Geothermal heat pump system

• US 5,758,514 A
• Filed: 05/02/1995
• Issued: 06/02/1998
• Est. Priority Date: 05/02/1995
• Status: Expired due to Fees

• Current Assignee: Envirotherm Heating & Cooling Systems, Inc.
• Original Assignee: Envirotherm Heating & Cooling Systems, Inc.
• Inventors: Carpenter, Frank K., Genung, John
• Primary Examiner(s): Wayner, William E.
• Application Number:
  US08/432,702
• Time in Patent Office: 1,127 Days
• Field of Search: 62/509, 62/324.6, 62/160, 62/174, 62/471, 62/324.4, 62/DIG. 17
• US Class Current: 62/471
• CPC Class Codes: F24T 10/30 using underground reservoirs for accumulating working fluids or intermediate fluids
• CPC Class Codes: F25B 13/00 Compression machines, plants or systems, with reversible cycle defrosting cycles F25B47/02
• CPC Class Codes: F25B 2313/002 geothermal
• CPC Class Codes: F25B 2313/02522 during defrosting
• CPC Class Codes: F25B 2313/02541 during cooling
• CPC Class Codes: F25B 2313/02543 during heating
• CPC Class Codes: F25B 2313/0292 related to reversing valves
• CPC Class Codes: F25B 2313/0293 related to the indoor fan, e.g. controlling speed
• CPC Class Codes: F25B 2313/0315 Temperature sensors near the outdoor heat exchanger
• CPC Class Codes: F25B 2400/05 Compression system with heat exchange between particular parts of the system
• CPC Class Codes: F25B 2400/16 Receivers
• CPC Class Codes: F25B 2500/01 Geometry problems, e.g. for reducing size
• CPC Class Codes: F25B 2600/2513 Expansion valves
• CPC Class Codes: F25B 2700/1931 Discharge pressures
• CPC Class Codes: F25B 2700/1933 Suction pressures
• CPC Class Codes: F25B 2700/2104 of an indoor room or compartment
• CPC Class Codes: F25B 2700/21151 at the suction side of the compressor
• CPC Class Codes: F25B 30/06 characterised by the source of low potential heat
• CPC Class Codes: F25B 40/04 Desuperheaters
• CPC Class Codes: F25B 41/38 specially adapted for reversible cycles, e.g. bidirectional expansion restrictors
• CPC Class Codes: F25B 45/00 : Arrangements for charging or discharging refrigerant
• CPC Class Codes: Y02E 10/10 : Geothermal energy

Abstract

A geothermal heating and/or cooling system includes one or more of a plurality of features that enhance the efficiency of the system. Preferably, the system includes a subterranean heat exchanger having tubes disposed against a conductive sheet. The system also preferably includes a reservoir vessel for holding a supply of heat transfer fluid in a liquid phase. Also, the system preferably includes heat exchange means for exchanging heat between the heat transfer fluid and the outdoor air. In addition, the system preferably has an automatically adjusting cooling expansion valve controlled by a sensor disposed to detect the pressure or temperature of heat transfer fluid exiting an indoor air handler in a cooling mode, the system also preferably has an automatically adjusting heating expansion valve controlled by a sensor that is preferably located so as to detect the temperature or pressure of heat transfer fluid flowing from the subterranean heat exchanger to a gas compressor. The enhancements may be used individually or in various combinations.

Claims

1. In a heating and cooling system having a subterranean heat exchanger in thermal communication with the earth, a dynamic load heat exchanger in thermal communication with a dynamic load, a conduit circuit for circulating a phase-change heat transfer fluid so as to convey thermal energy from one said heat exchanger to the other, a gas compressor in said conduit circuit for compressing said heat transfer fluid while in the gas phase, an expansion valve in a section of said conduit circuit that carries the heat transfer fluid from said dynamic load heat exchanger to said subterranean heat exchanger when the system is being operated in the heating mode or the cooling mode!, and a trap vessel in said conduit circuit for trapping any liquid present in the heat transfer fluid that is about to be sucked into the compressor, the improvement wherein

said system includes a reservoir vessel in said conduit circuit for holding a reserve supply of said heat transfer fluid in liquid phase, the reservoir vessel being located in said section of the conduit circuit that carries heat transfer fluid from said gas compressor to said subterranean heat exchanger in the heating mode and from the subterranean heat exchanger to said gas compressor in the cooling mode, at a location between said gas compressor and said expansion valve.

2. The system of claim 1, further comprising a tube coupled between the expansion valve and a section of the conduit circuit adjacent to the subterranean heat exchanger for pressure equalization.

3. The system of claim 1, wherein said expansion valve is coupled through a by-pass line to a section of the conduit circuit to equalize pressure and is without an internal bleed port.

4. The system of claim 1 further comprising an oil separator and means for transferring oil received with the heat transfer fluid from the conduit circuit by the reservoir vessel from the reservior vessel to the oil separator.

5. The system of claim 1 further comprising means for transferring oil received with the heat transfer fluid from the conduit circuit by the reservoir vessel from the reservoir vessel to the gas compressor.

6. The system of claim 1 wherein the subterranean heat exchanger comprises first and second heat transfer fluid distributors for transferring the heat transfer fluid between the conduit circuit and the subterranean heat exchanger, and an insulating divider between the first and second heat transfer fluid distributors.

7. In a heating and cooling system having a subterranean heat exchanger in thermal communication with the earth, a dynamic load heat exchanger in thermal communication with a dynamic load, a conduit circuit for circulating a phase-change heat transfer fluid so as to convey thermal energy from one said heat exchanger to the other, a gas compressor in said conduit circuit for compressing said heat transfer fluid while in the gas phase, an expansion valve in a section of said conduit circuit that carries the heat transfer fluid from said dynamic load heat exchanger to said subterranean heat exchanger when the system is being operated in the heating mode, a trap vessel in said conduit circuit for trapping any liquid present in the heat transfer fluid that is about to be sucked into the compressor, and a receiver in said conduit circuit, the improvement wherein

said receiver is a variable-capacity, dual direction receiver comprising:

a vessel having a bottom, a side wall, and a top;

a first tube having an end that extends through the top of said vessel to a position adjacent to the bottom of said vessel;

a second tube having an end that extends through the top of said vessel to a position that may be selected to be a desired distance from the bottom of said vessel; and

a third tube having an end that extends through the top of said vessel to a position intermediate the position of the end of the first tube and the position of the end of the second tube for carrying heat transfer fluid to the vessel during a cooling mode.

8. A variable-capacity, dual direction receiver according to claim 7, wherein the third tube carries the heat transfer fluid from the vessel during a heating mode.

9. A subassembly for a heating and cooling system, said subassembly comprising:

a receiver;

a first heat transfer fluid conduit passing through said receiver;

a flow-control valve located in said first heat transfer fluid conduit at a position external to said receiver;

a bypass conduit comprising a second heat transfer fluid conduit having two ends, each end being connected to said first heat transfer fluid conduit at a different side of said flow-control valve, and a check valve located in said second heat transfer fluid conduit; and

a third heat transfer fluid conduit having two ends, one end being connected to said first heat transfer fluid conduit at a connection point located at a side of said flow-control valve opposite said receiver, and the other end being located inside said receiver.

10. The system of claim 9 wherein the section of said first heat transfer fluid conduit located inside said receiver is coiled.

11. The system of claim 9 wherein said subassembly further comprises:

a vessel having an inlet port and a discharge port, said discharge port being connected to an end of said first heat transfer fluid conduit that is on an opposite side of said flow-control valve from said receiver;

a fourth heat transfer fluid conduit connected to both the inlet port and the discharge port of said vessel;

another check valve located in said fourth heat transfer fluid conduit; and

a fifth heat transfer fluid conduit passing through the interior of said vessel.