GB2133031A

GB2133031A - Cooling agent

Info

Publication number: GB2133031A
Application number: GB08327021A
Authority: GB
Inventors: Efim Semonovich Bondar; Igor Petrovich Naumenko; Valery Fedorovich Vozny; Vladimir Alexandrovic Nikolsky; Valery Mikhailovich Yagodin; Evgeny Nikolaevich Vazhnov; Vladimir Nikolaevich Orlov; Vladimir Ivanovich Tikhonov
Original assignee: VNI EX K I ELEKTRO
Current assignee: VNI EX K I ELEKTRO
Priority date: 1980-10-16
Filing date: 1983-10-10
Publication date: 1984-07-18
Also published as: DE3141202C2; AT392570B; GB2133031B; FR2492511B1; GB2085565A; PL132450B1; IT8124519A0; IT1139228B; PL233464A1; GB2085565B; GB8327021D0; FR2492511A1; ATA438981A; DE3141202A1

Abstract

Liquefaction of the cooling agent before its cooling is carried out by dissolving in the components of the mixture liquefied at the working pressure those which are in the vapour phase at the working pressure. The cooling agent includes difluorodichloromethane in the amount of 10-50 vol.%, a component having a normal boiling point within the range from -55 DEG C to 85 DEG C in the amount of 10-50 vol.%, a component having a normal boiling point within the range from -30 DEG C to 55 DEG C in the amount of 10-50 vol.%, and a component having a normal boiling point within the range from 16 DEG C to 35 DEG C in the amount of 10-75 vol.%. The use in home refrigerators of the cooling agent of the present invention considerably increases maximum specific cold capacity of the refrigeration unit.

Description

1 GB 2 133 031 A 1

SPECIFICATION

Cooling agent The invention relatesto cooling agentsforuse in 70 refrigeration, particularly forfreezing andstoring products.

Thecooling agent of the invention maybe used in the food industry, in the household and in medicine for cooling and freezing, and also in short and long term storage of any products, both food and biologic al, as well as in otherfields of technology wherever it is necessaryto obtain and maintain cold at a level of minus 240C or below at minimum energy require ments.

Our U.K. patent application GB 2 085 565A,from which this application has been divided, describes and claims a refrigeration method using a cooling agent comprising a mixture of components boiling at differenttemperatures and in which the coolant agent 85 issubjected to the following sequence of operations in the following order: compression to a working pressure, partial liquefaction to form a liquid and vapour mixture, complete liquefaction, cooling, throt tling, partial and complete evaporation of the cooling 90 agent; complete liquefaction of the cooling agent before its cooling being effected bydissolving in components of the mixture liquefied atthe working pressurethose among the componentswhich are in the vapour phase atthe working pressure.

For effecting complete liquefaction of the cooling agent, the cooling agent is preferably precompressed to a pressure between 10 and 14 kg/cM2.

In home compression refrigerators having at least two compartments, it is preferred to evaporate the cooling agent partiallyfor providing temperatures enabling freezing and long-term storage in one of the refrigeration compartments, and to evaporatethe cooling agent completelyfor providing temperatures enabling a short-term storage of products, the cooling 105 agent being preferably throttled to a pressure between 0.5 and 3 k g1CM2.

The cooling of the present invention contains difluorodichloromethane in an amount of 10 to 50 vol.%, at least one component having a normal boiling point within the range from -WC to -SWC in an amount of 10 to 50 vol.% such as C02, trifluoromonochloromethane, ortrifluoromonobromomethane, a component having a normal boiling pointwithin the rangefrom -30OCto -WC in an amount of 10to 50 vol.% such asdifluoromonochloromethane or propane, and at least one component having a normal boiling pointwithin the range from +160Cto -300C in an amountof 10 to 75 vol.% such as difluoromonochloroethane,difluoromonochlorobromomethane,or octafluorocyclobutane.

The cooling agent may contain the components in thefollowing proportioning (in vol.%):

trifluoromonochloromethane 10-50 60 difluoromonochloromethane 10-15 octafluorocyclobutane 20-70 difluorochloromethane or difluorochloromethane 65 trifluoromonobromomethane octafluorocyclobutane difluoromonochloromethane 20-70 the balance, or difluorochloromethane trifluoromonochloromethane difluoromonochloroethane difluoromonochloromethane or difluorodichloromethane 10-15 trifluoromonochloromethane 10-50 difluoromonochlorobromomethane 10-70 difluoromonochloromethane or dif luorodichloromethane trifluoromonochloromethane octafluorocyclobutane trifluoromonobromomethane difluoromonochloromethane or C02 difluorodichloromethane difluoromonochloromethane difluoromonochloroethane the balance, 10-15 10-50 130 10-15 10-50 20-70 the balance, the balance, 10-20 5-30 20-60 5-30 the balance, 10-45 10-35 10-35 25-75.

The use of the method and cooling agent for freezing and storing products according to the invention ensures a substantial improvement of the specific cold capacity of refrigeration units in which the method and cooling agent are employed, and also improves cost effectiveness and reliability of such 95 refrigeration units.

Otherobjects and advantages of the invention will become apparentfrom the following description of the invention with referencetothe accompanying drawings, in which:

Figure 1 shows a cycle of operation of a home compression refrigerator given intheform of a diagram in coordinates temperature v. entropy; Figure 2shows a principle diagram of a refrigeration unit A method for freezing and storing products in home compression refrigerators consists in loading products into one or several refrigeration compartments in which desired temperature conditions are provided.

Atemperature of maximum -24Cforthe freezing function and -18'Cforthe storage function is maintained inthefreezing and long-storage corn partment. Atemperature within the rangefrom O'Cto +WC is maintained in a short-term storage compart- mentfor all functions of the refrigerator. These temperature conditions are provided owing to the fact that a cooling agent is subjected to the following sequence of operations also illustrated in Figures 1 and 2.

A cooling agent is compressed (process 1-11 in Figure 1) in a compressor 1 (Figure 2), cooled (process 11-111) with the removal of heat (ql) into the environment, then partially condensed in a condenser 2 forthe formation of a liquid and vapour mixture. Noncondensed components of a cooling agent are dissolved in condensed components (process 111-1V) with the removal of heat (q2). Subsequentlythe cooling agent is fed to a heat exchanger or evaporator3 where it is cooled to a temperatureTv (process IV-V). The cooling agent is then throttled through a throttle 4with 2 GB 2 133 031 A 2 a temperature decrease from TvtoTv, (processV-VI) and isfedto an evaporator5 ofthefreezing and long-term storage compartment with the removal of heat (q3) from this compartment during long-term storage and from the products in the freezing function (process VI-VII), the cooling agent being heated and evaporated only partially and being in a liquid and vapour phase. Subsequently the cooling agentwhich is in the liquid and vapour phase is fed tothe heat exchangeror evaporator3 in which the cooling agent is evaporated completelyto remove heat (q4) from the short-term product storage compartment and to remove heat (q5) from the compressed cooling agent fed to the heat exchanger3 from the condenser 2.

The cooling agent is then fed to the compressor 1 for re-compression.

The ratio of the pressure of compressed cooling agent (referred to below as cooling agent) to the pressure of expanded cooling agent or a compression ratio P1/P2 is substantially lower compared to known methods. Thus, the compression ratio of a refrigeration unit using a widely known method of freezing and storage with the employment of Freon-1 2 is 14. Optimum value of compression ratio forthe method according to the invention is onlyfrom 3 to 5. Lower compression ratio results in an improved volumetric efficiency of the compressorwhich is equal to the ratio of the actual hourcapacity of the compressorto the ideal capacity, that is to the volume described by the piston during one hour. Lowering the compression ratio from 14to 4 results in a 2-3-fold increase in the volumetric efficiency of the compressor, hence in a 2-3-fold improvement of the compressor efficiency and substantial improvement of the efficiency of the refrigeration unit. This brings about a reduction of specific energy consumption forfreezing and storing products.

For a complete liquefaction of a cooling agent it is compressed to a pressure between 10 and 14 kg ICM2, and to evaporatethe cooling agentfinally it is enough to throttle itto a pressure between 0.5 and 3 kg/cM2.

If a cooling agent is compressed to a pressure below 10kg 1CM2 or above 14 kg/cM2 and throttled to a pressure below 0.5 kg 1CM2 or above 3 kg 1CM2, the process of liquefaction of the cooling agent and its evaporation cannot provide for a desired improvement in the specific cold capacity of the refrigeration unit.

The implementation of the method will become apparentfrom the following embodimeritthereof.

A cooling agent in the vapour phase was liquefied in the compressor 1 to a pressure between 10 and 14 kg/cM2 and was fed to the condenser 2. The cooling agentwas cooled in the condenser 2 to give up heat to the environment (air or water). Owing to the heat removal from the cooling agent vapour, its components boiling at higher temperature where condensed, that is the cooling agent was partially liquefied to form a liquid and vapour mixture, while still being at a higher pressure.

Atthis pressure and at a temperature between 20 and 450C a complete liquefaction of the cooling agent was effected by dissolving its components boiling at lower temperaturewhich were in the vapour phase under such conditions, in the liquefied components.

The liquefied cooling agent was cooled in the heat exchangers 3 with a liquid and vapour emulsion, which was formed owing to the partial evaporation of the cooling agent in the evaporatorwhich was fed in the form of a reverse flow to the heat exchanger.

The cooled cooling agent was then fed through the throttle 4 in which its pressure and temperature were reduced, to the evaporator 5. During the throttling the pressure of the cooling agentwas reduced to 0.5- 3 kg/cM2.

The cooling agent boiled (evaporated) in the evaporator 5, a desired amount of heat was removed from objects being cooled so that their temperature decreased as much as to -30'C. This is the process of partial evaporation during which major part of components with lower boiling point are evaporated.After the liquid and vapour mixture have left the evaporator 5, the evaporation of the component with lower boiling point was over, and components of the cooling agent having higher boiling point started evaporating. The process of complete evaporation of the cooling agentwas effected in the heat exchanger3 in which the heat required forthe cooling agent boiling was taken off theforward flow as a result of the heat exchange between theforward and reverse flows. The resultant cooling agent vapourwastaken off bythe compressor 1 forthe re-compression thus closing the cycle of operation of the refrigeration unit.

It is preferablyto maintain the delivery pressure of 12 kg/crn2 and the suction pressure of 3 kg/cm2.

By dissolving non-liquefied components of the cooling agent in its liquefied components in the refrigeration cycle of a single-stage compression refrigeration machine a complete liquefaction ofthe cooling agent may be achieved at a lower condensation pressure, hence at a lower delivery pressure. This makes it possible to reducethe ratio of the delivery pressureto the suction pressure thus improving the specific cold capacity of the refrigeration unit and the efficiency of the compressor owing to a reduction of energy losses in the compressor.

For carrying out the method it is necessary to choose a cooling agent in such a manner as to ensure desired temperatures for storage and freezing at optimum lowered value of the compression ratio.

Forthat purpose, a cooling agent contains difluorodich loromethane with a normal boiling temperature of -29.80C and also components having a normal boiling temperature within the range from -55'Cto -85'C, a component having a normal boiling. point within the rangefrom - 30'Cto -WIC, and cQmponents having a normal boiling pointwithin the range from +160Cto -300C.

Such components may comprise any widely known compoundssuch as C02.trifluoromonochloromethane, trifluoromonobrornomethane having a normal boiling (sublimation) pointof - 79,8'C, -81'C, -570C, -750C, respectively, difluoromonochloromethane, propane having a normal boiling point of -40.80C, -40'C, respectively; difluoromonochloroethane, difluoromonochlorobromomethane, octafluorocyclobutane having a normal boiling point of -9.250C, -3.0C, -5.80C, respectively.

Using cooling agents of the following composition minimum cost and maximum effectiveness maybe i 11 -i 3 GB 2 133 031 A 3 achieved:

1) difluorodichloromethane,trifluoromonochloromethane, difluoromonochloromethane, difluoromonochloroethane; 2) C02, difluorodichloromethane, difluoromonoch- 70 foromethane, difluoromonochloroethane; 3) trifluoromonochloromethane, difluoromonoch loromethane, octafluorocyclobutane, difluorodichlor ometharie; 4) difluorodichloromethane, trifluoromonochfor- 75 omethane, difluoromonochloroethane, difluoromo nochloromethane; 5) difluorodichforomethane, trifluoromonochlor omethane, difl uoromonoch lorobromo methane, dif luoromonochloromethane; 6) difluorodichloromethane,trifluoromonochlor- omethane, octafluorocyclobutane, trifluoromonobro momethane, difluoromonochloromethane; and any other possible combinations.

The components are preferably propor tioned as follows (vol.%):

trifluoromonochloromethane difluoromonochloromethane octafluorocyclobutane difluorodichloromethane or difluorodichloromethane trifluoromonobromomethane octafluorocyclobutane difluoromonochloromethane or difluorodichloromethane trifluoromonochloromethane difluoromonochloroethane difluoromonochloromethane or difluorodichforomethane trifluoromonochloromethane octafluorocyclobutane trifluoromonobromomethane difluoromonochloromethane or C02 difluorodichloromethane difluoromonochloromethane difluoromonochloroethane 10-50 10-15 20-70 the balance; 90 10-15 10-50 20-70 Each cooling agent is a mixture of components stored in pressurized bottles. A quantity of each componentof a volume corresponding to a pre- set percentage of this component in the mixtureis dischargedfrom each bottletoacommon receiver. First a component having the lowest pressure of liquefied gasvapour, and namely octafluorocyclobutane, difluoromonochloroethane, difluoromonochlorobromomethane, difluorochloromethane is discharged from the bottleto the receiver, then gases with a greater pressure of liquefied gasvapour such as difluoromonochloromethane, trifluoromonobromomethane, trifluoromonochloromethane. Examples of possible modifications of combinations of componentsfor preparing a cooling agent according tothe invention are given below: Example 1 Thefollowing components are mixed: difluorodichloromethane, C02, difluoromonochloromethane and difluoromonochloroethaneto prepare a cooling agent having the following composition (in vol.%): difluorodichioromethane C02 difluoromonochloromethane difluoromonochloroethane 14 20 When used in home refrigerators, such coolant ensures a compression ratio of between 4 and 5 and provides desired temperature conditions in refrigerathe balance; 95 tion compartments: from O'Cto +5Cintheshortterm storage compartment, maximum -24C in the freezing and long-term storage compartment for the freezing function and - 1 80C forthe long-term storage function. the balance; 100 Example2 10-15 10-50 20-70 10-20 5-30 20-60 5-30 the balance; 10-45 10-35 10-35 25-75.

If the low-boiling components are used within ranges smallerthan those specified above and the high-boiling components are used within ranges greaterthan those specified above, necessary temperature conditions in refrigerator compartments cannot be provided, that is thetemperature in the short-term- storage compartmentwill be below O'C and the temperature in the long-term storage compartment will not reach - 1 80C.

If the low-boiling components are used within ranges greaterthan those specified above and the high-boiling components are used within ranges smallerthan those specified above,the low-boiling componentswill notbeableto dissolve in the high-boiling components, hence desired temperature conditions will not be provided intheshort-term storage compartment, that is the temperature in this compartment will be above +5'C.

The following components are mixed in a container: difluorodichloromethane,trifluoromonochloromethane, difluoromonochloromethane, octafluorocyclobutaneto prepare a coolant having the 105 following composition (vol.%): difluorodichloromethane trifluoromonochloromethane trifluoromonobromomethane difluoromonochloromethane 110 octafluorocyclobutane 22 10 22 22 24.

This cooling agent ensures a compression ratio of the compressor between 4 and 5 and maintenance of thefollowing temperature conditions: from O'Cto +50C in the short-term storage compartment and maximum -240C in the longterm storage and freezing compartment forthe freezing function and 18'Cforthe long-term storage functi.on. Example 3 The following components are mixed in a container: difluorodichloromethane,trifluoromonochloromethane, difluoromonochloromethane and difluoromonochloroethane to prepare a cooling agent having the following composition (vol.%):

difluorodichloromethane trifluoromonochloromethane difluoromonochloromethane difluoromonochloroethane 20 25 30.

4 Example 4 A cooling agent having the following composition (vol.%) was prepared by the above-described method:

difluorodichforomethane trifluoromonochloromethane difluoromonochloromethane difluoromonochloroethane 15 25 50.

Example 5

A cooling agent having the following composition (vol.%) was prepared by the above-described method:

difluorodichloromethane trifluoromonochforomethane difluoromonochloromethane difluoromonochloroethane 20 10 50.

Example 6

A cooling agent having thefollowing composition 85 (vol.%) is prepared bythe above-described method:

difluorodichloromethane trifluoromonochloromethane difluoromonochloromethane difluoromonochloroethane 15 25 40.

The cooling agents of Examples 3to 6 ensured the achievement of compression ratio between 4 and 5 and provided in the regrigeration compartments of a compression refrigeratorthe above-mentioned desired temperature conditions.

In addition to the above-described compositions, thefollowing mixtures can be prepared to providethe desired temperature conditions:

Example 7 difluorodichloromethane trifluoromonobromomethane octafluorocyclobutane difluoromonochloromethane 40 Example 8 difluarodichforomethane trifluoromonobromomethane octafluorocyclobutane difluoromonochloromethane 45 Example 9 difluorodichloromethane trifluoromonobromomethane octafluorocyclobutane difluoromonochloromethane Example 10 difluorodichloromethane trifluoromonoch loro methane difluoromonochloroethane difluoromonochloromethane Example 11 difluorodichloromethane trifluoromonochloromethane difluoromonochloroethane difluoromonochloromethane Example 12 difluorodichloromethane trifluoromonochloromethane difluoromonochforoethane difluoromonochloromethane Example 13

50 20 15.

30 40 15.

10 70 10 50 20 15.

20 50 15.

10 70 10 GB 2 133 031 A difluorodichloromethane trifluoromonochloromethane difluoromonochlorobromomethane difluoromonochforomethane Example 14 difluorodichloromethane trifluoromonochloromethane difluoromonochforobromomethane difluoromonochloramethane Example 15 difluorodichforomethane trifluoromonochloromethane difluoromonochlorobromomethane difluoromonochloromethane Example 16 difluorodichloromethane octafluorocyclobutane difluoromonochloromethane trifluoromonochloromethane trifluoromonobromomethane Example 17 difluorodichforomethane octafluorocyclobutane difluoromonochloromethane trifluoromonochloromethane trifluoromonobromomethane Example 18 difluorodichloromethane octafluorocyclobutane difluoromonochloromethane trifluoromonochloromethane trifluoromonobromomethane 50 20 15.

18 20 44 18.

10 70 10.

15 5 5.

29 36 11 12 12.

20 10 30 30.

The tests showed that maximum specific cold capacity of a refrigeration unitfunctioning with the cooling agent according to the invention was substantially higherthan with the use of prior art cooling agents.

Moreover, the cooling temperature may be lo- wered by increasing the percentage of components having a boiling point below -500C atthe atmospheric pressure, butthis would somewhat lowerthe specific cold capacity of the refrigeration unit.

The specific cold capacity of the refrigeration unit is substantially improved upon an increase in the content of components having a boiling point above -1 OOC atthe atmospheric pressure, butthis results in an increase in the cooling temperature and it may even become close to the boiling point of the highest

Claims

boiling component of the cooling agent. CLAIMS

1. A cooling agent containing, in vol.%:

difluorodichloromethane 10-50 at least one component having a 120 normal boiling point within the range from -WC to -851C a component having a normal boiling point within the range from -WC to -550C 125 at least one componerit having a normal boiling point within the range from + 1 60C to -300C 10-5Q 10-50 10-75.

2. A cooling agent as claimed in claim 1, the 130 component(s) having a normal boiling pointwithin 11 f -3 ip -ie the range from -55T to -85T being selected from C02, trifluoromonochloromethane, and trifluoromonobromomethane, the component having a normal boiling point within the range from -30OC to -55T being difluoromonochloromethane or propane, and the component(s) having a normal boiling point within the range from+ 1 60C to -300C being selected from difluoromonochloroethane, difluoromonochlorobromomethane, and octafluorocyclobutane.

3. A cooling agent as claimed in claim 2, containing, in vol.%: trifluoromonochloromethane difluoromonochloromethane octafluorocyclobutane difluorodichloromethane 10-50 10-50 20-70 the balance.

4. A cooling agent as claimed in claim 2, contain- ing, in vol.%:

difluorodichloromethane 10-15 trifluoromonobromo methane 10-50 octafluorocyclobutane 20-70 difluoromonochloromethane the balance.

5. A cooling agent as claimed in claim 2, contain25 ing, in vol.%:

difluorodichloromethane trifluoromonochloromethane difluoromonochforoethane difluoromonochloromethane 10-15 10-50 20-70 the balance.

6. A cooling agent as claimed in claim 2, contain- ing, in vol.%:

difluorodichloromethane 10-15 trifluoromonochloromethane 10-50 difluoromonochlorobromomethane 10-70 difl uoromonoch loro methane the balance.

7. A cooling agent as claimed in claim 2, containing, in vol.%:

difluorodichloromethane trifluoromonochloromethane octafluorocyclobutane trifluoromonobromomethane difluoromonochloromethane 10-20 5-30 20-60 5-30 the balance.

8. A cooling agent as claimed in claim 2, containing, in vol.%: C02 (liquid) difluorodichloromethane 50 difluoromonochloromethane difluoromonochloroethane 10-45 10-35 10-35 25-75.

9. A cooling agent as claimed in claim 8, containing, in vol.%: 55 C02 (liquid) difluorodichloromethane difluoromonochloroethane difluoromonochloromethane 14 20 46 20.

10. A cooling agent as claimed in claim 1, containing, in vol.%: trifluoromonochloromethane trifl uoromonobromo methane difluoromonochloromethane 65 difluorodichloromethane GB 2 133 031 A 5 octafluorocyclobutane 24.

11. A cooling agent as claimed in claim 5, containing, in vol.%:

trifluoromonochloromethane difluoromonochloromethane difluorodichloromethane difluoromonochloroethane 25 40.

12. A cooling agent as claimed in any of claims 1 to 11, substantially as described herein.

13. A cooling agent substantially as described in any of Examples 1 to 18.

Printed for Her Majesty's Stationery Office by The Tweeddale Press Ltd., Berwick,upon-Tweed, 1,984. Published atthe Patent Office,25 Southampton Buildings, London WC2A lAYfrom which copies may beobtained.

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