Split-compressor 1 has: by the split-compressor mechanism of low-pressure side compressor section (low-pressure side compressor section) 1-1 and high side compressors portion (high side compressors portion) 1-2 formations.Low-pressure side compressor section 1-1 and high side compressors portion 1-2 use the rotary compressor portion that is made of cylinder, rotor, impeller, end plate to constitute.Low-pressure side compressor section 1-1 and high side compressors portion 1-2 place in the closed container 1-3 with the state of configuration arranged side by side.
The 1c of suction portion of the discharge portion 1b of low-pressure side compressor section 1-1 and high side compressors portion 1-2 is provided with in the mode at the lateral opening of each cylinder, for approaching mutually, is arranged on same position at circumferencial direction.The 1c of suction portion of the discharge portion 1b of low-pressure side compressor section 1-1 and high side compressors portion 1-2 is communicated with by connecting pipings 1-4.This connecting pipings 1-4 (being also referred to as intermediate pressure space 1-4 sometimes) shortens the path-length of cold-producing medium with highly low summary U word shape to constitute like that, its both ends connect closed container 1-3, be connected in the discharge portion 1b of low-pressure side compressor section 1-1 and the 1c of suction portion of high side compressors portion 1-2, its middle body exposes in the outside of closed container 1-3 and is provided with like that.By connecting pipings 1-4 is set, can reduce the circulating resistance to the 1c of suction portion of high side compressors portion 1-2 from the discharge portion 1b of low-pressure side compressor section 1-1.
Cross valve 2 is examples of refrigerant passage transfer valve.This cross valve 2, be to switch to make the kind of refrigeration cycle that the cold-producing medium of discharging from split-compressor 1 flows by the order of outdoor heat exchanger the 3, the 1st decompressor 4, gas-liquid separator the 5, the 2nd decompressor 6 and indoor side heat exchanger 7 and make the cold-producing medium of discharging from split-compressor 1 heat circulation by what the order of indoor side heat exchanger the 7, the 2nd decompressor 6, gas-liquid separator the 5, the 1st decompressor 4 and outdoor heat exchanger 3 flowed.Therefore, outdoor heat exchanger 3 constitutes the high-pressure side heat exchanger when kind of refrigeration cycle, is heating circulation time formation high-pressure side heat exchanger.In addition, indoor side heat exchanger 7 constitutes the low-pressure side heat exchanger heating circulation time formation high-pressure side heat exchanger when kind of refrigeration cycle.
The 1st decompressor 4 is located between outdoor heat exchanger 3 and the gas-liquid separator 5, when kind of refrigeration cycle, constitute the high-pressure side decompressor that makes from the cold-producing medium decompression of outdoor heat exchanger 3, heat circulation time, constituting the low-pressure side decompressor that makes from the cold-producing medium decompression of gas-liquid separator 5.The 2nd decompressor 6 is located between gas-liquid separator 5 and the indoor side heat exchanger 7, when kind of refrigeration cycle, constitute the low-pressure side decompressor that makes from the cold-producing medium decompression of gas-liquid separator 5, heat circulation time, constituting the high-pressure side decompressor that makes from the cold-producing medium decompression of indoor side heat exchanger 7.And in the present embodiment, the 1st decompressor 4 and the 4th decompressor 6, by the controllable expansion valve of throttle opening, formation such as electrodynamic type for example.
Gas-liquid separator 5 is arranged between the 1st decompressor 4 and the 2nd decompressor 6, is the gas-liquid that is used to separate by cold-producing medium.Gas-liquid separator 5 separates the gas-liquid from the gas-liquid mixed refrigerant of the 1st decompressor 4 when kind of refrigeration cycle, make liquid refrigerant flow into the 2nd decompressor 6, makes gas refrigerant flow into importing pipe arrangement 8 (also be sometimes referred to as and inject pipe arrangement 8) and constitutes like that.In addition, gas-liquid separator 5 is heating circulation time, separates the gas-liquid from the gas-liquid mixed refrigerant of the 2nd decompressor 6, makes liquid refrigerant flow into the 1st decompressor 4, makes gas refrigerant flow into importing pipe arrangement 8 and constitutes like that.For reaching such function, be provided with and import pipe arrangement 8 to be communicated with the upper space of gas-liquid separator 5, be provided with from the refrigerant piping of the 1st decompressor 4 and from the refrigerant piping of the 2nd decompressor 6 to be communicated with the both sides of gas-liquid separator 5 lower space.
The 1c of suction portion of the gas vent 5g of gas-liquid separator 5 and high side compressors portion 1-2 is by importing pipe arrangement 8 and injection control valve 9 connections.Import pipe arrangement 8 and be in order to: from the gas vent of gas-liquid separator 5 suction side that cryogen imports high side compressors portion 1-2 is suppressed (promptly in the centre, gas injects), use the refrigerant gas of discharging from low-pressure side compressor section 1-1, impose the suitable degree of superheat and make it suck high side compressors portion 1-2 from the refrigerant cools of the gas vent 5g of gas-liquid separator 5.And import the part (being the mid portion of the connecting pipings 1-4 in intermediate pressure space) that pipe arrangement 8 is connected to the closed container outside that is positioned at connecting pipings 1-4, the middle compacting cryogen introducing port 1j that imports pipe arrangement 8 front openings is set at connecting pipings 1-4.By making up the formation of relevant connecting pipings 1-4 and importing pipe arrangement 8, can form easily from low-pressure side compressor section 1-1 to the refrigerant passage of high side compressors portion 1-2 with from the refrigerant passage of gas-liquid separator 5 to high side compressors portion 1-2.And injection control valve 9 is to be made of electric expansion valve, is arranged on the centre that imports pipe arrangement 8, and control imports the flow of pipe arrangement 8, relaxes the impulsive sound that often has in open and close valve.
Air-supply arrangement in the air conditioner 50 is by the outdoor air-supply arrangement that places off-premises station and place the air-supply arrangement of indoor set to form.Outdoor air-supply arrangement has: in outside heat exchanger 3, make the outdoor draft fan 11 of outdoor air flow and the outdoor air supply motor 12 of driving outdoor draft fan 11.Indoor with supply unit has: the indoor blower motor 14 that makes the indoor blower 13 and the driving indoor blower 13 of indoor circulation of air in indoor side heat exchanger 7.In the present embodiment, use aerofoil fan, use oscillating fan (cross flow fan) as indoor blower 13 as outdoor draft fan 11.
Control system in the air conditioner 50 has: Temperature Detector 20~24 and place the control device 10 of off-premises station to constitute.Temperature Detector 20~24 is by the Temperature Detector 20 that detects the discharge portion 1d temperature of high side compressors portion 1-2; Temperature Detector 21 with the inlet temperature that detects room air; Temperature Detector (the 1st Temperature Detector) 22 with the saturation temperature that detects gas-liquid separator 5 cold-producing mediums; Temperature Detector 23 with the inlet temperature of sensing chamber outer air; Constitute with near the Temperature Detector (the 2nd Temperature Detector) 24 of the temperature middle compacting cryogen introducing port 1j that detects high side compressors portion 1-2 suction sides.Temperature Detector 20,21,23 constitutes the 3rd Temperature Detector.And certain temperature that also comprises this part in the nigh temperature.
At this, owing to press in the middle of the refrigerant pressure between the 1st decompressor 4 and the 2nd decompressor 6 becomes, if so the installation site of the 1st temperature sensor 22 gets final product on the refrigerant loop between the 1st decompressor 4 and the 2nd decompressor 6, the selected free degree of erecting bed is wide, handle easily.
In addition, in freeze cycle, the time be installed between the 1st decompressor 4 that becomes gas-liquid separator 5 upstream sides and the gas-liquid separator 5 in refrigeration and get final product with cooling and warming double-purpose functional.Thus, even when producing the injection adverse current, the detected temperatures in the 1st Temperature Detector is not subjected to the influence of adverse current fully yet, becomes the temperature near the saturation temperature of the refrigerant pressure in the correct gas-liquid separator.
And the 2nd Temperature Detector 24 detects near the temperature of the importing pipe arrangement (injection pipe arrangement) 8 of the connecting portion of middle compacting cryogen introducing port 1j and connecting pipings (intermediate pressure space) 1-4.Thus, compare, can promptly detect the temperature of the middle compacting cryogen of compacting cryogen introducing port 1j in the middle of importing, can improve control accuracy according to this temperature with the situation of in connecting pipings 1-4, establishing the 2nd Temperature Detector 24.
In addition, the 2nd Temperature Detector 24 as shown in Figure 5, importing on the pipe arrangement, if place the position of leaving more than the middle compacting of the distance cryogen introducing port 15mm to get final product (not shown the 2nd Temperature Detector 24 of Fig. 5, and injecting on the pipe arrangement 8 at least, by the connecting portion (intermediate refrigerant introducing port 1j) of intermediate pressure space 1-4 and injection pipe arrangement 8 be arranged on and injection control valve 9 between.Especially the intermediate refrigerant introducing port 1j on the preferred distance injection pipe arrangement 8 as shown in Figure 5 is arranged between 15mm~100mm).Like this, can the sleeve pipe that thermistor is used be installed importing on the pipe arrangement fine weldering, fully accuracy of detection, respond the temperature of the inlet temperature that detects relevant high side compressors portion fast.
And then, under identical conditions, the operation freeze cycle, change the installation site of the 2nd temperature sensor, the implantation temperature difference of the detected temperatures difference in detected temperatures in the 2nd Temperature Detector and the 1st Temperature Detector is shown in Fig. 4 with the experimental result how aperture of corresponding low-pressure side expansion valve (being the 2nd decompressor during refrigeration) changes.
Fig. 4 is the aperture of the 2nd decompressor of air conditioner refrigeration operation of expression present embodiment and the curve map of implantation temperature difference.Fig. 5 is the figure of compressor side measurement point of the implantation temperature difference of presentation graphs 4.
Investigate this figure as can be known, in the little place of the aperture of valve, although the installation site of the 2nd Temperature Detector is different, curve suddenly rises.By riser portions in the little scope of aperture, many overwhelmingly in the gas-liquid separator 5 owing to liquid refrigerant, all the time impact the inner tubal wall that imports pipe arrangement 8 so inject the drop of cold-producing medium in the installation place of the 2nd temperature sensor, the temperature that pipe is closed is cooled to saturation temperature, and the implantation temperature difference is the following value of 0K.In this aperture scope, even change aperture, it is poor also not change implantation temperature, is the scope that can not control usually.
The aperture of the 2nd decompressor is if become a little greatly from riser portions, and then in the installation place of the 2nd Temperature Detector, the mass dryness fraction that imports the injection cold-producing medium in the pipe arrangement 8 rises, and the drop amount reduces, and the drop that collides the inner tubal wall that imports pipe arrangement 8 also reduces.Therefore, the cold-producing medium heat of discharging from the low-pressure side compressor section transmits by the junction surface of middle compacting cryogen introducing port, because of the influence of its heat is risen tube wall temperature.This scope becomes greatly because of there being aperture to change the implantation temperature difference slightly, to control is the scope that can not utilize, and freeze cycle enters above-mentioned common uncontrollable scope or under the situation of controlling the scope that can not utilize, makes low-pressure side device standard-sized sheet, or close and inject control, need to break away from from this state.
If further strengthen aperture, by the little place of valve opening, the middle aperture for following closely then still has difference by the installation place slope, and becomes slow inclination, by this scope being used in control, can better control.If further strengthen aperture, then further reduce the drop amount of injecting cold-producing medium in the installation place of the 2nd Temperature Detector, mass dryness fraction only makes the temperature of tube wall descend a little near 1, can be used in control to this scope.By this curve, the installation place of the 2nd temperature sensor is if be decided to be on the importing pipe arrangement then better from the position of centre compacting cryogen introducing port 15~100mm.
Thus, the appropriateness influence accepting the heat effects of low-pressure side compressor section discharge temperature and inject this two aspect of cold-producing medium humidity effect respectively, the 2nd Temperature Detector can detect the temperature that the inlet temperature of corresponding high side compressors portion changes.
If further strengthen aperture, then in the installation place of the 2nd Temperature Detector, becoming in importing pipe arrangement does not contain the injection liquid refrigerant, and mass dryness fraction is 1.Therefore, the tube wall that cooling imports pipe arrangement only becomes gasiform injection cold-producing medium, and the heat transmission in the gas-liquid two-phase flow when being hanged down by mass dryness fraction becomes the heat transmission in the low vapor phase stream of heet transfer rate.Therefore, cooling effect is huge to be subtracted, and the temperature of tube wall is subjected to strongly from the influence of the refrigerant temperature of low-pressure side compressor section discharge, so the temperature of tube wall descends slightly.Even aperture further strengthens aperture thus, the temperature of tube wall also just has rising slightly, seems the curve that is smooth.In this scope, in any case change aperture, to implantation temperature difference also no change, this part also is the part that is unsuitable for controlling.
In 4 curves shown in Figure 4, dirty, then sharply rise from the junction of two streams of middle compacting cryogen introducing port, link unexpected flat portions.This is considered to because variation from above-mentioned riser portions to the par causes because of aperture variation a little.Thus, in the detected temperatures of collaborating subordinate's stream certainly, the control of injection rate is difficult.
Also the suction side of high side compressors portion 1-1 is installed by the 2nd Temperature Detector 24 at middle compacting cryogen introducing port 1j than intermediate pressure space (connecting pipings) 1-4, but the state of the cold-producing medium after observation post injects thus.But, if actual doing tested, just be subjected near the temperature domination of machine container (closed container) by compression of this pipe arrangement temperature as can be known, it is difficult detecting small variations in temperature.
Control device 10 according to the testing result of Temperature Detector 24,22, has the function of the temperature difference between near the temperature of gas vent 5g of suppressing near temperature of cryogen introducing port 1j and gas-liquid separator 5 in the computing centre.Therefore,, can use widely used reliability is high in air conditioner thermistor etc., can simply constitute and do not produced Wet Compression, the superfluous air conditioner 50 of crossing hot compression conscientiously as temperature sensor.
In addition, control device 10 is controlled split-compressor 1, cross valve 2, outdoor draft fan motor 12, indoor blower motor the 14, the 1st decompressor the 4, the 2nd decompressor 6, injection control valve 9 etc. according to the detected temperatures of the Temperature Detector 20~24 of each one and user's operating instruction.And in the present embodiment, control device 10 shows a control device with calculation function, with the control device of function with each machine of control, even and these separately constitute also can, even or further also can separately constitute the control device of function with each machine of control.
Below, with reference to Fig. 1 and Fig. 2, the run action of air conditioner 50 is described.Fig. 2 is the Mollier curve map of demonstration by the refrigerant condition of the freeze cycle of the air conditioner of present embodiment.In this Fig. 2, the Mollier curve map when representing to adopt the gas of present embodiment to inject with solid line simultaneously, dots the Mollier curve map when not adopting the comparative example that gas injects.
At first, the heating operation to air conditioner 50 describes.When heating operation, as the dotted line of Fig. 1, switch cross valve 2, form kind of refrigeration cycle, simultaneously, operation split-compressor 1, outdoor draft fan motor 12 and indoor blower motor 14.
Be inhaled into the gas refrigerant a of split-compressor 1, be compressed at split-compressor 1, become the gas refrigerant d of HTHP, dotted arrow direction along Fig. 1 flows, by cross valve 2,, carry out heat exchange with room air heating the indoor side heat exchanger 7 that circulation time enters becomes condenser, be cooled, condensation, become the cold-producing medium i of liquid or gas-liquid mixed.Fig. 2 shows the situation of liquid refrigerant i.
The cold-producing medium i that condensation becomes liquid or gas-liquid mixed refrigerant enters the 2nd decompressor 6, is expanded and decompression by the 2nd decompressor 6, becomes the cold-producing medium h of gas-liquid mixed.This gas-liquid mixed refrigerant h enters gas-liquid separator 5 and carries out gas-liquid separation.Separated liquid refrigerant is trapped in the lower space of gas-liquid separator 5, becomes liquid refrigerant f, flows out to the 1st decompressor 4.In addition, separated gas refrigerant is trapped in the upper space of gas-liquid separator 5, becomes gas refrigerant g, flows out to import pipe arrangement 8.
From the liquid refrigerant f that gas-liquid separator 5 flows out, in the 1st decompressor 4, be inflated and reduce pressure, become gas-liquid mixed refrigerant e.This gas-liquid mixed refrigerant e is heating circulation time, enters the outdoor heat exchanger 3 that becomes evaporimeter, with the outdoor air heat exchange and be heated, becomes gas refrigerant a and turns back to split-compressor 1.
When being correlated with heating operation, by opening the injection control valve 9 that imports pipe arrangement 8, the gas refrigerant g that discharges with fluid separation applications, from gas-liquid separator 5 in gas-liquid separator 5 suppresses cryogen introducing port 1j by heat conduction pipe arrangement 8 and mixes with the discharging refrigerant b of low-pressure side compressor section 1-1 from the centre, discharging refrigerant b descends temperature by gas refrigerant g cooling.At this moment, injection control valve 9 is opened several times step by step, and impulsive sound is eliminated in the drastic change of the freeze cycle when opening injection valve.Mixed gas refrigerant c is inhaled into high side compressors portion 1-2, is compressed in high side compressors portion 1-2, becomes above-mentioned discharging refrigerant d.
By the above-mentioned action that heats circulation repeatedly, continue heating operation.
When carrying out the refrigerating operaton of air conditioner 50, the solid line switching cross valve 2 as Fig. 1 forms kind of refrigeration cycle, simultaneously, and operation split-compressor 1, outdoor draft fan motor 12 and indoor blower motor 14.The Mollier curve map of refrigerating operaton, because except that cold-producing medium flows opposite this point, basic identical with the Mollier curve map that heats circulation, so the repetitive description thereof will be omitted by its symbol of expression in parantheses.
At this,, inject the situation of the present embodiment that circulates and do not adopt the heating capacity and the refrigerating capacity of the comparative example situation of gas injection circulation to describe adopting gas by above-mentioned gas-liquid separator 5 and importing pipe arrangement 8 with reference to Fig. 2.
In heating operation, be G if establish the refrigerant flow of the condenser 7 of comparative example situation, the refrigerant flow of establishing the injection of present embodiment situation is G1, the refrigerant flow that then flows through condenser 7 in the present embodiment is G+G1.Therefore, the long-pending heating capacity of the enthalpy difference of condenser gateway and refrigerant flow is compared also with comparative example and will be increased.
On the other hand, in refrigerating operaton, the evaporability of comparative example (that is refrigerating capacity) represents that with the enthalpy difference of a point and e ' some the enthalpy difference that the evaporability of present embodiment (that is refrigerating capacity) is ordered with a point and e is represented.Because the enthalpy that present embodiment e is ordered is also littler than the enthalpy of comparative example e ' point, so in the present embodiment, compare evaporability (that is refrigerating capacity) also increases with comparative example.
Below, referring to figs. 1 through Fig. 3, the 1st decompressor the 4, the 2nd decompressor 6 of air conditioner 50 and the control of injection control valve 9 are described.Fig. 3 shows the aperture of 1st decompressor 4 of air conditioner 50 when heating operation of present embodiment and the curve map of operation characteristic.The pressure characteristic of Fig. 3 (a) expression gas-liquid separator 5, the characteristic of the temperature difference of Fig. 3 (b) expression the 1st Temperature Detector 22 and the 2nd Temperature Detector 24, Fig. 3 (c) is an expression COP ratio characteristic.
In the air conditioner 50 of present embodiment, according to Temperature Detector 20,21,23 detected temperature by detection running status and environment temperature state, control high- pressure side decompressor 4 or 6, according to detect Temperature Detector 22, the 24 detected temperature that the middle compacting cryogen that separates imports the state of high side compressors portion 1-2 suction sides, control low- pressure side decompressor 6 or 4 in gas-liquid separator 5.Like this, by specific decompressor of controlling according to running status and the decompressor of controlling according to gas injection state, can make control become extremely simple by control device 10.Even and in the control of control device 10 also under the complicated situation, also can the not specific decompressor of controlling according to gas injection state, control any one or two sides' decompressor.
And under the situation of the operation of adopting gas to inject, in open circuit injection control valve 9, control the amount of restriction of the 1st decompressor 4, make the pressure of gas-liquid separator 5, promptly the pressure P sh of the 1c of suction portion of the pressure P d1 of the discharge portion 1b of intermediate pressure Pm low-pressure side compressor section 1-1 and high side compressors portion 1-2 is also high.Like this, in gas-liquid separator 5 by the gas refrigerant of the intermediate pressure of gas-liquid separation, by importing pipe arrangement 8,, flow into the 1c of suction portion of high side compressors portion 1-2 at centre compacting cryogen introducing port 1j and gas refrigerant interflow from the discharge portion of low-pressure side compressor section 1-1.And it is also lower if intermediate pressure Pm becomes than the pressure of the discharge portion 1b of low-pressure side compressor section 1-1, then the gas refrigerant from the discharge portion 1b of low-pressure side compressor section 1-1 flows into gas-liquid separators 5 by importing pipe arrangement 8, so the time need close injection control valve 9.
In the secondary compression compound expansion circulation as present embodiment, intermediate pressure Pm is high more, the saturated gas cold-producing medium g of compacting cryogen introducing port 1j in the middle of correspondence is injected into, and the ratio of saturated liquid cold-producing medium h just becomes many more.This intermediate pressure Pm can be adjusted arbitrarily by 2 expansion valves (the 1st decompressor 4 and the 2nd decompressor 6), and because the pressure of the 1b of export department of the low-pressure side compressor section 1-1 of split-compressor 1 is certain, so make intermediate pressure Pm high more, pressure differential between the 1b of export department of intermediate pressure Pm and low-pressure side compressor section 1-1 just becomes big more, and the refrigerant amount of injection increases.Therefore, increase intermediate pressure Pm more, just can increase refrigerating capacity more because of injecting.
But, if during greater than certain intermediate pressure Pm, then in the middle of the specific enthalpy of compacting cryogen introducing port 1j become also littler than the specific enthalpy of saturated gas line.That is, at this moment,, there is liquid refrigerant at the intermediate pressure gas cryogen that injects at centre compacting cryogen introducing port 1j.Like this, become the 1c of suction portion inhalant liquid cryogen, split-compressor 1 is applied bad influence, reliability is reduced from high side compressors portion 1-2.
Therefore, in the present embodiment,, carry out expansion valve control in order not become the intermediate pressure Pm (in other words, making the cold-producing medium that sucks high side compressors portion 1-2 more than the temperature of gas field) that in the intermediate pressure gas cryogen, has liquid refrigerant.That is, control device 10 is according to controlling the 1st decompressor 4 or the 2nd decompressor 6 by the 1st Temperature Detector 22 detected temperature with by the 2nd Temperature Detector 24 detected temperature.Be specially, control device 10 computings according to this temperature difference that calculates, are regulated the amount of restriction of the 1st decompressor 4 or the 2nd decompressor 6 by the 1st Temperature Detector 22 detected temperature with by the temperature difference between the 2nd Temperature Detector 24 detected temperature.This temperature difference be near the inlet temperature of high side compressors portion and near near the saturation temperature of the gas-liquid separator internal pressure of the suction pressure of high side compressors portion temperature between temperature difference, Here it is near the degree of superheat that is drawn into the cold-producing medium of high side compressors portion, control just like the control of the degree of superheat of the suction inlet cold-producing medium that carries out high side compressors portion, therefore, security might as well, can obtain having the freeze cycle of reliability.
In addition, in the present embodiment, control device 10 limits variable quantity each time when regulating the aperture of the 1st decompressor 4 or the 2nd decompressor 6.Like this, variable quantity each time diminishes, and also little to the influence of whole freezing circulation, other freeze cycle control appliance is caught the little variation of this appearance, carries out the repair action to the freeze cycle of the best, so freeze cycle does not have big at random.
And, when suction cold-producing medium too small when this temperature difference, high side compressors portion has possible that liquid returns, remove above-mentioned each aperture and change quantitative limitation, open and close to the aperture of stipulating with 1 time, can prevent danger that hydraulic pressure contracts in possible trouble.If the decision content of the temperature difference that this is too small is the 1st setting, be decided to be suitable value by experiment in advance.In an embodiment it is decided to be 2K (absolute temperature).
By controlling the 1st decompressor 4 or the 2nd decompressor 6 as mentioned above, owing to can be decided to be less than the intermediate pressure Pm that in the intermediate pressure gas cryogen, does not have liquid refrigerant, so can prevent from the high side compressors 1-2 of split-compressor 1, to import the liquid cold-producing medium, to improve the reliability of split-compressor 1.
Under the situation of carrying out the gas injection,, in the suction gas of high side compressors portion 1-2, do not comprise the minimum cold-producing medium of liquid refrigerant and temperature for best as the refrigerant condition that sucks high side compressors portion 1-2.Thus, the gas refrigerant that sucks degree of superheat 0K (absolute temperature) from the 1c of suction portion of high side compressors portion 1-2 is desirable, and because degree of superheat 0K (absolute temperature) is the temperature identical with the gas-liquid mixed state, the existing difficulty of historical facts or anecdotes.Inventors have carried out all research in order to obtain near this suitable degree of superheat, the result, by according to as the above-mentioned suction side that imports high side compressors portions 1-2 from gas-liquid separator 5 in the middle of two temperature of compacting cryogen, control decompressor 4 or 6 can be realized fully satisfying practical air conditioner 50.
Utilize each characteristic when heating operation shown in Figure 3, further be specifically described.If adjust interrelated between the aperture of low-pressure side expansion valve 4 and the intermediate pressure Pm,, have 1 negative correlations characteristic as can be known then as the curve of Fig. 3 (a).Therefore, by the aperture of control low-pressure side expansion valve 4, can easily control intermediate pressure Pm.
And, if adjust the aperture of low-pressure side expansion valve 4 and the relation between the heat conduction pipe arrangement temperature difference (near the temperature difference near the temperature the middle compacting cryogen introducing port 1j and the gas vent 5g of gas-liquid separator 5 between the temperature), then as the curve of Fig. 3 (b), as can be known: little from the aperture of low-pressure side expansion valve 4, along with the aperture that makes inflated with low pressure valve 4 increases, the temperature difference that imports pipe arrangement 8 becomes big, and has the part that imports the big variation of pipe arrangement temperature difference with the small aperture difference in centre.
And, if adjust the aperture of low-pressure side expansion valve 4 and the relation of COP ratio (ratio of the COP when COP when the compacting cryogen imports in the middle of not having and middle compacting cryogen import), then, there is the aperture scope of the good low-pressure side expansion valve 4 of COP ratio as can be known as Fig. 3 (c).
This result is investigated in examination, as seen: owing to import the pipe arrangement temperature difference for negative at the little place of aperture of low-pressure side expansion valve 4, thus too rise at this part intermediate pressure Pm, the oversupply liquid refrigerant, the efficient of split-compressor 1 reduces.Be also shown in: if make the aperture of low-pressure side expansion valve 4 excessive, then import the pipe arrangement temperature difference and become big, the COP ratio also descends, too become big so suck the degree of superheat of cold-producing medium in this part high-pressure side, the specific volume that the high-pressure side sucks cold-producing medium becomes big, and circulating mass of refrigerant reduces, simultaneously, the high-pressure side is got rid of temperature and is too risen the inefficiency of split-compressor 1.
Thus, in the present embodiment,, can obtain good secondary compression compound expansion freeze cycle by to import the aperture of pipe arrangement temperature difference control low-pressure side expansion valve 4.That is, control device 10, the amount of restriction of regulating low-pressure side expansion valve 4, with use the 1st Temperature Detector 22 detected temperature and with the temperature difference between the 2nd Temperature Detector 24 detected temperature as in the prescribed limit.Especially, be controlled at 2K (absolute temperature)~12K (absolute temperature) if will import the pipe arrangement temperature difference, the temperature difference that the aperture of then corresponding low-pressure side expansion valve 4 changes changes also greatly, control easily, suitable degree of superheat gas refrigerant is inhaled into simultaneously, the COP ratio can obtain the freeze cycle of excellent in efficiency also near peak.
And excessive when this temperature difference, the degree of superheat of the suction cold-producing medium of high side compressors portion becomes excessive, may have overheat of compressor, removes the variation quantitative limitation of above-mentioned each aperture, to open and close the aperture of regulation for 1 time, prevents overheat of compressor.
And more detailed result of study, if the revolution of compressor rises, then the discharge temperature of low-pressure side compressor section also rises, and influenced by it, the suitable degree of superheat when normally moving also rises.Therefore, determine the decision content of the excessive degree of superheat according to the revolution of compressor, as the 2nd setting.And, show the 2nd setting as Fig. 6, Fig. 7, when each such as freezes, heats at the pattern of freeze cycle, have and positive relevant of the revolution of compressor by being decided to be, can obtain good control result.Fig. 6 is the curve of compressor revolution when showing the air conditioner of present embodiment and refrigerating operaton and adverse current implantation temperature difference when beginning.Fig. 7 is the curve of compressor revolution when showing the heating operation of air conditioner of present embodiment and adverse current implantation temperature difference when beginning.
And, control device 10 is according to the operation result of temperature difference, even the throttle opening of low-pressure side expansion valve 4 is opened to more than the regulation aperture, be not more than under the situation of setting by the 1st Temperature Detector 22 detected temperature with by the temperature difference between the 2nd Temperature Detector 24 detected temperature, also carry out injection control valve 9 is closed such control once, thus, can prevent from rapidly to import liquid refrigerant, be expected to improve the reliability of split-compressor 1 in the high side compressors 1-2 of split-compressor 1.
Owing to obtain each operation characteristic among Fig. 3, so even the result that also can carry out same operation in kind of refrigeration cycle, as can be known: also can obtain similar operation characteristic during refrigerating operaton.Therefore, same control in the time of also may be during refrigerating operaton with heating operation.In the present embodiment, since have changeable kind of refrigeration cycle and heat circulation cross valve 2, even when switching kind of refrigeration cycle and heating the contrary circular flow of circulation, also can adjust the expansion valve 4 that is arranged between gas-liquid separator 5 and low-pressure side heat exchanger 3 or 7 or 6 aperture, no matter be kind of refrigeration cycle and which circulation that heats circulation, the inlet temperature that also can control high side compressors portion 1-2 is the suitable temperature of corresponding intermediate pressure Pm, can obtain in kind of refrigeration cycle, heat in the circulation of circulation two aspects, can carry out the air conditioner 50 of suitable freeze cycle operation.
And, in the air conditioner 50 of present embodiment, because with split-compressor 1, with outdoor heat exchanger 3, with gas-liquid separator 5 and decompressor 4,6 and importing pipe arrangement 8, place off-premises station together with control device 10, so can not increase arrangement components, utilize control device 10 to confirm the action of the equipment in the off-premises station that is configured in to off-premises station.Thus, can simply constitute and off-premises station is maintained small-sized, can obtain off-premises station as the high divergence type air conditioner of reliability.
And control device 10 of the present invention has the function of the per 1 time variable quantity of restriction when regulating the aperture of high-pressure side decompressor or low-pressure side decompressor.Like this, per 1 time variable quantity diminishes, and the influence that whole freezing is circulated also diminishes, and the control appliance of other freeze cycle is caught the little variation of this appearance, carries out the repair action to best freeze cycle, so freeze cycle does not have big disorder.
In example, adopted the air conditioner of stablizing this and refrigerating operaton, the situation of the aperture that reduces the low-pressure side decompressor has a little at length been inferred.Make each throttling variable quantity diminish, reduce aperture.If reduce aperture, then flow into the low-pressure side heat exchanger (below, abbreviate evaporimeter as.) the flow of cold-producing medium reduce.
On the other hand, the corresponding flow that flows out to the cold-producing medium in the evaporimeter in gas-liquid separator reduces, and the aperture of high-pressure side decompressor is constant, with dwindle the low-pressure side decompressor aperture before identical.Therefore, since identical before the flow of the cold-producing medium that flows into from high-pressure side heat exchanger (below, abbreviate condenser as) and the aperture of dwindling the low-pressure side decompressor, the rising of the cold-producing medium liquid level in the gas-liquid separator, the gas compartment of pushing top.
Because common gas-liquid separator so the gas refrigerant that is extruded is compressed, rises the pressure in the gas-liquid separator with heat-barrier material covering, insulation cold insulation a little.And the freeze cycle of low-pressure side is owing to the flow of the cold-producing medium of inflow evaporator reduces, so the degree of superheat of the cold-producing medium of evaporator outlet rises.Therefore, the degree of superheat of the suction cold-producing medium of low-pressure side compressor section also rises, and the specific volume that sucks cold-producing medium increases.
Because it is very little that the pressure in the gas-liquid separator rises, thus can think reduce the low-pressure side device aperture originally, the middle pressure of suppressing the cryogen introducing port is constant.Therefore, the part that specific volume increases, the flow that is drawn into the cold-producing medium of low-pressure side compressor section reduces.The flow of cold-producing medium reduces and the degree of superheat rises owing to suck, so the cold-producing medium discharge temperature of low-pressure side compressor section uprises.
And this sucks the reduction of refrigerant flow, lacks than the minimizing to the evaporimeter influx of the cold-producing medium originally that dwindles the low-pressure side decompressor, and for this reason, the suction pressure of the cold-producing medium of low-pressure side compressor descends some.Because of these some pressure reduce, the discharge pressure of low-pressure side compressor also descends some, and the pressure of middle compacting cryogen introducing port descends too.On the other hand, at infusion circuit, in gas-liquid separator, owing to follow the mobile stirring action of gas-liquid mixed refrigerant that flows into from the high-pressure side decompressor, and in gas compartment portion, the drop of the cold-producing medium that swimming.Because the cold-producing medium liquid level rises, the gas vent portion of gas-liquid separator sends the more gas-liquid mixed refrigerant of cold-producing medium into the importing pipe arrangement near liquid level.
Like this, the pressure of gas-liquid separator rises slightly, pressure by centre compacting cryogen introducing port descends, and the pressure reduction between the pressure of the pressure of gas-liquid separator and middle compacting cryogen introducing port increases, and the refrigerant flow that is injected into is than the preceding increase of the aperture of dwindling the low-pressure side decompressor.And, becoming many owing to comprise the cold-producing medium drop of the cold-producing medium that is injected into, the specific enthalpy of the cold-producing medium that is injected into is than the preceding minimizing of the aperture of dwindling the low-pressure side decompressor.
For this reason, the high side compressors portion of low-pressure side compressor section discharging refrigerant and injection cold-producing medium interflow, mixing sucks the specific enthalpy of cold-producing medium than the preceding minimizing of the aperture of dwindling the low-pressure side decompressor.Therefore, the temperature that high side compressors portion sucks cold-producing medium is preceding lower than the aperture of dwindling the low-pressure side decompressor, and specific volume reduces.Conversely, on high-tension side refrigerant loop, no change after the aperture that just reduces the low-pressure side decompressor.
But, because sucking the specific volume of cold-producing medium, above-mentioned high side compressors portion reduces, the refrigerant flow of temporary suction high side compressors portion increases.Follow this, the refrigerant flow of discharging from high side compressors portion also increases.And, because sucking the specific enthalpy of cold-producing medium, high side compressors portion reduces, and the specific enthalpy of high side compressors portion discharging refrigerant also reduces, and the temperature of discharging refrigerant reduces.Like this, reduce, but flow becomes many cold-producing medium inlet chamber outer heat-exchangers than temperature before the aperture of dwindling the low-pressure side decompressor.
Thus, in the outlet of outdoor heat converter, the temperature of liquid refrigerant does not reach the temperature of liquid refrigerant before the aperture of dwindling the low-pressure side decompressor, compares also and rises with the temperature of liquid refrigerant before dwindling low-pressure side decompressor aperture.Like this, temperature rises, and flow becomes many liquid refrigerants and enters the high-pressure side decompressor, is depressurized, expands.If make the liquid refrigerant of this state be decompressed to the pressure of gas-liquid separator, then before the decompression in gas-liquid mixed territory partly becomes than the aperture of dwindling the low-pressure side decompressor, go back big.Therefore, it is big that the resistance in this gas-liquid mixed territory becomes, and can not flow Wan flow and become many cold-producing mediums.
Therefore, the cold-producing medium that can flow Wan must be trapped in the outdoor heat converter, and condensing pressure is risen.Follow condensing pressure to rise, the discharge pressure of high side compressors portion rises, and the volumetric efficiency of high side compressors portion worsens, and the refrigerant flow of discharging from high side compressors portion reduces.By this explanation as can be known, the liquid level rising in the gas-liquid separator begins simultaneously with the throttling action of low-pressure side decompressor.Its result, the mass dryness fraction of the increase of injection rate and injection cold-producing medium reduces and also begins immediately.
Injecting cold-producing medium needs a little time to pass through this importing pipe arrangement.After the some time, the variations in temperature of compacting cryogen introducing port begins in the middle of the connecting pipings that imports pipe arrangement in this point.Import pipe arrangement and constitute with thin copper pipe, its length only is between the split-compressor and gas-liquid separator that is connected in the identical off-premises station.Generally, when decision imports piping length, for the vibration that absorbs compressor, prevent vibration transmission, should consider necessary length.
But even consider this length, the length that imports pipe arrangement is compared also just part with the ensemble length of main refrigerant circuit.Therefore, the thermal capacity that imports pipe arrangement is also little, and the state variation of injecting cold-producing medium is postponed.For this reason, the aperture of low-pressure side decompressor change the several seconds~variations in temperature as middle compacting cryogen introducing port after tens of seconds occurs.By further the control of low-pressure side decompressor being fed back, can be promptly near being changed to the freeze cycle state of target with this.
And in the present invention, if the revolution of compressor rises, it is big that the internal circulating load of cold-producing medium just becomes, and because heat exchanger big or small constant, so condensation temperature, evaporating temperature when arriving slow speed, are evaporated and can not fully be carried out at condensation.For this is replenished, condensing pressure rises, and condensation temperature uprises, and evaporating pressure descends, the evaporating temperature step-down.On the other hand, the discharge pressure of low-pressure side compressor section becomes average near multiplying each other between the suction pressure of the discharge pressure of high side compressors portion and low-pressure side compressor section.
Therefore, the discharge pressure of low-pressure side compressor section is approximate constant, is the state that suction pressure descends.Like this, it is big that the compression ratio of low-pressure side compressor section becomes, even make the degree of superheat of the degree of superheat during with slow speed that sucks cold-producing medium identical, it is big that the degree of superheat of the discharging refrigerant of low-pressure side compressor section also becomes.At this state, even suppose that identical injection rate is arranged, because of the influence of the discharging refrigerant that becomes low-pressure side compressor section high temperature, near the temperature the middle compacting cryogen introducing port also rises.
Like this, even do not cause adverse current, because the revolution of compressor rises, the degree of superheat of middle compacting cryogen introducing port rises.Moreover, because if causing the degree of superheat of the then middle compacting cryogen of adverse current introducing port further rises, so can define the possible degree of superheat of adverse current according to the revolution of compressor.And, if to by the heat source side heat exchanger, utilize the changed condition of the heat of side heat exchanger, the change intermediate pressure is then better.Judge the possibility that has or not adverse current with the temperature difference between the temperature of near temperature the centre compacting cryogen introducing port and gas-liquid separator, carry out the aperture control of low-pressure side decompressor.
By experiment as can be known, compare the easier adverse current that causes of refrigerating operaton with heating operation.This is that evaporating temperature need be decided to be the following suitable low temperature of indoor dew-point temperature owing in air conditioner, also will ask for the humidity of room air when refrigerating operaton.Meanwhile, must indoor set be set at indoor narrow space.Therefore, the limited size system of indoor heat exchanger in order to satisfy desired heat exchange amount, needs the decline evaporating temperature equally.
In contrast, the restriction of the size of off-premises station size is strict unlike indoor set, even make outdoor heat converter a little bigger a little, also can not influence actual use.At this moment, owing to can reduce the consumed power of compressor, so can become energy-conservation efficient mechanism by further reducing the condensing pressure of outdoor heat exchange.Like this, air conditioner becomes the formation that indoor heat converter is little, outdoor heat converter is big.Make the air conditioner refrigeration operation with such heat exchanger, available expansion valve etc. are adjusted to suitable freeze cycle.
At this moment, the distribution of refrigerant amount is compared during with kind of refrigeration cycle, needs the K cryogenic treatment part in liquid territory not need when heating during refrigeration in outdoor heat converter, so this part of minimizing.Opposite in indoor heat converter, low mass dryness fraction territory is to the part in overheated gas territory by from refrigeration the time, and the part at liquid territory circulation time when heating necessitates, so increase.At this,,, get final product less when heating so after offseting, become the refrigerant amount that suitable freeze cycle needs because outdoor heat converter is bigger than indoor heat converter.
In the practical application, near after two sides' the necessary amount, enclose freeze cycle with under various conditions experimental verification.Become its unnecessary cold-producing medium and be absorbed into reservoir, nonabsorbable part rises the liquid level in the gas-liquid separator.If the liquid level of gas-liquid separator rises, then and the distance between the gas vent dwindle, inject to have variations in temperature to become slightly to be easy to liquid.
Otherwise, when refrigerating operaton,, the variations in temperature liquid level descends because of being arranged slightly, and gas-liquid mixed gas flows into the low-pressure side decompressor, and gas-liquid separator can not be worked, and it is unusual that freeze cycle becomes.In addition, if room temperature rises, cooling load increases, promote the cold-producing medium evaporation in the evaporimeter, the refrigerant temperature in the evaporator outlet rises.Because refrigerant temperature rises, it is big that the specific volume of cold-producing medium becomes, and promotes evaporator pressure, and the pressure reduction between the gas-liquid separator diminishes, and reduces from the refrigerant flow of gas-liquid separator inflow evaporator.
Reduce opposite with the refrigerant flow that flows out to evaporimeter in the gas-liquid evaporimeter, because the aperture of high-pressure side decompressor is constant, so the refrigerant flow that flows into from condenser is with identical in the past, the cold-producing medium liquid level in the gas-liquid separator rises, and pushes the space of upper gas.Because gas-liquid separator covers, is incubated cold insulation with heat-barrier material usually, so extruded gas refrigerant slightly rises the pressure in the compressed gas-liquid separator.Because the pressure in the gas-liquid separator slightly rises, reduce by the refrigerant flow that the high-pressure side decompressor flows into gas-liquid separator from condenser, but less than the degree that reduces the liquid level that rises.
On the other hand, evaporating pressure rises also influential to the downstream side of evaporimeter, because evaporating pressure rises, the suction pressure of low-pressure side compressor also rises.Risen by this pressure, the specific volume of the cold-producing medium that is inhaled into diminishes, and the flow of the cold-producing medium that is inhaled into increases.Follow this, the refrigerant flow that is discharged to the discharge side of low-pressure side compressor section increases, and the discharge pressure of low-pressure side compressor section also rises.Parameter and the different of environmental condition that pressure in the rising of this pressure and the gas-liquid separator rises because of freeze cycle vary, and briefly which side is big.
Because follow in the gas-liquid separator stirring action that flows of the gas-liquid mixed refrigerant that flows into from the high-pressure side decompressor, the cold-producing medium drop is swimming in gas portion space.Therefore, under the big situation in the pressure rising side in gas-liquid separator, rise by the cold-producing medium liquid level in the gas-liquid separator, the gas vent portion of gas-liquid separator is near liquid level, and the cold-producing medium drop more gas-liquid mixed refrigerant that will become is sent into the importing pipe arrangement.
High side compressors portion is owing to suck the cold-producing medium of the low-pressure side compressor section that rises from pressure, so the refrigerant flow that high side compressors portion discharges increases, discharge pressure also rises.Therefore, condensing pressure, condensation temperature rise, in condenser, and cold-producing medium heat release, condensation that flow is increased.Because condensing pressure rises, increase so flow into the refrigerant flow of high-pressure side decompressor, promote the cold-producing medium liquid level in the gas-liquid separator.
And,,, the cold-producing medium liquid level in the gas-liquid separator is descended by the refrigerant flow increase of low-pressure side decompressor because the refrigerant pressure in the gas-liquid separator rises.Such action cycle property ground carries out according to the refrigerant pressure of its each time, the distribution of cold-producing medium, the temperature of surrounding environment etc., and, the revolution of compressor, the throttling of expansion valve change according to coming the instruction of self-controller to apply, and the best freeze cycle that is contracted to corresponding surrounding environment change is carried out.Above-described action is the rising by the discharge pressure of low-pressure side compressor section, the big situation in pressure rising side in the gas-liquid separator.
Below, to the little situation in pressure rising side in the gas-liquid separator, investigate each variation of temperature from the viewpoint of temperature detection.At this moment, the part of the discharging refrigerant of low-pressure side compressor section is importing the pipe arrangement adverse current, is flowing into gas-liquid separator.The discharging refrigerant that enters the low-pressure side compressor section of gas-liquid separator is cooled in the upper inside wall of gas-liquid separator, a part of condensation, and not condensation of major part ground promotes the cold-producing medium liquid level.If become such state, the afunction of gas-liquid separator then, can not carry out gas-liquid separation, the cold-producing medium liquid level drops to the flow export to the low-pressure side decompressor, in the pipe arrangement of low-pressure side decompressor, on the state basis from the gas-liquid mixed gas of high-pressure side decompressor, the discharging refrigerant of low-pressure side compressor section mixes.
Such operation is owing to the original running status with secondary compression compound expansion freeze cycle differs greatly, so should return to original running status as early as possible.If continue such state, then the discharge temperature of the temperature of the top of gas-liquid separator and importing pipe arrangement and low-pressure side compressor section about equally.In addition, under the not many situation of the amount of the gas refrigerant that adverse current is come, carry out heat exchange, become temperature near the saturation temperature of gas-liquid separator inner refrigerant pressure with the liquid cold-producing medium that flows to the pipe arrangement temperature of the downstream side of low-pressure side decompressor.
But, if the gas refrigerant quantitative change that adverse current is come is many, then together flowing liquid cold-producing medium and heat exchange with regard to the temperature between the saturation temperature of the discharge temperature of insufficient demonstration low-pressure side compressor section and gas-liquid separator inner refrigerant pressure with carrying out.And the situation of the saturation temperature of the bottom demonstration gas-liquid separator inner refrigerant pressure of gas-liquid separator is many, and gas-liquid separator is because deceleration separates gas-liquid from mobile, the high efficiency of the gas-liquid mixed refrigerant of high-pressure side decompressor, so its internal diameter chap.Therefore, for guaranteeing resistance to pressure, can not expect wall thickness thickening, thermal capacitance quantitative change greatly, thermal response rapidly.
On the other hand, in the pipe arrangement that connects high-pressure side decompressor and gas-liquid separator, focus on refrigerant pressure in the gas-liquid separator with the high-pressure side decompressor in that pipe arrangement is inner, the gas-liquid mixed refrigerant that becomes saturation temperature is mobile, can obtain normal temperature.In addition, since upper reaches pipe arrangement gas liquid mix refrigerant when refrigeration, working fluid cold-producing medium when heating, so also carefully get final product than the pipe of flowing gas cold-producing medium, tube wall also can approach, therefore, thermal capacity is little, so can obtain the little temperature information of time delay.
Thus, in the present invention, the place as the saturation temperature that detects gas-liquid separator inner refrigerant pressure has fixed on the upper reaches pipe arrangement between high-pressure side decompressor and the gas-liquid separator.By determining like this, even when producing adverse current, also can continue and control.If describe this in detail, then because the discharge pressure of low-pressure side compressor section when higher than the pressure in the gas-liquid separator, the flow that is inhaled into the cold-producing medium of high side compressors portion increases.Follow this, the flow of the cold-producing medium of discharging from high side compressors portion also rises, and is pressed into condenser.
On the other hand because the refrigerant pressure in the gas-liquid separator also rises, so and the difference between the condensing pressure diminish, because of the aperture of the high-pressure side decompressor that connects condensator outlet constant, so the refrigerant flow minimizing by the high-pressure side decompressor.Increase although flow into the refrigerant flow of condenser, because the flow that flows out reduces, so condensing pressure rises, discharge pressure also rises.Because discharge pressure rises, the refrigerant flow of discharging from the high side compressors portion that an end rises slightly subtracts, and does not drop to the flow before indoor temperature rises, and is the state of some risings thus.
On the other hand, because condensing pressure rises, the flow of the cold-producing medium of the high-pressure side decompressor that descends by an end slightly increases, and the amount that offsets with the refrigerant flow of discharging from high side compressors portion increases.Therefore, the cold-producing medium liquid level in the gas-liquid separator rises, and the refrigerant pressure in the gas-liquid separator also rises.And,, slightly subtract so be inhaled into the refrigerant flow of low-pressure side compressor section because the discharge pressure of low-pressure side compressor section uprises.Therefore, the evaporating pressure that an end rises slightly subtracts, and does not drop to the evaporating pressure before indoor temperature rises, and is the state of some risings.
The flow of the cold-producing medium by the low-pressure side decompressor is the flow of the cold-producing medium that flows into from the high-pressure side decompressor, adds that adverse current imports the flow of flow of the gas refrigerant of pipe arrangement.Owing to follow the rising of the gas-liquid separator inner refrigerant pressure that increases from the cold-producing medium influx of above-mentioned high-pressure side decompressor, in order to flow through this flow, the refrigerant pressure in the gas-liquid separator increases.Because this pressure increases, the amount of the cold-producing medium of the refrigerant flow that is inhaled into the low-pressure side compressor section of offseting is by low-pressure side decompressor inflow evaporator.
As if the freeze cycle that applies the present invention to such state be moved, then for the temperature of the inlet temperature that detects relevant high side compressors portion, because the detected temperatures near the 2nd test section in the middle of being located at the compacting cryogen introducing port, become temperature near the discharge temperature of low-pressure side compressor section because of producing adverse current.On the other hand, temperature for the saturation temperature that detects relevant gas-liquid separator inner refrigerant pressure, be installed in the outlet temperature that detected temperatures in the 1st test section of the upper reaches pipe arrangement between high-pressure side decompressor and gas-liquid separator is close to the high-pressure side decompressor, i.e. the temperature of the saturation temperature of gas-liquid separator inner refrigerant pressure.
Like this, the detected temperatures in the 1st test section is not influenced by adverse current fully, becomes correctly the temperature near the saturation temperature of gas-liquid separator inner refrigerant pressure.Temperature difference in 2 test sections is under the situation of the 2nd set point of temperature difference determined according to the revolution of compressor, the aperture of low-pressure side decompressor is narrowed down to the aperture of regulation once.By such control, the refrigerant pressure in the gas-liquid separator rises, and the refrigerant flow of inflow evaporator reduces simultaneously, and the suction pressure of low-pressure side compressor section descends.Therefore, the discharge pressure of low-pressure side compressor section also descends, from importing the cold-producing medium in the pipe arrangement injection gas-liquid separator.
By the aperture of experiment regulation in advance, the suitable value by being set at corresponding ambient temperature causes adverse current, before the freeze cycle havoc, owing to the control of promptly carrying out to suitable freeze cycle, so the reliability of freeze cycle improves.The installation site of the 2nd Temperature Detector can be detected with the position of getting relevant temperature in the inlet temperature that shows high side compressors portion, in addition, decidable from the number of the liquid refrigerant of importing pipe arrangement, can prevent the position that hydraulic pressure shrinks in possible trouble.
Therefore, as the position of having both the two, importing the position that is defined as on the pipe arrangement between middle compacting cryogen introducing port and the injection control valve among the present invention.The cryogen introducing port is suppressed in such position in the middle of the connecting pipings interflow that imports pipe arrangement and compressor, transmitted the influence of heat of discharge temperature of low-pressure side compressor section of the tube wall of heat conduction pipe arrangement.When dropping in and import pipe arrangement when flowing injecting refrigerant liquid that cold-producing medium comprised, collide to the tube wall that imports pipe arrangement, obtain heat and evaporation from tube wall.Therefore, the influence of this heat relaxes, and tube wall temperature becomes the temperature between the discharge temperature of saturation temperature and low-pressure side compressor section.
Owing to suppress the influence of the heat of cryogen introducing port from this centre, when after a little while, far review the position that imports pipe arrangement since centre compacting cryogen introducing port in the amount of injecting the liquid refrigerant that cold-producing medium comprised, inject the overheated beginning of cold-producing medium.Otherwise, when for a long time,, injecting the cold-producing medium liquid refrigerant that also mixes even at centre compacting cryogen introducing port in the amount of injecting the liquid refrigerant that cold-producing medium comprised, what hydraulic pressure contracted is dangerous high.
Utilize this, the installation site of the 2nd Temperature Detector is fixed on the suitable position that imports pipe arrangement, in this position the 2nd Temperature Detector is installed, detected temperature and to use temperature difference between the detected temperature of the 1st Temperature Detector relevant with the saturation temperature of gas-liquid separator inner refrigerant pressure be the 1st setting (for example 2K (absolute temperature)) when following is judged as liquid and returns the dangerous high of high side compressors portion.According to this judgement, the low-pressure side decompressor is opened to the regulation aperture once, the refrigerant pressure in the gas-liquid separator is descended, reduce injection rate, can avoid the danger that hydraulic pressure contracts at once.
And, if becoming the gas injection that the injection cold-producing medium does not contain liquid refrigerant fully, then because of conflict, and temperature is not descended to the importing pipe arrangement of the drop that in the importing cold-producing medium that relaxes from the heat affecting of the discharge temperature of the low-pressure side compressor section of centre compacting cryogen introducing port, comprises.Therefore, the temperature of the 2nd Temperature Detector portion becomes the high temperature of gas refrigerant temperature that flows than in importing pipe arrangement, and, if the gas injection rate tails off, then compressor cross the thermal hazard height, simultaneously, the temperature of the 2nd temperature detecting part becomes higher.
And then if the adverse current of produce injecting, then the discharging refrigerant from the low-pressure side compressor section of gas-liquid mixed refrigerant with adverse current of high-pressure side decompressor mixes.Therefore, gas-liquid mixed refrigerant flows into low-pressure side decompressor, the afunction of gas-liquid separator because of the adverse current cold-producing medium with the state that mass dryness fraction rises.
And, owing to do not carry out intactly being inhaled into high side compressors portion by the cold-producing medium of the cooling of injecting, so the cold-producing medium discharge temperature of high side compressors portion rises.At this moment, if around temperature conditions poor, then the cold-producing medium discharge temperature uprises unusually, has the distortion of the synthetic resin members cause in the refrigerant loop etc. and the danger of sex change.If such adverse current state continuance then because the reliability of freeze cycle is impaired, should make adverse current no longer continue.At such adverse current state, near the temperature the middle compacting cryogen introducing port is owing to the not cooling because of injecting, so become the temperature more much higher than the temperature of gas-liquid separator.
Utilize this, the temperature difference between 1st Temperature Detector relevant with the saturation temperature of refrigerant pressure in the gas-liquid separator is during greater than the 2nd setting (for example, 12K (absolute temperature)), and being judged as need be by the cooling of the compressor that injects.According to this judgement, the low-pressure side decompressor is closed to the regulation aperture once, the refrigerant pressure in the gas-liquid separator is risen, the amount of the drop that injects cold-producing medium is increased, injection rate is increased, can avoid the thermal hazard of crossing of compressor at once.Thus, it is suitably relevant with the inlet temperature of high side compressors portion that the detected temperatures of the 2nd Temperature Detector can obtain, and can prevent danger that hydraulic pressure contracts in possible trouble, and can prevent by injecting the overheat of compressor that adverse current causes.
Generally, the test section that detects the refrigerant piping temperature is welded in sleeve fibre cylindraceous on the pipe arrangement, and the temperature detecting part that thoroughly embeds thermistor in the inside of sleeve is installed like this.This is because by fine weldering portion, the temperature of pipe arrangement is delivered to entire sleeve, and thoroughly embeds this sleeve, by using the temperature detecting part that heats or cool off thermistor from heat conduction on every side, the temperature with pipe arrangement is identical as early as possible to make the temperature of thermistor temp test section, and error is reduced.The fibre that imports fibre weldering and the sleeve pipe between the connecting pipings of the front end of pipe arrangement and compressor and import between the pipe arrangement welds, be before or after all influences of non-functional.
Therefore, consider the direction of torch firing flame when fibre welds and the direction of finger scolding tin etc., organize operation.But, when the later process operation,, then can not guarantee the reliability (thickness of intensity, wet linear distance, the soldering tin material during junction surface of fine weldering portion if melt at the soldering tin material of the fibre weldering portion that preceding working procedure is carried out.The thickness of wet linear distance, soldering tin material during sleeve).In order to ensure this, the distance before and after should making between fine weldering place has separation to a certain degree.
The result of consideration inventor's etc. tentative mistake, response speed and fine weldering operation, temperature error etc., as a whole, if greater than 15mm, the fibre weldering that does not then damage accuracy of detection, response speed as can be known is possible as the interval from the junction surface between the injection pipe arrangement connecting pipings to the measured thermistor central part of the tube axial direction that imports pipe arrangement.
If the 2nd Temperature Detector that the place is set is near excessively far from centre compacting cryogen introducing port, then the heat affecting of the discharge temperature of low-pressure side compressor section is strong excessively, the humidity effect that injects cold-producing medium almost becomes nothing, the liquid that is difficult to detect in advance to compressor returns.And, if the 2nd Temperature Detector that the place is set is far away excessively far from centre compacting cryogen introducing port, then the heat affecting of the discharge temperature of low-pressure side compressor section tails off, and detects to inject its temperature of cold-producing medium, with the associated degradation of the inlet temperature of high side compressors portion.
Change the result that tests along distance as can be known, comprise fine weldering to make the 15mm that goes up restriction from centre compacting cryogen introducing port to the tubular axis of thermistor position, if from 15mm to 100mm, but practical control then.
Below, the action of the freeze cycle that opened and closed by injection control valve is narrated.If open control valve, then the cold-producing medium of gas-liquid separator comprises drop, is injected into the suction inlet of high side compressors portion.Therefore, the inlet temperature of high side compressors portion sharply descends, and discharge temperature also sharply descends.On the other hand, in gas-liquid separator, flow out to compressor owing to inject cold-producing medium, the refrigerant pressure in the gas-liquid separator reduces, and the flow that flows out to the cold-producing medium of evaporimeter reduces, and the refrigerant flow that flows into from condenser increases.Thus, evaporating pressure descends, and the refrigerant flow that is inhaled into the low-pressure side compressor section reduces, and condensing pressure also descends, and the refrigerant flow of discharging from high side compressors portion also increases.
Therefore, the discharge pressure of low-pressure side compressor section descends, and the flow of the cold-producing medium that is injected also increases.Like this, an end injection rate increases, the discharge temperature of compressor descends, and if the control interval one of freeze cycle arrives, then discharge temperature descends, so the high-pressure side decompressor is by throttling.And because the temperature of near temperature the middle compacting cryogen introducing port and gas-liquid separator is approaching, so the low-pressure side decompressor is opened, freeze cycle is controlled to elimination because of opening the direction that influences that injection control valve causes.
Follow the switching of injection control valve, importing pipe arrangement generation shock wave, big more this shock wave of difference between the refrigerant pressure in the gas-liquid separator and the suction pressure of high side compressors portion is just strong more.This shock wave transmits refrigerant piping, can hear sometimes at the unusual sound of indoor conduct, at this moment, gives the user with the sense of feeling uncertain, uneasy sense.In the present invention,, adopt electric expansion valve here for anti-, when opening, open electric expansion valve inchmeal, when closing, to close than this also fast speed as injection valve.Like this, eliminate the impulsive sound when opening injection valve, relax the impulsive sound when closing.Not closing inchmeal when closing, is because be in operation and close injection valve, when having liquid to return compressor dangerous, loses the reliability of compressor, in order to avoid the forfeiture of freeze cycle function, act of rescue ground quick closedown.
In addition, in the present embodiment, in when refrigeration with two series when heating, be similar to, determine that with 1 positive correlations the 2nd set point of temperature is poor, and the present invention is not limited to this.According to the purposes of freeze cycle, also can freeze, heat function in addition by each and determine series, and, even press each, also can obtain same effect by more the temperature province of sectionalization is definite serial in the said function.And, certainly, because of the difference of the set of data of freeze cycle, even relevant beyond 1 correlations also can.Moreover, in an embodiment, the cooling and warming two-purpose air conditioner is illustrated, and the present invention is not limited to this, even to freezing special use or heat special-purpose air conditioner and also can obtain same effect.
As mentioned above, according to present embodiment, have: the split-compressor portion that high side compressors portion and low-pressure side compressor section are arranged; With the high-pressure side heat exchanger; And gas-liquid separator; With the low-pressure side heat exchanger; And be arranged on upstream side decompressor between above-mentioned high-pressure side heat exchanger and the above-mentioned gas-liquid separator; And be arranged on downstream side decompressor between above-mentioned gas-liquid separator and the above-mentioned low-pressure side heat exchanger; With from the gas vent of above-mentioned gas-liquid separator the importing pipe arrangement that cryogen imports to the suction side of above-mentioned high side compressors portion is suppressed in the centre, in the refrigerating plant that is arranged on the injection control valve in the middle of the above-mentioned importing pipe arrangement, the refrigerant superheat degree of suction inlet of corresponding above-mentioned high side compressors portion is set and the temperature difference testing agency that changes and having according to using several detected temperature difference restriction variable quantities of temperature difference testing agencies and controlling the control device of aperture limitation function of the aperture of above-mentioned upstream side decompressor or above-mentioned downstream side decompressor.
Like this, be restricted to little amount because the aperture of the decompressor of 1 control changes, so the state variation of whole freezing conversion is little, the pressure of gas-liquid separator also changes a little.But the pressure of existing gas-liquid separator and the discharge pressure difference of low-pressure side compressor section are little, change really because of this small pressure differential changes injection rate.Injecting the temperature of the middle compacting cryogen introducing port of the discharge pipe arrangement that imports pipe arrangement and low-pressure side compressor section reacts sensitively to the variation of this injection rate.Therefore, the temperature of this one changes before the variation of whole freezing circulation.Catch the temperature that this changes in advance, and the aperture of control decompressor.
Therefore, can not cause big overregulating, vibrate, can make freeze cycle promptly stable, when the minimizing of control appliance action frequency, reliability improve, can obtain can not making the refrigerating plant of user's uneasiness yet.In addition, owing to the control of controlling as the refrigerant superheat degree that carries out high side compressors portion suction inlet, so can obtain the freeze cycle that stability might as well, have reliability.
And, contract for fear of hydraulic pressure, with the detected temperature difference of above-mentioned temperature difference testing agency, it is poor to be lower than the 1st predetermined set point of temperature, or for fear of overheat of compressor, greater than the situation of the 2nd predetermined set point of temperature difference the time, with above-mentioned control device as part or all the control device of aperture restriction cancellation function with the above-mentioned aperture limitation function of releasing.
If it is too much to be injected into the liquid refrigerating dosage that is comprised in the cold-producing medium of high side compressors portion suction inlet by the importing pipe arrangement, the danger that hydraulic pressure contracts then appears.At this moment, near the temperature the middle compacting cryogen introducing port descends, and the temperature difference between the gas-liquid separator diminishes.Utilize this,, then be judged as may strengthening that hydraulic pressure contracts, promptly open the low-pressure side decompressor to the regulation aperture if this temperature difference diminishes.
And, if the pressure of gas-liquid separator becomes lower than the discharge pressure of low-pressure side compressor section, then cold-producing medium adverse current during importing pipe arrangement of also discharging from the low-pressure side compressor section sometimes, and intrusion gas-liquid separator.If this adverse current produces, then the discharging refrigerant from the low-pressure side compressor section of gas-liquid mixed refrigerant with adverse current of high-pressure side decompressor mixes.Therefore, gas-liquid mixed refrigerant flows into the low-pressure side decompressor with the state that rises because of adverse current cold-producing medium mass dryness fraction, the function of forfeiture gas-liquid separator.
Moreover, because the cold-producing medium that does not carry out cooling off because of injection is intactly sucked high side compressors portion, so the cold-producing medium discharge temperature of high side compressors portion rises.At this moment, if around temperature conditions poor, then the cold-producing medium discharge temperature uprises unusually, has the distortion cause synthetic resin members in the refrigerant loop etc. and the danger of sex change.If such adverse current state continuance then because the reliability of freeze cycle is impaired, is necessary to make adverse current no longer to continue.At such adverse current state, because near the temperature the middle compacting cryogen introducing port becomes nothing because of the cooling of injecting, so become the temperature more much higher than the temperature of gas-liquid separator.
Utilize this, under the situation that this temperature difference becomes excessive, the possibility that is judged as adverse current is strong, promptly closes the low-pressure side decompressor to the target aperture.Like this because can prevent that hydraulic pressure contracts and the danger of adverse current in possible trouble, so can prevent from self-hydraulic to contract and import the injection adverse current of pipe arrangement, can obtain the refrigerating plant of the reliability raising of freeze cycle.
And, with above-mentioned control device as having the control device of determining the arithmetical organ of above-mentioned the 2nd set point of temperature difference according to the revolution of compressor.
If the revolution of compressor rises, then the discharge temperature of low-pressure side compressor section also rises, and influenced by it, and the suitable degree of superheat when normally moving also rises.Therefore, no matter be when heavy-duty service at a high speed, still when the underrun of low speed, all can prevent adverse current conscientiously, simultaneously, only when the adverse current possibility is arranged, carry out the control rapidly of low-pressure side decompressor.Usually the time, continue the operation in the moderate change as far as possible, avoid the sudden turn of events of freeze cycle, owing to do not apply unwanted stress to equipment, so be expected to improve the reliability of freeze cycle, simultaneously, the meaningless uneasiness sense of user that can avoid the sudden turn of events because of freeze cycle to cause.Can obtain refrigerating plant.
And above-mentioned the 2nd set point of temperature difference has and the positive correlation of revolution at the determined compressor of pattern of each freeze cycle.
At the heat source side heat exchanger, when utilizing the refrigeration of the big variation of temperature conditions of side heat exchanger, when heating, in the time of all can preventing from conscientiously no matter to be heavy-duty service or the adverse current during underrun, simultaneously, only when the adverse current possibility is arranged, carry out the control rapidly of low-pressure side decompressor.Can obtain when common, continue operation to change slowly as far as possible, avoid the drastic change of freeze cycle, owing to do not apply unwanted stress to equipment, so be expected to improve when no matter being refrigeration or when heating freeze cycle reliability, simultaneously, the refrigerating plant of the meaningless uneasiness sense of the user that can avoid the drastic change because of freeze cycle to cause.
And, said temperature difference testing agency has the 1st Temperature Detector that detects the temperature relevant with the saturation temperature of the suction refrigerant pressure that is equivalent to above-mentioned high side compressors portion, with the 2nd Temperature Detector of the temperature of the temperature correlation of detection and above-mentioned suction cold-producing medium, the installation site of above-mentioned the 1st Temperature Detector is located between upstream side decompressor and the downstream side decompressor.
The pressure between upstream side decompressor and downstream side decompressor and the pressure of gas-liquid separator equate, because the pressure of gas-liquid separator is near the suction pressure of high side compressors portion, so by detecting saturation temperature, can be used as the relevant temperature of saturation temperature with the suction pressure of high side compressors portion near gas-liquid separator pressure.Like this, because the control of low-pressure side decompressor is correct, so freeze cycle stable operation, simultaneously, the selection free degree that detects the place increases, and can obtain can selecting by the freeze cycle requirement refrigerating plant of best place.
And, by the installation site of above-mentioned the 1st temperature sensor is set between above-mentioned upstream side decompressor and above-mentioned gas-liquid separator, because the detected temperatures in the 1st temperature sensor is not subjected to the influence of adverse current fully, become correctly temperature near the saturation temperature of the refrigerant pressure in the gas-liquid separator, so produce adverse current, before the freeze cycle havoc, because of carrying out the control of quick, suitable freeze cycle, so can obtain having the air conditioner of refrigerating plant of the reliability raising of freeze cycle.
And, have: sucking on the refrigerant passage of portion to the high-pressure side from the low-pressure side discharge portion, the split-compressor that is exposed to the outer connecting pipings of pressure vessel is arranged; With with the above-mentioned importing pipe arrangement at above-mentioned connecting pipings interflow, on above-mentioned importing pipe arrangement, in the middle of above-mentioned between compacting cryogen introducing port and the above-mentioned injection control valve, the installation site of establishing above-mentioned the 2nd Temperature Detector.
Thus, reflect the temperature at the position of controlling the result and carry out the control of low-pressure side decompressor owing to detect sensitivity, so can show the result of control rapidly.Therefore, with as the situation of existing variations in temperature control with the big position of thermal capacity compare, the delay of time is little.Therefore, can prevent from incidently when time delay is big excessive overregulate and vibrate.
And the 2nd temperature sensor can obtain suitable relevant of inlet temperature with high side compressors portion.When and the 1st Temperature Detector between temperature difference when the 1st setting is following, judge that liquid returns the dangerous high of high side compressors portion, open the low-pressure side decompressor once to the regulation aperture, the refrigerant pressure in the gas-liquid separator is descended, reduce injection rate.And, when and the 1st Temperature Detector between temperature difference when the 2nd setting is above, being judged as need be by the compressor cooling of injecting, close the aperture of low-pressure side decompressor once to regulation, refrigerant pressure in the gas-liquid separator is risen, the drop amount of injecting cold-producing medium is increased, and injection rate also increases simultaneously, so it is dangerous in possible trouble and can prevent the refrigerating plant of the overheat of compressor that causes because of the injection adverse current to obtain preventing that hydraulic pressure from contracting.
And, be located at the position more than the above-mentioned middle compacting cryogen introducing port 15mm of distance on the above-mentioned importing pipe arrangement by installation site with above-mentioned the 2nd temperature sensor, can import fine weldering installation thermistor sleeve pipe on the pipe arrangement, precision, quick response fully detects the temperature relevant with the inlet temperature of high side compressors portion.And, be located at the position of the above-mentioned middle compacting cryogen introducing port 15~100mm of distance on the above-mentioned importing pipe arrangement by installation site with above-mentioned the 2nd temperature sensor, appropriateness is subjected to the influence of heat of discharge temperature of low-pressure side compressor section and the influence of injecting humidity effect two aspects of cold-producing medium respectively, because the 2nd Temperature Detector can detect the temperature relevant with the inlet temperature of high side compressors portion, contract danger in possible trouble and can prevent the refrigerating plant of the overheat of compressor that causes because of the injection adverse current so can obtain to prevent hydraulic pressure.
And, as above-mentioned injection control valve, use expansion valve, when increasing the aperture of above-mentioned injection control valve, by separately increasing aperture for several times, the impact change of tune that the sudden turn of events of the freeze cycle when opening injection valve is caused does not have the impulsive sound when mitigation is closed.And, owing to when existing liquid to return compressor dangerous, close injection valve as early as possible, thus can obtain making the impulsive sound of following the injection valve switching low, prevent from the user is caused meaningless doubt and uneasiness, simultaneously, can guarantee the reliability of compressor.