Enhanced liquid pressure cycle having an ejector

Abstract

The enhanced liquid pressure cycle having an ejector consists of a high-pressure positive displacement liquid rotary pump (liquid pressure pump). The liquid pressure pump provides the primary high-pressure mass flow to the evaporator and the pressure mass flow to the driving force input to a condensing and mixing ejector. The system is further enhanced by a vapor compressor/turbine/motor combination which provides the ability to suck out and lower the refrigerant pressure output from the evaporator while the interconnected turbine offsets the power input requirements of the vapor compressor. The high-pressure liquid from the liquid pressure pump is divided into two pressure streams. The first stream is directed to an expansion valve then on to an evaporator for space air or other medium cooling. The second stream is directed to the driving force input port of an ejector. This high-pressure input mixes with the low-pressure output from the turbine. The result of this mixing provides for sufficient pressure enhancement to condense the combination liquid and vapor refrigerant as it passes through the condenser. The liquid flow from the condenser proceeds back to the liquid pressure pump and the cycle is repeated. The horsepower to pressurize a liquid for a given mass flow of refrigerant for the enhanced liquid pressure cycle is significantly less than the horsepower required for a vapor compression cycle of equal mass flow.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a refrigeration system, which utilizes a positive displacement rotary liquid pump for its primary high-pressure refrigerant generation and is further enhanced with a vapor compressor/turbine/motor combination along with corresponding expansion valve, evaporator, ejector and condenser.

2. Description of the Prior Art

The vapor compression refrigeration cycle is the leading cooling method for millions of residential and commercial installations. The vapor compression cycle utilizes a vapor compressor to increase a low-pressure refrigerant gas to a high-pressure Refrigerant gas. The high-pressure gas then passes through an air or water-cooled condenser where the gas changes state into a high-pressure liquid upon the removal of heat from the high-pressure gas. This high-pressure liquid then passes through an expansion valve into an evaporator. During this expansion process, heat is absorbed in the evaporator with space air or other medium being circulated through the evaporator. The net result is the cooling of the conditioned space or medium.

The vapor compression cycle has only been improved on the margins. Typical improvements include more efficient vapor compressor designs, larger condenser and evaporator coils, use of variable speed modulation, use of liquid centrifugal pumps for increased expansion valve efficiency and the use of ejectors to reduce the amount of work expended by a vapor compressor. The goal of the enhanced liquid pressure cycle is to overcome the limited on the margin improvements of the vapor compression cycle.

SUMMARY

The enhanced liquid pressure cycle having an ejector consists of a high-pressure positive displacement liquid rotary pump (liquid pressure pump). The liquid pressure pump provides the primary high-pressure mass flow to the evaporator and the pressure mass flow to the driving force input to a condensing and mixing ejector. The system is further enhanced by a vapor compressor/turbine/motor combination which provides the ability to suck out and lower the refrigerant pressure output from the evaporator while the interconnected turbine offsets the power input requirements of the vapor compressor.

The high-pressure liquid from the liquid pressure pump is divided into two pressure streams. The first stream is directed to an expansion valve then on to an evaporator for space air or other medium cooling. The second stream is directed to the driving force input port of an ejector. This high-pressure input mixes with the low-pressure gas output from the turbine. The result of this mixing provides for sufficient pressure enhancement to condense the combination liquid and vapor refrigerant as it passes through the condenser. The liquid flow from the condenser proceeds back to the liquid pressure pump and the cycle is repeated.

The horsepower to pressurize a liquid for a given mass flow of refrigerant for the enhanced liquid pressure cycle is significantly less than the horsepower required for a vapor compression cycle of equal mass flow.

It is an object of the invention to provide a simple refrigeration system with significant advantages over systems of prior art.

Additional objects and advantages of the invention are set forth, in part in the description which follows, and in part, will be obvious from description or may learned by practice of the invention. The objects and advantages of the invention will be realized in detail by means of the instrumentalities and combinations particularly pointed out in the appended claim.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawing is incorporated in and form a part of the specification and together with the descriptions serves to explain the principles of the invention in which FIG. 1 is a schematic diagram of the enhanced liquid pressure cycle having an ejector.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

It is understood that both the foregoing general description and following detailed description are exemplary and explanatory only, and are not restrictive of the invention as claimed. The accompanying drawing which is incorporated herein for reference, and constitute part of the specifications, illustrate certain embodiments of the invention, and together with the detailed description serve to explain the principles of the present invention.

Reference will now be made in detail to the embodiment of the refrigeration system of the present invention. This example is illustrative only and should not be construed to limit the invention unnecessarily.

As shown in FIG. 1, the refrigeration cycle of the present invention begins with increasing the pressure of a liquid refrigerant HFC-134A with a high-pressure liquid pressure pump 10 powered by a fixed or variable speed motor 11.

This high-pressure liquid travels through conduit 12 and enters the expansion valve 14 then into evaporator 15. The expansion valve 14 opens and closes depending upon the set point temperature requirements of the evaporator 15. There are several schemes to accomplish this control function currently in use today. During this expansion process, heat is absorbed in the evaporator 15 with space air or other medium being circulated through the evaporator 15.

The low-pressure gas output of the evaporator 15 proceeds through conduit 16 to compressor 17. The compressor 17 provides a reliable means of sucking and lowering the pressure in evaporator 15 and compresses the low pressure gas into a high-pressure gas.

The high-pressure gas proceeds through conduit 18 to the turbine 19 where it is expanded into a low-pressure gas. During this expansion the horsepower generated by the turbine 19 offsets or reduces the horsepower input required for compressor 17. It is to be noted that the electrical motor 20, compressor 17 and turbine 19 are interconnected on a common drive shaft 21. This allows the electrical motor 20 to provide the basic horsepower input to the compressor 17 which is significantly offset by the horsepower output of the turbine 19. The expanded low-pressure gas output of the turbine 19 proceeds through conduit 22 into the low-pressure port 23b of the ejector 23. Concurrently approximately fifty to seventy five percent of the high-pressure flow from the liquid pressure pump 10 proceeds through conduit 12 and 13 to the driving force input port 23a of the ejector 23. This high-pressure liquid input mixes with the low-pressure gas output from the turbine 19 whereby the combined pressure is sufficient to condense the refrigerant output of condenser 25. The pressure enhancement capabilities of a typical ejector is more fully described in an early U.S. Pat. No. 3,277,660 and most recently refined in U.S. Pat. No. 6,438,993. Upon leaving ejector 23, the refrigerant flow proceeds through conduit 24 and enters condenser 25 where heat is removed from the refrigerant with a cooling media being circulated through condenser 25 thereby condensing into a liquid. Upon leaving condenser 25, the liquid refrigerant then proceeds through conduit 26 to a liquid receiver 27 then through conduit 28 to the liquid pressure pump 10 where the cycle is repeated.

It will be apparent to those skilled in the art that various modifications can be made in the construction and configuration of the present invention without departing from the scope or spirit of the invention. For example, the embodiment mentioned above is illustrative and explanatory only. Various changes can be made in material as well as the configuration of the device to engineer the specific desired outcome. Thus it is intended that the present invention cover the modifications and variations of the invention, provided they come within the scope of the appended claims and their equivalents.

Claims

1. An enhanced liquid pressure cycle having an ejector comprising:

a positive displacement rotary liquid pump for the systems primary high pressure generation;

an expansion valve disposed at the inlet side of the evaporator;

an evaporator for evaporating low-pressure refrigerant thereby absorbing heat after being decompressed by an expansion valve;

an ejector for mixing the high-pressure stream and a low-pressure stream whose combined output pressure is sufficient for the operating conditions of the condenser;

a condenser for cooling and condensing into a liquid the refrigerant discharged by the ejector;

a compressor/turbine/motor combination which operates as a single unit interconnected with a common drive shaft whereby the compressor component sucks out and lowers the pressure in the evaporator. The compressor high-pressure output is inputted into the turbine component where the high-pressure gas is expanded generating an offsetting horsepower required by the compressor. The third component, the electric motor, provides the basic starting horsepower and makes up for any offsetting horsepower deficiency between the compressor and turbine;

a liquid receiver to insure that sufficient liquid refrigerant is available for the liquid pressure pump.

2. An enhanced liquid pressure cycle having an ejector according to claim 1 wherein the mixing refrigerant is HFC-404A;

3. An enhanced liquid pressure cycle having an ejector according to claim 1 wherein the mixing refrigerant is HFC-407A;

4. An enhanced liquid pressure cycle having an ejector according to claim 1 wherein the mixing refrigerant is HFC-410A.