Liquid pressure cycle having an ejector

Abstract

The liquid pressure cycle having an ejector pressurizes the liquid refrigerant of the system with a positive displacement rotary pump rather than pressurizing the vapor refrigerant with a vapor compressor. This high-pressure liquid proceeds 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 evaporator. The result of this mixing provides for sufficient pressure enhancement to condense the combination refrigerant vapor as it passes through the condenser. The liquid flow from the condenser proceeds back to the liquid pressure pump and the cycle is repeated.

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 high-pressure refrigerant generation along with corresponding expansion valve, evaporator, ejector and condenser.

2. Description of the Prior Art

The vapor compression refrigeration cycle is the predominate 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 liquid pressure cycle is to overcome the limited on the margin improvements of the vapor compression cycle.

SUMMARY

The liquid pressure cycle having an ejector pressurizes the liquid refrigerant of the system with a positive displacement rotary pump rather than pressurizing the vapor refrigerant with a compressor. The high-pressure liquid divides 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 evaporator. The result of this mixing provides for sufficient pressure enhancement to condense the combination refrigerant vapor 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 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 in the 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 liquid pressure cycle having an ejector.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

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 with a high-pressure positive displacement rotary pump 10 powered by a fixed or variable speed motor 11.

This high-pressure liquid travels through conduit 12 and enters the expansion valve 13 then into the evaporator 14. The expansion valve 13 opens and closes depending upon the set point temperature requirements of the evaporator 14. There are several schemes to accomplish this control function currently in use today. During this expansion process, heat is absorbed in the evaporator 14 with space air or other medium being circulated through the evaporator 14.

The low-pressure gas output of the evaporator 14 proceeds through conduit 15 to the low-pressure port 17b of the ejector 17. Concurrently approximately fifty percent of the high-pressure flow from the liquid pressure pump 10 proceeds through conduit 16 to the driving force port 17a of the ejector 17. This high-pressure liquid input decompresses and mixes with the low-pressure gas output from evaporator 14. The ejector process results in sufficient pressure enhancement which is required for the temperature conditions of condenser 19. Upon leaving ejector 17, the refrigerant flow proceeds through conduit 18 and enters condenser 19 where heat is removed from the refrigerant thereby condensing into a liquid. 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 condenser 19, the liquid refrigerant then proceeds through conduit 20 to the high-pressure liquid pressure pump 10 and 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. A liquid pressure cycle comprising:

a positive displacement rotary liquid pump for high pressure generation;

an expansion valve disposed at the outlet side of the high-pressure liquid pump;

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

an ejector for mixing high-pressure and low-pressure refrigerant streams whose combined output pressure is enhanced and sent to a condenser;

a condenser for cooling and condensing refrigerant discharged from the ejector.