US3171268A

US3171268A - Closed cycle refrigeration system

Info

Publication number: US3171268A
Application number: US191543A
Authority: US
Inventors: Silver Alexander
Original assignee: Garrett Corp
Current assignee: Garrett Corp
Priority date: 1962-05-01
Filing date: 1962-05-01
Publication date: 1965-03-02
Anticipated expiration: 1982-03-02

Description

March 1965 A. SILVER 3,171, 68

CLOSED CYCLE REFRIGERATION SYSTEM Filed May 1, 1962 2 Sheets-Sheet 1 IN TEE-C001. ER

E VA PORA TOR REFRIGERATED SPACE INVENTOR. ALEXANDER SILVER,

BY vzwfipi A Home March 2, 1965 A. SILVER 3,171,258

CLOSED CYCLE REFRIGERATION SYSTEM Filed May 1, 1962 Fig.2

2 Sheets-Sheet 2 E VAPOR/170R RE FR/GERA TED SPACE IN TEE-6 OOLER INVENTOR.

ALEXANDER SILVER,

United States Patent ice 3,171,268 CLOSED CYCLE REFRIGERATION SYSTEM Alexander Silver, Tarzana, Calif, assignor to The Garrett Corporation, Los Angeles, Calif, a corporation of California Filed May 1, 1962, Ser. No. 191,543 3 Claims. (Cl. 62-498) This invention relates to a closed cycle refrigeration system and in particular relates to a closed vapor cycle refrigeration system in which an expansion turbine is utilized in conjunction with an external power source to operate a centrifugal compressor which impels refrigerant fluid through the refrigeration system.

In the operation of a closed cycle refrigeration system it is often desired to utilize a centrifugal compressor assembly capable of propelling a large volume of refrigerant fluid at a low pressure. In such systems difficulty sometimes is encountered in obtaining sufficiently high discharge pressure from the compressor so that refrigerant vapor may be condensed when the coolant fluid, utilized for effecting vapor condensation, has a relatively high temperature. When the temperature of the coolant is high and the pressure of the refrigerant fluid is correspondingly low condensation of refrigerant vapor will not be effected. Under these conditions an expansion valve and an evapo-- rator unit, which constitute a part of such a refrigerant cycle, are not capable of performing their designed function.

When the closed cycle refrigeration system is operating effectively refrigerant liquid is delivered to an expansion valve and an evaporator unit. The refrigerant liquid absorbs heat from the space to be refrigerated and the refrigerant liquid thereby is transformed from a liquid to a vapor state. Thus, it is apparent that when refrigerant vapor is not condensed to a liquid state prior to its delivery to an expansion valve and evaporator unit these portions of the refrigerant cycle cannot function properly and the desired refrigeration effect cannot be achieved.

Further, in the operation of a closed cycle refrigeration system considerable power is required for operating the equipment used to propel refrigerant fluid through the system. For example, in order to create a desired volume flow rate and fluid pressure condition for the refrigerant fluid, excessively large and complex motive equipment may be required. This motive equipment demands a high energy supply source so that the desired conditions of flow rate and pressure may be maintained within the refrigeration system. In providing for economical and effective refrigeration the conservation of power is an important result to be achieved.

Accordingly, it is an object of this invention to provide a closed cycle refrigeration system wherein a high volume flow rate of refrigerant fluid is maintained with the use of a minimum amount of power from an outside source.

Another object of this invention is to provide a refrigeration system which is versatile as to the type of refrigerant fluids which may be utilized in achieving economical and effective refrigeration.

Another object of this invention is to provide a closed cycle refrigeration system in which predetermined pressure and temperature conditions are easily maintained for the effective condensation of refrigerant vapor.

Another object of this invention is to provide a refrigerant system in which refrigerant fluid is transferred at low pressure to an intercooler unit in which the temperature of coolant fluid may be maintained at a relatively high level.

That these and other objects and advantages of the invention are obtained will be readily apparent from the following detailed descriptions, when read in conjunction with the accompanying drawings in which:

FIGURE 1 is a schematic diagram showing the closed cycle refrigeration system;

FIGURE 2 is a schematic diagram showing the same system with a liquid pump included in the system.

Referring to FIGURE 1 of the drawings, reference character 1 designates an expansion valve. A portion of the refrigerant liquid which flows through valve 1 is expanded into a vapor state. The refrigerant fluid which flows from expansion valve 1 passes into an evaporator unit 2. Evaporator 2 is located within the space 3 which is to be cooled by refrigeration. Refrigerant fluid flowing through evaporator 2 absorbs heat from the space 3. As heat is absorbed by the refrigerant fluid the fluid is transformed into a vapor state. Refrigerant vapor then flows from evaporator 2 into a compressor unit 4. In this refrigeration cycle compressor 4 may be a centrifugal compressor which iscapable of producing a large volume flow rate at a low discharge pressure.

Refrigerant vapor is discharged from compressor 4 into an intercooler unit 5. A coolant fluid 6 is circulated through the intercooler 5 by any well known means for producing fluid circulation. Heat in the refrigerant vapor is transferred to the coolant fluid 6 before the refrigerant vapor flows into a condenser-evaporator unit 7, or through a turbine 8. Reference character 9 designates a valve which controls the flow of coolant fluid to the intercooler unit 5.

Referigerant vapor flowing from intercooler 5 into turbine 8 passes through a valve 10. Valve 10 may be operated to control the flow of refrigerant vapor to turbine 8. The flow of refrigerant vapor through turbine 8 imparts a propelling force to the blading structure within the turbine unit. Also, in flowing through turbine 8 the refrigerant vapor undergoes an isentropic expansion.

Turbine 8 is connected by .a shaft 11 to compressor 4. The rotation of turbine 8 drives compressor 4 through the shaft connection 11. A motor 12 also is connected to compressor 4 through shaft 11. Turbine 8 and motor 12 share the load in driving compressor 4.

As refrigerant vapor undergoes isentropic expansion through turbine 8 the temperature of the refrigerant vapor is lowered. Refrigerant vapor from turbine 8 flows through coils 13 within condenser unit 7. The low temperature vapor flowing from turbine 8 through coils 13 absorbs heat from refrigerant fluid flowing from intercooler 5. Thus, a further lowering of the temperature of the refrigerant fluid from intercooler 5 is effected by the heat exchange process which takes place within condenser 7. When none of the refrigerant fluid flowing from intercooler 5 has been changed to a liquid state prior to its entry into condenser 7 the heat exchange process within condenser 7 effects complete condensation of this fluid. In the event that fluid is completely condensed in intercooler 5, valve 10 may be closed and turbine 8 may be taken out of the closed vapor system. In this latter event the sole function of condenser unit 7 is to collect condensate from intercooler 5.

The operational position of valve 10 controls the amount of fluid which is passed through turbine 8. Thus, valve 10 may be used to control the amount of power supplied to compressor 4 by the turbine 8.

It is apparent that while turbine 8 is operating the power required to operate motor 12 for driving compressor 4 will be substantially reduced. Also, it is apparent that in this refrigeration system there is no necessity for maintaining a substantially low temperature for the coolant fluid which flows through an intercooler in order to obtain effective cooling within the space cooled by refrigeration.

Patented Mar. 2, 1965,

FIGURE 2 shows the same refrigeration system as illustrated in FIGURE 1 with the exception that a liquid boost pump has been added to the system. The addition of. this pump is for the purpose of mtaining adequate circulation pressure. within the system when the evaporator unit and the space to be refrigerated are located at a substantially higher elevation than other equipment used in the system. The liquid pump 14 is driven by motor 12 through

gear connections

15 and 16. Thus, by the addition of pump 14 eflicient refrigeration is assured regardless of the elevated location of the space that requires refrigeration.

It will be apparent to those skilled in the art that the novel principles of the invention disclosed herein will suggest various other modifications and applications of the same. It is accordingly desired that the present invention shall not be limited to the specific embodiment thereof described herein.

Having thus described my invention I claim:

1. A closed cycle refrigeration system comprising:

a centrifugal compressor for producing a high volume flow rate of refrigerant fluid at a low discharge pressure;

heat exchange means for cooling fluid discharged by said compressor;

a turbine driven by expansion of a portion of the fluid cooled by said cooling means, said turbine being connected to said compressor to drive said compressor;

additional drive means coupled with said compressor to assist in driving the same;

a condenser unit including conduit means coupled with said heat exchange means for condensing the remainder of vapor flowing from said cooling means;

conduit means within said condenser unit through which fluid exhausted from said turbine is circulated in heatexchanging relation to said remainder of the vapor to condense same;

an expansion valve in fluid communication with said condenser;

an evaporator unit connected to said expansion valve to receive vaporized fluid therefrom, said evaporator unit being located in a space which is to be cooled by refrigeration; and

conduit means delivering vaporized fluid directly from the evaporator unit and from the condenser to said compressor.

2. A closed cycle refrigerant system in accordance with claim 1 in which said turbine is an isentropic expansion device and said refrigerant fluid flowing through said turbine undergoes an isentropic expansion.

3. A closed cycle refrigeration system comprising:

a rotary centrifugal compressor for producing a high 7 volume flow rate of refrigerant fluid at a low discharge pressure;

heat exchange means for cooling fluid discharged by said compressor;

a turbine driven by expansion of a first portion of the fluid cooled by said cooling means, said turbine being mechanically connected to said compressor to drive said compressor;

electric motor means operated by an outside source of electric power for driving said compressor, said motor means and said turbine sharing the load of driving said compressor;

a condenser unit including conduit means coupled with said heat exchange means for condensing a second portion of the vapor flowing from said cooling means;

conduit means within said condenser unit through which fluid exhausted from said turbine is circulated in heat-exchanging relation to said second portion of the vapor to condense same;

an expansion valve in fluid communication with said condenser;

an evaporator unit connected to said expansion valve to receive vaporized fluid therefrom, said evaporator unit being located in a space which is to be cooled by refrigeration;

and conduit means delivering vaporized fluid directly from the evaporator unit and from the condenser to said compressor without substantial addition of heat to the vaporized fluid.

References Cited in the file of this patent UNITED STATES PATENTS 1,379,102 Jefleries May 24, 1921

Claims

1. A CLOSED CYCLE REFRIGERATION SYSTEM COMPRISING: A CENTRIFUGAL COMPRESSOR FOR PRODUCING A HIGH VOLUME FLOW RATE OF REFRIGERANT FLUID AT A LOW DISCHARGE PRESSURE; HEAT EXCHANGE MEANS FOR COOLING FLUID DISCHARGED BY SAID COMPRESSOR; A TURBINE DRIVEN BY EXPANSION OF A PORTION OF THE FLUID COOLED BY SAID COOLING MEANS, SAID TURBINE BEING CONNECTED TO SAID COMPRESSOR TO DRIVEN SAID COMPRESSOR; ADDITIONAL DRIVE MEANS COUPLED WITH SAID COMPRESSOR TO ASSIST IN DRIVING THE SAME; A CONDENSER UNIT INCLUDING CONDUIT MEANS COUPLED WITH SAID HEAT EXCHANGE MEANS FOR CONDENSING THE REMAINDER OF VAPOR FLOWING FROM SAID COOLING MEANS; CONDUIT MEANS WITHIN SAID CONDENSER UNIT THROUGH WHICH FLUID EXHAUSTED FROM SAID TURBINE IS CIRCULATED IN HEATEXCHANGING RELATION TO SAID REMAINDER OF THE VAPOR TO CONDENSE SAME; AN EXPANSION VALVE IN FLUID COMMUNICATION WITH SAID CONDENSER; AN EVAPORATOR UNIT CONNECTED TO SAID EXPANSION VALVE TO RECEIVE VAPORIZED FLUID THEREFROM, SAID EVAPORATOR UNIT BEING LOCATED IN A SPACE WHICH IS TO BE COOLED BY REFRIGERATION; AND CONDUIT MEANS DELIVERING VAPORIZED FLUID DIRECTLY FROM THE EVAPORATOR UNIT AND FROM THE CONDENSER TO SAID COMPRESSOR.