US3402570A

US3402570A - Refrigeration systems and refrigerants used therewith

Info

Publication number: US3402570A
Application number: US604214A
Authority: US
Inventors: Ralph C Schlichtig
Original assignee: Individual
Current assignee: Individual
Priority date: 1966-12-23
Filing date: 1966-12-23
Publication date: 1968-09-24
Anticipated expiration: 1985-09-24

Description

p 24, 1958 R. c. SCHLICHTIG 3,402,570

REFRIGERATION SYSTEMS AND REFRIGERANTS USED THEREWITH Filed Dec. 23, 1966 5 Sheets-Sheet 1 Q' HH mmmmeif E APOFATOE HEAT Xt'f/ANGFE 5:5 I y INVENTOR- FAtP/l 6. yam/(W276 ATTORNEY M P 1968 R. c. SCHLICHTIG REFRIGERATION SYSTEMS AND REFRIGERANTS USED THEREWITH 5 SheetS -Sheet 2 Filed Dec. 23, 1966 IIOOO WWW NORMAL 50/! //V6 POI/V75 $8 mwskmwwq w M04; renew/v Pz/ w E Se t. 24, 1968 R. c. SCHLICHTIG I 3,402,570

REFRIGERATION SYSTEMS AND REFRIGERANTS USED THEREWITH Filed Dec. 23, 19 66 T s Sheets-Sheet s Urv itt d, Stat s P te 'Ofice Patented Sept. 24, 1968 $402,570 REFRIGERATION SYSTEMS AND REFRIGERANTS USED THEREWITH Ralph CiSchlichtig, 11212 3rd 5., :,:.Seattle',-Wa sh. 98168 1 Continuation-in-part of application Ser. No. 452,648, a ,May 3, 1965. his application Dec. 23, 1966, Ser.

604, 14 a 's tllaims. (Cl m-483) a 'ABSTRAQT OF THE DISCLGSURE In each of the two disclosed embodiments of a thermally powered refrigeration system an ejector is so interrelated with an evaporation heat exchanger,.which receives a solutionof refrigerant ,and absorbentmaterial from an absorber, that the ejector pumps refrigerant vapor from the evaporation-heat exchanger to a refrigerant condenser for condensing, to thereby minimize the cost of the refrigerationsystem while still maintaining a high coefficient of performance for the system. The ejector in each embodiment also cooperates with associated apparatus in the particular embodiment to effect-a precooling of the refrigerant before it enters a refrigerant evaporator for evaporatio n.,Several two.component refrigerants are disclosed which can. be effectively used in each of the two embodiments to further improve their coefficient of performance.

This application is a continuation-in-part application of United States patent application Ser. No. 452,648, filed by applicant on May 3, 1965, now Patent No. 3,298,- 196, and entitled Dynamic Pump Type Refrigeration System31 @This invention relates to refrigeration systems and refrigerants used therewith, ,and more particularly to nonmechanical thermally powered refrigeration systems employing ejectors andthose fluorocarbon refrigerants that will give nonmechanical thermally-powered systems a highly desirable coefficient of performance in addition to the quality of safety inherent in fluorocarbon vapors.

! In thedynamicpump type refrigeration system described in the above-mentioned patent application both an ejector and a condenser assisted by absorption cooperate in athermally powered system to pump refrigerant vapor of effectively a single component from an evaporator to a condenser in such an arrangement that the ejector draws refrigerant vapor directly from the evaporator and discharges it ,into thecondenser assisted by absorption at a pressure less than that required for condensation in a condenser unassisted by absorption. The condenser aided by ab sorption -reduces the back pressure on the ejector so the ejector can pump more refrigerant vapor from the evaporator. The power vapor for the ejector is largely absorbent vapor. 1 V

, The refrigeration system shown and described in the present ,application has incorporated therein some of the components of the refrigeration system shown in FIG. 1 of theaforementioned patent application Ser. No. 452,648; howeverin contrast thereto in the two embodiments (FIG. I and "FIG. 4) "shownheriinfa pu'r'np means, specifically an ejector, and an absorber cooperateto pump refrigerant vaport'o a condenser in such manner that the absorber draws-vapor directly from the evaporator, and the ejector cooperates by receivingrefrigerant vapor supplied at a pressure above that within theevaporator and delivers it directly to 'the condenser..-'The ejector cooperates with the absorber through-:an-evaporation heat exchanger to help the absorber to pump more refrigerant vapor from the evaporator with much'less heat exchange and much less solution of refrigerant and absorbent material circulating between the absorber aud the boiler generator than would be necessary for operation of a normal type absorption type refrigeration system. The power vapor for the ejector in the present application is mostly refrigerant vapor. In addition, the system is matched with special refrigerant combinations to take the fullest advantageof physical and thermodynamic properties with a two component fluorocarbon refrigerant. Additional improvements are made by adding a refrigerant precooler and by so constructing the boiler generator that it has an additional function.- f

In absorption type refrigeration systems it is necessary to repeatedly or cyclically separate refrigerant from the absorbent material that has absorbed much refrigerant, hereafter referred to as rich solution, by means of a boiler. The absorbent material must have a relatively high boiling point to effect good separation of the refrigerant from the absorbent material by distillation. At a given pressure the boiling point of a solution of refrigerant and absorbent material varies inversely with the molar proportion of refrigerant contained in the absorbent material so that at the end of the distillation process in the boiler when the proportion of refrigerant dissolved in the absonbent material is relatively small, hereafter referred to as weak solution, the boiling point of such weak solution may be very high. Although from purely thermodynamic considerations a very high boiler temperature is an advantage, in practice the very high boiler temperature inherent in a single pressure prior-art type boiler will limit the net amount of heat received from the fuel source because of boiler heat radiation and other losses and will effect chemical decomposition of refrigerant and absorbent material and corrosion of associated apparatus, and will also increase the necessary area of heat transfer surfaces for the heating and cooling of circulating solutions of refrigerant and absorbent material with resulting increase in initial cost of the refrigeration system.

In refrigeration cycles the temperature of the refrigerant in the condenser, which supplies refrigerant liquid to the evaporator, is greater than the temperature of the refrigerant in the evaporator. As refrigerant liquid has a specific heat which is considerably higher than that of vaporized refrigerant leaving the evaporator, prior-art heat exchangers between incoming refrigerant liquid to the evaporator and outgoing refrigerant vapor from the evaporator can only partially prevent incoming refrigerant liquid from carrying large quantities of parasitic heat to the evaporator.

In any refrigeration cycle using a condenser and an evaporator, heat is absorbed in the evaporator because of the heat of vaporization of the refrigerant. But as parasitic heat is carried back to the evaporator by virtue of the specific heat of the liquid refrigerant, it is necessary to use a refrigerant liquid that has a large-value heat of vaporization as well as low specific heat. But a refrigerant must also have a low boiling point, and the general rule with single component refrigerants is that the boiling point increases in proportion with the molar heat of vaporization. This rule is especially true with nonpolar fluorocarbon compounds, as illustrated by the graph of FIG. 2.

Ejectors as used in a refrigeration system have a tendency to decrease rapidly in fluid flow ratio between the secondary and the primary as the ratio of discharge pressure to secondary or load intake pressure increases toward a cut-off limit. It is also true that absorption systems, as well as ejector type systems, are very adversely affected by large pressure ratios between the condenser and the evaporator as determined by the temperature difference between the ambient temperature of the absorber and the condenser, and the temperature of the evaporator; and this adverse effect may be severe in cases where the absorber and condenser are cooled by ambient air. Refrigerants that have high molar heats of vaporization also tend to have larger ratios of vapor pressure between two given temperatures. For example, between the temperatures of F. and 115 F. the vapor pressure increases 3.47 fold For CClF -CClF (R114) which has a molar heat of va- Jorization of 10,000 B.t.u., while the vapor pressure in- :reases 3.88 fold for CCl F (R11) which has a molar heat )f vaporization of 10,760 B.t.u. Thus simple absorption systems or simple ejector systems with single component luorocarbon working substances operate with limited co- :fficient of performance, and this limit is lower if there is a large temperature difference between the evaporator and the ambient temperature of the absorber and the :ondenser.

Therefore an object of this invention is to provide a thermally powered refrigeration system in which a pump means, specifically an ejector, cooperates with an absorption system in such a way that the absorber receives more refrigerant vapor from the evaporator, thus giving the system a high coefiicient of performance and low fuel cost.

Another object of this invention is to provide a thermally powered refrigeration system in which a pump means, specifically an ejector, cooperates in such a way with an absorber to reduce the required liquid heat exchange, and thus to reduce the cost of the overall system.

Another object of this invention is to provide a thermally powered refrigeration system that can use safe fiuorocarbons for working fluids so it is safe to build the system as a packaged unit for inside installation. Another object of this invention is to provide in a thermally powered refrigeration system means for reducing the quantity of liquid circulating to and from a high pressure boiler, to thus reduce the electric power cost for pumping such liquid.

Another object of this invention is to provide a thermally powered air conditioning system in which a pump means, specifically an ejector, cooperates with an absorber such that the absorber and condenser of the system can be cooled with ambient air.

Another object of this invention is to provide a thermally powered refrigeration system combining a pump means, specifically an ejector, with a two stage absorber so that the second stage of the absorber is cooled so that it absorbs more refrigerant vapor from the evaporator.

Another object of this invention is to provide a thermally powered refrigeration system in which a pump means, specifically an ejector, cooperates with the system in such a manner that refrigerant vapor is withdrawn from the system at a pressure that is intermediate between that of the condenser and the evaporator and is returned directly to the condenser from the ejector, thus allowing the absorbent material in the absorber to absorb more refrigerant vapor before the rich solution is pumped to the boiler.

Still another object of this invention is to combine in a thermally powered refrigeration system a boiler generator means by which vapor refrigerant is separated from the absorbent material at more than a single pressure to thereby reduce the temperature of the final and weakest solution of refrigerant and absorbent material, to thus protect the refrigerant and absorbent material from thermal decomposition.

Still another object of this invention is to combine a pump means, specifically an ejector, in an absorption system such that the ejector uses vapor already generated by the boiler of the absorption system' to effect a precooling of refrigerant liquid that is returning to the evaporator.

Still another object of this invention is to provide in a thermally powered refrigeration system a relatively nontoxic and nonfiammable refrigerant having two components of somewhat restricted solubility in such a mixture that one component can be absorbed more readily than the other and so that the ratio of the condenser pressure to the evaporator pressure for the mixture is less than the ratio of condenser pressure to evaporator pressure for one of the components taken at the corresponding condenser and evaporator temperatures, to thereby increase the coefiicient of performance of the refrigeration system.

Other objects of this invention will become apparent from the following description when taken in conjunction with the accompanying drawings in which:

FIG. 1 is a schematic diagram of one embodiment. of this invention in which an ejector is employed in a thermally, powered refrigeration system to. lower. the temperature of an evaporation heat-exchanger to increase refrigerant vapor absorption within the system;

FIG. 2 is a straight'line graph showing that for nonpolar fluorocarbon refrigerants the heats of vaporization for the various examples are in linear relation to" the respective boiling points, but that the polar fluorocarbon refrigerants have abnormally large 'heats' of vaporization corresponding to given boiling points;

FIG. 3 are graphs showing'the vapor pressures of mixtures of CHCl F (R21) and CClgF (R11) refrigerants in varying molar proportions at 45 F. and F.

FIG. 4 is a schematic diagram of another embodiment of this invention in which an ejector is employed in a thermally powered refrigeration system to cause reevaporation of refrigerant in the system and the return of the resulting refrigerant vapor directly to the condenser for condensing.

Referring to FIG. 1 there is shown a thermally powered refrigeration system 10 illustrating one embodiment of this invention. The refrigeration system 10 will operate with a single component refrigerant, but it-will operate better with a two component refrigerant such as CHClgF (R21) and CCl F (R11). Operation will first be explained with a single component refrigerant, and later with a two component refrigerant so as to set forth further teachings of this invention.

A boiler 12 is heated from a heat source, not shown, and generates refrigerant vapor under relatively high pressure to power an ejector 13 and to separate refrigerant from absorbent liquid material. An analyzer 16, which is closely associated with and is part of the boiler 12, functions to further separate refrigerant vapor from absorbent vapor by condensing out absorbent vapor. The analyzer 16 contains a boiler inlet tube 14 and a boiler outlet tube 18 spiralled very close to one another in heat transfer relationship, with the outlet tube 18 extending past the inlet tube 14 to near the bottom of the boiler 12.

The ejector 13 comprises power inlet means 20, refrigerant inlet means 22 and discharge means 24 and preferably is of the centrifugal type disclosed in US. Patent No. 3,215,088 or in FIG. 2 of US. Patent No. 3,298,196. The power inlet means 20, of the ejector 13, is operatively associated with the boiler 12 for receiving refrigerant vapor therefrom. On the other hand, the refrigerant inlet means 22 of the ejector 13 is operatively associated with an evaporation heat exchanger 26 for drawing refrigerant vapor therefrom. The discharge means 24, of the ejector 13, is operatively associated with a condenser 28 to discharge refrigerant vapor into the condenser 28 for condensing. In other words, the ejector 13 functions as a vapor pump to pump secondary refrigerant vapor from the evaporation heat exchanger 26 and deliver the vapor to be condensed at a higher pressure to the condenser 28. The high pressure power vapor for the ejector 13 comes from' the boiler 12 through a power vapor supply con-' duit 30. V

The term flow ratio as usedherein with reference to the ejector 13 refers to the ratio ofmoles of secondary re-. frigerant vapor pumped in through a conduit 32to the number of moles of primary power vapor supplied through the conduit 30. The effectiveness of the ejector 13 is generally proportional to its flow ratio. The flow ratio ofrthe ejector 13 can be improved by having a small ratio ofdischarge pressure at the condenser 28 to the pressure of the secondary refrigerant vapor within the conduit32, and also by having the primary power vapor within the c0n'- duit 30 delivered at higher pressure, and further-by having the primary power vapor within the conduit 30 of higher 5 molecular weight than that of the secondary vapor within the conduit 32. i

The condenser 28 is of the conventional finned type and is cooled by ambient air. A lower portion 34 of the condenser 28 functions to accumulate condensed and liquifi'ed refrigerant. In order to regulate the flow of liquid refrigerant ffom the condenser 28 to the evaporation heat exchanger 26 through a conduit 36, a flow regulator 38 is provided; The flow regulator 38 prevents refrigerant vapor from flowing from the condenser 28 and through the conduit 36.

An absorber 40 has two main parts, a high temperature section 42 and an ambient temperature section 44 with radiation fins 46 for dissipating heat at ambient temperature, and houses a preheat exchanger 48 which is shown as a tube that is formed into a helical coil and through which a rich solution of absorbent material and dissolved refrigerant flows so as to be preheated on its way back to the boiler .12. A conduit 50 is inter-connected between the outlet tube 1 8, of the boiler 12, and the top of the high temperature section 42, of the absorber 40, for delivering a weak solution of refrigerant and absorbent material to the absorber 40. A distributor 52 is disposed within the absorber 40 so that such weak solution entering from the conduit 50 is restricted in flow and spreads out over the surface of the coiled preheat exchanger 48 in absorbing contact with refrigerant vapor received from a finned evaporator 54 which provides a cooling effect to the space to be cooled or refrigerated. The refrigerant vapor from the evaporator 54 enters the high temperature section 42, of the absorber 40, at evaporator pressure by means of a conduit 56 and heats the preheat exchanger 48 and the rich solution therein with which it is in thermal contact, as refrigerant vapor is absorbed within the high temperature section 42 and liberates its heat of vaporization. As the liquid absorbent material within the high temperature section 42 becomes laden with refrigerant, the resulting rich solution drops into the ambient temperature section 44, of the adsorber 40, where more refrigerant vapor can be absorbed at the lower ambient temperature.

The evaporation heat exchanger 26 includes an outer compartment 62 which is insulated from ambient heat, and an inner compartment 64 which functions as an evaporator. The evaporation heat exchanger 26 is operatively associated with the absorber 40 and with the condenser'28 so that a solution of refrigerant and absorbent material passes from the absorber 40 into the outer compartment 62, of the evaporation heat exchanger 26, and so that condensed refrigerant passes from the condenser 28 into the inner compartment 64 of the evaporation heat exchanger 26. The evaporation heat exchanger 26 is also operatively associated with the evaporator 54 so that a portion. of the refrigerant evaporated within the evaporator 54 passes into the outer compartment 62 of the evaporation heat exchanger 26 and is absorbed by the cooled absorbent material within the outer compartment 62. In particular, the remaining refrigerant vapor in the ambient temperature section 44, of the absorber 40, which has been received from the evaporator 54 and has not been absorbed in the absorber 40, passes from the ambient temperature section 44, of the absorber 40, through a connecting conduit 58 to the evaporation heat exchanger 26. Absorbent liquid material and its dissolved refrigerant drains to the outer compartment 62, of the evaporation heat exchanger 26, by a conduit 60 and is disposed in heat transfer relationship with theinner compartment 64. Liquid refrigerant enters the inner compartment 64, which is at a pressure above the pressure within the evaporator 54, by means of the conduit 36. Refrigerant vapor is pumped out of the inner compartment 64 by the ejector 13 and cooling results from evaporation of a portion of the liquid refrigerant disposed within the inner compartment 64. The remaining portion of the liquid refrigerant disposed within the inner compartment 64 is cooled;

and absorbent material with dissolved refrigerant dis posed within the outer compartment 62 is llkCWlSl cooled several degrees below ambient temperature as i flows from the conduit-60 and trickles down over thr outer surface-of the cool inner compartment 64, ofth evaporation heat exchanger 26,. in absorbingcontact witl refrigerant vapor received from the conduit 58. The ab sorbent material thus cooled acquires the capacity to ab sorb considerably more refrigerant vapor, therefore more refrigerant vapor is absorbed by the absorbent material tc thus become a. rich solution of refrigerant and absorbent material, and heat thus liberated is removed by evaporation of refrigerant liquid within the inner compartment 64.

In order to pump the rich solution of refrigerant and absorbent material from the outer compartment 62 of the evaporation heat exchanger 26 through the preheat exchanger 48 of the absorber 40 and into the inlet tube 14, of the analyzer 16, a pump 66 and conduit means 68 is provided.

The remaining cooled liquid refrigerant disposed within the inner compartment 64, of the evaporation heat exchanger 26, is conveyed to the evaporator 54 by means of a syphon tube 70 which has a flow restriction 72 for reg- ,ulatin'g the flow of liquid refrigerant to the evaporator 54. The inner compartment '64, of the evaporation heat exchanger 26, thus also functions as a refrigerant precooler for the refrigerant liquid conveyed to the evaporator 54.

The evaporator 54 as illustrated is of the conventional finned type 'which evaporates, at reduced pressure, refrigerant liquid which is received through the siphon tube 70, and thereby cools and refrigerates the surrounding space. Resulting cool refrigerant vapor leaves the evaporator 54 through the conduit 56 in heat transfer relationship with the syphon tube 70 and the refrigerant liquid therein in order to further cool the refrigerant liquid flowing to the evaporator 54 through the syphon tube 70.

In order to prevent any nonevaporated liquid refrigerant from overflowing from the evaporator 54 and into the absorber 40, which action would dilute and weaken the absorbent material in the absorber 40, a sump 74 is provided to collect such overflow of liquid refrigerant. A conduit 76 is interconnected between the sump 74 and the pump 66 so as to return such collected overflow re frigerant to the boiler 12.

The operation of the refrigeration system 10 as shown in FIG. 1 will now be described in its simplest operation with a refrigerant of one volatile component and an absorbent material that is much less volatile. Liquid absorbent material containing a relatively high concentration of dissolved refrigerant, in other words rich solution, is pumped into the heated boiler .12 by way of the inlet tube 14, of the analyzer 1'6, and onto the surface of the outlet tube .18 so as to vaporize a portion of the refrigerant dissolved in the incoming rich solution, which refrigerant vapor flows or passes into the power inlet means 20 of the ejector 13. The remaining refrigerant and the absorbent in which it is dissolved settles downward in the boiler 12 at a higher temperature as a less rich solution. As more refrigerant is boiled off the solution becomes weakest at the bottom of the boiler 12 where the temperature is the highest. Some absorbent is boiled off with the refrigerant from the weak solution in the boiler 12, but most of the vaporized absorbent condenses on the outer surface of the inlet tube 14 and gives up heat to preheat the rich solution of refrigerant and absorbent material entering the boiler 12 and to vaporize a portion of the dissolved refrigerant to add to that vapor passing through the conduit 30 to the power inlet means 20 of the ejector 13.

The boiler 12 must -be heated to a sufiiciently high temperature to produce vapor at a pressure sufficiently high to power the ejector 13. A relatively hot weak solution of refrigerant and absorbent material leaves the bottom of the boiler 12 by means of the outlet tube 18 and gives up much of its heat to further heat the rich soution of refrigerant and absorbent material flowing downvard in the inlet tube 14 and over the surface of the outet tube 18. Such weak solution then flows by way of the :onduit 50 to the absorber 40. The weak solution which s now .partly cooled enters the absorber 40 at the top of ts high temperature section 42 and is distributed by the listributer 52 overthe-surface of and in thermal contact with the preheat exchanger 48 where such weak solution s in absorbing contact with refrigerant vapor coming fromthe evaporator 54 by way of the conduit 56 at evaporator pressure. As refrigerant vapor is absorbed by :heweak solution, the resulting heat of vaporization givan up by the absorbed refrigerant vapor is transferred to the rich solution that is disposed within the passage'of the preheat exchanger 48 and that is on its way back to the boiler 12. As a solution of refrigerant in absorbent will take on more refrigerant vapor as the solution drops in temperature, further absorption of refrigerant vapor takes place as the solution runs down into the cooler ambient temperature section 44 of the absorber 40. The refrigerant vapor-laden liquid absorbent material then flows through the conduit 60 into the outer compartment 62, of the evaporation heat exchanger 26, over the outer surface 80 of the inner compartment 64 where it is further cooled to below ambient temperature in contact with refrigerant vapor which flows from the absorber 40 and through the conduit 58 to the outer compartment 62 where the pressure is still the same as within the evaporator 54. Here the absorbent solution reaches its greatest degree of saturation with refrigerant vapor. This rich solution is then pumped out of the outer compartment 62, of the evaporation heat exchanger 26, through the conduit means 68 and the preheat exchanger 48, of the absorber 40, back to the inlet tube 14 of the analyzer 16. This rich solution is preheated while passing through the preheat exchanger 48.

The vapor produced in the boiler 12 is directed through the conduit and into the power inlet means 20 of the ejector 13 which, by action of the ejector 13, effects a reductionlof pressure at the refrigerant inlet means 22, of the ejector 13, so that refrigerant vapor is pumped from the inner compartment 64 of the evaporation heat exchanger 26. The combined power vapor and the pumped secondary vapor, substantially all of which is refrigerant, is compressed and discharged into the condenser 28 through the discharge means 24 of the ejector 13. The discharge pressure of the refrigerant vapor discharged into the condenser 28 is sufficient that the refrigerant condenses to a liquid near ambient temperature in the condenser 28, and the heat of condensation that is liberated is dissipated to the ambient air by means of the radiation fins 82.

The refrigerant that condenses in the condenser 28 flows through the flow regulator 38, such as a float valve, and through the conduit 36 into the inner compartment 64, of the evaporation heat exchanger 26, where the pressure is less than that in the condenser 28 but is greater than that in the evaporator 54. Here in the inner compartment 64 a portion of the condensed refrigerant evaporates and passes to the refrigerant inlet means 22 of the ejector 13, but the remaining portion of the condensed refrigerant disposed within the inner compartment 64 that is cooled leaves by way of the restriction 72 through the syphon tube 70 and into the evaporator 54. Here in the evaporator 54 the refrigerant evaporates thus providing a cooling effect, and the refrigerant vapor thus produced is conducted to the absorber 40 by way of the conduit 56.

The absorbent material suitable for use in an absorption refrigeration system must have a high boiling point, must be chemically stable, should have low molecular specific heat, must be reasonably inexpensive, must be noncorrosive, and must be compatible with the refrigerants chosen. Water has a reasonably high boiling point and might appear to be excellent because it is a good solvent and appears to satisfy most of the other conditions. But water is a very highly polar liquid, therefore refrigerants of sufficiently low boiling point must also be highly polar to be sufliciently soluble. Such water soluble refrigerants as ammonia and sulfur dioxide are toxic, flammable, or corrosive. 0n the other hand, fluorocarbons are usually stable, nontoxic and nonflammable, butare uncompatible with water. Therefore, it is desirable that both the absorbent material and the refrigerant be fluorocarbons. The few inexpensive. fluorocarbon compounds having high boiling points and high critical temperatures seem to be nonpolar. A satisfactory example of a fluorocarbon absorbent is difluorotetrachloroethane CCI F CCI F (R112) that has the following physical properties: Boiling point'199 F., molar specific heat 42 B.t.u., molecular weight 203.9. Trifluorotrichloroethane CC1 F-CClF (R113) may also be used as an absorbent material for lower boiling point refrigerants. It has the following physical properties: Molecular weight 187, boiling point 118 F., molar specific heat 40.8 B.t.u.

Fluorocarbon refrigerants for air conditioning should have boiling points in the temperature range under 50 F., should be relatively inexpensive, should have low molecular weight and specific heat, and should have high heats of vaporization. Also they must be nearly perfectly soluble in the absorbent as shown by a nearly straight line relationship between their total vapor pressure and the molar proportion of refrigerant in absorbent material. Furthermore, the ratio of the vapor pressure of the refrigerant at condensing temperature to the vapor pressure at evaporating temperature should be as small as possible in order that the absorbent liquid material 'at saturation can have the greatest molar proportion of dissolved refrigerant.

Two physical properties, boiling point and heat of vaporization, of several available and for the most part relatively inexpensive fluorocarbons are compared by a line graph in FIG. 2. The fluorocarbons CClF -CF (R), CCI F (R12), CBrClF (R12B1),

(R114), CCl F (R11), Ccl F-CClF (R113) and CBrF -CBrF (R114B2) along the straight line of FIG. 2 are nonpolar while the three fiuorocarbons, CHCIF (R22), CHF -CClF (R124a) and CHCI F (R21), have abnormally high heats of vaporization and are polar. These three polar fluorocarbons are sufficiently different from the other nonpolar fluorocarbons including R112 as to restrict the solubility of the polar fluorocarbon in a nonpolar fluorocarbon liquid, which restriction makes the vapor pressure of such a solution to deviate above the straight line molar proportion versus pressure representing Raoults law. A similar deviation is shown in FIG. 3 for the polar and nonpolar compounds of R21 and R11, respectively, A similar difference affecting mutual solubility exists between R22 and R12 to cause a similar deviation from Raoults law. However this deviation above the line will be shown to be an advantage in the case of two refrigerant components one of which is polar and the other nonpolar.

Vapor pressures increase rapidly with temperature for the separate fluorocarbon liquids with large values of heat of vaporization, as is illustrated by approximate val ues in the folowing table: i

But as taken from FIG. 3 and shown in the last row of the above table, a liquid mixture of a polar fluorocarbon refrigerant and a nonpolar fluorocarbon refrigerant can have a smaller ratio of vapor pressure at 115 F. to vapor pressure at 45 F. than is the case of a single liquid compound component, without sacrificing either the vapor pressure or the heat of vaporization of the individual components. In addition, the refrigerant mixture can be chosen so that selective absorption in favor of the nonpolar component of the refrigerant mixture can take place in the absorbent material, thus causing the total vapor pressure of the resulting solution of refrigerant and absorbent material to rise less than would be the case with the same number of moles of the polar component such as R21 being absorbed alone. Also some separation on evaporation of a two component refrigerant can take place so that the lighter polar component will dominate in producing a vapor of lower molecular weight. This resulting lower molecular weight is an advantage when the vapor serves as secondary vapor pumped by an ejector.

The effect of a two component refrigerant in the absorber 40 and in the outer compartment 62, of the evaporation heat exchanger 26, will now be described. As hereinbefore mentioned, R21 is polar and R11 is nonpolar thus restricting the mutual solubility of the two components so that the total vapor pressure of the refrigerant liquid mixture of R21 and R11 in the evaporator 54 is greater than the vapor pressure obtained by a straight line molar interpolation based on the vapor pressures of pure R11 and of pure R21 taken separately, as shown by the curves of FIG. 3. In other words the two liquid refrigerant mixture of R21 and R11 has a vapor pressure that is greater than would be given by Raoults law. Furthermore, test results associated with the curves of FIG. 3 and other refrigerant mixtures such as R21 and R114 have shown that for mixed liquid compositions in a region to the left of the peak of the vapor pressure curve when such a peak occurs, that is to say in a region of composition in which there is a greater proportion of nonpolar refrigerant than at the peak of the curve, the vapor phase of refrigerant mixture has a greater molar proportion of polar component than the proportion of polar component in the liquid phase from which the vapor originated. Tests have also shown that the reverse is true to the right of the peak of the curve, while at the peak of the curve the composition of the vapor is more nearly like that of the liquid phase with which it is in equilibrium. But in the vapor phase the partial vapor pressure of each refrigerant component is proportional to its molar fraction of the total vapor, independent of polarity and other physical properties. Therefore a composition range of R21 and R11 exists in which the partial vapor pressure of nonpolar component is at least as great a proportion of the total vapor pressure as the proportion of nonpolar component in the liquid refrigerant mixture from which it evaporated. Also the molar amount of a given vapor component that a nonpolar absorbent material will absorb from a limitless supply of refrigerant vapor mixture is inversely proportional to the volatility of the given component, is less if the component is polar rather than nonpolar, and is proportional to the partial vapor pressure of the given component. Thus from a limitless supply of a refrigerant vapor mixture of equal molar parts of R21 and of R11 a liquid absorbent material such as R112 will absorb more of the nonpolar R11 than of the polar R21.

In operation therefore proportionally more moles of the nonpolar fluorocarbon R11 than R21 is absorbed within the absorber 40 at the beginning in the high temperature section 42. of the absorber 40, where there is effectively a limitless supply of mixed refrigerant vapor entering, thus reducing the amount of R11 in the refrigerant vapor mixture that passes on to the cooler ambient temperature section 44 or tothe still cooler outer compartment 62, of the evaporation heat exchanger 26, where absorption of the remaining refrigerant vapor takes place. As it takes'more moles of the less volatile and nonpolar R11 to raise the vapor pressure of a solution of a refrigerant and a nonpolar absorbent to a given equilibrium pressure level than it would take of a polar and more volatile refrigerant component like R21, selective absorption of R11 in the high temperature section 42, of the absorber 40, in contact with an effectively limitless stream of mixed refrigerant vapor brings about absorption of a greater total number of moles of refrigerant vapor in the high temperature section 42 and a corresponding decrease in the total remaining moles of refrigerant vapor absorbed within the outer compartment 62 of the evaporation heat exchanger 26. Thus proportionally more heat is liberated at the higher temperature level within the absorber 40 than would be liberated if only one of either R11 or R21 were being absorbed in the absorber 40 as a single component refrigerant, and similarly proportionally less heat is liberated in the outer compartment 62 of the evaporation heat exchanger 26. Of course a two component refrigerant of polar R22 and nonpolar R12 could be used to produce the aforementioned deviation from Raoults law and also effect the aforementioned selective absorption so that more R12 would be absorbed in the high temperature section 42 and less on the outer compartment 62, of the evaporation heat exchanger 26, so that more heat would be liberated in the high temperature section 42 and so less heat would be liberated in the outer compartment 62 of the evaporation heat exchanger 26.

The overall operation of the refrigeration system 10 shown in FIG. 1 will now be described with a two component refrigerant of R21 and R11 chosen as an example and with R112 as an example of absorbent material. However it is to be understood that for instance, a two component refrigerant such as R22 and R12 could also be used in the refrigeration system 10 with R112 or R113 as the absorbent material. Varying operating conditions and engineering details make the molar proportions of the three liquids of the system vary at any point in the system, so examples of molar proportions at various points of the system can only be given in relative trends that help to clarify features of the invention. All percent proportions of fluorocarbon compounds illustrated hereafter will be in molar percent proportions.

The densities at 77 F. of the example two refrigerant components R21 and R11 and liquid absorbent material R112 are as follows: density of R21, 85.28 pounds per cubic 'foot, density of R11, 92.1 pounds per cubic foot, and density of R112, 102 pounds per cubic foot.

The weak solution of R11, R21 and R112 in the bottom of the boiler 12 has settled there because it has become nearly depleted of R21 and R11, having the assumed proportions of 92% R112, 6% R11 and 2% R21, and has higher density than a rich solution of R11 and R21 in R112 as can be determined by the above relative densities. For example, boiling may'take place in the boiler 12 near 300 F. at a boiler pressure sufficient to operate the ejector 13. This hot weak solution in the boiler 12 is partially cooled as it leaves the outlet tube 18, of the analyzer 16, and before it is sprayed over the preheat exchanger 48, of the absorber 40, in absorbing contact with refrigerant vapor of assumed composition 50% R21 and 50% R11. In the high temperature section 42, of the absorber 40, proportionally more R11 than R21 is absorbed because ofthe higher boiling point and lower volatility of R11, and the liberated heat of vaporization raises the temperature of such weak solution as well as the preheat exchanger 48 with which such weak solution is in contact to approach an equilibrium value between ambient temperature and the temperature of the boiler 12. The equilibrium temperature is that temperature at which the total vapor pressure of such weak solution equals the vapor pressure within the evaporator 54 containing 50% R21 and 50% R11. As more R11 and R21 is absorbed by this solution moving downward within the high temperature section 42, this equilibrium temperature drops to near ambient temperature.

At this equilibrium temperature it is probable that the richer solution has come to the proportions 72%-R112, R11 and 8% R21 by the time it flows downward into the cooler outer compartment 62, of the evaporation heatexchanger 26, having absorbed an additional twenty percent (20%) refrigerant mixture. If the entering weak solution had simply absorbed equal amounts ofRll and R21 fromthe 50% R21 and 50% R11 refrigerant vapor the total equilibrium vapor pressure would-have been reached when the absorbent solution came to the, pro.- portions of 76% R112, 14% R11 and 10% R21, then having'absorbed but 16% additional refrigerant mixture. Thus, there has actually, been something like one quarter more refrigerant vapor absorbed in the absorber 40. The remaining refrigerant vapor containing a greater proportion of R21 than R11 passes from the absorber 40 on into the outer compartment 62, of the evaporation heat exchanger 26, so that the final rich solution disposed in the bottom of the outer compartment 62 reaches the proportions 60% R112, 22% R11 and 18% R21 by the time the last remnant of refrigerant vapor is dissolved. As the composition of the final rich solution of refrigerant and absorbent material is effectively determined only by the temperature within the inner compartment 62, of the evaporation heat exchanger 26, and the vapor pressure of the original 50% R21 and 50% R11 refrigerant existing in the evaporator 54, any additional refrigerant vapor absorbed in the absorber 40 reduces the proportion of refrigerant vapor absorbed in the inner compartment 62 of the evaporation heat exchanger 26 and thus reduces the proportion of heat of vaporization that must be absorbed by the action of the evaporation heat exchanger 26. This permits the ejector 13 to further reduce the pressure of the refrigerant vapor within the inner compartment 64, of the evaporation heat exchanger 26, which in turn reduces the temperature therein to thus permit the final rich solution of refrigerant and absorbent material within the outer compartment 62 to require a greater concentration of refrigerant in absorbent material.

The composition of power vapor delivered to the ejector 13 is the same 50% R21 and 50% R11 as in the evaporator 54, and-has a molecular weight of 119.9. Also the composition of the vapor evaporated from the 50% R21 and 50% R11 refrigerant liquid within the inner compartment 64 of the evaporation heat exchanger 26 is more nearly 65% R21 and R11, with corresponding molecular weight of 111.8. Thus the molecular weight of the secondary vapor supplied to the ejector 13 is less than the molecular weight of the power vapor coming from the boiler 12. This difference in molecular weight between power vapor and secondary vapor increases the efiiciency of the ejector 13 as a pump.

Referring to FIG. 4 there is illustrated another embodiment of the teachings of this invention in which like components of FIGS. 1 and 4 have been given the same reference characters.

A heated boiler 112, heat source not shown, functions to separate refrigerant vapor from a rich solution of refrigerant and absorbent material and to direct refrigerant vapor under pressure to a conduit 114 through which the refrigerant vapor flows to the power inlet means 20 of the ejector 13. An analyzer 116 operates at the same pressure as in the corresponding analyzer 16 of FIG. 1 and an inlet tube 118 and an outlet tube 120 function in a similar manner as the corresponding tubes 14 and 18 in FIG. 1 to separate refrigerant vapor from absorbent material. But a pressure and flow control means 122 permits the outer compartment 124, of the boiler 112, to operate at a lower pressure than the inner compartment 126 of the boiler 112 so that additional refrigerant vapor can be separated from the absorbent material and so that the weak solution of refrigerant and absorbent material leaving the boiler 112 is more nearly completely separated absorbent. To do the same degree of separating at the higher pressure withinthe inner compartment 126, of the boiler 112, would .require a considerably higher boiling temperature and this higher boilingtem perature would effect a greaterdegree ofdecomposition of the refrigerant and absorbent material.-The pressure andrfiow control means 122 is apressure compensated float valve, however other equivalent control mechanisms can be used. I t

The secondary refrigerant inlet means 22 of the ejector13 is operatively associated with an evaporation heat exchanger 128 for pumping refrigerant vapor from the evaporation heat exchanger 128 into the refrigerant inlet means 22, andthe discharge means 24, of the ejector 13, is operatively associated with a conventional con? denser 130 to discharge refrigerant vapor into the condenser 130 for condensing. Also .the power inlet means 20, of the ejector 13, is operatively associated with the boiler 112 for receiving refrigerant vapor from the boiler 112.

A conduit 132 is interconnected between the outer compartment 124, of the boiler 112, and the condenser 130 so that refrigerant vapor passes from the outer com-v partment 124 to the condenser 130 for condensing. A fractionating section 134, of the conduit 132, is in thermal contact with a solution of refrigerant and absorbent material which is disposed within the evaporation heat exchanger 128 and which is somewhat cooler than the refrigerant vapor and any entrained absorbent vapor flowing in the conduit 132 so that the less volatile absorbent vapor that is entrained with refrigerant vapor flowing in the conduit 132 is condensed out as liquid and returns to the outer compartment 124 of the boiler 112.

The condenser 130 is cooled to near ambient temperature by ambient air circulating over radiation fins 136. A precooler 138 is interconnected between the condenser 130 and an evaporator 140 and with the refrigerant inlet means 22, of the ejector 13, so that condensed refrigerant flows from the condenser 130 through a conduit 142 and a flow regulator 144 into the precooler 138. The flow regulator 144 may be a conventional float valve for regulating the flow of the liquid refrigerant from the condenser 130 to the precooler 138.

In operation the ejector 13 reduces the pressure within the precooler 138 so that a portion of the condensed refrigerant within the precooler 138 evaporates, vthus cooling the remaining portion of the condensed refrigerant within the precooler 138 before such.cooled remaining portion of refrigerant passes to theevaporator 140 through a fiow regulator 146 and a conduit 148. The fiow regulator 146 regulates the flow of cooled liquid refrigerant to the evaporator 140 and may be a con,- ventional float valve.

In order to pump and remove from the evaporator 140 refrigerant vapor that evaporates within the evaporator 140 and absorb such refrigerant vapor, an absorber 150 is operatively connected to the evaporator 140 by means of a conduit 152. The absorber 150 includes a high temperature section 154, an ambient temperature section 156, having radiation fins 158, a preheat exchange and a distributer 162.

The evaporation heat exchanger 128 includes a housing 164 for receiving a rich solution of, refrigerantand absorbent material from the absorber 150. In particular, a rich solution of refrigerant and absorbent material is pumped by means of a pump 166 from the ambient temperature section 156 and through a conduit means 168, through the preheat exchanger 160, through a conduit 170 and into the housing 164 of the evaporation heat exchanger 128. The evaporation heat exchanger 128, also includes a helical shaped heat exchange tube 172 which is disposed in heat exchange relationship with the rich solution of refrigerant and absorbent material ,disposed within the housing 164. In order to pass a relatively hot weak solution of.refrigerant and absorbent material through the heat exchange tube 172Hofthe evaporation heat exchanger 1 28 and into the high tern;

13 peratu're section 154, of the absorber 150, conduit means 174 interconnects the heat exchange tube 172 with the outlet tube 120, of the boiler 112, and with the high temperature section 154 of the absorber 150.

In order to'increase the absorbing capacity of the absorber 150, an opening 176 is provided in the conduit means 174 so that the weak solution of refrigerant and absorbent material disposed'in the bottom of the housing 164, of the evaporation heat exchanger 128, flows into the opening 176 and returns to the high temperature section 154 of the absorber 150. A restriction 178 is provided in the conduit means 174 so as to regulate the flow of hot weak solution of refrigerant and absorbent material from the boiler 112 to the high temperature section 154 of the absorber 150;

A boiler pump 180 is interconnected between the inlet tube 118, of the boiler 112, and the housing 164, of the evaporation heat exchanger 128, by conduit means 182 in order to pump the rich solution of refrigerant and absorbent material from the upper part of the housing 164 into the boiler 112.

The operation of the refrigeration system illustrated in FIG. 4 will now be described in a simple mode with a refrigerant of one volatile component and a liquid absorbent material that is very much less volatile. However a two component refrigerant such as described with reference to the embodiment of FIG. 1 can be used in this system with similar advantages to those shown for the refrigeration system of FIG. 1. Rich solution of refrigerant and absorbent material is pumped into the heated boiler 112 by way of the inlet tube 118 of the analyzer 116. Refrigerant vapor is separated from this rich solution in the analyzer 116 at high pressure and is conducted out through the conduit 114 to the power inlet means to power the ejector 13; the separation of the refrigerant vapor being similar to that described with reference to the refrigeration system 10 of FIG. 1. As the solution of refrigerant and absorbent material loses refrigerant by evaporation it becomes more dense than the aforementioned rich solution and settles to the bottom of the inner compartment 126 from where it is forced out through the pressure and flow control means 122 into the outer compartment 124, of the boiler 112, where the pressure is lower and is near that pressure within the condenser 130.

In the outer compartment 124, of the boiler 112, additional refrigerant vapor with some entrained absorbent vapor is boiled off at a pressure near the pressure within the condenser 130, and this vapor leaves the outer compartment 124 by the conduit 132 and the fractionating section 134 where absorbent is condensed to a liquid to be returned to the boiler 112 through the conduit 132 so that separated refrigerant vapor is delivered to be condensed to a liquid in the condenser 130. The hot weak solution of refrigerant and absorbent material left in the outer compartment 124 of the boiler 112 leaves through the outlet tube 120 and flows through the conduit means 174, the restriction 178, and the heat exchanger tube 172, of the evaporation heat exchanger 128, to the high temperature section 154 of the absorber 150.

The weak solution of refrigerant and absorbent material from the boiler 112 enters the top of the high temperature section 154, of the absorber 150, and flows over the distributer 162 so the weak solution becomes distributed over the surface and in thermal contact with the preheat exchanger 160 and is disposed in absorbing contact with refrigerant vapor coming from the evaporator 140 and at the same low pressure as within the evaporator 140. As refrigerant vapor is absorbed by such weak solution entering from the boiler 112, resulting heat of vaporation that is liberated is transferred to the rich solution of refrigerant and absorbent material that is flowing within the preheat exchanger 160. This solution of refrigerant and absorber material becomes cooler and continues to absorb more refrigerant vapor as it 14 moves downward along the preheat exchanger 160.until it drops into the ambient temperature section 156, of the absorber 150, where further refrigerant vapor is absorbed with liberation of heat of vaporation and the solution finally becomes a rich solution of refrigerant and absorbent material.

The rich solution of refrigerant and absorbent material is pumped from the absorber by the pump 166'and through the preheat exchanger and the'conduit 170 into the housing 164 of the evaporation heat excanger 128. Such rich solution is preheated as it passes through the preheat exchanger 160 to aid in forming refrigerant vapor to be compressed by the ejector, and a portion-of the absorbed refrigerant may be converted to vapor under reduced pressure caused by pumping action of the ejector 13 even before the preheated solution reaches the housing 164 of the evaporation heat exchanger 160. As the preheated rich solution reaches the top portion of the evaporation heat exchanger 128 a portion of such solution enters the conduit means 182 to be pumped back to the boiler 112 by the boiler pump 180, while the remaining portion of such rich solution receives additional heat from the hot weak solution of refrigerant and absorbent material flowing through the heat exchange tube 172, of the evaporation heat exchanger 128, and from heat of condensation due to hot absorbent vapor condensing within the fractionating section 134 so that a portion of dissolved refrigerant is evaporated from this remaining portion of rich solution within the housing 164 at the reduced pressure caused by the pumping action of the ejector 13. The resulting refrigerant vapor within the evaporation heat exchanger 128 is pumped back through a conduit 184 and the ejector 13 to be condensed to a liquid in the condenser 130. The portion of solution of refrigerant and absorbent material remaining within the housing 164 of the evaporation heat exchanger 128 settles lower in the evaporation heat exchanger 128 as it becomes more dense on losing refrigerant of less density by evaporation, and enters the opening 176 to combine with the hot weak solution of refrigerant and absorbent material that is returning to the high temperature section 154, of the absorber 150, from the boiler 112. In operation the pressure within the housing 164 is greater than the pressure within the evaporator 140.

A portion of the liquid condensed refrigerant disposed Within the precooler 138 is evaporated and the resulting refrigerant vapor is pumped from the precooler 138 by action of the ejector 13 through a conduit 186 and the conduit 184 so that the remaining portion of the condensed refrigerant disposed within the precooler 138 is precooled before such cooled condensed refrigerant portion flows into the evaporator 140, thus allowing the space that surrounds the evaporator 140 to be cooled Without carrying such a large amount of heat of vaporization of the refrigerant to the absorber 150usince a portion of the heat of vaporization of the refrigerant is pumped from the precooler 138 to the condenser 130 and the remaining cooled liquid refrigerant flowing into the evaporator 140 can still do as much cooling of the space to be cooled as a larger amounts of non precooled refrigerant can.

It is to be understood that the boiler 12 of FIG. 1 can be connected in the refrigeration system of FIG. 4- in place of the boiler 112. Of course the conduit 132 and the fractionating section 134 would be removed if such a substitution were made.

The apparatus embodying the teachings of this invention has several advantages. For instance, a refrigeration system constructed in accordance with the teachings of this invention can operate efficiently with safe fluorocarbon working mediums. In addition, a refrigeration system constructed in accordance with the teachings of this invention can operate efllciently with ambient air cooling of the absorber and the condenser. Further, the cost of such refrigeration systems in minimized. Also, the efficiency of such refrigeration systems constructed in accordance with the teachings of this invention can be further increased by utilizing selected pairs of fluorocarbonrefrigerants as hereinbefore described. Since certain changes may be made in the above described apparatus and different embodiments of the invention may be made without departing from the spirit andthe scope thereof, it is intended that all matter containedin-theabove description or shown in the accompanying drawingsshall be interpreted as illustrative and not in a limiting sense.

-.I- claim as my invention: refrigeration system comprising the following connected to form a. closed system: boiler means for vaporizing refrigerant; a condenser for condensing refrigerant; an evaporator for evaporating refrigerant and providing a cooling effect; an absorber for absorbing refrigerant vapor; an evaporation heat exchanger operatively associated with absorber for receiving a solution of refrigerant and absorbent material from said absorber and for producing refrigerant vapor, at least a part of such solution being returned to said boiler means from said evaporation heat exchanger; and pump means having power inlet means, refrigerant inlet means and discharge means, said pump means being so operatively associated with said boiler means, with said evaporation heat exchanger, and with said condenser that refrigerant vapor passes from said boiler means and into the power inlet means of said pump means and from said evaporation heat exchanger and into the refrigerant inlet means of said pump means to thus discharge refrigerant vapor from the discharge means of said pump means and into said condenser for condensing.

2. A refrigeration system comprising the following connected to form a closed system: boiler means for vaporizing refrigerant; a condenser for condensing refrigerant; and evaporator for evaporating refrigerant and providing a cooling effect; an absorber for absorbing refrigerant vapor; an evaporation heat exchanger having a first compartment and a second compartment disposed in heat transfer relationship with the first compartment, said evaporation heat exchanger being operatively associated with said absorber and with said condenser so that a solution of refrigerant and absorbent material passes from said absorber into the first compartment of said evaporation heat exchanger, at least a portion of such solution within the first compartment of said evaporation heat exchanger being returned to said boiler means, and so that condensed refrigerant passes from said condenser into the second compartment of said evaporation heat exchanger, said evaporation heat exchanger also being operatively associated with said evaporator so that a portion of the refrigerant evaporated within said evaporator passes into the first compartment of said evaporation heat exchanger and is absorbed by the absorbent material disposed therewithin; and pump means having power inlet means, refrigerant inlet means and discharge means, the power inlet means of said pump means being operatively associated with said boiler means for receiving refrigerant vapor from said boiler means, the refrigerant inlet means of said pump means being operatively associated with the second compartment of said evaporation heat exchanger so as to draw refrigerant vapor therefrom and thus reduce the pressure within such second compartment and thereby effect an evaporation of at least a portion of the condensed refrigerant within such second compartment and thus reduce the temperature of the solution of refrigerant and absorbent material disposed within the first compartment of said evaporation heat exchanger, and the discharge means of said pump means being operatively associated with said condenser to discharge refrigerant vapor into said condenser for condensing. 1

3. The refrigeration system in accordance with claim 2 in which said pump means is an ejector having powcr inlet means, refrigerant inlet means and discharge means.

4. A refrigeration system for using at least a two component refrigerant, one component being more volatile than the other component, and comprising the following connected to form a closed system; boiler means for vaporizing refrigerant; a condenser for condensing refrigerant; an evaporator for evaporating refrigerant and providing a cooling effect; an absorber operatively associated with said evaporator for receiving refrigerant vapor from said evaporator; an evaporation heat exchanger having a first compartment and a second compartment disposed in heat transfer relationship with the first compartment, said evaporation heat exchanger being so operatively as sociated with said absorber and with said condenser that a solution of refrigerant and absorbent material passes from said absorber into the first compartment of said evaporation heat exchanger, at least a portion of such solution within the first compartment of said evaporation heat exchanger being returned to said boiler means, and that a portion of the refrigerant vapor received from said evaporator passes from said absorber into the first compartment of said evaporation heat exchanger with proportionally more of the less volatile component of refrigerant being absorbed in said absorber than in absorbent material disposed within the first compartment of said evaporation heat exchanger, and that condensed rfrig erant flows from said condenser into the second compartment of said evaporation heat exchanger; and pump means having power inlet means, refrigerant inlet means and discharge means, the power inlet means of said pump means being operatively associated with said boiler means for receiving refrigerant vapor from said boiler means, the refrigerant inlet means of said pump means being operatively associated with the second compartment of said evaporation heat exchanger so as to draw refrigerant vapor therefrom and thus reduce the pressure within such second compartment and thereby effect an evaporation of at least a portion of the condensed refrig rant within such second compartment and thus reduce the temperature of the solution of refrigerant and absorbent material disposed within the first compartment of said evaporation heat exchanger, and the discharge means of said pump means being operatively associated with said condenser to discharge refrigerant vapor into said condenser for condensing.

5. A refrigeration system comprising the following connected to form a closed system: boiler means for vaporizing refrigerant; a condenser for condensing refrigerant; an evaporator for evaporating refrigerant and providing a cooling effect; an absorber for absorbing refrigerant vapor; an evaporation heat exchanger for receiving a rich solution of refrigerant and absorbent material from said absorber and for passing a weak solution of refrigerant and absorbent material, flowing from said boiler means to said absorber, in heat exchange relationship with such received rich solution of refrigerant and absorbent material so as to effect a separation of refrigerant from such received rich solution of refrigerant and absorbent material by evaporation thus producing refrigerant vapor and leaving a residue of liquid; means for effecting a flow of at least part of such liquid residue to said boiler means; and pump means having power inlet means, refrigerant inlet means and discharge means, the power inlet means of said pump means being operatively associated with said boiler means for receiving refrigerant vapor from said boiler means, the refrigerant inlet m ans of said pump means being operatively associated with said evaporation heat exchanger for pumping refrigerant vapor from said evaporation heat exchanger into the refrigerant inlet means of said pump means, and the discharge means of said pump means being operatively associated with said condenser to discharge refrigerant vapor into said condenser for condensing.

6. The refrigeration system in accordance with claim 5 in which said pump means is an ejector having a power 17 inlet means, a refrigerant inlet means and discharge means.

7. The refrigeration system in accordance with claim 5 in which a precooler is interconnected between said condenser and said evaporator and with the refrigerant inlet means of said pump means so that condensed refrigerant flows from said condenser into said precooler and said pump means reduces the pressure within said precooler so that a portion of the condens d refrigerant within said precooler evaporates thus cooling other associated condensed refrigerant within said precooler before such associa'ted'condensed refrigerant flows into said evaporator.

8. The combination comprising, an evaporator for evaporating refrigerant and providing a cooling effect; a condenser for condensing refrigerant; a precooler, said precooler being operatively associated with said condenser for receiving condensed refrigerant from said condenser; and an ejector pump for reducing the pressure within said precooler to thereby evaporate a portion 0 the condensed refrigerant disposed within said precoole to thus cool other associated condensed refrigerant Withil said precooler and for withdrawing evaporated refrigeran from said precooler, said precooler being operatively as sociated with said evaporator so that cooled condenser refrigerant disposed within said precooler flows into Sait evaporator for evaporation.

References Cited UNITED STATES PATENTS 1,761,762 6/1930 Whitney 62501 1,887,957 11/1932 Altenkirch 62483 X1 1,949,732 3/1934 Whitney 62500 XI 2,446,988 8/1948 Flukes 62-481 MEYER PERLIN, Primary Examiner.

U.S. DEPARTMENT OF COMMERCE PATENT OFFICE Washington, 0.6. 20231 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,402,570 September 24, 1968 Ralph C. Schlichtig It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 15, line 18, before "absorber" insert said (SEAL) Attest:

Edward M. Fletcher, Jr.

Attesting Officer Commissioner of Patents WILLIAM E. SCHUYLER, JR.