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:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    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. 
         [0003]    2. Description of Related Art 
         [0004]    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. 
         [0005]    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. 
         [0006]    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. 
         [0007]    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. 
         [0008]    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 
       [0009]    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. 
         [0010]    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. 
         [0011]    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. 
         [0012]    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. 
         [0013]    It is still yet a further object of the present invention to provide a hybrid system for air conditioning that is controlled by occupants&#39; demand with the aid of sensors to enhance the efficiency of the cooling system. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  illustrates a block diagram of a conventional air conditioned space; 
           [0015]      FIG. 2  illustrates a block diagram of the hybrid system for the air conditioned space of the present invention; 
           [0016]      FIG. 3  illustrates a diagram of the operation of a thermoelectric element of the hybrid system of  FIG. 2 . according to the present invention; 
           [0017]      FIG. 4  illustrates a schematic view of a hybrid air conditioned space according to the present invention; and 
           [0018]      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 
       [0019]    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 T 1 , T 2 , T n-1  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 1 , T 2 , T n-1  and T n  are equal to the temperature of T set  of the larger space. Rooms  20 ,  25 , and  35  each have thermostat. Raising the temperature T 1  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. 
         [0020]    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 1 , T 2 , T n-1  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. 
         [0021]    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. 
         [0022]    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. 
         [0023]    Referring to  FIG. 2 , a user in room  60  may want a cooler temperature T 1(H)  in comparison to T set(H)  in space  50 . In this example, the desired temperature T 1(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 T 1(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 T set(H)  at 72° F. 
         [0024]    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. 
         [0025]    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. 
         [0026]    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 . 
         [0027]    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.