CN2765110Y

CN2765110Y - Natural actuating medium eclipsed type refrigerating plant

Info

Publication number: CN2765110Y
Application number: CN 200420056008
Authority: CN
Inventors: 马一太; 宁静红; 李敏霞; 苏维诚
Original assignee: Tianjin University
Current assignee: Tianjin University
Priority date: 2004-12-22
Filing date: 2004-12-22
Publication date: 2006-03-15
Anticipated expiration: 2014-12-22

Abstract

The utility model can provide a lapped type refrigerating device using green natural actuating medium R290 and CO2 as refrigerant, and the utility model can used for the low temperature environment in the business, the industry, the medical treatment, etc. The utility model is mainly provided with a compressor, an oil separator, a condenser evaporator, a CO2 liquid reservoir, a dry filter, an expansion valve, etc. A refrigerating device is composed of two single-stage compression refrigeration circulation systems. The refrigerating device can use R290 as the refrigerating actuating medium in the high-pressure stage circulation system, and the refrigerating device can use CO2 as the refrigerating actuating medium in the low-pressure stage circulation system. R290 and CO2 can carry out heat exchange in the condenser evaporator so as to form a lapped type refrigerating circulation device. The utility model can provide-30DGE to-45DGE cryogenic temperature environment in a freezing box. The utility model can control flow quantity of CO2 entering the freezing box according to the requirement so as to regulate the temperature in the freezing box. The utility model has the advantages of simple structure and green environmental protection. The low-pressure stage circulation system of CO2 can not produce pollution for the environment in the freezing box. The high-pressure stage circulating system side of R290 can be arranged at the outdoor space.

Description

Natural refrigerant cascade refrigeration device

Technical field

The utility model belongs to the refrigerating plant under a kind of low temperature environment.

Background technology

The manually synthetic refrigeration working medium of chloro-fluoro-carbon kind has destruction and produces greenhouse effects ozone layer, refrigeration industry is faced a severe challenge, depletion of the ozone layer and global warmization have become increasingly serious global environment problem, seek problem efficient, that the environmental protection refrigeration working medium has become the common concern of current international community.From long-term safety to environment, should avoid the non-natural refrigerant that uses those finally can be discharged in the biosphere and influence the ecological balance as far as possible, reinstating natural refrigerant again is a kind of selection as safe as a house.In the application of refrigeration system, if evaporating temperature and condensation temperature differ greatly, and the cryogenic temperature requirement is lower again, still can not find a kind of suitable cold-producing medium at present, not only satisfies the not too high while of condensing pressure but also satisfy the not too low requirement of evaporating pressure.Can adopt the cascade refrigeration system to this kind operating condition, it can evaporate condensation at ambient temperature again under low evaporating temperature.The cascade refrigeration system generally is made up of two single stage compress kind of refrigeration cycle, adopt R22 and R13 to make cold-producing medium usually, but R22 and R13 not only destroys atmospheric ozone layer, and can produce serious greenhouse effects.Therefore need to adopt new cold-producing medium to satisfy the needs of cascade refrigeration system.CO ₂As refrigeration working medium a lot of advantages are arranged, it has, and pipeline size is less, the pump energy consumption is low, heat exchange efficiency is high and do not have characteristics such as etching problem.Operating condition CO at above-mentioned proposition ₂Compare with other cold-producing medium, even CO when cryogenic temperature is low ₂Viscosity also very little, heat transfer property is good because utilize latent heat, its refrigerating capacity is quite big.Therefore the relevant personnel once proposed NH ₃/ CO ₂The scheme of cascade refrigeration circulation, hiigh pressure stage NH ₃, low-pressure stage CO ₂Make cold-producing medium, but NH ₃Can pollute environment and food.R290 (propane) is used for the existing history for many years of large-scale refrigerating plant in petrochemical industry as working medium, itself and NH ₃Equally have good thermal performance, cheap, and also R290 and plain oil and frame for movement material have compatibility, ODP=O, and GWP is very little, does not need to synthesize, and does not change the content of nature hydrocarbon, and greenhouse effects are not directly influenced; The refrigerating effect per unit swept volume of propane is bigger, is well suited for Rotary Compressor.Heat transfer property is slightly inferior to ammonia, but than CFC, HCFC and HFC are far better.Therefore parameters extremely close with R22 (seeing Table 1) such as the Main physical character of propane such as normal boiling point, freezing point, critical-temperature, critical pressure adopt propane former machine and production line not to be transformed, and directly can belongs to direct substitute.

Summary of the invention

The purpose of this utility model provides a kind of can be used under the low temperature environments such as commerce, industry and medical treatment with green natural refrigerant R290 and CO ₂Cascade refrigeration device for cold-producing medium.

Followingly narrate with reference to 1 pair of structural principle of the present utility model of accompanying drawing.Natural refrigerant cascade refrigeration device mainly has: CO ₂Compressor 1, CO ₂Oil eliminator 2, condenser/evaporator 3, CO ₂High pressure reservoir 4, device for drying and filtering 5, CO ₂Low-pressure oil storage 6, stop valve 7, household freezer 8, CO ₂Vapour liquid separator 9, R290 compressor 10, R290 oil eliminator 11, condenser 12, R290 reservoir 13, device for drying and filtering 14 and expansion valve 15 etc.Refrigerating plant is made of two single stage compress kind of refrigeration cycle: the low-pressure stage circulation side is by CO ₂Compressor 1, CO ₂Oil eliminator 2, condenser/evaporator 3, CO ₂High pressure reservoir 4, device for drying and filtering 5, CO ₂Low-pressure oil storage 6, stop valve 7, household freezer 8, CO ₂Vapour liquid separator 9 and expansion valve 15 are formed; The hiigh pressure stage circulation side is made up of R290 compressor 10, R290 oil eliminator 11, condenser 12, R290 reservoir 13, device for drying and filtering 14, expansion valve 15, condenser/evaporator 3, water tank 16 and water pump 17.Adopting R290 in the hiigh pressure stage circulation is refrigeration working medium, adopts CO in the low-pressure stage circulation ₂Be refrigeration working medium, R290 and CO ₂In condenser/evaporator 3, carry out heat exchange, form the cascade refrigeration EGR.CO ₂The pipe side entrance 18 of the outlet of oil eliminator 2 and condenser/evaporator 3 joins CO ₂The outlet 20 of the inlet of high pressure reservoir 4 and condenser/evaporator 3 pipe sides is joined.The outlet drying filter 14 of R290 reservoir 13 and expansion valve 15 join with the inlet 19 of condenser/evaporator 3 shell-sides, and R290 compressor 10 inlets join with the outlet 21 of condenser/evaporator 3 shell-sides.The outlet of R290 oil eliminator 11 and condenser 12 pipe side entrances 22 join, and the pipe side outlet 24 of the inlet of R290 reservoir 13 and condenser 12 joins.Cooling water is provided by water tank 16, enters the inlet 23 of condenser 12 shell-sides through water pump 17 and stop valve, and the cooling water backwater is connected to water tank 16 by the outlet 25 of condenser 12 shell-sides.

R290 (propane) has combustibility, and its combustion limits are 2.2%～9.5%, but propane is as R290/CO ₂The high temperature circulation of cascade refrigeration circulation, be placed on machine room or outdoor, simultaneously for small-sized R290 and CO ₂Cascade refrigeration circulation because the internal circulating load of propane is little,,, can greatly reduce the possibility of leaking, so R290/CO if product structure and production technology are improved and adopt sealing material even all leak the concentration that also can not reach capacity ₂In small refrigeration systems, has very big advantage.

Description of drawings

Accompanying drawing 1 is that each assembly of the utility model connects and the kind of refrigeration cycle schematic flow sheet.

Wherein: 1-CO ₂Compressor; 2-CO ₂Oil eliminator; The 3-condenser/evaporator; 4-CO ₂The high pressure reservoir; The 5-device for drying and filtering; 6-CO ₂Low-pressure oil storage; The 7-stop valve; The 8-household freezer; 9-CO ₂Vapour liquid separator; The 10-R290 compressor; The 11-R290 oil eliminator; The 12-condenser; The 13-R290 reservoir; The 14-device for drying and filtering; The 15-expansion valve; The 16-water tank; The 17-water pump; 18-condensation evaporation organ pipe side entrance; 19-condenser/evaporator shell-side inlet; 20-condensation evaporation organ pipe side outlet; The outlet of 21-condenser/evaporator shell-side; 22-condenser tube side entrance; 23-condenser shell-side inlet; 24-condenser tube side outlet; The outlet of 25-condenser shell-side.

The specific embodiment

CO ₂Gas compresses back pressure and raises in compressor 1, through CO ₂Oil eliminator 2 comes out CO with lubricating oil separation ₂In condenser/evaporator 3, carry out entering high pressure reservoir 4 after the heat exchange condensation becomes high temperature high pressure liquid with R290, flow through behind the device for drying and filtering 5, again through expansion valve 15 throttling step-downs, become low-temp low-pressure liquid and enter low-pressure oil storage 6, heat absorption is evaporated in household freezer 8, becomes the gas of low-temp low-pressure.Cause liquid hammer, CO for having prevented that not evaporated liquid flows into compressor fully ₂Flow through and enter CO behind the vapour liquid separator 9 ₂Compressor 1 is finished the circulation of low-pressure stage.For guaranteeing CO ₂Compressor 1 lubricated, CO ₂Oil eliminator 2 isolated lubricating oil utilize difference in height to send CO in time back to ₂The crankcase of compressor 1.R290 gas compresses back pressure and raises in compressor 10, through R290 oil eliminator 11 lubricating oil separation among the R290 is gone out, and carries out heat exchange with cooling water then in condenser 12.Enter R290 reservoir 13 after the R290 condensation, the device for drying and filtering 14 of flowing through, again through expansion valve 15 throttling step-downs becomes low-temp low-pressure liquid and enters condenser/evaporator 3.In condenser/evaporator 3 with CO ₂Carry out the heat exchange evaporation, become the gas of low-temp low-pressure, enter R290 compressor 10, finish the circulation of hiigh pressure stage.The heat exchange of condenser 12 is provided by water tank 16, water pump 17.CO ₂Flow in the pipe of condenser/evaporator 3, R290 flows between package, and cooling water flows between condenser 12 packages.Because CO ₂Critical-temperature low (31.1 ℃), critical pressure height (7.4MP), said system design can guarantee CO ₂CO in the low-pressure stage circulation ₂Evaporation at normal temperatures, intensity and reliability after pressure raises.

It below is the embodiment experimental result of utilizing refrigerating capacity to do for the utility model of 4kW.CO ₂Compressor 1 is selected the semiclosed CO of Italian DORIN company for use ₂Dedicated compressor, what the R290 compressor was selected for use is the fully-closed vortex formula refrigeration compressor of U.S. COPELAND company.

Embodiment 1:

Circulation	Working medium flow kg/s	Compressor horsepower kW	Pressure of inspiration(Pi) bar	Pressure at expulsion bar	Condensing pressure bar	Evaporating pressure bar	Suction temperature ℃	Delivery temperature ℃	Condensation temperature ℃	Evaporating temperature ℃
Circulation	Working medium flow kg/s	Compressor horsepower kW	Pressure of inspiration(Pi) bar	Pressure at expulsion bar	Condensing pressure bar	Evaporating pressure bar	Suction temperature ℃	Delivery temperature ℃	Condensation temperature ℃	Evaporating temperature ℃	R290	0.01767	1.721	2.548	10.81	10.81	2.548	-19	50.42	30	-19
CO ₂	0.01496	0.8473	9.325	23.59	23.59	9.325	-42	33.67	-14	-42	R290	0.01767	1.721	2.548	10.81	10.81	2.548	-19	50.42	30	-19

Embodiment 2:

Circulation	Working medium flow kg/s	Compressor horsepower kW	Pressure of inspiration(Pi) bar	Pressure at expulsion bar	Condensing pressure bar	Evaporating pressure bar	Suction temperature ℃	Delivery temperature ℃	Condensation temperature ℃	Evaporating temperature ℃
Circulation	Working medium flow kg/s	Compressor horsepower kW	Pressure of inspiration(Pi) bar	Pressure at expulsion bar	Condensing pressure bar	Evaporating pressure bar	Suction temperature ℃	Delivery temperature ℃	Condensation temperature ℃	Evaporating temperature ℃	R290	0.01892	2.03	2.201	10.81	10.81	2.201	-23	52.94	30	-23
CO ₂	0.01464	1.1	6.286	20.94	20.94	6.286	-52	46.37	-18	-52	R290	0.01892	2.03	2.201	10.81	10.81	2.201	-23	52.94	30	-23

Utilize the utility model to can be used as medical low temperature test household freezer.-30 ℃ to-45 ℃ cryogenic temperature environment can be provided in household freezer.According to different experiment needs, by the size that adjusting enters the valve opening degree before the household freezer, control enters the CO of household freezer ₂Flow is regulated the temperature in the experiment household freezer, adapts to different temperature needs.Freezer door is provided with observation window, can observe the situation in the household freezer at any time.

Advantage of the present utility model is, simple in structure, easy to operate, environmental protection.CO ₂The low-pressure stage circulation is not polluted the experimental situation in the household freezer, and satisfies the demand of different experiments environment temperature; Because of CO ₂The refrigerating capacity of unit volume is bigger, CO ₂Compressor is relative with pipeline size less, CO ₂Low-pressure stage loop structure compactness, the ground of standing is little.The circulation of R290 hiigh pressure stage can be placed on outdoor, prevents the R290 burning of leaking.

Table 1 R22, CO ₂, the R290 performance indications

The characteristic of cold-producing medium	R22	CO ₂	R290
The characteristic of cold-producing medium	R22	CO ₂	R290	Molecular weight	86.48	44.01	44.1
The viscosity (10 of saturated liquid in the time of-15 ℃ ^-7Pa S)	2164	1341	1563	Molecular weight	86.48	44.01	44.1
	2164	1341	1563	The heat conductivility of saturated liquid in the time of-15 ℃ (W/m K)	0.1075	0.11298	0.1159
Specific volume (the m of the saturated gas in the time of-15 ℃ ³/kg)	0.07766	0.01647	0.1535		0.1075	0.11298	0.1159
	0.07766	0.01647	0.1535	Specific volume (the m of the saturated gas in the time of-40 ℃ ³/kg)	0.02058	0.03828	0.3825
Refrigerating effect per unit swept volume (kJ/m in the time of-40 ℃ ³)	1133	8422	1125		0.02058	0.03828	0.3825

Claims

1. natural refrigerant cascade refrigeration device mainly has CO ₂Compressor (1), CO ₂Oil eliminator (2), condenser/evaporator (3), CO ₂High pressure reservoir (4), device for drying and filtering (5), CO ₂Low-pressure oil storage (6), stop valve (7), household freezer (8), CO ₂Vapour liquid separator (9), R290 compressor (10), R290 oil eliminator (11), condenser (12) R290 reservoir (13), device for drying and filtering (14) and expansion valve (15), refrigerating plant is made up of two single stage compress kind of refrigeration cycle, it is characterized in that adopting R290 in the hiigh pressure stage circulation is refrigeration working medium, adopts CO in the low-pressure stage circulation ₂Be refrigeration working medium, R290 and CO ₂In condenser/evaporator (3), carry out heat exchange, form the cascade refrigeration EGR.

2. according to the described natural refrigerant cascade refrigeration of claim 1 device, it is characterized in that CO ₂The pipe side entrance (18) of the outlet of oil eliminator (2) and described condenser/evaporator (3) joins CO ₂The pipe side outlet (20) of the inlet of high pressure reservoir (4) and described condenser/evaporator (3) joins, R290 reservoir (13) outlet drying filter (14) and expansion valve (15) join with the shell-side inlet (19) of described condenser/evaporator (3), and R290 compressor (10) inlet joins with the outlet (21) of described condenser/evaporator (3) shell-side.

3. according to the described natural refrigerant cascade refrigeration of claim 1 device, the outlet and condenser (12) the pipe side entrance (22) that it is characterized in that R290 oil eliminator (11) join, the pipe side outlet (24) of the inlet of R290 reservoir (13) and condenser (12) joins, cooling water is provided by water tank (16), enter the inlet (23) of condenser (12) shell-side through water pump (17), the cooling water backwater is connected to water tank (16) by the outlet (25) of condenser (12) shell-side.