Mobile split-unit, air-to-air climate control system

Our System (20) is comprised of a small Battery-Powered, Split-Unit, Air-to-Air Heat Pump (30 & 50); and associated circuitry (60) to charge and condition the battery or batteries (41) any time an external power source (16) is available. The System (20) provides protection for the batteries (41) and systems of the vehicle (10) on which the System (20) is mounted when the vehicle alternator (15) is not producing any voltage.

Skip to: Description  ·  Claims  · Patent History  ·  Patent History

This application claims the benefit of PPA Ser. No. 60/755,319, filed 2005 Dec. 31 by the present inventors.






1. Field of Invention

This invention generally relates to a heat pump that runs off of batteries, specifically to a system comprised of a small battery-powered, split-unit, air-to-air heat pump.

2. Prior Art

A standard practice for truck drivers is to let their trucks idle when stopped for their mandatory rest period. This is to keep the interior of the truck comfortable without violating the security of the vehicle by opening windows. What is the impact of this idling on society and the drivers? Research indicates that there are approximately 2.6 million Class 8 trucks that engage in overnight idling. Based upon representative industry statistics, the idling time for a typical over-the-road Class 8 diesel fuel truck is eight hours per night, 300 nights per year, burning about one gallon of fuel for each hour at idle. That could be up to 6.24 billion gallons a year. Studies have also shown that lengthy idling can reduce the operating life of engine oil by 75 percent. Idling does not burn fuel efficiently; it causes build-up of carbon and unburned fuel residue on parts such as spark plugs, fuel injectors, valve seats, and piston crowns. A simple cutback in idling can save annual maintenance costs of at least $2000 per truck.

Many communities and some states are instituting anti-idling laws in order to reduce noise and air pollution. Due to these anti-idling laws and the need to cut fuel and truck costs, the drivers must find alternate solutions to provide for their comfort without risking their security during rest stops. There are currently three different power solutions.

One such solution is to plug into shore power. Then the driver needs both auxiliary electric heat and air conditioning (A/C) units installed. Together the units consume much needed storage space. In addition the A/C unit requires a large hole in the truck for mounting. Or the unit may be mounted on the inside or outside of the cab. This would require a vent hole or two for airflow. Shore power, unfortunately, is not always available when and where the truck driver must stop, requiring the driver to continue on to another place, stop without A/C or heat, or install one of these other solutions.

Another popular solution is to add an auxiliary generator, mostly diesel-powered. A gas generator emits less pollution than a diesel generator. The gas generator, however, requires an additional fuel tank. The diesel generator taps into one of the truck tanks. Both types of generators are noisy, heavy, use expensive fuel, pollute the air, and are costly to buy. In the following patents a generator has been installed to provide power during the engine off condition. Different ways are implemented to heat and cool the interior of the cab. In patent 2006/0107920 to Serkh et al., 2006 May 25, a generator is used to run the truck A/C and heat. This is invasive to the engine and time-consuming to install. In U.S. Pat. No. 6,932,148 B1 to Brummett et al., 2005 Aug. 23, and Pub. No. US 2003/0070849 to Whittaker, 2003 Apr. 17, an auxiliary A/C is added, and the heat is absorbed from the generator. The device taps into existing vent systems to get the warm and cool air into the truck where it is needed destroying the integrity of the existing vent system. In Pub. No. US 2003/0034147 A1 to Houck et al., 2003 Feb. 20, the generator runs an A/C unit, with a 2000 W-heating element, that is mounted in one-half of the storage space under the bunk. This takes up a large amount of the inside storage space, which is a limited quantity. In U.S. Pat. No. 6,889,762 B2 to Zeigler et al., 2005 May 10, the generator, the vehicle batteries, or shore power can run the auxiliary A/C and heat. Batteries on a truck are designed to handle short bursts of draw down, followed by immediate recharging, as seen when the truck is started. Battery life would be severely reduced by complete depletion of its charge caused by ten hours of almost continuous use by a heater or A/C unit. For that matter it would not even last that long on the first charge. So the Zeigler system, designed to shut down the A/C or heater before truck battery charge is reduced too far to start the truck, leaves the driver without cool air or heat for the last part of her/his rest stop unless s/he uses a generator. The driver would have to replace his/her batteries often with such deep discharge every night. FIG. 6 shows a diesel-fired heater under the bunk to save on battery life or generator usage. Safety is compromised when the occupant is forced to sleep above a combustible liquid located in close proximity to a fire. The third power solution is auxiliary batteries. Batteries take up less room than the generator, are quieter than a generator, and do not pollute when used. They are, however, limited on power; so the power consumption of the heating and cooling devices must be limited in order not to drain them too fast. U.S. Pat. No. 6,453,678 B1 to Sundhar, 2002 Sep. 24, uses a battery to run a thermoelectric chip and/or a cold storage device. A eutectic battery (cold storage device) big enough to cool the truck cab long enough for a mandatory rest break would be heavy and space-consuming. A thermoelectric chip would drain the battery fast. The solar panel is good for recharging but will not work at night or on overcast days. In U.S. Pat. No. 5,899,081 to Evans et al., 1999 May 4, there is a heat pump run by auxiliary, deep-cycle batteries which helps the space problem and energy consumption, but the batteries are charged by a solenoid, which does not fully recharge or condition the batteries. The condition of the batteries will degrade quickly with such usage, and have to be replaced often. Since their heat pump is not a split unit, mounting it would require a hole the size of the unit to be cut in the truck. A less-invasive mounting on either the inside or outside of the cab would require two large vent holes or one larger hole for a bi-directional vent pipe for proper circulation of air to the other side of the cab wall. Another objection we have found is that there is no drain for condensation when in air conditioner mode if it is mounted inside, potentially causing moisture and water damage in the cab of the truck. In our international search we found WO 2005/108135 patent by Coe et al. that uses very specialized batteries to run both the truck systems and a one-piece heat pump. These batteries solve the deep discharge and recharge problem seen in the Evans patent. But they present other problems. A bank of eight of these batteries as described in their preferred embodiment would take up about one third of the under-bunk storage space inside the cab of the truck. They are space consuming, heavy, and expensive. They have to be special ordered if anything goes wrong with one. And at the 15 percent of state of charge where the system shuts down if the driver has any extra draw down from auxiliary truck systems there might not be enough charge left to start the truck. Even without extra draw down the truck would have to start first time the key is turned every time because of the draw down curve of reserve power. They are using purchased heat pumps and inverters that do not exactly fit the requirements of the space. The heat pump, with only 89 percent efficiency and 8000 BTU output, would not have a duration cycle of sufficient length to remove the humidity in moderate temperatures to make conditions comfortable. If the heat pump were made smaller, the inverter would then be too big for efficient energy use.


Accordingly several advantages of this invention are its mobility and economy. This entire System consists of a Battery-Operated, Split-Unit, Air-to-Air Heat Pump, auxiliary Battery or Batteries, Power Control Unit (PCU), Micro Controller Unit (MCU), and Remote Control. We are keeping all parts of our System as small, lightweight, and compact as possible due to space and weight limitations. The vehicles that this System targets are Class 2 to 8 commercial vehicles. This System uses 5500 BTUs to put out 5300 BTUs of cooling or heating. We are keeping a tight rein on energy expenditure with microchip control of many of the functions of our system. We estimate 95 percent efficiency with our System. The System has integrated recharging and conditioning circuitry for the protection of the auxiliary battery or batteries and protection of the truck batteries. This System is: flexible; small in size; able to protect the primary vehicle batteries and systems; lightweight; non-polluting; quiet; able to run off battery or batteries or shore power; has a drain for condensation during cooling that does not allow bugs or dirt to back up into the Unit; and uses renewable energy. Our System does not directly consume hydrocarbon fuels. There will be a dramatic difference made in fuel economy and maintenance while retaining comfort for the drivers who use it. The Climate Control System will enhance the everyday lives of all Americans because it is a solution that cuts down on noise and air pollutants in the environment. By using less fuel there will be more fuel left in our reserves; lower demand, better prices. This System will cause a reduction in the dependence on foreign oil because the system runs on battery or batteries and is highly efficient. This, in turn, will reduce the burden of energy prices on independent truck drivers and fleet owners by reducing the amount of fuel they consume. The battery or batteries recharge while the truck is in its normal operation, which increases the viability and deployment of renewable energy technologies. All of these benefits taken together will increase the efficiency and reduce the energy intensity of the commercial transportation industry. Our idle-reduction System will provide truck drivers greater freedom in accomplishing their transportation goals while maintaining their own health and safety; thus ensuring safer highways for everyone.

In our other embodiments the System is used in other sizes of vehicles, tents, portable shelters, and other small-enclosed spaces. Further objects and advantages will become apparent from a consideration of the ensuing description and drawings.


In accordance with the invention, this Mobile, Split-Unit, Air-to-Air Climate Control System uses a rechargeable, deep-cycle battery or bank of batteries to run a split-unit, air-to-air heat pump to control the temperature of the interior space of vehicles, portable shelters, and small enclosures. The System includes microchip-controlled electronics as a charging/conditioning/switching system to get the best life and usage from the auxiliary battery or batteries as well as to protect an external power source's electrical systems. We have a fully integrated system that is 95 percent efficient.


FIG. 1 is a block diagram of the System as installed on and in a vehicle

FIG. 2 is a block diagram with the Power Control Unit (PCU) expanded

FIG. 3 is a diagram of the Split-Unit, Air-to-Air Heat Pump


    • 10. The vehicle or truck
    • 11. Exterior of vehicle; i.e. frame under vehicle, cab, etc.
    • 12. Living space
    • 13. Storage space; i.e. under bunk, in closet, etc.
    • 14. Vehicle battery or batteries
    • 15. Vehicle alternator
    • 16. Outside or auxiliary source of power (i.e. shore power, generator, solar array)
    • 20. Mobile Split-Unit, Air-to-Air Climate Control System
    • 30. Outside part of Heat Pump, mounted on 11.
    • 31. Air intake on 30.
    • 32. Air exhaust on 30.
    • 33. Refrigerant lines
    • 34. Compressor
    • 35. Reversing valve
    • 36. Expansion device
    • 37. Check valve
    • 38. Fan assembly
    • 39. Heat exchanger
    • 40. Battery box or frame, mounted on 11.
    • 41. Auxiliary deep-charge battery or batteries, supported by 40.
    • 50. Inside part of Heat Pump, mounted in 13.
    • 51. Drain for condensation, with valve
    • 52. Air intake on 50.
    • 53. Air outflow on 50.
    • 60. Power Control Unit (PCU) mounted in 13.
    • 61. Control Board (CB)
    • 63. Battery charger and conditioning circuit.
    • 64. Power Conversion Circuits (PCC)
    • 65. Electronic switches or relays
    • 66. Bus Lines
    • 67. Data, Sense, & Control Lines (DSCLines)
    • 68. Low current lines
    • 69. High current lines
    • 70. Micro Controller Unit (MCU) mounted in 12.
    • 71. Infrared (IR) remote, kept in 12.


FIG. 1 shows our small Split-Unit, Air-to-Air Climate Control System 20 installed on and in vehicle 10, which in the preferred embodiment is an over-the-road truck. System 20 uses small refrigerant compressor 34 that consumes about 3 amps of current. Unit parts 30, 40, 50, 60, & 70 can be mounted on and in over-the-road truck 10. Outside unit 30 is installed on the outside of cab 11, usually on the back by way of a shelf. Auxiliary battery or batteries 41 are installed in battery box or frame 40. Box or frame 40 is mounted on the outside of cab 11, usually on the frame of truck 10. Inside unit 50 and Power Control Unit (PCU) 60 are installed in storage space 13. Inside unit 50 is best on the floor for installation of condensation drain 51, comprised of a simple condensation removal device. Micro Controller Unit (MCU) 70 is mounted on a wall in living space 12. Infrared (IR) remote 71 will be kept where it is handy to the driver when s/he stops to rest.

FIG. 2 shows connections to run System 20 with and without use of outside power source 16. Battery or batteries 41 is connected through Power Conversion Circuits (PCC) 64 to run heat pump unit 30 & 50 and control circuitry 61 & 70. This System 20 when fully charged will condition the air in the truck for about ten hours while the driver is resting with truck 10 off. To keep from discharging truck batteries 14 while truck 10 is off or if alternator 15 quits, there is electronically controlled switch or relay 65 to cut off the electrical connection to truck 10. To charge and condition auxiliary battery or batteries 41, relay 65 closes to connect charging circuit 63 to truck batteries 14 after alternator 15 voltage is back up to 12.5 volts. The battery voltage is converted from 12 volts to 18 volts to run auxiliary battery charger 63 thus insuring a full charge on auxiliary battery or batteries 41. Outside source of power 16 at 115 volts is sometimes available so we have included circuitry 63 to allow auxiliary battery or batteries 41 to charge and System 20 to run from that source. As can be seen in FIG. 2 high current electric lines 69 come from truck batteries 14 and auxiliary batteries 41 through 12 volt, dc relays 65 to changer 63 and PCC 64. Data, Sense, & Control Lines (DSCLines) 67 go from Control Board 61 to all units, circuit boards, and auxiliary batteries 41. Low current lines 68 go to all units and circuit boards. Where both DSCLines 67 and low current lines 68 go to outside unit 30, inside unit 50, and MCU 70 we use bus lines 66.

FIG. 3 shows our Heat Pump 30 & 50 has the standard components of heat pumps with compressor 34, to compress and pump refrigerant through the lines 33, and reversing valve 35 to reverse the refrigerant flow through heat exchangers 39 with the change from cooling to heating. There are check valves 37 to make the refrigerant go through the correct expansion device 36. There is fan assembly 38 for each part of heat pump unit 30 & 50 for forced airflow 31, 32, 52, & 53 through each unit 30 & 50. Of course there are refrigerant lines 33 between units 30 & 50 and inside them.

Operation—Preferred Embodiment

The operation of our Climate Control System 20 is best described in two parts:

1. Charge Sense Mode

Charge sense mode consists of two conditions, charge and discharge. The charge condition is implemented and dependent on truck charging system 15. Truck electrical system 15 is charging when the engine (not shown) is running. When truck system15 is charging, PCU 60 senses the correct power and it begins to charge auxiliary batteries 41. As auxiliary batteries 41 are charging, the amount of power required to charge batteries 41 depends on the charge level of auxiliary batteries 41.

If batteries 41 were significantly discharged, the charge level is at a high rate. If batteries 41 where not discharged very much or not at all, the charge rate is low. The conditioning takes place throughout the charging cycle in the accepted industry standards method for deep cycle batteries.

When truck alternator 15 is not running PCU 60 will sense the loss of power and will not charge auxiliary batteries 41 or draw power from any other truck systems. In the event there is a problem with the truck charging system, PCU 60 will not charge, thereby maintaining the trucks main batteries 14 longer.

2. Run Mode

The truck driver controls System 20. There are several options for selection: fan mode, multi-speed, heat mode, cool mode, and temperature. These modes originate in MCU 70, where their function is to control heat pump units 30 & 50 and fan 38 for the desires of the truck driver. MCU 70 incorporates heat pump control and temperature control, as well as feedback to the driver of the condition and charge current of main battery 14 and auxiliary battery 41.

When auxiliary batteries 41 are depleted, System 20 shuts down to protect auxiliary batteries 41. When alternative source of power 16 is available, auxiliary batteries 41 can be charged if they require charging. System 20 can be operated at the same time if desired.

Due to the integration of our System 20, the high efficiency (95 percent) of Heat Pump 30 & 50, and storage capacity of deep-cycle batteries 41, our System 20 is capable of controlling the temperature in a truck cab under most weather conditions in the U.S. for about ten hours.

Description—Secondary Embodiment

In our second embodiment, we see this System 20 in a smaller version with fewer or smaller batteries 41 in order to condition the interior of a car or van while the driver is absent from the vehicle for a few hours, i.e. in a store or restaurant. The reason to condition the interior of the car during this time is for the comfort of pets or people who choose to stay in the vehicle. The smaller system will fit in the trunk and/or under the back seat. It will provide comfort for two to four hours.

Description-Tertiary Embodiment

In our third embodiment, we see this System 20 in a larger version with a larger battery bank 41 for use in campers, horse trailers, tents, and portable buildings. The mounting of the various parts of System 20 depends on the size and configuration of the area to be conditioned. These will require more battery support and larger heat pump units, especially in the tents and portable buildings, depending on the amount of time the user will wish to have, and the weather conditions encountered.

This System 20 is quite versatile and adaptable to different situations. The number and capacities of batteries 41 can be varied quite extensively. The size of Heat Pump 30 &50 can be varied to some extent and still be mobile. PCU 60 is adaptable as to types of external power sources 16, charge time, and charge speed. Adaptability in our System 20 is important to us.


Thus the reader will see that this Conditioning System remedies many problems facing the transportation industry. It addresses many issues including anti-idling laws, conservation of resources, and reduction of maintenance. This Battery-Powered, Split-Unit, Air-to-Air Climate Control System saves on fuel, maintenance, air pollution, and noise pollution. It is also conducive to highway safety by allowing drivers worry-free and comfortable rest. Being truck drivers ourselves we see the needs that this System meets. Also in talking to other drivers we meet out on the road, we realize not all drivers want all of the features. We can work with them to meet their specific needs within the parameters of the claims we have made on this System. While the above description contains many specifics, these should not be construed as limitations on the scope of the invention, but rather as an exemplification of the embodiments listed thereof. Many other variations are possible. For example:

    • Use of the System to climate-control a tent in the Arabian desert using a solar array to power the rest of the System, or
    • Use of the System to climate-control a remote building in an alpine setting for sports enthusiasts who get caught in a storm, using a solar array to keep a bank of batteries charged for a possible emergency, or
    • Use of the System to climate-control a trailer when transporting horses across country during inclement weather using power from the vehicle pulling the trailer to charge the System.

Accordingly, the scope of the System should be determined not by the embodiments illustrated, but by the appended claims and their legal equivalents.


1. A method for temperature control of an enclosed area, comprising the steps of:

a. providing a bank of one or more deep cycle batteries, and
b. connecting them to a converting circuit, so that the output of said converting circuit runs a split-unit heat pump, and
c. putting energy back into said bank of batteries by way of a battery charger and conditioner, and
d. getting said energy from an engine or an outside source by way of said converting circuit,
whereby said enclosed space may be heated or cooled without constant use of said engine, said outside source, or opening windows.

2. The method for temperature control of claim 1 further including a means for draining condensate out of said enclosed space.

3. A self-contained mobile system for temperature control of an enclosed area, comprising:

a. a split-unit heat pump,
b. a bank of one or more deep cycle batteries,
c. a means for converting the direct current output of said batteries to the alternating current needed to run said heat pump,
d. a means for fully recharging and conditioning said batteries from a vehicle engine or an outside source,
e. a means to protect said batteries,
f. a means to protect a vehicle's batteries and systems,
whereby said enclosed area may be temperature controlled as desired without the constant running of said engine, connection to said outside source, or opening windows.

4. The self-contained mobile system of claim 3 wherein said heat pump has a drain for condensate.

5. The self-contained mobile system of claim 3 wherein said enclosed area is a vehicle.

6. The self-contained mobile system of claim 5 wherein said vehicle is a truck.

7. The self-contained mobile system of claim 3 wherein said enclosed area is an inside of a tent.

8. The self-contained mobile system of claim 3 wherein said enclosed area is an inside of a portable building.

9. A method for heating or cooling the inside of an enclosed space with a split-unit, air-to-air heat pump from deep cycle batteries; including circuitry to properly recharge and condition said batteries from an engine or outside source.

10. The method for heating or cooling of claim 9 further including a means to drain condensation to the outside of said area.

11. The method for heating or cooling of claim 9 wherein said space is a vehicle.

12. The method for heating or cooling of claim 11 wherein said vehicle is a truck or car.

13. The method for heating or cooling of claim 11 wherein said vehicle is a recreational vehicle.

14. The method for heating or cooling of claim 9 wherein said space is a horse trailer.

15. The method for heating or cooling of claim 9 wherein said space is a portable structure.

16. The method for heating or cooling of claim 16 wherein said portable structure is a tent or a temporary building.

17. The method for heating or cooling of claim 9 wherein said space is an enclosure in a barn or a shed.

18. The method for heating or cooling of claim 9 wherein said space is a house in a remote area where commercial power is unavailable.

Patent History
Publication number: 20070151273
Type: Application
Filed: Oct 17, 2006
Publication Date: Jul 5, 2007
Inventors: James Roger Nelson (Murdock, NE), John Robert McNaught (Alvo, NE)
Application Number: 11/582,915
Current U.S. Class: With Alternately Usable Energy Sources (62/236); With Electrical Motor Drive (62/323.3)
International Classification: F25B 27/00 (20060101);