Heat Pump and Method

1. Field of the Invention

The invention herein pertains to a device for air to air cooling and heating the interior of a building by directing the flow of a refrigerant from a compressor through two heat exchangers which are commonly referred to as evaporators or condensers.

2. Description Of The Prior Art And Objectives Of The Invention

Engineers have known for many years that the evaporator and condenser in refrigeration equipment can be interchanged by reversing the direction of the refrigerant (freon) flow from the compressor. By reversing the flow direction either a heating or cooling function can be performed and such refrigeration equipment which is commonly referred to as a heat pump generally includes an outdoor coil which is positioned on the exterior of the building, an indoor coil positioned within the building and an expansion valve for reducing the pressure of the refrigerant. Both the indoor and outdoor coil function as a condenser or as an evaporator as determined by the mode of the heat pump.

Various types of heat pumps having reverse refrigerant cycles which may be either self contained or split (condenser and evaporator in separate locations) have met with moderate success in certain installations but have also had certain disadvantages. For example, corrosion can greatly shorten the life of a conventional outdoor coil, especially in areas which have a high salt air content. In addition, the outdoor coil is directly exposed to the extreme seasonal elements which may hamper its function in all modes of operation. Also, conventional heat pumps dehumidify the air and auxiliary equipment must be installed to maintain a suitable interior building humidity. Small residential structures including trailers or modular homes often have a high heat buildup in the attic area during summer months which require fans or other venting systems that create additional concerns and require additional energy expenditures.

With these and other disadvantages known to current heating and cooling systems, the present invention was conceived and one of its objectives is to provide a heat pump and method which is economical to use and provides satisfactory results and low maintenance and operating cost for the user.

It is another objective of the present invention to provide a heat pump with both the "indoor coil" and "outdoor coil" within a single housing and in which the "indoor coil" and "outdoor coil" are adjacently mounted in separate compartments or chambers with the housing located entirely within the conditioned building structure.

It is still another objective of the present invention to provide a heat pump which delivers exterior air across the "outdoor coil" from the attic or crawl space of the building and which exhausts that same air from the heat pump housing to the exterior and requires no outside wall for installation, thereby reducing the wind chill and defrosting of the "outdoor coil", subsequently reducing the defrost cycles and without direct exposure of the "outdoor coil" to the sun's solar heat and outside ambient temperature.

It is yet another objective of the present invention to utilize the condensate collected from the evaporator to humidify the interior air during the heating cycle.

It is another objective of the present invention to provide a condensate drain through the exterior exhaust duct to minimize installation costs.

It is still another objective of the present invention to provide an air to air heat pump and method with 100% elimination of outside noise.

An additional advantage of the invention is to provide a heat pump and method which is readily adaptable to auxiliary heat sinks and sources without substantial alteration to the apparatus.

It is also an objective of the present invention to provide a heat pump having an economic operation with high indoor air quality as a result of a controlable mix of indoor and outdoor air.

Various other advantages and objectives of the invention will become apparent to those skilled in the art as a more detailed presentation of the invention is set forth below.

The aforesaid and other objectives of the invention are accomplished by utilizing a heat pump which comprises a two compartment configuration wherein the first compartment includes a compressor, a first condenser-evaporator and a first fan and the second compartment which is positioned vertically below the first compartment includes a reversing valve, a second condenser-evaporator and a second fan (the term condenser-evaporator is used herein to designate the dual function of the component).

The method of the invention includes directing the compessed refrigerant gas which may be freon to a reversing valve where, depending on whether the heating or cooling cycle is employed, either passing the compressed gas to the upper condenser-evaporator over which exterior air is passed for exhaust purposes or passing the compressed gas to the lower condenser-evaporator which conditions the interior air.

FIG. 1 is a schematic view of the left side of the heat pump of the invention as may be installed in a permanent residential structure;

FIG. 2 is an enlarged front view with the lower condensor-evaporator cut-away;

FIG. 3 is an enlarged view of the right side of the heat pump as shown in FIG. 1;

FIG. 4 is a schematic right side elevational view of a second embodiment of the heat pump; and

FIG. 5 shows an enlarged view of the fresh air vent cover and mechanism as shown in FIG. 4.

The preferred embodiment of the apparatus includes a housing having an upper compartment with a first condenser-evaporator, a compressor and an air entry duct through which air from an attic area is delivered. A lower or second compartment is provided with a second condenser-evaporator through which interior room air passes for conditioning. The first and second compartments are vertically aligned to provide compactness and air from the first compartment is exhausted through the bottom of the heat pump and therefore no exterior wall is required for installation purposes. The preferred method of the invention comprises directing air from an attic area of the building structure by a fan positioned in front of the condenser-evaporator within the upper compartment of the heat pump and exhausting the spent air as it passes from the condenser-evaporator through the bottom of the heat pump to an area underneath the building. Interior room air is circulated by a second fan positioned within the bottom or second compartment of the heat pump through a second condenser-evaporator where it is returned to the interior of the building for heating or cooling. During the heating cycle, condensate is drained from the upper condenser-evaporator to the lower condenser-evaporator for use in humidifying the room air.

Turning now to the drawings, FIG. 1 demonstrates in schematic fashion heat pump 10 positioned in room 11 of building 12 which may be for example a small house or office building. Attic area 13 may have a large heat buildup during summer months and as shown air from the attic area is directed by upper fan 14 through upper condenser-evaporator 15 and is subsequently exhausted through the bottom of heat pump 10 through exterior exhaust duct 16 into crawl space 17 below building 12. Thus, a separate exhaust fan is not needed for attic area 13 and upper fan 14 tends to pressurize crawl space 17 by its continual direction of excess air thereto. In addition to the exterior air flow as just described, interior room air is forced by lower fan 18 through lower second condenser-evaporator 19 where it is conditioned and passes through interior duct 20, through vent cover 21 and back into room 11. Lower condenser-evaporator drain line 22 is shown inside exterior exhaust duct 16 and no separate drain line opening must be provided within the subflooring or bottom of heat pump 10.

In FIG. 2, an enlarged front view of heat pump 10 is shown whereby compressor 23 is positioned in upper compartment 24 along with upper fan 14 and control box 25. Upper fan 14 is of the propeller type having a one quarter horsepower motor 32 rated at 230 volts, 60 cycles to provide 950 c.f.m.

Lower compartment 26 of heat pump housing 27 includes lower fan 18 which is commonly referred to as a "squirrel cage" fan and is also rated 950 c.f.m., 230 volts, 60 cycles and is one third horsepower. As further shown, lower condensor-evaporator 19 demonstrated in cut-away fashion in FIG. 2 provides for interior air passing therethrough to lower fan 18 where it is exhausted through interior exhaust duct 20 and back into room 11. Service line 29 provides the electrical power required to operate lower fan 18. Exterior exhaust duct 16 is shown positioned behind interior exhaust duct 20 in FIG. 2 and drain line 22 is demonstrated as being within exterior exhaust duct 16 as earlier described.

In FIG. 3, attic duct connector 30 is shown without attic duct 31. As would be understood, air from attic area 13 as demonstrated in Fig. 1 passes through attic duct connector 30 and through upper condenser-evaporator 15 and is exhausted through exterior exhaust duct 16. Upper fan 14 is powered by upper fan motor 32 which may be for example a one quarter horesepower motor sized to move 950 c.f.m. This size upper fan has been found sufficient when cooling capacity of heat pump 10 is rated at 2 tons and other fan types such as the "squirrel cage" fan could be employed.

Compressor 23 provides the pressurized refrigerant gas which may be for example freon through outlet line 33 and into reversing valve 34 which is controlled by solenoid 35 affixed thereto as in conventional refrigerant directional reversing systems. If the thermostats (not shown) in control box 25 call for heat, reversing valve 34 directs the hot refrigerant gas into line 37 which carries it into lower condenser-evaporator 19. Condenser-evaporator 19 then provides heat to warm the room air passing thereacross whereby such warm air is returned through interior exhaust duct 20 back to the interior of building 12 as shown in FIG. 1. The refrigerant liquid exits lower condenser-evaporator 19 through the small copper conduit lines 36 shown as three lines in FIG. 3. Copper conduit lines 36 may be approximately 1/4 inch in diameter and provide adequate capacity within the system as shown although other sizes and numbers of lines may be utilized on different systems. Copper conduit lines 36 distribute the refrigerant into line 37 which passes the refrigerant into expansion valve 38. Expansion valve 38 includes external equalizer line 39 which is joined to suction or low pressure line 40. A cap (capillary) tube device may be used in place of expansion valve 38 as is conventional within the trade. Expansion valve 38 also includes temperature sensor 49 which is affixed to suction line 40 which senses the temperature of the return refrigerant prior to its entry into compressor 23. Expansion valve 38 reduces the pressure of the refrigerant prior to entry into conduit lines 41 which direct the refrigerant into upper condensor-evaporator 15.

In order to maintain the operation of upper condenser-evaporator 15, especially during such times as the attic temperature may drop to approximately 45.degree. F. or lower, which would cause condenser-evaporator 15 to be covered and blocked by frost, defrost sensor 42 is affixed to condenser-evaporator 15 and is joined to defrost timer 43 in control box 25. If condenser-evaporator 15 falls below a prescribed, adjustable temperature level, defrost timer 43 times out and the refrigerant direction is reversed to remove the frost buildup from condenser-evaporator 15 as in conventional heat pump system defrosters. The refrigerant passing through conduit lines 41 exits condenser-evaporator 15 through line 44 where the refrigerant then passes back into reversing valve 34, through suction line 40 and back into compressor 23, thus completing its flow for the heating cycle.

Condenser-evaporators 15 and 19 are shown mounted in a vertical fashion but may be tilted or slanted in order to improve air passing therethrough. Additionally, outdoor air from attic area 13 may be adjustably vented into interior exhaust duct 20 to provide a control mix of indoor and outdoor air for the interior of the building as shown by vent control 50 in FIG. 5. Handle 51 is attached to wire 52 contained within flexible coiled conduit 53 to operate hinged vent cover 54. The positioning of handle 51 and vent cover 54 is illustrated in FIG. 4 and as understood by pulling handle 51 vent cover 54 opens to allow additional fresh air to exit rear duct 61 within heat pump 60. The fresh air is shown in heat pump 60 in FIG. 4 as moving upward through squirrel cage fan 64 and exhausting into the attic or other location as required.

Also during the heating cycle, condensate is collected in upper drain tray 45 and is passed through drain line 46 into lower compartment 26 to provide humidity as air exits lower condenser-evaporator 19. The height of drain line tip 47 can be moved as required to provide the proper humidity supplement. For example, if additonal humidity is required drain line tip 47 is moved upwardly to the vertical middle of lower condenser-evaporator 19 and if less humidity is required, drain line tip 47 is positioned near the bottom of condenser-evaporator 19 as shown in FIG. 3.

During the cooling cycle, the refrigerant direction is reversed from that as described in the heating cycle whereupon it first passes through reversing valve 34 from compressor outlet line 33 and into upper condenser-evaporator 15 which acts as a condensor whereas lower condenser-evaporator 19 acts as an evaporator during the cooling cycle.

The compactness of heat pump 10 is a highly desirable quality since mobile homes, modular buildings and other small structures have limited space and the vertical, interior arrangement of the upper and lower compartments within housing 27 is advantageous to both the installer and owner.

As further shown in FIG. 3, upper condenser-evaporator 15 is positioned proximate the left side of housing 27 whereas lower condenser-evaporator 19 is positioned along the right side of housing 27, also as shown in FIG. 3. These opposingly positioned condenser-evaporators allow for a gradual sloping of drain line 46 and provide for a large volume of usable space in the relatively small interior of housing 27 for sufficiently sized fans, compressors, ducts and other components contained therein. Also, as heat pump 10 exhaust through the bottom of housing 27, it is not necessary to position heat pump 10 against an exterior wall as it may be more usable conveniently located within the interior of a building or mobile home.

Heat pump 60 as shown in FIG. 4 includes upper condenser-evaporator 70 and lower condenser-evaporator 71 of equal dimensions and capacities. As both condenser-evaporators are of the same dimensions an efficient heat pump is provided which has furnished heating and cooling capacities in standard tests as follows:

The compactness of heat pump 60 is also believed to contribute to its efficient operation in that the shortened freon-containing lines between condenser-evaporators make heat pump 60 very temperature response sensitive and by use of cap (capillary) tube 72 as shown in FIG. 4 a better C.O.P. in heating and a bettter E.E.R. in cooling is realized. It is understood the cap tube 72 replaces expansion valve 38 (FIG. 3) and cap tube 72 comprises a trio of coiled copper tubes 73 having an i.d. of approximately 0.026 to 0.036 inches.

Auxiliary electrical resistance heaters 48, known as "strip heaters" are shown in FIG. 3 and are available if additional heat requirements are needed under extreme weather conditions. The use of heaters 48 is controlled by a thermostat (not shown) within control box 25.

The examples and drawings presented herein are for illustrative purposes and not intended to limit the scope of the appended claims.