Patent Application
20070295017
In the description which follows, like parts are indicated throughout the specification and drawings with the same reference numerals, respectively. The figures may not be drawn to scale and the proportions of certain parts may have been exaggerated for convenience of illustration.
Referring now to
For convenience, reference will now be made to
An engine coolant line 40 is shown connected through a valve 42 to a secondary heat exchange coil 44 in air handler cabinet 10 for supplying heat to the additional area or passenger space of the vehicle away from the driver area. The valve 42 is operated mechanically by a control wire 45 which may be connected to a knob located on the dash of the vehicle. The secondary heat exchange coil 44 returns engine coolant fluid on a line 46 to the line 38 and accordingly to engine 22. Heated engine coolant will also go to a main heat exchanging coil 41 in the driver compartment of the recreational vehicle, and this is shown by a high water pressure dash line 48 connected to line 40 and a dash return water line 50 connected to line 38 coming from the recreational vehicle cab heater 41. A main fan 63 moves air through primary heater coil 41 and out outlets of the dashboard. Fan or blower 63 typically has a 12 volt motor that is supplied with power from the vehicle's batteries (not shown) and main engine alternator 23.
Optionally, the vehicle may have a diesel-fired boiler or hot water heater 65 that is connected into a pressurized water system (not shown) of the vehicle. The pressurized water system typically includes a pump and an accumulator. Boiler 65 supplies hot water in a conventional manner for a shower and sinks. In addition, boiler 65 may be connected to a circulating pump 67, which in turn is connected by lines 69 to either secondary heat exchanger 44 or alternatively to a third heat exchanger 71 located in air handling cabinet 10 adjacent secondary heat exchanger 44.
As is typical of most air conditioned vehicles, outside air is drawn in through the vehicle grill, through the engine compartment air conditioner condenser coil 24, the engine radiator 36, and then used to also cool the engine 22. After the refrigerant fluid obtained from compressor 20 is cooled in main heat exchanger coil 24, it is supplied on a line 52 through a receiver reservoir 54 and an expansion valve 56 to a secondary evaporator coil 58 in air handler cabinet 10 via line 16. A dashline 60 shows the high pressure refrigerant also being supplied to a cab or main evaporator coil 61, typically mounted in the heating cooling duct work within the dashboard of the driver's compartment of the recreational vehicle. Fan 63 moves air through main evaporator coil 61.
The refrigerant, after cooling air flowing through the secondary evaporator coil 58, is returned to main compressor 20 via previously designated line 18 and an accumulator, surge drum, or surge header reservoir 59. Reservoir 59 provides a chamber for storing low-side liquid refrigerant in a refrigeration system to prevent slugging (i.e. ingestion of liquid rather than gas) of main compressor 20 due to varying conditions of air flow through air handler cabinet 10 and associated evaporator coils from auxiliary fan 70. A dash-line 62 returns refrigerant to accumulator 59 and to main compressor 20 from dashboard evaporator coil 61 in the vehicle driver's compartment.
It will be noted that heater coils 44, 71 and evaporator coil 58 are arranged side-by-side in air handler cabinet 10 to accommodate serial flow heat exchange, and the three are further coupled to heat exchanger evaporator coils 64 and 66 of two separate auxiliary heating and cooling systems, also located in air handler cabinet 10. An auxiliary AC electrical motor designated M2 and also as 68 is used to power an auxiliary fan 70 which draws air serially through each of the coils 44, 71, 58, 64 and 66, and discharges this air to the previously designated duct work 14 of
A first auxiliary compressor designated as 72 (C2) is located in air handler cabinet 10. First auxiliary compressor 72 has a 120 volt AC motor incorporated within it. First auxiliary compressor 72 supplies high pressure freon or refrigerant through an auxiliary condenser coil designated as 74 and an expansion valve 78, to the previously mentioned auxiliary evaporator coil 66 and back through an accumulator reservoir 76 to a suction input side of auxiliary compressor 72. Auxiliary condenser coil 74 and expansion valve 78 are also located in air handler cabinet 10.
The auxiliary cooling system optionally may also include a second auxiliary compressor 80 (C3), which has a similar set of components, including an auxiliary condenser coil 82 and an expansion valve 86, serially connected to pass refrigerant to the previously mentioned auxiliary evaporator coil 64 and return the freon through an accumulator reservoir 84 to the suction input of second auxiliary compressor 80. Second auxiliary compressor 80 has a 120 volt AC motor that is incorporated within it. A second auxiliary AC electrical motor 88 is shown powering a fan 90 for passing outside cooling air through the auxiliary condenser coils 74 and 82 and discharging this air to the environment. Second auxiliary compressor 80, expansion valve 86 and condenser coil 82 are also located in air handler cabinet 10.
Both of the auxiliary motors 68 and 88 are preferably multi-speed 120 volt AC motors to assist the overall system in preventing damage to auxiliary compressors 72, 80 due conditions of inadequate air flow causing the evaporator coils to ice over and often further causing liquid freon to pass into the compressors 72, 80 themselves when accumulators are not used, or inadequate air flow through the coils 74, 82, causes extremely high head pressures in the compressors 72, 80. Either of these situations potentially causes damage to mechanical parts of associated compressors. Normally auxiliary compressors 72, 80 and the associated auxiliary condensers 74, 82 and evaporators 64, 66, operate with a different refrigerant than the refrigerant used with main compressor 20, main condenser 24, main evaporator 61, and main secondary evaporator 58. The reason is that the auxiliary system compressors 72, 80 are powered by 120 volt AC power while the main system compressor 20 is powered by main engine 22. For example, the auxiliary system may use R-22 refrigerant while the main system uses R-134.
Referring now to
In
A lead 100 is connected a direct current (DC) input of a 12 volt DC to 115 volt alternating current (AC) power converter designated as 120, also called an inverter. An AC output of converter 120 is labeled 122 and supplies AC power to a normally closed contact of a set of relay contacts designated as RL4, which relay contacts are further connected via a lead 102 through a set of normally closed relay contacts RL3E (E being the designation for the fifth set of contacts for the relay coil RL3) to a low speed input of motor 68 on a low speed lead 104. The motor 68 also has a lead connected to ground 92. Converter 120 has sufficient capacity to supply AC power to fan motors 68, 88 while the vehicle is in transit if heating and cooling of the living space is desired. However, in this embodiment, converter 120 is not sufficiently large to power either of the AC auxiliary compressors 72, 80.
The cool contact of HEAT/COOL switch 98 is connected to a lead 106 which supplies power to a coil of a relay RL1 who's other side is connected to ground 92. Lead 106 is also connected through a thermostat 108, also designated as T1, and through a coil 110 to ground 92. The coil 110 activates a clutch for the main engine driven compressor C1 (20). Lead 106 is connected through a set of contacts labeled RL1 to the previously designated lead 100. As shown, RL1 is normally open (NO) but the contacts close upon energization of relay coil RL1.
The vehicle preferably has an on-board 120 volt alternating current (AC) power provider, which in this example comprises generator 112, but other devices capable of supplying 120 AC voltage are feasible. Generator 112 is connected through a normally open switch 114 to a lead 116. Generator 112 is driven by an auxiliary engine 113 carried by the vehicle. In this embodiment, generator 112 is capable of supplying the necessary AC power to operate auxiliary compressor 72 and the AC fan motors 68, 88. A normally closed set of relay contacts RL3A connects lead 116 to a lead 118. Lead 118 supplies a hot lead or non-grounded lead alternating signal to one side of a relay coil RL4 having its other lead connected to ground 92. Lead 118 is also connected to the normally open contact of the contacts RL4 previously designated, and to a lead of a normally open set of contacts designated as RL3D. An output o£ the switch contacts RL3D is connected to the high speed input lead of motor 68. Optionally, generator 112 could be sized to power both auxiliary compressors 72, 80 simultaneously.
A 120 volt AC utility source is connected between ground 92 and a hot lead or non-grounded lead 124. While the vehicle is not traveling, the operator may connect to an electrical receptacle on the vehicle via a power cord extending to a 120 volt AC utility power source. If so, the 120 volt utility power can be used to simultaneously operate both auxiliary compressors 72, 80 and the AC fan motors 68, 88. The lead 124 is connected through an electrical plug or other disconnectible interface 126 to an ON-OFF switch 128. An output of the ON-OFF switch 128 is connected to a lead 130. A coil of a relay RL3 is connected between lead 130 and ground 92. Lead 130 is also connected to normally open set of relay contacts labeled as RL2C.
The normally unswitched terminal of switch RL2C is connected to one side of the compressor 80, which is also designated as C3 and whose other side is connected to ground 92. The lead 130 is further connected to one end of a normally open set of switch contacts RL3B, whose normally open contact is connected to lead 118. Lead 130 is also connected to a normally open set of contacts labeled RL2D. The normally unconnected contact of contacts RL2D is connected to the high speed lead of a motor 88, also designated as motor M1. A low speed lead of motor 88 is connected to a normally open terminal of a set of normally open contacts RL2B and then through a normally closed set of contacts RL3C to lead 118.
A thermostat labeled T2 and designated as 132 is connected in series with a coil for relay RL2 between ground 92 and the lead 118. A set of normally open relay contacts designated as RL2A is connected in series with a compressor 72 also designated as C2 between lead 118 and ground 92.
Referring to both
Heat can also be distributed through air ducts 12 while in transit by using diesel-fired boiler 65. When actuated, pump 67 will circulate water heated by boiler 65 through heat exchanger 71. Fan 70 moves air through heat exchanger 71 into ducts 12. When parked, and the outside temperature above about 40 degrees F., preferably compressors 73 and 80 are operated in a heat pump mode for heating the vehicle. The heat pump mode is conventional, and when an air refrigeration unit is used to heat air, the action of the condensers 74, 82 and evaporator coils 64, 66 are interchanged. If the outside temperature is below about 40 degrees F., diesel-fired boiler 65 and pump 69 are preferably operated to circulate hot water through heat exchanger 71. The electrical power when parked can be either by the onboard generator or by utility line power.
If it is desired to cool the living space of the recreational vehicle while in transit, the switch 98 is switched to the lower or COOL position to apply power to relay coil RL1. This will activate the switch contacts RL1 from the normally open position to a closed position so that alternating current can again flow through the previously described path of the contacts of RL4 and RL3E to the motor 68 and it is again activated in the low speed condition. The thermostat 108, when it is calling for cooling, will allow through coil 110 and activate the clutch for main engine compressor 20 so that freon is circulated through the main condenser coil 24, the expansion valve 56 and the secondary evaporator coil 58 before being returned to main compressor 20. The air is circulated in the living space of the recreational vehicle by the motor 68 as mentioned above. The refrigerant gas is simultaneously circulated through a further expansion valve and evaporator coil 61 in the driver's compartment of the recreational vehicle in a manner standard in the industry.
The main compressor 20 might only be able to cool the entire recreational vehicle, including the driver's compartment, when the outside temperatures are fairly moderate. If more cooling is necessary while traveling, the on-board generator 112 and its auxiliary engine 113 would be activated and switch 114 would be closed. Power would then flow through the coil of relay RL4, thereby changing the position of the contacts RL4 so that power is supplied through lead 118 to lead 102 and through the contacts of normally closed switch RL3E to the low speed of motor 68.
In this mode, air is again circulated through the recreational vehicle. The thermostat 132 allows activation of the relay coil RL2 to close switch contacts RL2A and RL2B. This activates both the auxiliary compressor 72 and condenser fan motor 88. Compressor 72 can then circulate refrigerated fluids through the heat exchanger coils 74 and 66 in the conventional fashion to supply additional cooling to the recreational vehicle over that supplied by the engine driven compressor 20. The fan motor 68 in the low speed condition will typically still supply adequate air flow across the juxtaposed coils in air handler 10 to keep them from icing over if the freon levels are properly adjusted in the refrigerant paths for compressors 20 and 72 (in other words while both are running on an adequately warm day).
If desired, air handler motors having more than two speeds may be utilized and the circuitry illustrated may be modified to run at different speeds, whether 1, 2 or 3 compressors are supplying refrigerant to the multiple heat exchangers.
When the vehicle is parked at a source of utility company power, and plugged in via the receptacle connection 126, the switch 114 can be closed to activate relay coil RL3. This will disconnect the power from on-board generator 110 to compressor 72 by opening contacts RL3A and will disconnect the application of power to the low speed terminal of condenser fan motor 88 by opening normally closed relay contacts RL3C. At the same time, power will be applied from the utility company to lead 318 via the closing of normally open relay contacts RL3B. This will activate the thermostat 132 and again activate the coil of relay RL2 to close the contacts of RL2A to activate auxiliary compressor 72, close contacts RL2D to activate the high speed terminal of compressor fan motor 88 and close normally open contact RL2C to activate compressor 80.
It may be noted that the activation of coil RL3 opens the normally closed contacts RL3E and closes the contacts RL3D to place the common air handler fan motor 68 in the high speed condition. Thus, for operating the two auxiliary compressors 72 and 80, the air handler fan motor 68 is in the high speed position drawing or circulating air throughout the recreational vehicle at a speed which will prevent icing over of the evaporator coils. Further the motor 88 is also in the high speed condition and is passing enough air over the condenser coils 74 and 82 to prevent excessive head pressures in the compressors 72 and 80.
Although typically the two auxiliary compressors 72 and 80 would be adequate in a situation where the vehicle is parked to cool the entire recreational vehicle, the air flow provided by fan motor 68 in the high speed condition would normally be adequate to prevent icing over of the evaporator coils if it was determined that it was so hot that the engine compressor 20 needed to be used for cooling the vehicle in addition to the other two compressors 72 and 80.
As set forth in this preferred embodiment, when air conditioning is called for, whether heating or cooling, the air handler fan motor 68 preferably runs continuously, and the cycling of condenser fan motor 88 in response to thermostat 132 would not affect air being circulated in the recreational vehicle by the air handler motor 68. Again, the circuitry illustrated can readily be modified to turn off the air handler motor 68 when the proper temperature is reached in the recreational vehicle and no compressors are operating.
The system thus has several modes of operation. The vehicle may be driven on the road with heat or cooling supplied conventionally only through the dashboard vents. Referring to
For heating the living space while in transit, the operator would continue to supply heat through main heater coil 41 and main fan 63 and in addition open valve 42 to supply main engine coolant from radiator 36 to secondary heater coil 44 in air handler cabinet 10. Fan motor 68 would be activated to continuously circulate the heated air through ducts 14 (
For cooling the living space while in transit using only the main cooling system, the operator would typically continue to supply refrigerant from main compressor 20 to main condenser 24 and evaporator 61, and in addition begin supplying refrigerant to secondary evaporator 58 in air handler cabinet 10. Fan motor 68 would be activated to circulate the cooled air through ducts 14 (
If additional cooling is needed while in transit, the operator could start auxiliary engine 113 and on board generator 112 to supply AC power to auxiliary compressor 72. In that event, compressor 72 circulates refrigerant through auxiliary condenser 74 and auxiliary evaporator 66, and condenser fan 88 moves air across condenser 74. Fan 68 would continue to operate.
For cooling while parked near a utility power source, 120 volt utility power can be used to operate one or both compressors 72, 80 and to supply AC power to fans 68 and 88. Main fan 63 and main compressor 20 would not be running in this mode. For heating while parked near a utility power source, if the weather is not below about 40 degrees F., one or both auxiliary compressors 72, 80 could be run in a heat pump mode. Alternately, a supplemental heater (not shown), such as a diesel heater, could be employed.
While in the foregoing specification a detailed description of a specific embodiment of the invention has been set forth for the purpose of illustration, it will be understood that many of the details given herein may be varied considerably by those skilled in the art without departing from the spirit and scope of the invention. For example, while a receiver reservoir has only been shown for use in the vehicle engine driven refrigeration system using compressor 20 where there is typically a wide range of air flow volume through the condenser coil, such a reservoir could readily be added to the systems utilizing compressors 72 and 80. Accordingly, the present invention is intended to be limited only by the scope of the appended claims and the applicable prior art.
