Apparatus and method for combined solar and heat pump heating and cooling system

• US 4,165,037 A
• Filed: 06/21/1976
• Issued: 08/21/1979
• Est. Priority Date: 06/21/1976
• Status: Expired due to Term

• Current Assignee: Donald M. Mccarson
• Original Assignee: Donald M. Mccarson
• Inventors: McCarson, Donald M.
• Primary Examiner(s): Yuen, Henry C.
• Application Number:
  US05/697,941
• Time in Patent Office: 1,156 Days
• Field of Search: 62/238, 62/1, 62/2, 62/160, 62/79, 62/217, 62/528, 62/324, 62/200, 62/199, 237/1 A, 237/2 B, 137/487.5, 137/601
• US Class Current: 237/1.00R
• CPC Class Codes: F24F 3/001 in which the air treatment in the central station takes place by means of a heat-pump or by means of a reversible cycle reversible cycle for humidifying and drying air F24F3/147
• CPC Class Codes: F24F 5/0046 using natural energy, e.g. solar energy, energy from the ground
• CPC Class Codes: F25B 13/00 Compression machines, plants or systems, with reversible cycle defrosting cycles F25B47/02
• CPC Class Codes: F25B 2313/008 Refrigerant heaters
• CPC Class Codes: F25B 2313/0215 the auxiliary heat exchanger being used parallel to the outdoor heat exchanger during heating operation
• CPC Class Codes: F25B 2313/0314 Temperature sensors near the indoor heat exchanger
• CPC Class Codes: F25B 2313/0315 Temperature sensors near the outdoor heat exchanger
• CPC Class Codes: F25B 2313/0316 Temperature sensors near the refrigerant heater
• CPC Class Codes: F25B 2400/24 Storage receiver heat
• CPC Class Codes: F25B 25/005 using primary and secondary systems
• CPC Class Codes: F25B 2500/02 Increasing the heating capacity of a reversible cycle during cold outdoor conditions
• CPC Class Codes: F25B 2500/31 Low ambient temperatures
• CPC Class Codes: F25B 30/02 of the compression type
• CPC Class Codes: F25B 30/06 characterised by the source of low potential heat
• CPC Class Codes: F25B 41/22 between evaporator and compressor

Abstract

A heating and cooling system is provided having an indoor heat exchanger, an outdoor heat exchanger, a refrigerant compressor, an auxiliary heat exchanger in parallel with the outdoor heat exchanger, a solar collector unit, with the auxiliary heat exchanger disposed within a fluid contained in a storage tank wherein the fluid is heated by circulation through the solar collector. Heat from the solar collector is utilized to heat an interior space as long as the temperature of the fluid is sufficient and thereafterwards the heat pump system is utilized for supplying heat as needed. When the efficiency of the heat pump system is substantially impaired due to low ambient conditions, the auxiliary heat exchanger is utilized to supplement heat capacity to the heat pump system.

Claims

1. A heating system for delivering heat to the interior space of a building structure comprising:

a first heat exchange coil disposed in heat exchange relationship with said interior space;

a second heat exchange coil in heat exchange relationship with a main heat source;

a fluid refrigerant line connecting said first and second heat exchange coils having a fluid refrigerant contained therein;

a compressor means connected in said refrigerant line between said first and second heat exchange coils having a suction side and a discharge side for compressing said refrigerant;

a third heat exchange coil connected in a parallel flow relationship with said second heat exchange coil in a parallel refrigerant line and in a series flow relationship with said compressor means, said third heat exchange coil being in heat exchange relationship with an auxiliary heat source;

expansion means connected in said refrigerant line for evaporating refrigerant in said second heat exchange coil, said refrigerant vapor being condensed in said first heat exchange coil for transferring heat from said main heat source to said interior space;

valve means connected in said parallel refrigerant line for selectively by-passing and expanding at least a part of said refrigerant through said third heat exchange coil as required for satisfying the heating requirements of said interior space; and

means combining refrigerant flow from said second and third heat exchange coil prior to entering said suction side of said compressor means affording regulation of said flow from said second and third heat exchange coils so as to efficiently utilize the heat available from said main heat source in combination with heat from said auxiliary heat source.

whereby the heat capacity of the heating system is effectively maintained for low outdoor temperature conditions.

2. The system set forth in claim 1 wherein said valve means comprises a full capacity expansion means and a reduced capacity expansion means through which said refrigerant may be selectively expanded in response to the heat exchange capacity of said second heat exchange coil being reduced.

3. The system set forth in claim 2 wherein said full capacity expansion means and said reduced capacity expansion means are connected in said by-pass refrigerant line in parallel.

4. The system set forth in claim 2 wherein said valve means further comprises flow control means for delivering refrigerant through said reduced expansion means when the heat exchange capacity of said second coil is reduced below a first predetermined level and for delivering refrigerant through said full capacity expansion means when the heat exchange capacity of said second coil is reduced below a second predetermined level.

5. The system set forth in claim 1 further comprising injection valve means connected in parallel across said third coil for injecting liquid refrigerant into vaporized refrigerant discharged from said third coil for cooling said vaporized refrigerant when discharged in a superheated condition.

6. The system set forth in claim 1 further comprising a pressure regulator valve connected in said refrigerant line on the suction side of said compressor for regulating the flow of refrigerant from said third coil so as to protect the compressor from being overloaded.

7. The system as set forth in claim 1 further comprising evaporator pressure regulator means connected in said parallel refrigerant line for regulating the pressure of refrigerant in said third heat exchange coil so as to prevent the lowering of the temperature of said auxiliary heat source below a critical level.

8. The system as set forth in claim 7 wherein said auxiliary heat source is a heat transfer liquid and said critical level is defined by the freezing point of said liquid.

9. The system set forth in claim 1 including cut-off valve means for terminating refrigerant flow through said second heat exchange coil when the heat exchange capacity thereof is reduced below a predetermined limit.

10. A heating apparatus and system for heating the interior space of a building structure comprising a first heat exchange coil disposed in heat exchange relation with said interior space, a second heat exchange coil disposed in heat exchange relationship with a main source of heat, a refrigerant flow line connecting said first and second heat exchange coils, a compressor connected in said refrigerant line between said first and second heat exchange coil for compressing said refrigerant, said compressor having a suction side and a discharge side, and expansion means disposed in said refrigerant line for expanding and vaporizing refrigerant in said second heat exchange coil, said refrigerant vapor being condensed in said first coil;

the improvement comprising a third heat exchange heat coil connected in said refrigerant line in parallel with said second heat exchange coil and in series with said compressor, said third heat exchange coil being disposed in heat exchange relation with an auxiliary heat source, said second and third heat exchange coils being connected in common series flow prior to entering said compressor affording regulation of said flow so as to efficiently supplement heat from said auxiliary heat source in combination with heat from said main heat source as required to maintain the heating capacity of said system;

solar collector means for absorbing and collecting solar radiation, a fluid flow line connected to said solar collector means for passing a heat transfer fluid in heat exchange relationship with said solar collector means, and pump means for circulating said heat transfer fluid in heat exchange relationship with said solar collector means and in heat exchange relationship with said auxiliary heating source.

11. The apparatus and system set forth in claim 10 further comprising a fourth heat exchange coil disposed in heat exchange relation with said interior space connected in said fluid flow line.

12. The apparatus and system set forth in claim 11 further comprising valve means connected in said fluid flow line for selectively delivering said heat transfer fluid through said fourth heat exchange coil.

13. The apparatus and system set forth in claim 12 further comprising blower means for delivering air over said fourth heat exchange coil to transfer heat from the fluid flowing therein to said interior space as heating is required therein.

14. The apparatus and system set forth in claim 10 further comprising a second expansion means connected in said refrigerant line for expanding refrigerant through said third heat exchange coil as it absorbs heat from said auxiliary heat source to vaporize said refrigerant.

15. The apparatus and system set forth in claim 14 wherein said second expansion means includes a full capacity expansion means and a reduced capacity expansion means through which refrigerant may be selectively expanded, and wherein flow control means are connected in said refrigerant line for selectively expanding said refrigerant through one of said expansion means in response to the heat exchange capacity of said second heat exchange coil being reduced for supplementing the total heating capacity of the system.

16. The apparatus and system set forth in claim 10 further comprising valve means connected in said refrigerant line for by-passing and expanding at least a part of said refrigerant through said third heat exchange coil in response to the heat exchange capacity of said second heat exchange coil being reduced below a predetermined level.

20. The method as set forth in claim 16 further comprising the steps of:

providing a partial capacity expansion means and a full capacity expansion means connected in said by-pass refrigerant line in a parallel relationship;

expanding said by-passed refrigerant through said partial capacity expansion means in response to the heat exchange capacity of said second coil being reduced below a first predetermined level; and

expanding said by-pass refrigerant through said full capacity expansion means in response to the heat exchange capacity of said second heat exchange coil being reduced below a second predetermined level.

17. A method for maintaining the effective heating capacity of a heat pump system having a first heat exchange coil disposed in heat exchange relation with an area to be heated, a second heat exchange coil disposed in heat exchange relationship with a main heat source, a refrigerant flow line connecting said first and second heat exchange coils having a fluid refrigerant contained therein, a compressor having a suction side and a discharge side connected in said refrigerant line between said first and second coils for compressing said refrigerant, expansion means disposed in said refrigerant line for expanding and vaporizing refrigerant in said second heat exchange coil, said vaporized refrigerant being condensed in said first heat exchange coil for transferring heat from said main heat source to said area to be heated;

said method comprising the steps of;

providing a third heat exchange coil in parallel flow relationship with said second heat exchange coil connected in a parallel refrigerant line;

providing an auxiliary heating source and disposing said third heat exchange coil in heat exchange relationship with said auxiliary heating source;

by-passing at least a part of said refrigerant through said parallel refrigerant line and expanding said by-pass refrigerant through said third heat exchange coil in response to the heat exchange capacity of said second heat exchange coil with said main heat source being reduced below a predetermined level; and

combining and controlling said refrigerant flow from said second and third heat exchange coils prior to entering said compressor to efficiently supplement heat from said auxiliary heat source in combination with heat from said main heat source.

18. The method as set forth in claim 17 wherein said auxiliary heating source is provided by a storage container, a heat transfer fluid contained in said storage container having a capacity for storing heat, and heating said heat transfer fluid by bringing said heat transfer fluid into heat exchange contact with a heat source.

19. The method as set forth in claim 18 wherein said heat source is a solar collector for collecting and absorbing solar radiation.

21. The method as set forth in claim 17 further comprising the step of providing an injection valve means in parallel across said third heat exchange coil for injecting liquid refrigerant into the vaporized refrigerant discharged from said third exchange coil in response to said vapor being discharged in a superheated condition for cooling and desuperheating said vapor.

22. The method as set forth in claim 17 further comprising providing a pressure regulator valve in said refrigerant line on said suction side of said compressor for regulating the flow of refrigerant from said third heat exchange coil so as to protect said compressor from being overloaded.

23. A method for heating an interior space of a building structure comprising the steps of:

(a) providing a solar collector for collecting and absorbing solar radiation and passing a heat transfer fluid in heat exchange relationship with said solar collector for absorbing the radiant heat therefrom to thereby heat said fluid;

(b) transferring heat from said heated fluid to said interior space when the temperature of said fluid is sufficient for satisfying the interior heating requirements;

(c) providing a first heat exchange coil in heat exchange relationship with said interior space and a second heat exchange coil in heat exchange relationship with a main heat source;

(d) providing a refrigerant flow line connecting said first and second heat exchange coils and providing a compressor having a suction side and a discharge side connected in said refrigerant flow line between said first and second coils for compressing a refrigerant contained in said refrigerant flow line;

(e) energizing said compressor when heat is required by said interior space and when the temperature of said heat transfer fluid is insufficient for heating said interior space;

(f) providing expansion means in said refrigerant flow line for expanding and evaporating refrigerant in said second heat exchange coil, said vaporized refrigerant being condensed in said first heat exchange coil for absorbing and transferring heat from said main heat source to said interior space when said compressor is energized;

(g) providing a third exchange heat exchange coil connected in parallel across said second heat exchange coil in a parallel refrigerant line and disposing said third heat exchange coil in heat exchange relationship with an auxiliary heat source;

(h) by-passing at least a part of said refrigerant through said parallel refrigerant line and said third heat exchange coil in response to the heat exchange capacity of said second heat exchange coil being reduced below a predetermined level;

(i) providing an expansion means in said parallel refrigerant line for expanding and evaporating refrigerant through said third heat exchange coil to absorb heat from said auxiliary heat source (transferring said abosrbed heat in combination with heat absorbed by said second heat exchange coil to be delivered to the suction side of said compressor.); and

(j) delivering said heat absorbed in said second heat exchange coil in combination with heat absorbed in said third heat exchange in common flow to said suction side of said compressor so as to afford efficient combination and utilization of heat available in said main and auxiliary heat sources in satisfying the heating requirements of said interior space.

24. The method as set forth in claim 23 wherein said second expansion means is provided by:

(a) a partial capacity expansion means for expanding refrigerant through said third heat exchange coil and utilizing only a part of the full heat transfer capacity of said third coil in response to the heat exchange capacity of said second heat exchange coil being reduced below a first predetermined level; and

(b) a full capacity expansion means for expanding refrigerant through said third exchange coil and utilizing the full heat exchange capacity of said third coil in response to the heat exchange capacity of said second heat exchange coil reduced below a seond predetermined level.

25. The method as set forth in claim 24 further comprising the step of cutting off the flow of refrigerant to said second heat exchange coil and by-passing all of the refrigerant through said third heat exchange coil when the heat exchange capacity of said second heat exchange coil drops below said second predetermined level.

26. The method as set forth in claim 23 further comprising the step of providing a pressure regulator valve in said refrigerant line on the suction side of said compressor for limiting the pressure of vapor delivered to said compressor by holding back the flow of vapor from said third heat exchange coil.

27. The method as set forth in claim 23 further comprising the step of providing a liquid injection valve in parallel across said third heat exchange coil for expanding liquid refrigerant into the discharge side of said third heat exchange coil to cool heated vapor leaving said third coil in a superheated condition.