CN1134630C - Improved control for absorption shillers - Google Patents

Abstract

In a first embodiment, an absorption chiller including a generator (26) and an absorber (24) is provided, with at least one stream of concentrated absorbent solution flowing from the generator (26) to the absorber (24). Separate flows of the concentrated absorbent solution are delivered to the surface contact portion (24a) of the absorber (24) and to a reservoir (24c), which may be the absorber sump. The chiller capacity is controlled by varying the flow rate ratio of absorbent solution flowing to the surface contact portion (24a) of the absorber (24) versus the reservoir. A controller (118) adjusts the flow ratio of absorbent solution to achieve the desired refrigeration capacity. In a second embodiment, a crystallization detection and recovery method for a two-stage absorption refrigeration machine (400) is provided. Crystallization in the low temperature heat exchanger (426) is detected through temperature comparisons between certain absorbent solution flows. The recovery sequence includes steps to remove crystallization and to prevent subsequent occurrences. Finally, in a third embodiment, a control system (500) for controlling overshoot in response to a setpoint input (515) to the control system (500) is provided. The control system (500) includes a feedback loop (505) connected to the control system (500) via a summing node (508); and a binomial filter (310) arranged to receive a setpoint input (515) and to provide a filtered setpoint output (520) to the control system (500) via the summing node (508). The control system includes the binomial filter (510) to provide a filtered setpoint output (520) having a gradual initial response to the control system via the summing node (508). A method of controlling a water chiller system using the control system (500) to provide a supply of leaving water at a preselected temperature is also provided.

Description

Improvement control to Absorption Refrigerator

Background of the present invention

Present invention relates in general to improvement control to Absorption Refrigerator.In first embodiment, the present invention relates to be used for heat is discharged to the absorption type heat switch of a radiator from thermic load the improving one's methods of particularly a kind of capacity that is used to change the absorption type heat switch.In another embodiment, the present invention relates to a kind of two-stage sorption refrigerator, more particularly, relate to a kind of control system that is used for detecting crystallization and recovers from crystallization in heat-exchange system.At last, in the 3rd embodiment, the present invention relates more specifically to a kind of control system, and this system has a binomial set-point filter, is used for eliminating overregulating, and don't can weakens reaction to technological fluctuation.

By absorption refrigeration, cooling that a refrigerating circuit uses compound cold-producing medium to circulate, heat pump and relevant apparatus are well-known.Described refrigerating circuit comprises a generator, a condenser, an evaporimeter and an absorber.Multiple compound-refrigerating agent system can be used for described device.Two examples wherein are ammonia/water system and lithium bromide/water system.

By an extra power compound-refrigerating agent in the generator and absorbent solution are heated.Described generator is heated to foot in (for example distilling out the stronger refrigerant vapour of volatility to this composite solution, for ammonia/water cold-producing medium, be ammonia steam, and be water vapour for lithium bromide/water system), stay the lower concentrated absorbent solution of volatility.To concentrate absorbent component then and enter described absorber.

Described condenser receives the vapo(u)rability cold-producing medium from described evaporimeter, and it is condensed into liquid form (condensate is otherwise known as).Because the heat that described steam condensation is discharged is discharged in the refrigerating plant of cooling tower, cooling water, some other external heat sink or another grade.

Described evaporimeter is by the direct or indirect liquid refrigerant of the condensation of the described thermic load of contact of evaporation, absorbs heat from thermic load (being other fluid or the object that content, cooling water or this system of air, the refrigerator of building is designed to cool off).Therefore, described evaporimeter evaporates described volatility cold-producing medium again.

Allow the refrigerant vapour that leaves evaporimeter contact by described absorber with the concentrated absorbent solution of leaving described generator.When this vapor phase reuptaked the lower solution of volatility mutually in the time, produce heat by this contact process.This heat is discharged into refrigerating plant or some other radiator of cooling tower, cooling water, another grade.Original combination cold-producing medium and absorbent solution form in this absorber again, are back to described generator then, finish described circulation.

In a kind of common absorption type heat switch, described evaporimeter and absorber are arranged in same container, reuptake so that the refrigerant vapour that produces in evaporimeter can be transported to described absorber easily.In described typical combined evaporimeter and absorber, described contact process comprises sprays concentrated absorbent solution, and it is contacted with refrigerant vapour.The existence of low temperature concentrated solution can produce saturated vapour pressure in absorber, this pressure is a little less than the saturated vapour pressure in the evaporimeter.The imbalance of described pressure can cause refrigerant vapour to flow to absorber by evaporimeter, and here it is reuptaked in the solution.The refrigerating capacity of described refrigeration machine is subjected to the influence of cold-producing medium evaporation rate in the evaporimeter, therefore, is directly flowed to the velocity correlation of absorber by evaporimeter with the cold-producing medium of evaporation.

Need to change the refrigerating capacity of Absorption Refrigerator, so that adapt to the different load that might add to this refrigeration machine.The modal method of control refrigerating capacity is the concentration that changes absorbent solution, and described absorbent solution is ejected in the described absorber with constant speed.Improve the concentration of the absorbent solution of absorber injection, can in this absorber, produce bigger pressure imbalance, this can cause more refrigerant vapour to flow to absorber from evaporimeter again, thereby causes cold-producing medium evaporation at faster speed in evaporimeter, and finally improves refrigerating capacity.On the contrary, reduce the concentration of the absorbent solution of absorber injection, can reduce its refrigeration capacity.

Changed the absorbent solution concentration that described absorber sprays by change by the flow that generator flows to the absorbent solution of absorber already.When the flow from generator changed, described refrigerating plant mixes with concentrated absorbent from generator by some rare compound of self-absorption in future tank kept the constant flow rate that enters described absorber.This device sprays by described absorber and carries described mixture then.For example, when from the flow-rate ratio of described generator when low, its circular flow will be very high, and enter the initial absorbent solution of described absorber also will be rarer.

Theoretically, if be reduced to 0 from the flow of the absorbent solution of generator, the capacity of described refrigerator also will be reduced to 0 (flow that flows in this case, the absorber shower nozzle only circulation of origin self-absorption tank constitutes).But, in fact this device must keep the minimum flow by described generator, to avoid that mobile stagnation and crystallization take place in described refrigerator heat exchanger.For refrigerating capacity being reduced to a specific point, this device must be by mixing absorbent solution further rare absorbent solution from generator with a large amount of excess refrigerant.But, before the further rare absorbent solution of absorber, the use of excess refrigerant can increase the response time of refrigerator, and needs a big cold-producing medium hutch.Concerning dwelling house, office and industrial heat exchange purposes, the user wishes that absorption chiller can adapt to low cooling load, but also can the change of load be responded rapidly, therefore, needs another kind of device.

For example, controller can not make the office block cooling system make rapid change between low and high refrigeration capacity by the concentration that changes the absorbent solution on the absorber shower nozzle.In the cloudy weather of part, if sun grow and dying down continuously in cloud, this system will be recycled to big refrigerating capacity when the sun sees through office's window irradiation and increase indoor air temperature from covering the low of solar time when black clouds or not having refrigerating capacity.When hanging down refrigerating capacity, described office cooling system is used excessive cold-producing medium and is watered down described absorbent solution, so that reduce its concentration.When the air themperature of office and then increases suddenly and when needing obviously to improve refrigerating capacity, described generator must evaporate excessive cold-producing medium described composite solution indeed, so that form concentrated absorbent again.Before can regaining its big refrigeration capacity, this refrigeration machine must in generator, form this absorbent again.But, when refrigerating capacity was recovered, the sun may be hidden into the black clouds back for a long time again and go.At this moment, this system must weaken its refrigeration capacity once more, because the sun has no longer heated this office.

Therefore, to control the method for the refrigerating capacity of Absorption Refrigerator be well-known by changing absorbent solution concentration, but existing systems is effective inadequately when working in low refrigerating capacity scope, because it has the long response time.In addition, even in order to work in low refrigeration capacity scope, a big cold-producing medium hutch must be equipped by described system.

On the other hand, the invention still further relates to a kind of two-stage sorption refrigerator, more particularly, relate to a kind of control system that is used for detecting and recovers from crystallization a system heat exchanger.During using two-stage sorption refrigerator, the appearance of accident or fault can cause absorbent solution to be solidified or crystallization in the circulation passage of this refrigeration machine.The concentrated solution passage that the modal position that crystallization takes place is described concentrated solution heat exchanger.At this moment, described absorbent solution was concentrated and was forced to be back to absorber by generator already.Between generator and absorber, carry concentrated solution by a heat exchanger, heat is discharged to rare absorbent solution of being delivered to absorber by generator pump.If make become overrich or be cooled to below its crystallization temperature of this absorbent solution for a certain reason, described concentrated solution circulation passage can be blocked, and because crystallization and final complete closed.The time of a few minutes can appear in this situation, and has understood already and 1 fen clock time of less than occurs.

There is multiple situation can cause in heat exchanger, taking place the crystallization of absorbent solution.For example, air or the existence of other inert gas in absorber can hinder the rare of wherein absorbent solution.This can cause the concentration of absorbent solution to raise.When this solution becomes got supersaturation, it will begin crystallization.If it is lower than normal operating temperature that Water in Condenser becomes suddenly, the temperature that can cause leaving rare absorbent solution of absorber reduces.Conversely, this can make the temperature of the absorbent solution in the heat exchanger be reduced to again to be lower than its crystalline temperature, and begins to stop up this heat exchanger.The excessive heat evaporimeter can cause the supersaturation of absorbent solution, and this also can cause the crystallization of hot switching path to be stopped up.

Wish fundamentally to avoid the generation of above-mentioned any situation.But, because fault or accident can not avoid taking place crystallization at any time in heat exchanger.When crystallization and heat exchange obstruction occurring, the method for the existing described hot switching path of cleaning is with external heat source this passage to be heated, and makes absorbent solution liquefaction wherein.But, this method is unacceptable, because it needs obviously to interrupt the work of this Absorption Refrigerator.Other existing crystallization detection and prevention system have adopted mechanical float valve in the absorbent solution circulation passage, this float valve can start when owing to crystallization adverse current taking place.But, confirmed already that this mechanical system was also unreliable, and expensive.

At last,, present invention relates in general to control system, more particularly, relate to a kind of control system, overregulate, and don't can reduce response technological fluctuation with elimination with binomial set-point filter in the third aspect.

In fact being used to monitor and control all types of systems all is existing with mechanical control system.Adopt control system normally because its advantage economically.For example, one of its advantage is to keep the capacity of a process near the work limit that needs.This control can also improve the security of described system, and can improve its efficient.

Existing two kinds of basic control system types.One type control system is a regulation and control system.Such control system mainly is used to the variation of described system and interference are responded.Example by the device of regulation and control system control comprises water refrigerating machine, and it is used for life cooling device cooling water is provided.

The control system of another kind of type is a tracking control system.Such control system can be followed the tracks of the variation of set point or relevant input.This control system has been improved the control of described refrigeration machine.For example, an initial set point is imported a system or refrigeration machine, and follow the tracks of all deviations that this refrigeration machine takes place, and keep this refrigeration machine as far as possible and under the set point of needs, work by this control system.

Say simply, a closed-loop control system comprises a processor, to the setting of in check variable element and the controller of practical measurement value and the value that needs relatively, and the difference between them is used for one of input signal of regulating automatically by the described processor of input.Described physical system to be controlled can be electric power, heating power, hydraulic pressure, pneumatic, gas, machinery or be described by any other physics or chemical process.

Generally, a system is designed to satisfy a kind of in two kinds of purposes.At first, servo control mechanism is designed to as far as possible closely to follow the tracks of the variation of set point.A lot of electric power or Machinery Control System all are servo control mechanisms.Secondly, a design of Regulator is become to keep the stable of output, although the variation of load or other interference is arranged.Regulate control and be widely used in controlling chemical process.Generally, by the change of tracking control system monitoring and setting point and make suitable adjustment.Regulation and control system is regulated, and fluctuates with compensate for process.

The stability of a control system, accuracy and response speed are determined by analyzing its stable state and changing performance.Need in the short as far as possible time, reach stable state, keep its output place again within the limits prescribed simultaneously.Steady-state behaviour is estimated with accuracy, controls the output of specific input by it.Described transformation performance, i.e. output since system from a kind of lower state to the output variation phenomenon that the variation of another kind of lower state causes, use such as maximum overregulate, the amount of rising time and response time estimates.

The quality that multiple factor affecting control is arranged comprises the fluctuation that is caused by set point change and processing load variations.Set point and technical load can be restricted to sets final control element, is positioned at described set point with the retentive control parameter.Therefore, the two all can cause final control element to be reorientated.For example, other fluctuation may be the variation of cooling water temperature in input process fluid variation of temperature and the water refrigerator.

In a lot of control systems, staged input response can cause overregulating.But, the staged input is widely used in analyzing many reasons.Test at first, easily.Secondly, the staged input is serious disturbance, and the Response Table of staged input is revealed contingent worst error.The feature that changes performance comprises existence and the amplitude that maximum is overregulated, and changes the frequency and the response time of fluctuation.

Under some occasion, described input variable can be overregulated the limit of its expectation, and the fluctuation of transformation takes place.It is maximum that described first overregulates, and its effect is that the designer is concerned about.Limiting to the principal element that this maximum overregulates is: (1) is avoided avoiding the long stabilization time relevant with the system of damping wretched insufficiency because the variable of control too departs from by the value of command signal defined the infringement that described process or machinery are caused with (2).

As indicated above, can be with control system as process modulator and tracking control unit.For example, can be with used for absorbing refrigerator in industrial use.In these purposes, may need refrigeration machine is controlled, to realize more than one tracking control function.The water refrigerator control of cooling off that is used to live is main process controller.Described refrigerator will leave the cooling water control of evaporimeter at a set point, and this set point changes never.Concerning such purposes, need usually a kind of higher integration increment is used for PID (ratio, integration and derivative) control loop, to eliminate the error of the coolant-temperature gage of leaving away that causes by technological fluctuation.Usually, higher integration increment is favourable, because it can make control system that the fluctuation of load is responded sooner.But, a problem relevant with using big integration increment is that when beginning, this controller can overregulate its set point.Another problem that is caused by high integration increment is shutdown at low temperatures.

The described problem of overregulating solved with the control function that is called as " soft loading " previously already.During set point changed, perhaps when beginning, refrigeration system can experience a timely and obvious variation.The typical response of described cooling system is to be loaded into 100%, to satisfy described variation.In order to compensate this big variation, the restriction when beginning of described soft value-added tax function is exported from the instruction of described controller, to slow down the load to this refrigerator.

But, described soft value-added tax function also has some problem.For example, described soft loading is set at the tail end of control system, and this makes that its effect is difficult to realize.Because this soft value-added tax function has limited its instruction output, rather than input, the mode that limits described output variation changes along with the dissimilar control system in the different refrigeration machines.For example, in order to limit the change of water temperature, described soft value-added tax function must limit described instruction, with the temperature of control water.In addition, the mode that limits described instruction also can influence controlled parameter.Concerning each system, this needs described instruction to change with each system.In addition, correctly take place, need a large amount of empirical work in order to make described response.

Another kind of relevant control occurs in certain occasion, wherein, needs to change the set point of the water temperature of leaving away.And, adopt big integration increment, can cause big overregulating.In addition, the cooling water set point in the existing life cooling device needs change every day.For example, described temperature may and reduce in the daytime in the rising at night.These clocklike change also can cause the above-mentioned problem of overregulating.

Therefore, wish to improve described integration control, so that this system response is faster by adjustment control.This reinforced integration control work usually is good, carries out set point up to needs and changes.Excessive and cause overregulating to the raising meeting of the integration increment of set point then.But, when identical system attempts to realize following the tracks of the control of type, can overregulate.Therefore, need a kind of can the elimination to overregulate and don't can reduce control system to the response of technological fluctuation.

US-A-5,195,028 have disclosed a kind of PI type 2DOF controller, and this controller comprises a set-point filter, is used to receive a set-point value, and exports a control set-point value.This set-point filter has the transfer function of following described set-point value, and can represent by following formula: $\frac{1+{\mathrm{\α\βT}}_1\·S}{{1+\mathrm{\βT}}_1\·S}$

Wherein, T _IIt is the time of integration, S is the Laplace operator, α is a constant, it can be set between 0 and 1, β is a constant, can be set between 0 and about 10, the error calculating section is used to calculate the control set-point value and by the error between the controlling value of a control system feedback, the control arithmetic section, be used to receive described error, carry out at least one PI (P: ratio, I: control computing integration), and export a control variables, and the applying portion that this control variables is used for described control system.

At US-A-5, disclosed a kind of absorption air handling system in 259,202.For stopping room air at once, the termination signal by room air conditioner regulates, and improvement starts the feature of this system, for example, after stopping this system works, implement at interval to restart with the short period, by the controller that is used for described room air conditioner a termination signal is transmitted into a control device, and according to the control of this signal by this control device executive termination burner, cooling medium circulating pump, cooling water and cold/hot water pump.But, a solution circulation pump works on, although and this solution keeps high concentration, still can be by absorber, a high temperature generator and a low temperature generator circulation more again.During this period, the show value of a temperature sensor reduces gradually, and, when this value reaches predetermined temperature, described control device switches to closed condition with a control valve by opening, and another control valve is switched to opening by closed condition, and starts described cooling medium circulating pump once more, and cooling medium is transported to a solution container of the bottom that is positioned at described absorber, so that dilute this solution.

The present invention's brief description

Therefore, an object of the present invention is according to load variations, technological fluctuation and other reason that need change Absorption Refrigerator change the fast method of its refrigeration capacity.

Another object of the present invention provides a kind of fast method that changes the response of refrigerator under low refrigerating capacity when working.

A further object of the present invention provides and a kind ofly enlarges the refrigeration work scope of refrigeration machine and don't damage its response or increase the method for the volume of this refrigerating plant.

One aspect of the present invention is the variable-displacement Absorption Refrigerator.This refrigeration machine comprises that one is used to produce the generator that concentrates absorbent solution and cold-producing medium, and an absorber, this absorber comprise a surface contact portion, concentrate absorbent solution here and contact with described cold-producing medium, and a container.Described refrigeration machine (for example also comprises at least one pipeline, conduit, pipeline, passage or public container), be used for a concentrated absorbent solution streams is transferred to the surface contact portion of described absorber from described generator, and another concentrated absorbent solution streams is transferred to described container from described generator.At last, this refrigerator comprises a fluid dram flow regulator (for example, valve or pump), is used to change the ratio from two fluid streams of described generator.

Another aspect of the present invention is a kind of method that changes the refrigerating capacity of Absorption Refrigerator.This method can be carried out in a generator mentioned above, an absorber and a container.A concentrated absorbent solution streams that is flowed to the surface contact portion of described absorber by described generator is provided.Another concentrated absorbent solution streams that is flowed to described container by described generator is provided.Determine the desirable refrigerating capacity of this refrigerator, and change flow proportional, so that described desirable refrigerating capacity to be provided from two fluid streams of described generator.

The present invention has some advantages.Advantage is to shorten the time that load variations or technological fluctuation are responded greatly.Another advantage is that the working range of this refrigerator can expand to the low capacity zone, and can not damage its response or need large-scale plant (as a big cryogen vessel).

Therefore, an object of the present invention is to provide a kind of reliable and cheap apparatus and method that are used for detecting the heat exchanger absorbent solution crystallization of two-stage sorption refrigerator.

Another object of the present invention provides a kind of method and apparatus of recovering from the crystallization of described absorbent solution of being used for after detecting described crystallization, and does not use external heat source.

On the other hand, the invention provides a kind of method that is used for detecting crystallization at two-stage sorption refrigerator, described refrigeration machine comprises a controller, an absorber, an evaporimeter, a high-temperature generator, a cryogenerator, a condenser, a low temperature heat exchanger, be used to make concentrated absorbent solution from high temperature and cryogenerator, be heat exchange relationship with rare absorbent solution from absorber, be used to guide the first passage of concentrated absorbent solution by described low temperature heat exchanger, be used for to concentrate absorbent solution is introduced described first passage by cryogenerator second channel, be used for to concentrate absorbent solution is introduced described first passage by described high-temperature generator third channel, be used for to concentrate absorbent solution is introduced described high-temperature generator by described cryogenerator four-way, be used for detecting the second channel temperature sensor that described second channel concentrates the temperature of absorbent solution, be used for detecting third channel concentrate absorbent solution temperature the third channel temperature sensor and be used for detecting the four-way temperature sensor that four-way concentrates the temperature of absorbent solution.

Described Absorption Refrigerator also comprises an evaporimeter jet pump, being used in the future, rare cold-producing medium of flash-pot coolant collector is transported at least one evaporimeter shower nozzle, an absorber jet pump, be used for to concentrate absorbent solution and be transported at least one absorber shower nozzle, be used for to concentrate absorbent solution is introduced described absorber by described low temperature heat exchanger five-way road, be used for rare absorbent solution is introduced by described gatherer the 6th passage of described absorber jet pump, with a valve of controlling by the controller that is installed on the 6th passage, be used for controlling rare absorbent solution flowing at the 6th passage.Temperature by the concentrated absorbent solution in the five-way road of five-way channel temp sensor detection between described low temperature heat exchanger and absorber.

When operate as normal, equal substantially by the detected temperature of second channel temperature sensor by the detected temperature of four-way temperature sensor, and the valve on the 6th passage cuts out.When crystallization begins to stop up first passage, begin to surpass by the detected temperature of four-way sensor by the detected temperature of second channel temperature sensor.According to crystallization detection method of the present invention, when equaling by the detected temperature of four-way temperature sensor by the detected temperature of second channel temperature sensor substantially and during by the mean value between the detected temperature of third channel temperature sensor, sending a crystallization alarm.This temperature is called as closing temperature.When meeting or exceeding described closing temperature by the detected temperature of second channel temperature sensor, promptly in described low temperature heat exchanger, detect crystallization, then described control system enters from crystallization recovers pattern.

According to this aspect of the invention, from crystallization recovery pattern, described control system is finished following steps described:

1. by being cut to the heat of thermal source, temporarily terminate in concentrating of absorbent solution in low temperature and the high-temperature generator;

2. by closing all systems pumps, temporarily stop the circulation of absorbent solution;

3. open the valve on the 6th passage between evaporimeter and the absorber jet pump, make rare absorbent solution flow to described absorber jet pump by described gatherer;

4. after closing about 3 minutes, described cryogenerator and high-temperature generator pump were restarted about 5 minutes, so that part washes away the high concentration absorbent solution that causes crystallization;

5. closed described cryogenerator and high-temperature generator pump once more about 3 minutes, so that eliminate any crystallization again that might between flush period, take place;

6. restart all systems pumps, close described valve, and by the heat input on described control system adjusting high temperature and the cryogenerator, so that the temperature of the concentrated absorbent solution between low temperature heat exchanger and absorber remains on certain level, make the crystallization temperature of concentrated solution at this position and the gap of actual temperature improve 5 (about 3 ℃) than existing gap.

Described control system can be carried out twice recovery circulation automatically.When detecting crystallization for the third time, all working of described Absorption Refrigerator all stops, because this shows the system problem that existence must be corrected.

For this reason, another embodiment of the invention provides a kind of control system, and this system has eliminated and overregulated, and don't can reduce the response to technological fluctuation.Specifically, a kind of embodiment of described control system comprises a binomial set-point filter, is used to filter the variation of set point, so that more progressive response is provided, overregulates thereby eliminated.

An aspect of of the present present invention is a kind of method of controlling the water refrigerator, is used to provide the cooling water of predetermined temperature of the binomial set point of this system of embodiment.Described water refrigerator has a control system, and this system has an input.This method is carried out as follows.Select a nominal set point temperatures.With a binomial wave filter this set point temperatures is filtered, so that the set point temperatures of a filtration is provided.The set point temperatures that to filter offers the input of described control system then.The set point temperatures of described filtration is the function of time and temperature.Preferably, the set point temperatures of described filtration is the existing temperature of cooling water at first, and the function as the time changes into asymptotic nominal set point temperatures then.

A more general aspect of the present invention is a kind of control system, and this system comprises a system input, and a backfeed loop and a binomial wave filter, this wave filter have the set point output of a set point input and a filtration.Described backfeed loop is connected with the input of this system by a summation joint.Described binomial wave filter is used to receive the nominal set point that is positioned at its set point input, and the set point output of a filtration is provided for this system's input by described summation joint thereupon.

Another aspect of the present invention is a kind of method of overregulating that reduces control system.A kind of control system with an input is provided.Select a nominal set point.With a binomial wave filter this nominal set point is filtered, so that the set point of a filtration is provided.The set point of this filtration is offered the input of described control system.The set point of this filtration is progressively near described nominal set point, thereby weakens or eliminated overregulating of described nominal set point.

A kind of advantage of embodiment with control system of binomial set-point filter is, use the set point that filters to allow the bigger integration increment of use in this control system, so that interference is reacted quickly to load, simultaneously, to starting and set point change responds, and don't can cause and overregulate.

In addition, an advantage of the embodiment of described control system with binomial set-point filter is the set point that filters to be used for soft loading to implement fairly simple.For example, it need not limit described output order, and described wave filter drives the track that needs are followed the tracks of in described control response in its front end work, and this track utilizes a secondary binomial wave filter to obtain.Such binomial wave filter can make described desirable set point improve gradually, rather than improves the situation that this unexpected raising occurs when not having wave filter just or an one-level wave filter only being arranged suddenly.

Another advantage of the embodiment of described control system with binomial set-point filter is that by filtering described set point, when temperature set-point changed, this control system can not run into the staged input.On the contrary, its reaction more similarly is a series of little technological fluctuations.

Another advantage of the embodiment of described control system with binomial set-point filter is, its uses and to be used to leave away the control of coolant controlled closed-loop path, because described binomial set point filters and is at the front end of this control system or imports a side and carry out.

Can understand above-mentioned one or several purpose by reading this specification, or one or several other purpose, these purposes can be passed through the disclosed all or part of realization of the present invention of this paper.

Brief description of drawings

Fig. 1 is the block diagram of absorption type refrigerating unit of the present invention.

Fig. 2 is the schematic diagram of a part of the absorption type refrigerating unit of one embodiment of this invention.

Fig. 3 is the schematic diagram of a part of the absorption type refrigerating unit of second embodiment of the present invention.

Fig. 4 is the schematic diagram that has adopted the two-stage sorption refrigerator of a kind of embodiment of the present invention.

Fig. 5 is the flow chart that expression the present invention recovers control system.

Fig. 6 is the block diagram of a kind of embodiment of control system of the present invention, represents a secondary binomial wave filter that is used for filtering the set point of this control system.

Fig. 7 is the curve of expression firsts and seconds wave filter to the response of a staged input.

The leave away curve of temperature of the cooling water of the time of Fig. 8 set point temperatures that to be expression filter corresponding to the binomial in the relative control system is when beginning, according to apparatus and method work of the present invention.

The leave away curve of temperature of the cooling water of Fig. 9 set point temperatures that to be expression filter corresponding to relative binomial, it is the result that set point changes in according to the control system of apparatus and method operation of the present invention.

Figure 10 is a kind of block diagram of embodiment of process control system, represents an absorber refrigerator with secondary binomial wave filter, and described wave filter is used for filtering the set point according to the control system of apparatus of the present invention and method operation.

The detailed description of the invention

Although will the present invention will be described in conjunction with one or more embodiments, be understandable that the present invention is not limited to these embodiments.On the contrary, the present invention includes the design and interior all alternative forms, improvement and the equivalents of scope that might be included in appended claims.

In this manual, do not relate to concrete cold-producing medium.Those of ordinary skills understand the refrigerant system in the device that can be used for the inventive method.Identical or different refrigerant system can be used for relevant apparatus.

This specification is from relating to the composition of typical absorption formula refrigeration solution in nature, and these compositions are the stronger cold-producing medium of volatility or refrigerant vapour (its liquid form is known as condensed steam sometimes) and the relatively poor absorption composition of volatility.These compositions can be used as solution and exist jointly, can be by heating separate it to this solution, thus the cold-producing medium that volatility is stronger therefrom distills away, and they can mix again so that rebuild described solution, and heat extraction.The all right condensation of described steam is so that heat extraction perhaps evaporates so that heat absorption.The absorption refrigeration agent solution of working by different way but can be used in the similar installation also can be used for the present invention.

At first referring to Fig. 1, the heat of the block representation absorption system among the figure and cold-producing medium shift.

With system 10 heat is transferred to radiator 14 by thermic load 12.As everyone knows, no matter the temperature of thermic load 12 is higher than, is lower than or equal the temperature of radiator 14, and described heat shifts all can carry out.

Enter the evaporimeter 16 of this device through passage 18 from the heat of load 12.(in Fig. 1, all heats that from an element, transfer or change over to all use alphabetical Q and then an arrow represent that arrow is represented the direction of conducting heat).Evaporimeter 16 is direct heat transfer with thermic load 12 and contacts, and the heat exchanger that perhaps connects evaporimeter 16 is direct heat transfer with thermic load 12 and contacts, to realize described heat transfer.

The heat Q evaporation that enters evaporimeter 16 had entered the condensed refrigerant steam of evaporimeter 16 already by passage 20.The effluent that flows out evaporimeter by passage 22 is a refrigerant vapour, and it carries the heat from thermic load 12.

The contact portion of absorber 24a receives refrigerant vapour by passage 22, and makes it and contact by the lower absorbent solution of the passage 28 and the volatility from generator 26 of 28a reception.The refrigerant vapour that is caused is absorbed in the lower absorption liquid of volatility can be owing to described absorption process and the described steam of condensation, discharge its evaporation heat, and discharge the dissolving heat.The heat Q that is produced enters radiator 14 by passage 30.The compound-refrigerating agent solution of rebuilding is discharged among the container 24c by passage 24b, here it with mix from the concentrated absorbent solution of generator 26 through passage 28 and 28b.In described typical absorption type refrigerating unit, described container 24c absorbs tank.But, any vessel, container or device that other is suitable for holding solution can be effective to described refrigeration machine equally.The solution of described container is transported to generator 26 by passage 34 through heat exchanger 35.Heat exchanger 35 carried out preheating to this cold-producing medium by passage 34 before described compound-refrigerating agent enters generator 26, employed heat may be the heat of discharging from described generator by absorbent solution passage 28.

Detect the temperature of the heat exchanger fluid that flows along the passage 18 in evaporimeter 16 downstreams by a temperature sensor 116.Connect temperature sensor 116 and controller 118 by control circuit 13.Connect controller 118 and flow regulator 111 by another control circuit 15.After the input that receives from temperature sensor 116, by controller 118 control flow regulators 111, and correspondingly regulate the contact portion that flows to absorber 24a through passage 28 and 28a by generator 26 and the ratio that flows to the absorbent solution of container 24c through passage 28 and 28b.Controller 118 can will flow into container 24c by passage 28b by all absorbent solutions deflections of passage 28 outflow generators 26 by indication flow regulator 111 flow proportional will be reduced to 0.Described flow regulator 111 can comprise a pump, valve, a series of pump or valve, or can regulate any other device of the flow that changes flow through passage 28a and 28b in this way.

In generator 26, by heater 36 the compound-refrigerating agent solution is heated to foot in distilling out the stronger refrigerant vapour of volatility, stay the lower absorbent solution of volatility.By passage 38 described refrigerant vapour is transported to condenser 40.Concentrate absorbent solution arrives absorber 24a by passage 28,28a and 28b contact portion and container 24c (as indicated above).

The refrigerant vapour that enters through passage 38 by condenser 40 condensations.The heat Q of condensation is discharged from, and arrives radiator 14 along passage 42.Condensed refrigerant steam is through passage 20 eductor condensers 40 then, and is back to evaporimeter 16, finishes described circulation.Therefore, enter described loop from the heat of thermic load 12 and heater 36, and heat leaves this loop by absorber 24 and condenser 40.Except the wasted heat of loss, all heats of taking from thermic load 12 and heater 36 all enter radiator 14.

Referring to Fig. 2, disclosed apparatus and method will combine with device shown in Figure 1 or work as an integral part of this device.Some part of Fig. 2 is equivalent to the relative section among Fig. 1, and therefore, they have identical numbering.

Fig. 2 represents a kind of specific embodiments of absorption system 10 of the present invention.

System 10 comprises 12, one radiators 14 of 40, one thermic loads of 26, one condensers of 24, one generators of 16, one absorbers of an evaporimeter and a heat exchanger 35.Generator 36 has 55 and concentrated absorbent outlets 85 of 75, one refrigerant vapour outlets of a rare absorbent inlet.

By an evaporimeter-absorber shell 23 in conjunction with evaporimeter 16 and absorber 24 parts.Evaporimeter 16 comprises 17, one cold-producing medium storage bins 99 of 18, one evaporator plates of 21, one thermic load coils of cold-producing medium shower nozzle and a pump 102.Absorber 24 comprises an absorber shower nozzle 101, heat exchange coil " X ", a contact portion 24a and an absorption tank 24a.The contact portion 24a of absorber 24 is space and surfaces of described evaporimeter-absorber shell 23 the insides, and here refrigerant vapour contacts with absorbent solution.In this embodiment, described contact site mainly is by the space of shower nozzle 101 coverings and the surface of heat exchange coil " X ".Described evaporimeter-absorber shell also has a compound-refrigerating agent outlet 107 that is communicated with passage 34, an absorbent mouth 130 that communicates with passage 28b, a cold-producing medium stores inlet 97, be used for by the cold-producing medium of passage 95 receptions from the outlet 93 of evaporator plate 17, a cold-producing medium stores outlet 100, the cold-producing medium that is used for will flowing out by passage 96 and pump 102 cold-producing medium storage bin 99 is transferred to the cold-producing medium shower nozzle, and an inlet 144 that is used to receive from the condensating refrigerant steam of passage 20.

System 10 has three sensors--and 115,116 and the driver 120 of 117--and controller 118 and adjustable frequency.System 10 also has three pumps.Pump 102 is connected with cold-producing medium storage bin 99 in mode mentioned above, and pump 103 is connected with the absorption tank with compound-refrigerating agent outlet 107 by pipe 34, and pump 111 is connected in the bonding part 131 between passage 28,28a and the 28b.

In generator 26, described compound-refrigerating agent solution is entered by rare refrigerant inlet 75, and is heated to foot in distilling out the stronger refrigerant vapour of volatility, stays the lower concentrated absorbent solution of volatility.Described refrigerant vapour exports 55, is transported to condenser 40 through pipeline 38 by refrigerant vapour, here is condensed.Concentrate absorbent solution by concentrating absorbent outlet 85, being transported to absorber 24 through pipeline 28.When concentrated absorber solution passed through pipeline 28 to absorber 24 motions, it will pass through heat exchanger 35, here is cooled by heat being passed to the compound-refrigerating agent solution that flows through pipeline 34.

By pipeline 20, and 144 enter evaporator plate 17 from the condensating refrigerant steam of condenser 40 by entering the mouth.From the condensating refrigerant steam of evaporator plate 17 by exporting 93 through pipeline 95, storing inlet 97 by cold-producing medium and enter cold-producing medium storage bin 99.Store outlet 100 cold-producing mediums that will be present in the cold-producing medium storage bin 99 by pump 102 by cold-producing medium and siphon away, force described cold-producing medium to flow to cold-producing medium shower nozzle 21 then through pipeline 96.Condensed refrigerant steam is by ejection in the cold-producing medium shower nozzle 21 of thermic load pipe 18 tops.The residual injection thing that remains liquid form is collected in the evaporator plate 17, here it with by 144 other condensed refrigerant vapor mixing that enter through pipeline 20 that enter the mouth.Condensating refrigerant steam in the evaporator plate 17 returns cold-producing medium storage bin 59 once more, and repeats above-mentioned circulation.

The heat that enters evaporimeter 16 is from thermic load 12 and by thermic load pipe 18.Heat and evaporimeter 16 by thermic load pipe 18 carry out heat exchange contact, and evaporation is ejected into condensating refrigerant in the evaporimeter 16 through cold-producing medium shower nozzle 21 by pipeline 96.The effluent of evaporimeter 16 is the refrigerant vapours that are contained in evaporimeter-absorber shell 23, and it is carrying the heat inflow absorber 24 from thermic load 12.

Concentrate absorbent solution and enter the contact portion 24a of absorber 24, and enter by absorbent mouth 130 and to absorb tank 24c by absorber shower nozzle 101.In this embodiment, the concentrated absorbent solution that enters contact portion 24a is regulated in order to following method with the ratio that enters the concentrated absorbent solution that absorbs tank 24c.Concentrate absorbent solution streams and enter junction surface 131 by pipeline 28, the pipe 28a that connects pump 111 here converges with the pipe 28b that is connected absorption tank 24c.Pump 111 is variable displacement pumps, by the concentrated absorbent solution of its metering inflow absorber shower nozzle 101.

When pump 111 when being higher than the capacity work of the flow by passage 28,131 merge at the junction surface from the reservoir solution of absorbent mouth 130 by pipe 28b with concentrated absorbent solution from pipe 28.Solution after the merging is inhaled into pump 111.Here it is forced through pipe 28a and enters absorber shower nozzle 101.Static or when being lower than the capacity work of the flow by passage 28 when pump 111, concentrate absorbent solution and enter junction surface 131 by pipeline 28, reach pump 111 and concentrate the degree that absorbent solution can not satisfy overall flow, enter absorption tank 24c by pipe 28b and by absorbent mouth 130 by pipe 28a suction.Complete when static when pump 111, the absorbent solution that enters absorber shower nozzle 101 by pipe 28a stops fully, therefore, flow proportional is reduced to 0.The another kind of method that adjusting enters the contact 24a and the ratio of the concentrated absorbent solution that absorbs tank 24c is managing 28b rather than on pipe 28a a pump being set, a pump to be set respectively on each root pipe perhaps.By changing the capacity of pump, regulate the flow that enters described absorber to be similar to aforesaid way.

Come the refrigeration machine steam of flash-pot 16 to contact the concentrated absorbent solution of leaving absorber shower nozzle 101.The refrigerant vapour that is caused is absorbed into can the described steam of condensation in the lower liquid of volatility.Discharge its evaporation heat, and discharge the dissolving heat that produces owing to described absorption process.The heat that is produced enters radiator 14 by managing 130.

Pump 103 exports the compound-refrigerating agent that 107 sucking-offs are rebuild by the compound-refrigerating agent, and forces it to enter generator 26 by pipeline 34.By heat exchanger preheating was carried out in the compound-refrigerating agent by pipeline 34 before described compound-refrigerating agent enters generator 26, employed heat may be to discharge the heat of generator by concentrating absorbent solution pipe 28.

Enter the evaporimeter 16 of this device by thermic load pipe 18 from the heat of load 12.Evaporimeter 16 is heat exchange contact with thermic load 12, to realize described heat exchange.When liquid flows out thermic load 12, detect the fluid temperature of the thermic load pipe 18 of flowing through by temperature sensor 115.When described flow direction thermic load 12, detect the temperature of the liquid of the thermic load pipe 18 of flowing through by temperature sensor 116.Respectively sensor 115 is connected with sensor 118 with control circuit 135 by control circuit 133.By control circuit 137 controller is connected with adjustable frequency driver 120.By control circuit 139 adjustable frequency driver 120 is connected with pump 131.By the pump output of adjustable frequency driver 120 according to the FREQUENCY CONTROL pump 111 of the AC power that flows to driver 120.

Controller 118 also is connected with sensor 117 by control circuit 140.By the temperature of 30 li in temperature sensor 117 detection pipelines, transfer to radiator 14 by this pipeline from the heat of absorber 20.Controller 118 also utilizes by the temperature of temperature sensor 117 detected pipelines 30 and controls adjustable frequency driver 120.

When controller 118 detects when changing in the necessary thermic load by temperature sensor 115,116 and 117, regulate adjustable frequency driver 120 by it, and and then regulate pump 111.For example, if controller 118 detects the increase of thermic load, it can improve the frequency of described adjustable frequency driver 120, can improve the speed of pump 111 like this, thereby improve the flow of the concentrated absorbent solution flow to absorber shower nozzle 101, and then this can improve the pressure differential in the absorber 24 again, cause more refrigerant vapour to flow to absorber 24 by evaporimeter 16, cause cold-producing medium faster speed evaporation in evaporimeter 16, thereby improve the refrigeration capacity of system 10 rapidly.On the contrary, when controller 118 detected the reduction of thermic load, it can reduce the speed of pump 111, so that the refrigeration capacity of reduction system 10.--and therefore reducing its flow proportional--to zero, can stop the flow that all flow to absorber shower nozzle 101, thereby effectively refrigeration capacity be reduced to 0 if controller 118 reduces the speed of pump 111.

Siphon away from the reconstruction compound-refrigerating agent that absorbs tank 24c by pump 103, and force it to enter generator 26, this pump can be a variable displacement pump, and it can also change the refrigeration capacity of this device by the total flow that change to flow into and flow out the absorbent solution of absorber 24 and compound-refrigerating agent.The another kind of method that in this way further changes refrigeration capacity is that a variable displacement pump is provided on pipeline 28 rather than pipeline 34, or a pump is provided respectively on each pipeline.

Fig. 3 represents another embodiment of the present invention.Be connected with flow control valve 111 by a control circuit 139 at Fig. 3 middle controller 118.Flow control valve 111 is divided from the more stable concentrated absorbent solution of the flow of generator 26 by pipe 28, and 28a enters absorber shower nozzle 101 by pipe, enters by pipe 28b and absorbent mouth 130 to absorb tank 24c.By controller 118 control flow control valves 111, change by evaporimeter 26 inflow absorber shower nozzles 101 with by evaporimeter 26 ratio of the concentrated absorbent solution of inflow absorber groove 24c again.Flow control valve 111 can be a proportioning valve, is installed in the simple valve on any among pipeline 28a and the 28c, or is installed in the separate valves on these two pipelines.

When the controller in this embodiment 118 detected the variation of thermic load, it can corresponding adjustment flow control valve 111.For example, if controller 118 detects the reduction of thermic load, it can be adjusted flow control valve 111 and change the partly or entirely concentrated absorbent solution that enters absorption tank 24c through pipeline 28, and then can reduce the flow of the concentrated absorbent solution of inflow absorber shower nozzle 101 again, reduce the pressure differential in the absorber 24, cause still less refrigerant vapour by evaporimeter 16 inflow absorbers 24, cause cold-producing medium in evaporimeter 16 with slower speed evaporation, and finally produce less refrigeration capacity.

Therefore, confirmed already absorption type refrigerating unit corresponding to the volume controlled of load variations faster than existing system and method, particularly when this device especially true during with low refrigeration capacity work.In addition, described device can be worked in bigger working range and can not damaged response or need bigger cold-producing medium storage bin.Flowing under the flow rate condition of absorber shower nozzle not according to described method adjusting, in order to reach the low capacity work of this scope, the needed cold-producing medium storage bin of suitable system is bigger more than 3 times than of the present invention.Set up a kind of specific embodiments of described apparatus and method already, these apparatus and method can respond quickly than existing apparatus and method, and need not obviously increase volume of a container.

Referring to Fig. 4, disclosed a second aspect of the present invention.A two-stage sorption refrigerator 400 comprises a cryogenerator 401 and a condenser 402 that is enclosed in the first fluid sealing shell 403.The second fluid sealability shell 404 that comprises an evaporimeter 405 and an absorber 406.A high-temperature generator 407 that is enclosed in the 3rd fluid sealability shell 408.Described absorber 406 comprises a heat exchanger 409, provides cooling fluid by pipeline 410 to this interchanger, and described cooling fluid also passes through condenser 402 by the cooling fluid source (not shown).Described cooling fluid leaves absorber exchange device 409 by passage 410, and enters condenser heat exchanger 411, and returns the cooling fluid source (not shown).

The cold-producing medium and the absorbent of various adequate types can be used for two-stage sorption refrigerator of the present invention.Being included in such as the lithium bromide absorbent solution in the cold-producing medium of water is that other people is satisfied.This paper said " concentrated solution " speech is meant the solution that concentrates in the absorbent." weak solution " is meant the solution that is diluted in the absorbent.

From such as the vapor stream in the source of evaporimeter (not shown) by the high-temperature generator heat exchanger 412 of steam channel 413 through high-temperature generators 407.Described steam channel 413 is sent condensate back to described vapour source by condensate heat exchanger 414.Certainly, be understandable that, can the thermal source that other is suitable be used for the concentrated absorbent solution of high-temperature generator 407.(for example, described high-temperature generator can with heating between the burner).Heat from the condensed steam in the high-temperature generator heat exchanger 412 causes the refrigerant solution in the high-temperature generator 407 to evaporate, thereby produces refrigerant vapour and concentrate described absorbent solution.

The refrigerant vapour that is produced in high-temperature generator 407 enters cryogenerator heat exchanger 456, enters cryogenerator 401 and this generator is heated condensation in condenser 402 then by refrigerant vapour passage 415.Weak solution in the cryogenerator 401 by with refrigerant vapour passage 415 in refrigerant vapour carry out heat exchange and be evaporated, and condensation in condenser 402 equally.The concentrated solution that at least a portion produces in cryogenerator 401 is transported to high-temperature generator pump 417 by four-way 416, and is pumped into high-temperature heat exchanger 419 by passage 418.In high-temperature heat exchanger 419, have a part of concentrated solution at least in passage 418, be transported in the process of high-temperature generator 407 high temperature concentrated solution by the passage 420 of flowing through at it and carry out heat exchange and be preheated.The a part of concentrated solution of passage 418 of flowing through flows into condensate heat exchangers 414 by passage 421, and here the condensate in it and the condensate passage 413 is heat exchange relationship, and then converges with solution in the passage 418, and is transported to high-temperature generator 407.

The high temperature concentrated solution flows into high temperature concentrated solution gatherer 422 by high-temperature generator 407 by passage 420 by high-temperature heat exchanger 419.High temperature concentrated solution from gatherer 422 mixes at mixing point 425 places with the low temperature concentrated solution that flows out cryogenerators 401 by second channel 424 by third channel 423 outflows.Concentrated solution after the merging flows into low temperature heat exchanger 426 by described mixing point 425 by first passage 427, enters absorber 406, absorber jet pump 429 and passage 430 by five-way road 428 then.

Liquid refrigerant from condenser 402 enters evaporimeter 405 by passage 431.Liquid refrigerant is evaporated in evaporimeter 405, thereby removes the heat of the cooling fluid of the passage 432 of flowing through by evaporator heat exchanger 433.This cooling fluid is recycled to a thermic load, so that form needed circulation.

Because absorber 406 is the vapor communication state with evaporimeter 405, described absorbent solution can absorb the refrigerant vapour of flash-pot 405, thereby removes the heat from evaporator section.At least a portion is collected in the gatherer 434 by the refrigerant liquid that evaporator heat exchanger 433 flows out.Described refrigerant liquid flows to reservoir vessel 436 by passage 435 by gatherer 434.Refrigerant liquid is transported to evaporimeter jet pump 438 by passage 437 by reservoir vessel 436, and this jet pump is by passage 439 refrigerant conveying liquid, so that be ejected in the evaporimeter 405 by shower nozzle 440.

Weak solution from absorber 406 flows to cryogenerator 401 by passage 441, cryogenerator pump 442, passage 443, low temperature heat exchanger 426 and passage 444, here is concentrated.In described low temperature heat exchanger 426, described concentrated solution with form heat exchange relationship from the weak solution of absorber 406 so that described weak solution is carried out preheating, described weak solution is transported to cryogenerator 401.

Concentrated solution from low temperature heat exchanger 426 flows to absorber jet pump 429 by five-way road 428.Force described concentrated solution to enter absorber 406 by absorber jet pump 429 by passage 430 and by absorber shower nozzle 445.A passage 446 is set between reservoir vessel 436 and absorber jet pump 429.Valve 447 controls of flow between reservoir vessel 436 and the absorber jet pump 429 by under normal circumstances closing.

When the concentrated solution generation crystallization in the low temperature heat exchanger 426, flowing of the concentrated solution in the first passage 427 is reverse because crystallization is stopped up.This effect makes it to detect crystallization by the temperature of monitoring particular solution stream.

Temperature by the concentrated solution in the four-way 416 of four-way temperature sensor 448 detections between cryogenerator 401 and high-temperature generator pump 417.Temperature by the concentrated solution in the second channel 424 of second channel temperature sensor 449 detections between cryogenerator 401 and mixing point 425.Detect the temperature of the high temperature concentrated solution in the third channel 423 by third channel temperature sensor 450.Detect the temperature of the concentrated solution in the five-way road 428 by five-way channel temp sensor 451.

The manipulation of described Absorption Refrigerator is normally finished by executor 453, and this executor has treatment circuit, for example, and a microprocessor.Controller 453 can be a feedback kind, and it comprises an input signal receiver 454 and a generator output signal 455.The output control signal is to be produced according to the signal that input signal receiver 454 receives by signal generator 455.

During normal stable state operation, equal substantially by second channel temperature sensor 449 detected temperature by four-way temperature sensor 448 detected temperature, and regulate heat input to high-temperature generator 407 by described control system, so that temperature by the concentrated solution in the five-way channel temp sensor 451 detected five-way roads 428 is remained on than high about 15 of the crystallization temperature of this concentrated solution.

When the concentrated solution generation crystallization in the low temperature heat exchanger 426, the fluid by first passage 427 begins owing to stop up oppositely.Therefore, begin to surpass by second channel temperature sensor 449 detected temperature by four-way temperature sensor 448 detected temperature.According to the present invention, send a crystallization alarm when meeting or exceeding by four-way temperature sensor 448 detected temperature with by the mathematical mean of third channel temperature sensor 450 detected temperature by second channel temperature sensor 449 detected temperature, and the indication correction operation, described mean temperature is determined by following formula:

Wherein:

T ₃Be by the detected temperature of third channel temperature sensor; With

T ₄Be by the detected temperature of four-way temperature sensor;

This temperature value is called as " closing temperature ".

If meet or exceed described closing temperature by second channel temperature sensor 449 detected temperature, then described control system begins to take measures so that the crystallization recovery of the concentrated solution in the low temperature heat exchanger 426 is normal.

In the recovery pattern, described control system is taked following steps:

1. close the thermal source of cryogenerator 401 and high-temperature generator 407, stop producing concentrated solution.In embodiment shown in Figure 4, this purpose is to realize by the steam supply that steam off valve 452 cuts off high-temperature generator 407;

2. by closing the circulation of high-temperature generator pump 417, cryogenerator pump 442, absorber jet pump 429 and evaporimeter jet pump 438 termination absorbent solutions;

3. allow weak solution flow to the solution of penetrating in the rare described absorber of solution of pump 429 usefulness by open valve 447 by reservoir vessel 436;

4. after about 3 minutes, about 5 minutes clock times of cryogenerator pump 442 that the concentrated solution of described crystallization is restarted and high-temperature generator pump 417 usefulness wash away.

5. cryogenerator pump 442 and high-temperature generator pump 417 are closed about 3 minutes (do like this is because described pump restarting in step 4 may cause provisional crystallization again) once more;

6. restart the thermal source of high-temperature generator 407.But, by the heat input of described control system adjusting to high-temperature generator 407 and cryogenerator 401, so that the temperature of leaving the concentrated solution of low temperature heat exchanger 426 by five-way road 428 remains on certain level, make the crystallization temperature and the difference between the actual temperature of concentrated solution at this position improve about 5 °F (3 ℃) than existing control difference; With

7. after having experienced described 3 minutes clock times of step 5, all pumps are all restarted.

Described control system is programmed, so that this system is with pre-determined number, the described recovery routine of twice execution for example.If detected crystallization number of times is higher than described pre-determined number, this control system can be closed all working of described Absorption Refrigerator, so that carry out necessary maintenance, corrects the described crystallisation problems that repeats to take place.

Fig. 5 is the flow chart of expression the invention described above recovery process.

Below another aspect of the present invention will be described.For example, the main effect that is used for the control system on the water refrigerator is process management.Process management comprises that the water of leaving away that keeps cooling is in the temperature of needs.Therefore, described control system must be made rapid response to technological fluctuation, so that reduce the described coolant-temperature gage and need difference amplitude and duration between the set point of leaving away.In order to reduce described difference, can adjust described control response to help overall action.

As indicated above, under some occasion, may encounter problems.For example, when carrying out the change of set point, and during setting, big integration increment can cause this system obviously to overregulate described set point.By filtering the change of set point, can eliminate and overregulate, and don't can reduce response technological fluctuation.

Therefore, setting wave filter of the present invention has another functional advantage.In the pre-boot process of this refrigeration machine, the set point of filtration is predisposed to the existing coolant-temperature gage of leaving away.When closed-loop path control was carried out, the initial error of the coolant-temperature gage of leaving away was 0.When the set point that filters during near desired set point, closed-loop path control will detect little error.This control system will be followed the tracks of described filtration set point over time.It is the sedimentation time that described filtration set point reaches the described used time of expection set point.By with the described sedimentation time as an adjustable input, the set point of filtration can replace being called as the effect of " soft loading " function.To filter the advantage that set point is used for soft loading at this control system front end is that it has used and has been used to leave away the control of coolant controlled closed-loop path already.The enforcement and the confirmation of described function have been simplified like this.

The embodiment of secondary binomial wave filter that is designed to the described control set point of pre-filtering is shown in the block diagram of Fig. 6.There is shown control system 500.Control system 500 comprises a backfeed loop 505, and this loop has a summation joint 508.Fig. 6 also shows generally with the 510 binomial wave filters of numbering.Binomial wave filter 510 is connected and installation is used to receive set point input 515.Subsequently, binomial set-point filter 510 can provide a set point output that is numbered 520 filtration.The set point 520 that filters is connected with backfeed loop 505 with control system 500 by a summation joint 508 as an input.As shown in Figure 6, binomial set-point filter 510 is arranged on input one side of control system 500.

Fig. 7 represents the response to a staged input.For example, described control system is that critical-damping is to underdamping secondary function (referring to Fig. 7) to the ideal response of staged input.Described wave filter receives a staged input (in typical method, the described water temperature set point of leaving away is changed) and imports a critical-damping secondary output.If the sedimentation time of described wave filter little to the foot in cut-off frequency was in the bandwidth range of open loop system, the pre-filtering set point can not increase the sedimentation time.

As shown in Figure 7, described input is the staged input of representing with the alphabetical I of numbering.The response curve of one-level wave filter is represented with the alphabetical F of numbering.Described one-level filter response F is having a steep slope near the starting point place, and this can cause partly producing a unexpected discontinuity in the beginning of described staged input.Opposite with described one-level response, also show a secondary response curve of representing with the alphabetical S of numbering.As shown in Figure 7, this secondary response curve S partly has slow slope in the beginning of this curve, so that provide a more level and smooth transition according to described staged input.As shown in Figure 7, one-level response F and staged input I's converges slightly faster than secondary response S.But, secondary response S is in the acceptable response time limit.

Fig. 8 is the curve map of a series of curves of expression.This curve is represented the work of a binomial set-point filter 510 on the absorption water refrigerating machine, and this wave filter moves according to apparatus and method of the present invention.The curve map of Fig. 8 is represented temperature on its vertical axis, and represents the duration on its horizontal axis.

As shown in the figure, initial a few minutes relate to burner and the pump that starts described refrigeration machine.For initial 12 minutes, this refrigeration machine began preheating, and this system moves shown a period of time.Big on 12 minutes time point, remove described control, and that binomial set-point filter 510 is predisposed to is identical with the coolant-temperature gage of leaving away.In case remove described control, this system preferably follows filtration set point shown in Figure 8.

In Fig. 8, water temperature begins to be approximately 82 °F, but filter configuration point shows that FS drops to 44 °F.The cooling water that leaves the evaporimeter curve that is numbered CWL is also followed the downward direction of filtration set point FS shown in Figure 8.Filter set point FS and leave the error of the cooling water time of CWL and be fed back to described control system.Fig. 8 shows, big when this error has just started unlike this refrigerator, set point is 44 ° when just starting, and cooling water temperature is 80-83 °.Therefore, the binomial set point in this embodiment of the present invention filters and eliminated the big error that occurs when just starting.The binomial of set point filters cooling water temperature is reduced with milder speed.In addition, as shown in Figure 8, can not overregulate with the cooling water generation of filtering setpoint profile FS leaving evaporimeter curve C WL.Also show the cooling water that enters evaporimeter curve C WE.The cooling water that enters evaporimeter curve C WE shows that in case its temperature reaches near 51 ° of levels shown in Figure 8, a loop control unit attempts to keep the described temperature that enters.Fig. 8 represents the cooling water that enters evaporimeter is slightly overregulated.When water temperature descended, load increased.

Because binomial set-point filter 510 is arranged on front end or importation (referring to Fig. 6) of described control system, opposite with output, its response is progressively, as shown in Figure 7.If there is not binomial wave filter 510, described absorption refrigeration chance is because 44 ° set point difference brings up to 100% with load at once.Because water temperature rising speed is very fast, like this, this refrigerator can begin to limit its loading again.More slowly in the system, this process can not well be worked, because this refrigeration machine can reach at full capacity before water temperature changes at some.Therefore, existing soft load mode reaction force is bigger, and is difficult to implement.But, on the contrary, the binomial set point pre-filtering of carrying out at the input phase of this control system has overcome these problems, and is as indicated above.

Fig. 9 illustrates the Absorption Refrigerator with constant load and is running into situation about occurring when set point descends.Referring to Fig. 9, described decline is to reduce to 49.5 ° from about 55 °.In addition, also show the cooling water that enters evaporimeter according to curve C WE.Fig. 9 is similar to response shown in Figure 7, and only its mode is opposite.

Fig. 9 represents that the operator resets the situation of water temperature in the morning, for example, resets after chilling temperature being set at the cooling refrigeration machine temperature of comfort temperature of higher temperature night.Therefore, the user wishes to reduce by day described cooling water temperature.

Therefore, Fig. 9 shows that described set point was reduced to 49.5 °F from 55 °F already.The secondary response of binomial set-point filter is similar to response shown in Figure 7.Described water temperature descends with stable speed, and reaches set point gradually.Chain-dotted line represents to leave the cooling water of evaporimeter.If there is not described binomial set point to filter, the initial reduction of water temperature might once produce 60 temperature error.But, the filtration of the set point that carries out with binomial set-point filter of the present invention only can slowly increase its load, replaces this refrigerator being risen to full load with a series of less variations at once.Therefore, the present invention more similarly be series of process fluctuation in action, these act on all in same series, replace the big jump of refrigeration machine once being brought up to 100% running status with this.Consequently, the present invention has avoided described refrigeration machine is loaded 100%, and makes temperature descend rapidly so that the very fast shutdown again of refrigeration machine.

The practical filter set point can converge with the described sedimentation time, but need not reset, up to this refrigeration machine shutdown.Then this refrigeration machine is set to the actual coolant-temperature gage of leaving away.Perhaps this refrigerator is followed actual set point.

Another advantage of the present invention is under reverse situation, and for example, set point becomes 55 °F, the work that the present invention equally can be favourable from 49 °F.For example, in the known refrigeration machine of major part, exist certain and be called as the differential problem that stops.If people attempt set point is brought up to the specified quantitative of the described differential shutdown of about representative, this refrigeration machine can the shutdown at once owing to the peaked upset of described differential shutdown.But, because the character more slowly of binomial set-point filter mentioned above, will improve its load gradually, and improve the temperature of its water of leaving away and can not shut down according to the refrigeration machine of the principle operation of embodiment of the present invention.

Figure 10 is an another embodiment of the present invention, and Figure 10 represents the Absorption Refrigerator as the part of big technology.For example, absorber shown in Figure 10 has adopted a binomial set-point filter 510 as indicated above.In this purposes, described Absorption Refrigerator only is the part of a relatively large holonomic system.In this purposes, may need refrigeration machine control, so that implement multiple tracking control function shown in Figure 10.In such application, the response of refrigeration machine is determined by binomial set-point filter 510.This makes the design ratio of technology controlling and process shown in Figure 10 be easier to, because the dynamics of refrigerator was fully aware of already.

Therefore, utilization of the present invention is avoided overregulating to the filtration of set point, has kept the response to technological fluctuation simultaneously again.As indicated above, can use the one-level wave filter; But, by finding relatively that with the response of firsts and seconds wave filter shown in Figure 7 described two-stage filter has milder initial response.On the contrary, the initial response of one-level wave filter is quite unexpected.

One-level wave filter or two-stage filter can the digital form computings.It is favourable doing like this, can use computer programming easily because the digitalization operation of described wave filter and mathematics embody.In addition, this programmability makes and a microcomputer can be used for control system.Following method can be used to develop a kind of one-level digitized filtered device of absolute version.As indicated above, consequently be convenient to the form of programming or similar type with microcomputer.

At first, use one-level Laplace transfer function: $G\left(s\right)=\frac{a}{s+a}$

Wherein a is the cut-off frequency of this wave filter.

Then, calculate pulse transmission function by following formula:

Γ (s)=∑ F (p) (1/1-e ^{-(s-p) .T}) residue

F(p)＝(1-e ^St/s)(a/s+a) _s＝p

Wherein, F (p) is the zero level distortion of Laplace, and s wherein replaces with p.

The limit of F (p) is zero-sum-a.Therefore, described pulsed transfer function is: Γ (s)=[(1-e ^-s.T/ p) (a) (1/1-e ^{-(s-p) .T})] _P=-a[(1-e ^-s.T) (a/p+a) (1/1-e ^{-(s-p) .T)}] _P=0

Γ(s)＝[(1-e ^-s.T)(-1/1-e ^-(s+a).T)]＝[(1-e ^-s.T)(1/1-e ^-s.T)]

Γ(s)＝e ^-s-.T(1-e ^-a.T)/1-e ^-s.T.e ^-a.T)

Realize conversion by following replacement to the Z territory:

Z ^-1＝e ^-s.T

Γ(z)＝(Z ^-1)(1-e ^-a-·T)/1-(Z ^-1)·e ^-a.T

At last, be converted into form able to programme in order to following method:

Γ(z)＝O(z)/I(z)

O(z)·[1-(Z ^-1)·e ^-a.T]＝I(z)·[(Z ^-1)·(1-e ^-a.T)]

O(z)·[1-e ^-a.T)·In-1+e ^-a.T·O _n-1

N=2...10 step :=10...100 sets sedimentation time :=5-60 minute

O ₀：＝0 I _n-1：＝0

O ₁:=0 I _Step:=10

T:=5 time second _n:=nT/60:

α：＝ω _c

O _n＝(1-e ^-a.T)·I _n-1+e ^-a.T·O _n-1

Therefore, can carry out digitalization operation with form able to programme to above-mentioned equation with a computer or microprocessor, similarly, the binomial wave filter can be represented with form able to programme.The binomial wave filter is defined as having identical and real limit.The characteristics that the binomial wave filter also has slow response, can not overregulate.The form able to programme of binomial wave filter is to determine with the basic skills identical with the one-level wave filter.Main equation provides below.

The Laplace form:

G(s)＝ωc ²/(s+ω _c) ²

Z distortion: G (z)=z (1-e ^{-T. ω c}-ω _cT-e ^{-T. ω c})+e ^-T.c(e ^{-T. ω c}-1+ ω _cT)/(z-e ^{-ω c.T}) ²

The algorithm of a kind of embodiment of two-stage filter 510 is as follows:

α=e ^{Δ t* cut-off frequency}

Coefficient 1=1-α-cut-off frequency ^*Δ t ^*α

Coefficient 2=-α ^*(1-α-cut-off frequency ^*Δ t)

Coefficient 3=2 ^*α

Coefficient 4=1-coefficient 1-coefficient 2-coefficient 3

Wherein

Δ t=circulation timei

(calculating of α can realize by a series of expansion coefficient.3 times launch to obtain suitable result:

α=1-Δ 2t ^*Cut-off frequency+Δ t ^*Δ t ^*Cut-off frequency ^*Cut-off frequency/2.

Therefore, as follows with the binomial wave filter of form performance able to programme: the set point of filtration _n=coefficient 1 ^*Set point _N-1+ coefficient 2 ^*Set point _N-2+ coefficient 3 ^*The set point that filters _N-1+ coefficient 4 ^*The set point that filters _N-2

In addition, the one-level with PID controller is provided with and will plays the effect of secondary.Therefore, this system can follow the secondary set point naturally.The response of secondary function may be characteristics with natural frequency and the damping that determines this function.By selecting binomial function (two identical limits), critical damping is carried out in described response, this means that described response is subjected to fast as far as possible damping, and can not overregulate.Therefore, have only a parameter, that is exactly to need the sedimentation time to set.

By the described set point of pre-filtering, when this set point changes, can not leave away unexpected, the big error of coolant-temperature gage of this control system.When the water temperature set point generation staged of leaving away changed, the set point of described filtration changed sub-fraction with described stepped each control cycle, and therefore, this control only little error can occur aspect the coolant-temperature gage of leaving away, and correspondingly reacts.When the set point that filters continued to change, this control system can occur little, but the error range that continues, and continue to change the coolant-temperature gage of leaving away.The set point of described filtration will begin progressively near the actual set point.Because the set point that filters is lentamente near the actual set point, this control will be played the effect (perhaps reducing described overregulating at least) that the coolant-temperature gage that prevents to leave away departs from the set point of expectation.

Although illustrated and illustrated concrete element of the present invention, embodiment and purposes already, ought to be understood that the present invention was not limited to these aspects, after reading above-mentioned explanation because those skilled in the art particularly can improve.Therefore, we wish to cover the improvement of having adopted described feature with appended claims, and these improvement belong to design of the present invention and scope.

Claims (19)

1. the Absorption Refrigerator of a variable refrigerating capacity comprises:

A. one is used to produce the generator that concentrates absorbent solution and cold-producing medium;

B. absorber has one and is used to surface contact portion that described concentrated absorbent solution is contacted with described cold-producing medium;

C. container;

D. at least one is used for first fluid streams of described concentrated absorbent solution is transferred to the surface contact portion of described absorber by described generator, and second burst of concentrated absorbent solution is transferred to the pipeline of described container by described generator; With

E. fluid dram flow regulator that is used to change the flow proportional of described first and second fluid streams.

2. refrigeration machine as claimed in claim 1, the surface contact portion of wherein said absorber comprises at least one shower nozzle.

3. refrigeration machine as claimed in claim 1, wherein, the surface contact portion of described absorber comprises at least one shower nozzle and at least one heat exchanger.

4. refrigeration machine as claimed in claim 1, wherein, described absorber also comprises a flute profile part.

5. refrigeration machine as claimed in claim 4, wherein, described container is the flute profile part of described absorber.

6. refrigeration machine as claimed in claim 1, also be included in the temperature sensor at the place, control point of described refrigeration machine, wherein, described fluid dram flow regulator operationally is connected with this temperature sensor, so that according to the flow proportional by described first and second fluid streams of the detected temperature change of this temperature sensor.

7. refrigeration machine as claimed in claim 1, wherein, pipeline by a branch is transferred to described absorber with described concentrated absorbent solution by described generator, the pipeline of described branch comprise one be used for described first fluid streams transfer to described absorber surface contact portion first branch and be used for described second fluid streams is transferred to second branch of described container.

8. refrigeration machine as claimed in claim 7, wherein, described fluid dram flow regulator is positioned on the branch point of described branch line.

9. refrigeration machine as claimed in claim 7, wherein, described fluid dram flow regulator is positioned in first branch of described branch line.

10. refrigeration machine as claimed in claim 1, wherein, described fluid dram flow regulator comprises at least one valve.

11. refrigeration machine as claimed in claim 1, wherein, described fluid dram flow regulator comprises at least one variable capacity pump.

12. refrigeration machine as claimed in claim 1 also comprises at least one variable capacity pump, is used to change the total flow that is flowed to the concentrated absorbent solution of described absorber by described generator.

13. a method that is used to change the refrigerating capacity of absorption type refrigerating unit, this method may further comprise the steps:

A. provide one to be used to produce the generator that concentrates absorbent solution and cold-producing medium;

B., an absorber is provided, and this absorber has one and is used to surface contact portion that described concentrated absorbent solution is contacted with described cold-producing medium;

C., a container is provided;

D., first burst of concentrated absorbent solution that is flowed to the surface contact portion of described absorber by described generator is provided, and second burst of concentrated absorbent solution that is flowed to described container by described generator is provided;

E. determine the desirable refrigerating capacity of described device at special time;

F. change the flow proportional of described first and second fluid streams, so that provide at least near described desirable refrigerating capacity.

14. as the method for claim 13, wherein, described concentrated absorbent solution is injected into the surface contact portion of described absorber.

15., wherein, determine that the method for the desirable refrigeration capacity of described device may further comprise the steps as the method for claim 13:

A. provide a temperature sensor, so that measure the temperature at place, control point in the described device; With

B. by locating the described desirable refrigeration capacity of detected temperature computation at described control point at special time.

16. as the method for claim 13, use a flow control valve at least, to change the flow proportional of described first and second fluid streams.

17. as the method for claim 13, use variable capacity pump at least, to change the flow proportional of described first and second fluid streams.

18. as the method for claim 13, wherein, by the refrigerating capacity that provides at least one variable capacity pump further to change described device, to change the total flow that flows to the concentrated absorbent solution of described absorber by described generator.

19. as the method for claim 13, wherein, by described flow proportional being reduced to 0 and the refrigerating capacity of described device is reduced to 0.

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