Heating and cooling systems incorporating thermal storage, and defrost cycles for same

• US 5,755,104 A
• Filed: 12/28/1995
• Issued: 05/26/1998
• Est. Priority Date: 12/28/1995
• Status: Expired due to Term

• Current Assignee: Store Heat and Produce Energy Incorporated
• Original Assignee: Store Heat and Produce Energy Incorporated
• Inventors: Emmert, Matthew D., Mankovskiy, Oleg, Rafalovich, Alexander P.
• Primary Examiner(s): Tanner, Harry B.
• Application Number:
  US08/583,138
• Time in Patent Office: 880 Days
• Field of Search: 62/81, 62/160, 62/151, 62/196.4, 62/197, 62/198, 62/205, 62/238.6, 62/238.7, 62/278, 62/277, 62/201, 165/10, 165/10 A, 165/902, 237/2 B
• US Class Current: 62/81
• CPC Class Codes: F25B 13/00 Compression machines, plants or systems, with reversible cycle defrosting cycles F25B47/02
• CPC Class Codes: F25B 2400/04 Refrigeration circuit bypassing means
• CPC Class Codes: F25B 2400/075 with parallel compressors
• CPC Class Codes: F25B 2400/24 Storage receiver heat
• CPC Class Codes: F25B 47/022 hot gas defrosting
• CPC Class Codes: F25D 16/00 Devices using a combination of a cooling mode associated with refrigerating machinery with a cooling mode not associated with refrigerating machinery

Abstract

An apparatus for heating or cooling a space comprises a main flow loop including a compressor (1012), an outside heat exchanger (1014), an inside heat exchanger (1016) connected to allow working fluid to circulate therebetween, and a first valve (1026) between the outside heat exchanger (1014) and the inside heat exchanger (1016) selectively to block flow between the outside heat exchanger (1014) and the inside heat exchanger (1016). A first bypass line extends between the outlet of the outside heat (1014) and the inlet of the inside heat exchanger (1016). A thermal storage device (1018) is positioned in the first bypass line. A second bypass line extends between the inlet of the inside heat exchanger (1016) and the outlet of the inside heat exchanger (1016) and communicates with the first bypass line to bypass the inside heat exchanger (1016). A second valve (1030) is positioned in the second bypass line to block flow through the second bypass line selectively. Also described is a method for operating a refrigeration system in a hot gas defrost mode, wherein negative thermal potential transferred to the refrigerant from the frosted evaporator is captured and stored in a thermal storage device for later use. In addition, described is a method for operating a refrigeration system in a low-temperature condensing cycle.

Claims

1. A method for operating a refrigeration system having a defrost cycle, the system including a condenser, a first metering device, a first bypass line for selectively bypassing the first metering device, a thermal storage device including a thermal storage medium, a second metering device, an evaporator, a second bypass line for selectively bypassing the second metering device and evaporator, a compressor, a refrigerant, a third bypass line for selectively directing hot refrigerant exiting the compressor to the evaporator and a fourth bypass line for selectively directing refrigerant liquefied in the evaporator to the first metering device and further through the thermal storage device and the second bypass line to the compressor, the method including the steps of:

(a) charging the thermal storage device by;

(i) desuperheating and condensing refrigerant from a vapor to a liquid in the condenser after the refrigerant is compressed;

(ii) flowing the liquid refrigerant through the first metering device;

(iii) evaporating the refrigerant in the thermal storage device and transferring negative thermal potential to the thermal storage medium from the refrigerant;

(iv) flowing refrigerant vapor through the second bypass line to the compressor; and

(v) compressing the refrigerant vapor in the compressor;

(b) discharging the thermal storage device by;

(i) desuperheating and condensing refrigerant vapor in the condenser after the refrigerant is compressed;

(ii) flowing the refrigerant through the first bypass line;

(iii) extracting heat from the refrigerant in the thermal storage device;

(iv) flowing liquid refrigerant through the second metering device;

(v) evaporating the refrigerant in the evaporator; and

(vi) compressing the refrigerant vapor in the compressor; and

(c) defrosting the evaporator by;

(i) desuperheating and condensing refrigerant directed by the third bypass line to the evaporator from vapor to liquid in the evaporator after the refrigerant is compressed;

(ii) flowing the liquid refrigerant through the fourth bypass line to the first metering device;

(iii) evaporating the refrigerant in the thermal storage device and simultaneously extracting heat from the refrigerant to the thermal storage medium;

(iv) flowing refrigerant vapor through the second bypass line to the compressor; and

(v) compressing the refrigerant vapor in the compressor.

2. A method for operating a refrigeration system in a cycle with low-temperature condensing, the system including a refrigerant and a refrigerant circuit including a compressor, a condenser, a first metering device having a setting for supercooling, a low-temperature condensing device, a second metering device set for superheating, and an evaporator, the method comprising the steps of:

compressing refrigerant vapor in the compressor;

after said compressing, condensing the refrigerant vapor to liquid in the condenser;

after said condensing, expanding the refrigerant in the first metering device set for supercooling to form a vaporized portion of refrigerant;

after said expanding, low-temperature condensing the vaporized portion of refrigerant in the low-temperature condenser;

after said low-temperature condensing, flowing the refrigerant through the second metering device set for superheating to expand the refrigerant;

after said flowing, evaporating refrigerant remaining in liquid form to vapor in the evaporator; and

after said evaporating, compressing the refrigerant vapor in the compressor.

3. The method of claim 2, wherein said low-temperature condenser is a thermal storage device.

4. The method of claim 3, also including the steps of:

defrosting the evaporator with compressed refrigerant vapor from the compressor, wherein negative thermal potential is transferred to the refrigerant vapor which is at least partially condensed to liquid;

after said defrosting, expanding the refrigerant in a metering device;

after said expanding, transferring negative thermal potential from the refrigerant to the thermal storage device, wherein the refrigerant is evaporated to vapor; and

after said transferring, compressing the refrigerant vapor in the compressor.

5. A system for operating a refrigeration cycle in a cycle with low-temperature condensing, comprising:

a refrigerant and a refrigerant circuit;

said refrigerant circuit including;

a compressor for compressing the refrigerant;

a condenser for condensing refrigerant exiting the compressor;

a supercooling metering device having a setting for supercooling for expanding refrigerant exiting the condenser;

a low-temperature condensing device for condensing refrigerant vapor exiting said supercooling metering device; and

a superheating metering device set for superheating for further expanding refrigerant exiting said low-temperature condensing device.

6. The system of claim 5 wherein said low-temperature condensing device is a thermal storage device.

7. A method for operating a refrigeration system in a low-temperature condensing mode, the system including a refrigerant and a refrigerant circuit including a compressor, a condenser, a first metering device having a setting for supercooling, a thermal storage device, including a refrigeration coil and a thermal storage medium, an evaporator, a bypass line for bypassing the evaporator, a second metering device set for superheating, and a third metering device set for superheating, the method comprising the steps of:

charging the thermal storage device by

a) desuperheating and condensing refrigerant from a vapor to a liquid in the condenser after the refrigerant is compressed;

b) flowing the liquid refrigerant through the second metering device;

c) evaporating the refrigerant in the refrigeration coil of the thermal storage device and transferring negative thermal potential to the thermal storage medium from the refrigerant;

d) flowing refrigerant vapor through the bypass line to the compressor; and

e) compressing the refrigerant vapor in the compressor discharging the thermal storage device by

a) desuperheating and condensing refrigerant vapor in the condenser after the refrigerant is compressed;

b) flowing the refrigerant through the first metering device set for supercooling;

c) re-condensing refrigerant by transferring thermal potential from the refrigerant to the charged thermal storage medium at a temperature level close to the temperature of the charged thermal storage medium;

d) flowing liquid refrigerant after the thermal storage device through the third metering device;

e) evaporating the refrigerant in the evaporator; and

f) compressing the refrigerant vapor in the compressor.