Liquid over-feeding air conditioning system and method

• US 5,245,833 A
• Filed: 05/19/1992
• Issued: 09/21/1993
• Est. Priority Date: 05/19/1992
• Status: Expired due to Fees

• Current Assignee: Martin Marietta Energy Systems, Inc.
• Original Assignee: Martin Marietta Energy Systems, Inc.
• Inventors: Mei, Viung C., Chen, Fang C.
• Primary Examiner(s): Capossela, Ronald C.
• Application Number:
  US07/885,337
• Time in Patent Office: 490 Days
• Field of Search: 62/113, 62/503, 62/513
• US Class Current: 62/113
• CPC Class Codes: F25B 2400/051 between the accumulator and another part of the cycle
• CPC Class Codes: F25B 40/00 Subcoolers, desuperheaters or superheaters
• CPC Class Codes: F25B 43/006 Accumulators
• CPC Class Codes: F28D 7/08 the conduits being otherwise bent, e.g. in a serpentine or zig-zag F28D7/10 takes precedenceF28D7/0016 and F28D7/0033 take precedence

Abstract

A refrigeration air conditioning system utilizing a liquid over-feeding operation is described. A liquid refrigerant accumulator-heat exchanger is placed in the system to provide a heat exchange relationship between hot liquid refrigerant discharged from condenser and a relatively cool mixture of liquid and vaporous refrigerant discharged from the evaporator. This heat exchange relationship substantially sub-cools the hot liquid refrigerant which undergoes little or no evaporation across the expansion device and provides a liquid over-feeding operation through the evaporator for effectively using 100 percent of evaporator for cooling purposes and for providing the aforementioned mixture of liquid and vaporous refrigerant.

Claims

1. An air conditioning system employing a vaporizable liquid refrigerant and comprising in combination, compressing means adapted to compress vaporous refrigerant, condensing means coupled to the compressing means by first conduit means for receiving the compressed vaporous refrigerant and condensing the vaporous refrigerant to liquid refrigerant, second conduit means for conveying the liquid refrigerant from the condensing means, heat exchange means operatively associated with a section of the second conduit means and comprising vertically oriented vessel means having a cavity therein for containing in a lower region thereof a pool of liquid refrigerant with one segment of the second conduit means being contained within the cavity with a substantial portion thereof being located in the lower region of the cavity in a heat exchange relationship with the liquid refrigerant in said pool, expansion means operatively associated with said second conduit means for receiving liquid refrigerant from the heat exchange means, refrigerant evaporating means coupled to the second conduit means for receiving liquid refrigerant from the condensing means through said expansion means, and third conduit means comprising first and second conduit sections with said first conduit section adapted to convey a mixture of liquid and vaporous refrigerant from the evaporating means into the cavity of said vessel means to form said pool of liquid refrigerant for primarily subcooling the liquid refrigerant in said one segment of the second conduit means to a temperature of at least about 20°

F. lower than that of the liquid refrigerant conveying from the condensing means into the heat exchange means and for vaporizing liquid refrigerant in said mixture and liquid refrigerant in said pool and with said second conduct section adapted to receive and convey substantially saturated vaporous refrigerant from said heat exchange means to said compressing means.

2. An air conditioning system employing a vaporizable liquid refrigerant as claimed in claim 1, wherein said first conduit section of the third conduit means extends into said cavity and has an open end thereof in communication with an upper region of said cavity at a location overlying the pool of liquid refrigerant, and wherein said second conduit section of the third conduit means extends into said cavity and has an open end thereof in communication with the upper region of the cavity at a location overlying the pool of liquid refrigerant and spaced from the open end of said first conduit section of the third conduit means.

3. An air conditioning system employing a vaporizable liquid refrigerant as claimed in claim 2, wherein nozzle means are disposed at the open end of said first conduit section for distributing said mixture of liquid and vaporous refrigerant through a substantial portion of the upper region of the cavity.

4. An air conditioning system employing a vaporizable liquid refrigerant as claimed in claim 2, wherein a portion of said second conduit section of the third conduit means is disposed in the lower region of the cavity in the pool of liquid refrigerant for providing a heat exchange relationship between liquid refrigerant in the pool of liquid refrigerant and vaporous refrigerant within said portion of said second conduit section of the third conduit means to sufficiently cool the vaporous refrigerant therein to effect substantial saturation thereof.

5. An air conditioning system employing a vaporizable liquid refrigerant as claimed in claim 2, wherein a substantial portion of said segment of the second conduit mans contained within the cavity is of a coiled configuration.

6. A method for operating an air conditioning system having refrigerant compressing means, refrigerant condensing means, refrigerant expansion means, and refrigerant evaporating means operatively interconnected by conduit means, comprising the step of passing liquid refrigerant discharged from the condensing means in a heat exchange relationship with a mixture of liquid and vaporous refrigerant discharged from the evaporating means and a pool of liquid refrigerant provided by liquid refrigerant from said mixture for vaporizing liquid refrigerant in said mixture and in said pool for sufficiently sub-cooling the liquid refrigerant discharged from the condensing means to provide substantially no evaporation of the sub-cooled liquid across the refrigerant expansion means and thereby over feeding of the evaporating means with liquid refrigerant for effecting contact of all cooling regions therein with liquid refrigerant and for providing said mixture of liquid and vaporous refrigerant discharged from the evaporating means, and conveying vaporous refrigerant from said mixture and from the vaporization of the liquid refrigerant contained in said mixture and in said pool to the refrigerant compressing means.

7. A method for operating an air conditioning system as claimed in claim 6, wherein the sub-cooling of liquid refrigerant discharged from the condensing means is provided primarily by being in a heat exchange relationship with the liquid refrigerant in the pool of liquid refrigerant, and wherein the sub-cooling of the liquid refrigerant is sufficient to provide the sub-cooled liquid refrigerant with a temperature of at least about 20°

F. lower than the temperature of the liquid refrigerant discharged from the condensing means.

8. A method for operating an air conditioning system as claimed in claim 7, wherein the temperature of the liquid refrigerant discharged from the condensing means is in the range of about 20°

to 30°

F. above ambient air temperature, and wherein the temperature of the sub-cooled liquid refrigerant of at least 20°

F. lower than the temperature of the liquid refrigerant discharged from the condensing means is a temperature in the range of about 20°

F. to 50°

F.

9. A method for operating an air conditioning system as claimed in claim 7, including the additional step of passing the vaporous refrigerant being conveyed to the compressing means in heat exchange relationship with the pool of liquid refrigerant for substantially saturating the vaporous refrigerant conveyed to the compressing means.

10. A method for operating an air conditioning system as claimed in claim 6, wherein the over feeding of the evaporating means with liquid refrigerant provides a sufficient excess of liquid refrigerant through the evaporating means to provide the mixture with a sufficient volume of liquid refrigerant to form the pool of liquid refrigerant and primarily effect said sub-cooling of the liquid refrigerant discharged from the condensing means.

11. A method for operating an air conditioning system as claimed in claim 10, wherein at least about 10 percent of said mixture discharged from the evaporating means is liquid refrigerant.

12. A method for operating an air conditioning system as claimed in claim 6 including the additional step of maintaining the pool of liquid refrigerant in said heat exchange relationship with the liquid refrigerant from the condensing means during the operation of the air conditioning system.

13. A method for operating an air conditioning system as claimed in claim 6, including the additional step of passing the vaporous refrigerant from the mixture and from the vaporization of the liquid refrigerant from the mixture and from the pool of liquid refrigerant in a heat exchange relationship with the pool of liquid refrigerant during the conveyance of the vaporous refrigerant to the refrigerant compressing means for effecting the substantial saturation thereof.