Cab heating systems and methods for vehicles

Abstract

A cab heating system for a vehicle comprising a turbine engine, a heat exchanger, and a duct. The turbine engine generates exhaust containing waste heat. The heat exchanger comprises a first portion, a second portion, and first and second lines for carrying auxiliary working fluid between the first and second portions. The duct is operatively connected to carry exhaust from the turbine engine to the first portion of the heat exchanger. The first portion of the heat exchanger transfers waste heat of the exhaust generated by the turbine engine to the auxiliary working fluid. The first line carries the auxiliary working fluid to the second portion of the heat exchanger. The heat exchanger extracts heat from the auxiliary working fluid. The second line carries the auxiliary working fluid to the first portion of the heat exchanger.

Description

TECHNICAL FIELD

The present invention relates to heating systems for use on movable structures such as vehicles and, in particular, to a heating system for a cab of a vehicle that employs waste heat from an onboard turbine.

BACKGROUND

Utility power is typically made available as an AC power signal distributed from one or more centralized sources to end users over a power distribution network. However, utility power is unavailable for certain structures. For example, movable structures such as vehicles do not have access to utility power when moving and cannot be easily connected to a power distribution network when parked. Similarly, remote structures such as cabins and military installations not near the utility power distribution network often cannot be practically powered using utility power.

DC power systems including batteries are often employed to provide power when utility power is unavailable. For example, trucks and boats typically employ a DC power system including a battery array to provide power at least to secondary vehicle electronics systems such as communications systems, navigation systems, ignition systems, heating and cooling systems, and the like. Shipping containers and remote cabins that operate using alternative primary power sources such as solar panels or generators also may include DC power systems including a battery or array of batteries to operate electronics systems when primary power is unavailable. Accordingly, most modern vehicles and remote structures use battery power sufficient to operate, at least for a limited period of time, electronics systems such as secondary vehicle electronics systems.

The capacity of a battery system used by a vehicle or remote structure is typically limited by factors such as size, weight, and cost. For example, a vehicle with an internal combustion engine may include a relatively small battery for use when the engine is not operating; a large battery array is impractical for vehicles with an internal combustion engine because the size of the batteries takes up valuable space and the weight of the batteries reduces vehicle efficiency when the vehicle is being moved by the engine. All electric vehicles have significantly greater battery capacity, but that battery capacity is often considered essential for the primary purpose of moving the vehicle, so the amount of battery capacity that can be dedicated to secondary vehicle electronics systems is limited. Battery systems employed by remote structures must be capable of providing power when the alternative power source is unavailable, but factors such as cost, size, and weight reduce the overall power storage capacity of such systems.

Heating and cooling systems have substantial energy requirements. Vehicles such as trucks or boats typically rely on the availability of the internal combustion engine when heating or cooling is required. When heating or cooling is required when the vehicle is parked or the boat is moored for more than a couple of minutes, the internal combustion engine will be operated in an idle mode solely to provide power to the heating and cooling system. Engine idling is inefficient and creates unnecessary pollution, and anti-idling laws are being enacted to prevent the use of idling engines, especially in congested environments like cities, truck stops, and harbors. For remote structures such as cabins or shipping containers, heating and cooling systems can be a major draw on battery power. Typically, an alternative or inferior heating or cooling source such as a wood burning stove, fans, or the like are used instead of a DC powered heating and cooling system.

The need thus exists for heating and cooling systems that operate using DC power having improved efficiency to optimize the use of battery power.

SUMMARY

The present invention may be embodied as a cab heating system for a vehicle comprising a turbine engine, a heat exchanger, and a duct. The turbine engine generates exhaust containing waste heat. The heat exchanger comprises a first portion, a second portion, and first and second lines for carrying auxiliary working fluid between the first and second portions. The duct is operatively connected to carry exhaust from the turbine engine to the first portion of the heat exchanger. The first portion of the heat exchanger transfers waste heat of the exhaust generated by the turbine engine to the auxiliary working fluid. The first line carries the auxiliary working fluid to the second portion of the heat exchanger. The heat exchanger extracts heat from the auxiliary working fluid. The second line carries the auxiliary working fluid to the first portion of the heat exchanger

The present invention may also be embodied as a method of heating a cab of a vehicle comprising the following steps. A turbine engine and a heat exchanger are provided. The heat exchanger comprises a first portion and a second portion. A duct is operatively connected to carry exhaust from the turbine engine to the first portion of the heat exchanger. The turbine engine is operated to generate exhaust containing waste heat such that the first portion of the heat exchanger transfers waste heat of the exhaust generated by the turbine engine to auxiliary working fluid. The auxiliary working fluid is caused to flow to the second portion of the heat exchanger. Heat is extracted from the auxiliary working fluid. The auxiliary working fluid is caused to flow to the first portion of the heat exchanger.

A vehicle heating and cooling system comprising a turbine engine generator, a heat exchanger, a compressor, an evaporator, and a duct. The turbine engine generator generates electricity and exhaust containing waste heat. The heat exchanger comprises a first portion and a second portion. The duct is operatively connected to carry exhaust from the turbine engine to the first portion of the heat exchanger. The first portion of the heat exchanger transfers waste heat of the exhaust generated by the turbine engine to auxiliary working fluid. The auxiliary working fluid flows from the first portion to the second portion of the heat exchanger. The second portion of the heat exchanger transfers heat from the auxiliary working fluid to main working fluid flowing between the compressor and the evaporator. The auxiliary working fluid flows from the second portion to the first portion of the heat exchanger.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a highly schematic side elevation view depicting a first example cab heating system of the present invention mounted on a vehicle;

FIG. 2A is a block diagram depicting details of a second example cab heating system;

FIG. 2B is a block diagram illustrating electrical components of the second example heating system; and

FIGS. 3A and 3B are block diagrams depicting details of a third example cab heating system operating in first and second configurations, respectively.

DETAILED DESCRIPTION

Several examples of the vehicle heating systems constructed in accordance with the present invention will be described separately below. In particular, a first example will be disclosed with reference to FIG. 1, a second example will be disclosed with reference to FIGS. 2A and 2B, and a third example will be described with reference to FIGS. 3A and 3B below.

In this application, the term “vehicle” refers to a movable structure when that structure is not connected to utility power either when being moved or when stationary and having electronics systems that operate on vehicle (DC) power. Examples of vehicles include trucks, automobiles, shipping containers, and boats. The present invention is of particular significance when applied to vehicles but may also have application to any structure, whether fixed or movable, that does not have access to utility power at least a portion of the time and is designed to operate primarily on DC power. The term “remote structure” will be used herein to refer to such structures.

I. First Example Vehicle Heating System

Depicted in FIG. 1 of the drawing is a vehicle 20 carrying a first example vehicle heating and cooling system 22 constructed in accordance with, and embodying, the principles of the present invention. The example vehicle 20 is or may be a conventional tractor adapted to pull a trailer (not shown) carrying goods.

The example vehicle 20 defines a cab area 30 in which a driver (not shown) sits. The first example vehicle heating and cooling system 22 comprises a turbine engine 40 and a heat exchanger system 42. A duct 44 is operatively connected between the turbine engine 40 and the heat exchanger system 42. A housing 46 supported by the vehicle 20 outside of the cab area 30 contains the turbine engine 42. The turbine engine 40 may be configured as a generator to generate electricity to supplement electricity generated by a main engine (not shown) of the vehicle 20 or when the main engine of the vehicle 20 is not operational.

The example heat exchanger system 42 comprises a first portion 50 and a second portion 52. First and second lines 54 and 56 carry working fluid in-between the first portion 50 and the second portion 52. When heat is transferred to the cab area 30, the example heat exchanger system 42 transfers waste heat from the turbine engine 40 through the duct 44 and around the first portion 50 of the heat exchanger system 42 such that heat is transferred to the working fluid within the first portion 50. The heated working fluid is caused to flow (e.g., pumped) through the first line 54, to the second portion 52 where heat is extracted, and back to the first portion 50 through the second line 56 for reheating.

The second portion of the example heat exchanger system 42 is configured to transfer waste heat from the turbine engine 40 to the cab area 30 to enhance the comfort of the driver. Typically, but not necessarily, the heat exchanger system 42 is operatively connected to a conventional cab HVAC system (not shown in FIG. 1) capable of both transferring heat to and removing heat from the cab area 30. When connected to a conventional cab HVAC system, the example heat exchanger system 42 is configured to supply auxiliary heat to the cab HVAC system in the heating mode.

II. Second Example Vehicle Heating System

Referring now to FIGS. 2A and 2B of the drawing, depicted therein is a second detailed example vehicle heating and cooling system 120 of the present invention. The second example vehicle heating and cooling system 120 is capable of operating in a cooling mode and in a heating mode. In the cooling mode, heat is transferred from an interior to an exterior of the vehicle 20 on which the second example heating system 120 is mounted. In the heating mode, heat is transferred from the exterior to an interior of the vehicle 20 on which the second example heating system 120 is mounted.

The second example vehicle heating and cooling system 120 comprises a compressor system 122, an interior system 124, and an auxiliary system 126 is connected to a battery 128 (FIG. 2B). The compressor system 122 and the interior system 124 are connected together by a first main line 130 and a second main line 132. The first and second main lines 130 and 132 allow main working fluid to be circulated between the compressor system 122 and the interior system 124. The compressor system 122 and the auxiliary heating system 126 are connected together by an auxiliary heat exchanger 134 that allows heat generated by the auxiliary heating system 126 to be transferred to the main working fluid.

The compressor system 122 comprises a compressor 140, a compressor side heat exchanger or condenser 142, a compressor thermal expansion valve 144, and an accumulator 146. The example condenser 142 comprises a plurality of heat exchanger portions 142a and 142b. A reversing valve 150 and compressor check valve 152 allow the second example vehicle heating and cooling system 120 to operate in the cooling mode and in the heating mode. The compressor system 122 further comprises a compressor distributor 160, a compressor fan 162, a fan motor 164, a compressor fluid temperature sensor 166, and a motor switch 168. The compressor distributor 160 allows fluid to flow through the heat exchanger portions 142a and 142b in parallel. The compressor fan 162, fan motor 164, temperature sensor 166, and motor switch 168 operate the fan 162 based on temperature of the primary working fluid flowing between the compressor system 122 and the interior system 124.

The interior system 124 comprises an interior heat exchanger or evaporator 170, an interior thermal expansion valve 172, and a dryer 174. The example interior system 124 further comprises an interior blower 180, an interior distributor 182, and an interior check valve 184. The example evaporator 170 comprises a plurality of interior heat exchanger sections 170a and 170b. The interior blower 180 carries heat from the evaporator 170 into the interior A. In combination with the reversing valve 150 and compressor check valve 152, the interior distributor 182 and interior check valve 184 allow the second example vehicle heating and cooling system 120 to operate in the cooling mode and in the heating mode. The interior distributor 182 allows fluid to flow through the interior heat exchanger portions 170a and 170b in parallel.

In the cooling mode, the compressor system 122 and the interior system 124 operate in a conventional manner as generally described in U.S. Pat. No. 6,615,602 to Wilkinson. The operation of the second example heating and cooling system 120 in the cooling mode will thus not be described in detail herein.

In the heating mode, the second example heating and cooling system 120 may operate in both a standard heating mode and in an augmented heating mode. In the standard heating mode, the compressor system 122 and the interior system 124 operate in a conventional manner as generally described in the U.S. Pat. No. 6,615,602. In the augmented heating mode, the heat generated by the compressor system 122 and transferred to the interior system 124 is augmented by the auxiliary heating system 126 as will now be described in detail.

In particular, the example auxiliary heating system 126 comprises a fuel tank 190, a fuel control valve 192, a turbine 194, an auxiliary fluid pump 196, and an auxiliary fluid line 198. The auxiliary fluid line 198 comprises a turbine section 198a and a heat exchanger section 198b. The turbine section 198a is located within the turbine 194, and the heat exchanger section 198b is located within the auxiliary heat exchanger 134.

The fuel tank 190 may be the main fuel tank of the vehicle on which the second example heating and cooling system 120 is mounted (e.g., diesel, gasoline) or may be a separate, auxiliary fuel tank containing the same or another type of fuel (e.g., propane). The fuel control valve 192 controls the flow of fuel from the fuel tank 190 to the turbine 194. The turbine 194 burns the fuel to generate electricity and, as a byproduct, creates waste heat. The auxiliary fluid pump 196 circulates auxiliary fluid (e.g., water) through the heating section 198a and the heat exchanger section 198b of the auxiliary fluid line 198. Heat from the turbine 194 is transferred to the auxiliary fluid in the turbine section 198a. Heat from the auxiliary fluid is transferred to the main fluid in the auxiliary heat exchanger 134. The auxiliary heating system 126 thus may be used to transfer heat to the main fluid when environmental and vehicle operation considerations do not allow the compressor system 122 efficiently to extract sufficient heat from the ambient air flowing across the compressor heat exchanger 142.

III. Third Example Vehicle Heating System

Referring now to FIGS. 3A and 3B of the drawing, depicted therein is a third example vehicle heating and cooling system 220 of the present invention. The third example vehicle heating and cooling system 220 is capable of operating in a cooling mode and in a heating mode. In the cooling mode, heat is transferred from an interior A to an exterior B of a vehicle (not shown) on which the third example heating system 220 is mounted. In the heating mode, heat is transferred from the exterior B to an interior A of the vehicle on which the third example heating system 220 is mounted. As with the first example heating and cooling system 20 described above with reference to FIG. 2, at least a portion of the power consumed by the third example heating and cooling system 220 is stored in a battery (not shown) of the vehicle 20.

The third example vehicle heating and cooling system 220 comprises a compressor system 222, an interior system 224, and an auxiliary system 226. The compressor system 222 and the interior system 224 are connected together by a first main line 230 and a second main line 232. The first and second main lines 230 and 232 allow main working fluid to be circulated between the compressor system 222 and the interior system 224. The compressor system 222 and the auxiliary heating system 226 are connected together by an auxiliary heat exchanger 234 that allows heat generated by the auxiliary heating system 226 to be transferred to the main working fluid. A control valve 236 and check valve 238 allow the third example heating and cooling system 220 to be placed in a main heating mode or an auxiliary heating mode as will be described in further detail below.

The compressor system 222 comprises a compressor 240, a compressor heat exchanger 242, a compressor thermal expansion valve 244, and an accumulator 246. The example compressor heat exchange 242 comprises a plurality of heat exchanger portions 242a and 242b. A reversing valve 250 and compressor check valve 252 allow the third example vehicle heating and cooling system 220 to operate in the cooling mode and in the heating mode. The compressor system 222 further comprises a compressor distributor 260, a compressor fan 262, a fan motor 264, a compressor fluid temperature sensor 266, and a motor switch 268. The compressor distributor 260 allows fluid to flow through the heat exchanger portions 242a and 242b in parallel. The compressor fan 262, fan motor 264, temperature sensor 266, and motor switch 268 operate the fan 262 based on temperature of the primary working fluid flowing between the compressor system 222 and the interior system 224.

The interior system 224 comprises an interior heat exchanger 270, an interior thermal expansion valve 272, and a dryer 274. The example interior system 224 further comprises an interior blower 280, an interior distributor 282, and an interior check valve 284. The example interior heat exchanger 270 comprises a plurality of interior heat exchanger sections 270a and 270b. The interior blower 280 carries heat from the interior heat exchanger 270 into the interior A. In combination with the reversing valve 250 and compressor check valve 252, the interior distributor 282 and interior check valve 284 allow the third example vehicle heating and cooling system 220 to operate in the cooling mode and in the heating mode. The interior distributor 282 allows fluid to flow through the interior heat exchanger portions 270a and 270b in parallel.

In the cooling mode, the compressor system 222 and the interior system 224 operate in a conventional manner as generally described in the U.S. Pat. No. 6,615,602. The operation of the third example heating and cooling system 220 in the cooling mode will thus not be described in detail herein.

In the heating mode, the third example heating and cooling system 220 may operate in both a standard heating mode and in an auxiliary heating mode. In the standard heating mode, the compressor system 222 and the interior system 224 operate in a conventional manner as generally described in the U.S. Pat. No. 6,615,602. In the augmented heating mode, the auxiliary heating system 226 is used instead of the compressor system 222 to transfer heat to the interior system 224 as will now be described in detail.

In particular, the example auxiliary heating system 226 comprises a fuel tank 290, a fuel control valve 292, a turbine 294, an auxiliary fluid pump 296, and an auxiliary fluid line 298. The auxiliary fluid line 298 comprises a turbine section 298a and a heat exchanger section 298b. The turbine section 298a is located within the turbine 294, and the heat exchanger section 298b is located within the auxiliary heat exchanger 234.

The fuel tank 290 may be the main fuel tank of the vehicle on which the third example heating and cooling system 220 is mounted (e.g., diesel, gasoline) or may be a separate, auxiliary fuel tank containing the same or another type of fuel (e.g., propane). The fuel control valve 292 controls the flow of fuel from the fuel tank 290 to the turbine 294. The turbine 294 burns the fuel to generate electricity and, as a byproduct, creates waste heat.

The auxiliary fluid pump 296 circulates auxiliary fluid (e.g., water) through the heating section 298a and the heat exchanger section 298b of the auxiliary fluid line 298. Heat from the turbine 294 is transferred to the auxiliary fluid in the turbine section 298a. Heat from the auxiliary fluid is transferred to the main fluid in the auxiliary heat exchanger 234. The control valve 236 and check valve 238 allow the auxiliary heating system 226 to be arranged in parallel with the compressor system 222 and thus may be used instead of the compressor system 222. The auxiliary heating system 226 thus may be used to transfer heat to the main fluid when environmental and vehicle operation considerations do not allow the compressor system 222 efficiently to extract sufficient heat from the ambient air flowing across the compressor heat exchanger 242.

Claims

1. A cab heating system for a vehicle comprising a vehicle battery, a fuel tank, and a cab HVAC system comprising a main working fluid that flows through a compressor operatively connected to the vehicle battery, a condenser, and an evaporator, the cab heating system comprising: a turbine engine operatively connected to the fuel tank, where the turbine engine is configured as a generator to burn fuel from the fuel tank to generate electricity for use by the vehicle battery, where the turbine engine generates exhaust containing waste heat;a heat exchanger comprising a first portion, a second portion, and first and second lines for carrying auxiliary working fluid between the first and second portions;a duct operatively connected to carry exhaust from the turbine engine to the first portion of the heat exchanger; whereinthe auxiliary fluid is circulated between the first and second portions of the heat exchanger such that the first line carries the auxiliary working fluid to the second portion of the heat exchanger, andthe second line carries the auxiliary working fluid to the first portion of the heat exchanger;the first portion of the heat exchanger transfers waste heat of the exhaust generated by the turbine engine to the auxiliary working fluid; andthe second portion of the heat exchanger extracts heat from the auxiliary working fluid and transfers the heat extracted from the auxiliary working fluid to the main working fluid to allow waste heat of the turbine engine to be used by the cab HVAC system.

2. The cab heating system as recited in claim 1, in which the HVAC system operates in: a cooling mode in which heat from the auxiliary fluid is not transferred to the main working fluid; anda heating mode in which the heat extracted from the auxiliary working fluid is transferred to the main working fluid.

3. The cab heating system as recited in claim 2, in which the main working fluid flows first through the compressor system and then through the second portion of the heat exchanger in the heating mode.

4. The cab heating system as recited in claim 2, in which the main working fluid flows in parallel through the compressor and the second portion of the heat exchanger in the heating mode.

5. The cab heating system as recited in claim 1, in which the main working fluid flows first through the compressor and then through the second portion of the heat exchanger when heat extracted from the auxiliary working fluid is transferred to the main working fluid.

6. The cab heating system as recited in claim 1, in which the main working fluid flows in parallel through the compressor and the second portion of the heat exchanger when heat extracted from the auxiliary working fluid is transferred to the main working fluid.

7. A method of heating a cab of a vehicle comprising a vehicle battery, a fuel tank, and a cab HVAC system comprising a main working fluid that flows through a compressor operatively connected to the vehicle battery, a condenser, and an evaporator, the method comprising the steps of: providing a turbine engine operatively connected to the fuel tank, where the turbine engine is configured as a generator to burn fuel from the fuel tank to generate electricity for use by the vehicle battery;providing a heat exchanger comprising a first portion and a second portion;operatively connecting a duct to carry exhaust from the turbine engine to the first portion of the heat exchanger;operating the turbine engine to generate exhaust containing waste heat such that the first portion of the heat exchanger transfers waste heat of the exhaust generated by the turbine engine to the auxiliary working fluid;circulating the auxiliary fluid between the first and second portions of the heat exchanger such that the first line carries the auxiliary working fluid to the second portion of the heat exchanger, andthe second line carries the auxiliary working fluid to the first portion of the heat exchanger;causing the first portion of the heat exchanger to transfer heat from the waste exhaust of the turbine engine to the auxiliary working fluid;causing the second portion of the heat exchanger to extract heat from the auxiliary working fluid and transfer the heat extracted from the auxiliary working fluid to the main working fluid to allow waste heat of the turbine engine to be used by the cab HVAC system.

8. The method as recited in claim 7, further comprising the step of operating the cab HVAC system in: a cooling mode in which heat from the auxiliary fluid is not transferred to the main working fluid; anda heating mode in which the heat extracted from the auxiliary working fluid is transferred to the main working fluid.

9. The method as recited in claim 7, further comprising the steps of: causing the main working fluid to flow through the cab HVAC system; andcausing the main working fluid to flow through the second portion of the heat exchanger when heat extracted from the auxiliary working fluid is transferred to the main working fluid.

10. The method as recited in claim 7, further comprising the steps of: causing the main working fluid to flow through the cab HVAC system; andcausing the main working fluid to flow through the second portion of the heat exchanger in the heating mode.

11. The method as recited in claim 7, further comprising the step of causing the main working fluid to flow in parallel through the cab HVAC system and the second portion of the heat exchanger when heat extracted from the auxiliary working fluid is transferred to the main working fluid.

12. The method as recited in claim 7, further comprising the step of causing the main working fluid to flow in parallel through the cab HVAC system and the second portion of the heat exchanger in the heating mode.

13. A vehicle heating and cooling system for a vehicle comprising a vehicle battery and a fuel tank, the vehicle heating a cooling system comprising: a turbine engine generator operatively connected to the fuel tank, where the turbine engine is configured as a generator to burn fuel from the fuel tank to generate electricity for use by the vehicle battery, andexhaust containing waste heat;a heat exchanger comprising a first portion and a second portion;a compressor, where the vehicle battery is operatively connected to the compressor;an evaporator;an evaporator; anda duct operatively connected to carry exhaust from the turbine engine to the first portion of the heat exchanger; whereinauxiliary working fluid circulates between the first portion of the heat exchanger and the second portion of the heat exchanger;the first portion of the heat exchanger transfers waste heat of the exhaust generated by the turbine engine to the auxiliary working fluid;the second portion of the heat exchanger extracts heat from the auxiliary working fluid and transfers the heat extracted from the auxiliary working fluid to main working fluid flowing between the compressor and the evaporator to allow waste heat of the turbine engine to be used to heat at least a portion of the vehicle.

14. The vehicle heating and cooling system as recited in claim 13, in which the compressor and the evaporator operate in: a cooling mode in which heat from the auxiliary fluid is not transferred to the main working fluid; anda heating mode in which the heat extracted from the auxiliary working fluid is transferred to the main working fluid.

15. The vehicle heating and cooling system as recited in claim 13, in which the main working fluid flows first through the compressor and then through the second portion of the heat exchanger when heat extracted from the auxiliary working fluid is transferred to the main working fluid.

16. The vehicle heating and cooling system as recited in claim 14, in which the main working fluid flows first through the compressor and then through the second portion of the heat exchanger in the heating mode.

17. The vehicle heating and cooling system as recited in claim 14, in which the main working fluid flows in parallel through the compressor and the second portion of the heat exchanger when heat extracted from the auxiliary working fluid is transferred to the main working fluid.

18. The vehicle heating and cooling system as recited in claim 14, in which the main working fluid flows in parallel through the compressor and the second portion of the heat exchanger in the heating mode.