EP1994340A2

EP1994340A2 - High efficiency hybrid a/c system

Info

Publication number: EP1994340A2
Application number: EP06737824A
Authority: EP
Inventors: Xiaomei Yu; Lei Chen
Original assignee: Carrier Corp
Current assignee: Carrier Corp
Priority date: 2006-03-10
Filing date: 2006-03-10
Publication date: 2008-11-26
Also published as: WO2007106080A2; WO2007106080A3; HK1138355A1; US20090094991A1; EP1994340A4; CN101636623A; CN101636623B

Abstract

A hybrid air conditioning system (45) having both a conventional air conditioning system (46) and thermoelectric modules (80, 85, 90, 95) to provide heating and cooling, the thermoelectric modules (80, 85, 90, 95) providing waste heat or waste cooling to offset the demand on the conventional air conditioning system (46) and thereby reducing energy consumption and enhancing efficiency of the overall system (45).

Description

HIGH EFFICIENCY HYBRID A/C SYSTEM

BACKGROUND OF THE INVENTION

1. Field of the Invention

[0001] The invention relates to a hybrid air conditioning system that uses conventional air conditioning equipment to provide primary temperature control and thermoelectric cooling and/or heating devices to provide localized temperature control.

2. Description of Related Art

[0002] The efficiency of hydronic cooling systems is dependent upon the chilled water setting temperature or the evaporator setting temperature. For a given system and a fixed ambient environment, the higher the temperature setting, the greater will be the system efficiency. Similarly, the efficiency of a heating system is directly dependent upon the condenser or heating water temperature in a conventional system. In this instance, again, for a given system and a fixed ambient environment, the lower the temperature setting the greater the system efficiency will be.

[0003] A thermoelectric device consists of semiconductor materials that transfer heat from the first side or heat source side to a second side or heat sink side as charge carriers move through the materials. Thermoelectric cooling and heating systems operate at higher efficiency when there is a small temperature difference between the heat source side and the heat sink side. A thermoelectric device is also more responsive to the change in temperature settings, higher reliability and lower maintenance needs because they have fewer moving parts than conventional systems. Such systems are also more responsive to temperature settings, lower in weight, quieter and can be more accurately controlled.

[0004] Vapor compression and absorption based air conditioning systems are used for cooling residential and commercial buildings where multiple zone temperature control is the most efficient mode and provides the greatest comfort to occupants. This on-demand zoning comfort control is difficult and expensive to realize using a conventional air conditioning system because the entire evaporator and condenser units have to be activated whenever there is a cooling need. A hybrid air conditioning system incorporating thermoelectric cooling devices has the capability to operate for partial cooling without running the prime cooling system at all times. Such a hybrid air conditioning system will achieve both efficiency and comfort for users.

[0005] Furthermore, by applying a hybrid cooling system that incorporates both conventional air conditioning and thermoelectric cooling, the conventional equipment can operate at a higher evaporator temperature or chilled water temperature compared to non-hybrid equipment. Therefore the cooling system is able to operate at a higher cooling efficiency. Similarly, such a hybrid system for heating allows its conventional equipment to operate at a lower condenser or heating water temperature compared to the conventional application and the thermoelectric devices may operate at small temperature differential condition, whereby the hybrid system operates at a higher efficiency.

[0006] Accordingly, there is a need for an air conditioning system that incorporates a bulk conventional system with a thermoelectric distributed system that enhances overall system efficiency and improved comfort level by utilizing waste heat and/or cool and redirected electricity in a more reliable and responsive system for zoned temperature control.

SUMMARY OF THE INVENTION [0007] It is an object of the present invention to provide a hybrid system for an air conditioned space that uses conventional air conditioning equipment and thermoelectric heating and cooling devices.

[0008] It is also an object of the present invention to provide a hybrid system for an air conditioned space that has thermoelectric elements that can selectively provide zoned heating and/or cooling in the air conditioned space.

[0009] It is a further object of the present invention to provide a hybrid system for an air conditioned space that uses conventional and thermoelectric heating/cooling elements to reduce the overall energy consumption of the air conditioned space.

[0010] It is still yet a further object of the present invention to provide a hybrid system for an air conditioned space that uses conventional and the waste heat from thermoelectric heating/cooling elements to enhance the overall efficiency of the hybrid system.

[0011] It is still yet a further object of the present invention to provide a hybrid system for air conditioning that is controlled by occupants' demand with the aid of sensors to enhance the efficiency of the cooling system.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Fig. 1 illustrates a block diagram of a conventional air conditioned space;

[0013] Fig. 2 illustrates a block diagram of the hybrid system for the air conditioned space of the present invention; [0014] Fig. 3 illustrates a diagram of the operation of a thermoelectric element of the hybrid system of Fig. 2. according to the present invention;

[0015] Fig. 4 illustrates a schematic view of a hybrid air conditioned space according to the present invention; and

[0016] Fig. 5 illustrates a schematic view of a hybrid air conditioning system that uses return air as the heat sink of a thermoelectric cooling unit and is controlled by sensors.

DETAILED DESCRIPTION OF THE INVENTION

[0017] Referring to Fig. 1 , there is a block diagram of an air conditioned space 10, e.g. a large office, that is heated and cooled using a conventional air conditioning system of prior art. A conventional space cooling system is operated using a compressor, and evaporator, an air diffuser and a thermostat (not shown). Space 10 has an interior space 15 that may be subdivided into several units, e.g. rooms 20, 25, 30 and 35, having temperatures Ti, T₂, T _n-i and T_n, respectively. In space 10, T_set represents the temperature to which a thermometer is set, for a cooling scenario. Each of the temperatures T-i, T₂, T_n-i and T_n are equal to the temperature of T_set of the larger space. Rooms 20, 25, 30 and 35 each have thermostat. Raising the temperature T₁ to a temperature above T_set in room 20 will be very difficult because of conduction from adjacent rooms 25, 30 and 35 and the entire space 10 are relatively cool. The response time to increase the temperature would be long. Similarly, in an air conditioned space in which the temperature a lower temperature is desired, the same inefficiency persists. Lowering a temperature in a localized space in a large hot area will not only consume energy, but the lowered temperature, by conduction to adjacent spaces will cool those areas to a degree as well, thus making the conventional system produce more heat. [0018] Referring to Fig. 2, a diagram showing the hybrid system 45 of the present invention is shown. Hybrid system 45 incorporates a conventional air conditioning system 46 and a localized thermoelectric air conditioning system 48. In this diagram, air conditioned space 50, e.g. an office building space, is set at a temperature T_set(_H)- Space 50 contains several spaces, e.g. office rooms. Spaces 60, 65, 70 and 75 are set at temperatures T-i, T₂, T_n-i and T_n, respectively. Further spaces 60, 65, 70 and 75 each contains a thermoelectric module 80, 85, 90 and 95, respectively. Thermoelectric modules 80, m 85, 90 and 95 are controlled by localized thermoelectric air conditioning system 48. Each thermoelectric module is capable of generating either a cooling effect or a heating effect depending on the direction of the flow of current from its power source. Hybrid system 45 also has a temperature sensor 49 to monitor the overall temperature in the building spaces.

[0019] Referring to Figs. 2 and 3, thermoelectric module 80 located in room 60 is shown operating in a cooling mode. In thermoelectric module 80, a DC voltage from a power source 115 is applied across module 80 having a series of P and N junctions 100. Current 110 flows in the direction shown. Junctions 100 in thermoelectric module 80 absorb heat from a surface 105 and release the heat to a surface 110 at the opposite side of module 80. Surface 105 where the heat energy is absorbed becomes cold and the opposite surface 110 where the heat energy is released becomes hot. This "heat pumping" phenomenon, known as the Peltier effect, is commonly used in thermoelectric refrigeration. Heat exchangers 125 and 135 are used to transport cool air or heat away from thermoelectric module 80. In this scenario, forced air from fan 130 can be used to cool room 60 as it blows through heat exchanger 125. Similarly, forced air from fan 140 is used to transport heat from heat exchanger 135 to heat other rooms 65, 70 or 75 or conventionally air conditioned space 50. By using the waste heat from thermoelectric module 80, the efficiency of conventional air conditioned system is increased. Further, the conventional air conditioning system does not have to exclusively produce heat to heat other rooms, but can utilize heat from module 80 to heat the other rooms. Modules 85, 90 and 95 would operate in the same fashion in a heating operation, except that the current 110 would flow in the opposite direction.

[0020] The benefit of using thermoelectric modules in either a cooling application or a heating application in a localized space within a larger air conditioned space is that such modules contribute to the overall system efficiency of the hybrid system. Additionally, such a system will have reduced energy consumption costs associated with the conventional portion of the system. Further, the responsiveness of a system in achieving a desired temperature using thermoelectric modules is much greater than the responsiveness of conventional air conditioning system elements.

[0021] Referring to Fig. 2, a user in room 60 may want a cooler temperature Ti_(H) in comparison to T_set_(H) in space 50. In this example, the desired temperature TI₍H> is 68°F while T_set(H) is 72°F. When thermoelectric module 80 is activated in the cooling mode, a surface 100 of thermoelectric module 80 becomes cool to lower temperature Ti_(H). Concurrently, surface 105 becomes hot and contributes to the warming of spaces 50, and rooms 85, 90 and 95 by conduction. Heat generated by thermoelectric module 80 reduces the amount of work that conventional system must provide to keep temperature

[0022] Referring to Figs. 3 and 4, a schematic of diagram of an office building incorporating a high efficiency system 200 is shown. System 200 has a light duty conventional rooftop system 205 for conventional air conditioning. System 200 has a compressor, an evaporator, a linear diffuser and other components associated with a conventional air conditioning system. Room 210 has a thermoelectric module 215 for localized temperature control. When occupants of room 210 would like a warmer room temperature than the temperatures in the surrounding rooms, thermoelectric module 215 is activated to raise the local temperature in room 210. Cool air generated concurrently by thermoelectric device 215 will be distributed to rooms 220, 225 and 230, depending upon cooling needs. Accordingly, system 200 would not have to work to maintain the lower temperature because of the waste generated by module 215. A thermal sensor placed in common area 240 would monitor the temperature of the entire space in response to cool air from thermoelectric module 215, and would accordingly, adjust the amount of cooling to be provided by conventional system 200. Monitor 245 optimizes the performance of system 200 in response to adjustments made to thermoelectric modules in each of rooms 220, 225 and 230. Monitor 245 offsets the amount to cooling or heating that conventional components of hybrid system 200 produce depending upon the waste heat provided by thermoelectric modules.

[0023] Another embodiment of a hybrid air conditioning system 300 of the present invention is shown in Fig. 5. In this embodiment, system 300 has a conventional outdoor air conditioning component 305, preferably situated on the roof of a building, and a thermoelectric component 315 located adjacent air conditioned space 310. Thermoelectric component 315 has a side 320 and a side 325. When the hybrid system 300 is in a cooling mode, cool air is absorbed at side 320 and heat is released at surface 325. Conventional component 305 provides the primary cooling that may be set at a slightly higher temperature than the desired temperature. Cool air from conventional component 305 is forced through vents 335 by fans (not shown) to air conditioned space 310. When thermoelectric component 315 is activated, side 320, in communication with air pre-conditioned, produces cold air to further contribute to the cooling of the space. Return air 340 is used as the heat sink for thermoelectric component 315. A portion of the return air 340 is also circulated from air conditioned space 310 to refresh the air. The air cooled by the conventional unit 305 can be further cooled by a thermoelectric component 315 to a desired temperature or outdoor air 345 can be cooled directly by the thermoelectric unit depending the requirement of cooling capacity that is determined by the demand of occupants. Hybrid system 300 is preferably activated by sensor 350 such as temperature and air freshness sensor, e.g. a carbon dioxide sensor.

[0024] While the embodiment of Fig. 5 was shown in a cooling mode, a similar configuration of components could also be used in a heating application. Hybrid system 300 is converted to a heating mode by changing the direction of flow of electricity in the thermoelectric component 315 and by changing the setting on conventional system 305.

[0025] While the instant disclosure has been described with reference to one or more exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope thereof. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from the scope thereof. Therefore, it is intended that the disclosure not be limited to the particular embodiment(s) disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims

Wherefore We Claim:

1. A hybrid air conditioning system (45) for conditioning a space (50) comprising:

a conventional air conditioning system (46) for providing cooling and heating to said space (50)

at least one thermoelectric module (80) located within a portion of space (60) separate from said space (50), said at least one thermoelectric module (80) capable of providing heating in a heating mode and cooling in a cooling mode;

wherein said at least one thermoelectric module (80) is capable of increasing an efficiency of said conventional air conditioning system (46) by utilizing waste heat or waste cooling generated by said at least one thermoelectric module (80) and by reducing electric demand.

2. The hybrid air conditioning system (45) of claim 1 , wherein said conventional air conditioning system (46) can be set at a temperature Ti, and said at least one thermoelectric module (80) can be set at temperature T₂, different from T-|.

3. The hybrid air conditioning system of claim 2, wherein said conventional system (46) is set at a temperature T-i, and when said at least one thermoelectric module (80) is set to a temperature T₂, higher than T-i, wherein waste cooling generated by said at least one thermoelectric module (80) is capable of being used by said conventional system (46) to achieve said set temperature T-i.

4. The hybrid air conditioning system (45) of claim 1 , wherein when said conventional system (48) is set at a temperature T-], and wherein when said at least one thermoelectric module (80) is set to a temperature T₂, lower than Ti, wherein waste heat generated by said at least one thermoelectric module (80) is capable of being utilized by said conventional system (46) to achieve set temperature T-_t.

5. The hybrid system (45) of claim 1 , wherein said conventional air conditioning system (46) further comprises a compressor, an evaporator, a linear diffuser and a thermostat.

6. The hybrid system (45) of claim 1 , further comprises a temperature sensor (49) in said air conditioned space, said temperature sensor (49) capable of adjusting an amount of heating or cooling generated by said conventional system (46) in response to waste heat or waste cooling generated by said at least one thermoelectric module (80).

7. The hybrid air conditioning (45) system of claim 1 , wherein said at least one thermoelectric modules (80) is a plurality of thermoelectric modules (80, 85, 90, 95) each located within a space separate from others of said plurality of modules.

8. The hybrid air conditioning system (45) of claim 1 , wherein said plurality of thermoelectric modules (80, 85, 90, 95) are each adjustable to a temperature.

9. A hybrid air conditioning system (45) for air conditioning a space as herein described with reference to any one of Figures. 1 , 2, 3, 4 or 5 of the accompanying drawings.

10. A hybrid air conditioning system (45) for conditioning a space (50) comprising:

a hybrid air conditioning system (48) for providing localized cooling and or heating to a portion of said space separate from said space (50), said hybrid air conditioning system (48) having at least one thermoelectric module (80) that is capable of providing heating in a heating mode and cooling in a cooling mode;

wherein said hybrid air conditioning system (48) is capable of increasing an efficiency of said conventional air conditioning system (46) by utilizing waste heat or waste cooling generated by said hybrid air ~ conditioning system (48) and by reducing electric demand.

11. The hybrid air conditioning system (45) of claim 10, wherein said hybrid air conditioning system (48) further comprises a plurality of thermoelectric modules (80, 85, 90, 95).

12. The hybrid air conditioning system (45) of claim 10, wherein said plurality of thermoelectric modules (80, 85, 90, 95) are located within said portion of said space separate from said space (50).

13. The hybrid air conditioning system (45) of claim 11 , wherein said conventional air conditioning system (46) can be set at a temperature Ti, and said at least one of said plurality of thermoelectric modules (80, 85, 90, 95) can be set at temperature T₂, different from T-i.

14. The hybrid air conditioning system (45) of claim 10, wherein said conventional air conditioning system (46) is set at a temperature T₁, and when said at least one of said plurality of thermoelectric modules (80, 85, 90, 95) is set to a temperature T₂, different than T-i, wherein waste heat or waste cooling generated by said at least one of said plurality of thermoelectric modules (80, 85, 90, 95) is capable of being used by said conventional system (46) to achieve said set temperature T-i.

15. The hybrid system (45) of claim 10, wherein said conventional air conditioning system (46) further comprises a compressor, an evaporator, a linear diffuser and a thermostat.

16. The hybrid system (45) of claim 10, further comprises a temperature sensor (49) in said air conditioned space, said temperature sensor (49) capable of adjusting an amount of heating or cooling generated by said conventional system (46) in response-to waste heat or waste cooling generated by said at least one of said plurality thermoelectric modules (80, 85, 90, 95).

17. A hybrid air conditioning system (45) for air conditioning a space as herein described with reference to any one of Figures. 1 , 2, 3, 4 or 5 of the accompanying drawings.