The present invention relates generally to systems for the collection, storage and transfer of heat energy and, more particularly, to heat pump systems.
The present invention is directed to a solar heat exchanger for assisting an air-to-air heat pump system. An air-to-air heat pump loses its ability to produce heat when the ambient temperature is low. The solar heat exchanger of the invention enables warm solar solution to be introduced into thermal contact with the saturated vapor. This may allow the refrigerant to extract more heat at low ambient temperatures, so an air-to-air heat pump will be able to produce its designed heating ability at lower temperatures. The solar heat exchanger may run simultaneously and in parallel with the heat pump to thereby improve the efficiency of the heat pump.
In an air-to-air heat pump system, when the ambient temperature is low, the system does not extract or produce the amount of heat that the system is capable of. Thus, in cold weather there may need to be backup heat, such as electric strip heat, or else the heat pump is locked out and the furnace is turned on. The present invention may introduce solar warmed water into the air-to-air heat pump. A heat exchanger is provided which may be thought of as a tube within a tube. The refrigerant may flow through the inside of the internal tube, and the warm solar water may flow through the external tube. Thus, the invention may introduce the warmed solar water into thermal contact with the refrigerant which has not reached full potential with regard to the amount of heat the refrigerant can extract from the air. The warm water may introduce heat into the refrigerant, and the heat may then be transferred to a condenser coil inside a building in which the heat pump is installed. Inside the building, the heat is introduced into the air and raises the air temperature within the building.
An advantage of the invention is that it enables a heat pump to heat a building adequately at low outside temperatures.
Another advantage is that the invention may use the free heat provided by solar panels to increase the efficiency of a heat pump.
The above-mentioned and other features and advantages of the invention will become more apparent to one with skill in the art upon examination of the following figures and detailed description. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, in the figures, like reference numerals designate corresponding parts throughout the different views.
a is a diagram of the heat exchanger of
b is a partially sectional diagram of the heat exchanger of
Referring to
A reversing valve 25 that reverses the flow of refrigerant through the circuit depending on whether system 10 is operating in a heating mode or a cooling mode. With a counterclockwise circulation, as indicated by arrows 16, system 10 operates in a heating mode (i.e., heats the indoor side of the circuit). Conversely, with a clockwise circulation, system 10 operates in a cooling mode. System 10 further includes a filter drier 26 and an accumulator 28.
According to the invention, a solar heat exchanger 30 is in contact with, and may encircle or surround conduit 20. Both exchanger 30 and conduit 20 may be formed of a thermally conductive material, such as copper, for example. Exchanger 30 may be donut-shaped or circular in cross section and substantially hollow. Exchanger 30 may have a fluid input 32 and a fluid output 34. Both input 32 and output 34 may be in fluid communication with solar heater 36. Solar heater 36 may heat water, propylene glycol, or some other heat transfer fluid and pump the water in the direction indicated by arrow 38 into exchanger 30.
While in exchanger 30, the heat in the water from heater 36 may be transferred to the saturated refrigerant in conduit 20. Such heat transfer may assist in heating indoor coil 12 and improve the efficiency of system 10. After passing through heat exchanger 30, the water exits through outlet 34 and returns to heater 36 where the water is re-heated and the cycle repeats.
According to the invention, when the water from heater 36 is hot enough, the heating operation of the air-to-air heat pump may be locked out such that all the heat produced by the system is produced exclusively by solar heater 36. Conversely, when system 10 operates in the cooling mode, solar heater 36 may be locked out such that the refrigerant is not heated further when passing through exchanger 30.
a illustrates exchanger 30 including input 32 and output 34.
In one embodiment, heat exchanger 30 has a length 40 (
In one embodiment, an inner cylindrical wall 42 of exchanger 30 is concentric with an outer cylindrical wall 44 of exchanger 30. Thus, exchanger 30 may have a donut-shaped cross section. However, in another embodiment, exchanger 30 has no inner wall 42 (or inner wall 42 may be thought of as being at least a part of conduit 20), and its opposite ends 46 are sealed fluid-tight against the outer surface of conduit 20. Thus, the heat transfer fluid with exchanger 30 directly contacts the outer surface of conduit 20. Thus, exchanger 30 may have a circular cross section. In both of these embodiments, the only path by which the heat transfer fluid may exit exchanger 30 may be through output 34.
Within tank 306, the heat from collector 302 may be transferred to another liquid such as water or propylene glycol that circulates between tank 306, heat exchanger 310, and water coil 312. Conduit 314 carries hot liquid to heat exchanger 310 and water coil 312. The heat in the liquid is transferred to heat exchanger 310 and water coil 312, and is returned to tank 306 for re-heating via conduit 316.
Heat exchanger 310 may be incorporated in an air-to-air heat pump 318 such that heat exchanger 310 assists in the heating of the heat pump's refrigerant, such as described above with regard to
A valve controller 410 may control valves 412, 414 which may divert the heated liquid from solar collector 402 to a heat dissipater 416 where the heat may be used immediately for heating water or air, for example. To the extent that the need for immediate heat is satisfied, heat may alternatively diverted by controller 410 to storage tank 406.
Within tank 406, the heat from collector 402 may be transferred to another liquid such as water that circulates between tank 406, water heater 418, and hot water coil 420. Conduit 422 carries hot liquid to water heater 418 and hot water coil 420. The water in water heater 418 may be further heated in water heater 418 and released for use via conduit 426. The water expelled through conduit 426 may be replenished via a cold water supply conduit 428.
The heat in the water in conduit 422 may be transferred to hot water air coil 420 where the heat may be transferred to air in a return air duct of a forced air system. After passing through hot water coil 420, the water is returned to tank 406 for re-heating via conduit 424. Conduit 424 also receives cold water from the cold water supply via conduit 428.
A check valve 430 and a shutoff valve 432 may be provided between conduit 422 and the cold water inlet of water heater 418. A bypass shut off valve 434 may be provided between conduit 428 and the cold water inlet of water heater 418. Thus, the cold water inlet of water heater 418 may be selectively in fluid communication with conduit 422 and/or with cold water source 428.
A shutoff valve 436 and a check valve 438 may be provided between conduit 428 and cold water inlet 424 of storage tank 406. A circulation pump 440 and a zone valve 442 may be provided between conduit 422 and the hot water inlet of hot water coil 420. Pump 440 may circulate water between hot water coil 420 and conduit 422.
As described above, the cold water inlet of the water heater may be selectively in fluid communication with a source of cold water 428, and the conduit 424 may be selectively in fluid communication with the source of cold water 428. Conduits 422 and 424 may be in fluid communication with each other within tank 406, and thus may be referred to herein as being a single, unitary conduit. This unitary conduit conjunctively formed by conduits 422, 424 may be in the form of a coil within tank 406. In one embodiment, this coil is disposed radially outwardly from the coil formed by conduits 404, 408. Hot water coil 420 of the forced air heating system may be in selective fluid communication with the conduit that is conjunctively formed by conduits 422 and 424.
Temperature switches 444, 446 may control the egress of hot water from tank 406 via conduit 422 and the ingress of cold water into tank 406 via conduit 424, respectively. Switches 444, 446 may be disposed underneath a layer of insulation on the outside of tank 406.
While the present invention has been described with reference to specific exemplary embodiments, it will be evident that various modifications and changes may be made to these embodiments without departing from the broader spirit and scope of the invention as set forth in the claims. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense.