Abstract:
A wall fan includes a control circuit both controlling the wall fan and a temperature control unit comprising a heater, a cooler, or a Heating, Ventilating, and Air Conditioning (HVAC) system. The control system receives a desired temperature and compares the desired temperature to an outdoor temperature. When the outdoor temperature indicates that drawing outside air into indoor space will drive the indoor air temperature towards the desired temperature, the control system activates the wall fan, and de-energizes the heater, cooler, or HVAC system. When the outdoor temperature indicates that drawing outside air into indoor space will not drive the indoor air temperature towards the desired temperature, the control system de-energizes the wall fan, and energizes the heater, cooler, or HVAC system.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims the priority of U.S. Provisional Patent Application Ser. No. 62/100,755 filed Jan. 7, 2015, which application is incorporated in its entirety herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to wall fans and in particular to a heating and cooling system with a temperature differential switch, the system configured to use the outside air to heat or cool a space when the temperature of the outside air is favorable rather than operating a heater or a cooler, or a Heating, Ventilating, and Air Conditioning (HVAC) system. 
     The cost of heating and air conditioning can be a substantial burden to users. Also, conventional heating and air conditioning systems create a carbon footprint damaging the environment. Conventional HVAC systems generally cycle a refrigerant to cool air or use a heater to heat air, and then circulate the cooled or heated air to various rooms. However, when a heater, a cooler, or an HVAC system is operating, and ambient outdoor air may also be available to drive indoor temperature a desired indoor temperature, known heaters, coolers, and HVAC systems do not take advantage of the potential energy savings. 
     Therefore, what is needed is a system which, depending on a desired indoor temperature and current outdoor temperature, will either draw the outdoor air into the indoor space when the outdoor air temperature is favorable, or will heat or cool indoor air when the outdoor air temperature is not favorable. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention addresses the above and other needs by providing a wall fan which includes a control circuit both controlling the wall fan and a temperature control unit comprising a heater, a cooler, or a Heating, Ventilating, and Air Conditioning (HVAC) system. The control system receives a desired temperature and compares the desired temperature to an outdoor temperature. When the outdoor temperature indicates that drawing outside air into indoor space will drive the indoor air temperature toward the desired temperature, the control system activates the wall fan, and de-energizes the temperature control unit. When the outdoor temperature indicates that drawing outside air into indoor space will not drive the indoor air temperature toward the desired temperature, the control system de-energizes the wall fan, and energizes the heater, cooler, or HVAC system 
     In accordance with one aspect of the invention, there is provided a heating and cooling system including a wall fan drawing outdoor air into a room to help a room temperature reach a desired temperature. The system includes a human interface for programming the desired indoor temperature, an indoor temperature sensor for measuring the actual indoor temperature, an outdoor temperature sensor for measuring the outdoor temperature, and a microprocessor electrically connected to the temperature sensors. The microprocessor may compare: (i) the indoor temperature with the desired temperature to determine whether the system needs to change the indoor temperature to reach the desired temperature, and (ii) if a change is required, compare the outdoor temperature, the indoor temperature, and the desired temperature to determine whether there is an advantage in drawing outdoor air into the room to obtain the desired temperature. The microprocessor may be connected to a relay switch configured to power either a fan or activate a heater, a cooler, or an HVAC system, depending on whether the outdoor temperature is favorable. 
     In accordance with another aspect of the invention, there is provided a method for controlling a heating system including a wall fan and a temperature control unit comprising one of a heater and an HVAC system. The method includes: setting heating mode and a low temperature Tl and a high temperature Th; measuring an outdoor temperature To and an indoor temperature Ti; comparing To and Ti, If To is not greater than Ti, de-energize the wall fan and energize the temperature control unit, waiting a period of time P and then repeating measuring the outdoor temperature To and the indoor temperature Ti, otherwise, if To is greater than Ti (i.e., can use outdoor air to heat the room), if Tl is less than Ti and Ti is less than Th, energize the wall fan and de-energize the temperature control unit, or alternatively de-energize the wall fan and energize the temperature control unit; and after the period of time P, again measuring the outdoor temperature To and the indoor temperature Ti and repeating the method. The temperature Tl is a lower preferred indoor temperature and the temperature Th is a higher preferred indoor temperature. 
     In accordance with yet another aspect of the invention, there is provided a method for controlling a cooling system including a wall fan and a temperature control unit comprising one of a cooler and an HVAC system. The method includes: setting cooling mode and the lower temperature Tl and the higher temperature Th; measuring an outdoor temperature To and an indoor temperature Ti; comparing Ti and To; If Ti is not greater than To, de-energize the wall fan and energize the temperature control unit; waiting a period of time P, and then repeating measuring the outdoor temperature To and the indoor temperature Ti; otherwise, if Ti is greater than To (i.e., can use outdoor air to cool the room), if Tl is less than Ti and Ti is less than Th, energize the wall fan and de-energize the temperature control unit or alternatively de-energize the wall fan off and energize the temperature control unit; and after the period of time P, again measuring the outdoor temperature To and the indoor temperature Ti and repeating the method. 
     In accordance with still another aspect of the invention, there is provided a wall fan including a control circuit configured to control an HVAC system. The control circuit receives outdoor temperature, indoor temperature, and a desired temperature. When outside air can drive the indoor temperature towards the desired temperature, the control circuit sends a signal to the HVAC system, or the HVAC thermostat, to deactivate the HVAC system to save energy. The wall fan and control circuit are advantageously an add-on to an existing HVAC system. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
       The above and other aspects, features and advantages of the present invention will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings wherein: 
         FIG. 1  shows rooms including a wall fan cooperating with a window heating or cooling unit according to the present invention. 
         FIG. 2  shows rooms including a wall fan cooperating with a Heating, Ventilating, and Air Conditioning (HVAC) system according to the present invention. 
         FIG. 3  shows a heating method according to the present invention. 
         FIG. 4  shows the operation of the heating method according to the present invention. 
         FIG. 5  shows a cooling method according to the present invention 
         FIG. 6  shows the operation of the cooling method according to the present invention. 
         FIG. 7  shows a circuit according to the present invention. 
     
    
    
     Corresponding reference characters indicate corresponding components throughout the several views of the drawings. 
     DETAILED DESCRIPTION OF THE INVENTION 
     The following description is of the best mode presently contemplated for carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of describing one or more preferred embodiments of the invention. The scope of the invention should be determined with reference to the claims. 
     Various references are made to energizing and de-energizing a wall fan or a temperature control unit. Such energizing and de-energizing refers to providing operating power, and the actual operation of the wall fan or a temperature control unit remains under the control of settings applied to the wall fan or a temperature control unit. Additionally, energizing and de-energizing may also refer to sending a signal to a control element (e.g. a thermostat) controlling the temperature control unit which overrides any mechanical or electrical programming which turns the temperature control unit ON. 
     A temperature controlled area  10   a  including a wall fan  14  cooperating with a window heating or cooling unit  16   a  according to the present invention are shown in  FIG. 1 . The wall fan  14  and temperature control unit  16   a  are mounted to an external wall  13 , preferably in windows  15 . A control panel  26  may be mounted to the wall or be part of wall fan  14 . The control panel  26  allows a user to select heating or cooling, and lower temperature Tl and a higher temperature Th determining when and if the wall fan or the heating/cooling unit will be utilized. An outdoor temperature sensor  28   a  measures outdoor temperature To and in indoor temperature sensor  28   b  measures an indoor temperature Ti. The temperatures Tl and Th, To, and Ti are all provided to a processor  50  (see  FIG. 7 ). The temperature control unit  16   a  may be a heating and/or cooler. 
     The processor  50  determines if the wall fan  14  should be energized or de-energized, and if the heating/cooling unit  16   a  should be de-energized or energized, based on the method of  FIGS. 3 and 5 . The sensors  28   a  and  28   b  are connected to the control panel  26  by wires  30   a ,  30   b . The control panel  26  controls the switch  27  which includes relays or the like, and the switch  27  controls power provided to the window fan  14  and the heating/cooling unit  16   a . For example, the switch  27  may include a normally open, double throw relay, and a relay contact will flip from a wall fan cord  17   a  to a heater/cooling unit cord  17   b  when a signal is receive from the control panel  26 . In other embodiments, the temperature sensors  28   a  and  28   b  may be connected to the switch  27 , and the switch  27  may include a control circuit. When the heating/cooling unit  16   a  receives power, it will operate based on its normal operation. 
     A temperature controlled area  10   b  including two rooms  12   a  and  12   b  including the wall fan  14  cooperating with a Heating, Ventilating, and a temperature control unit comprising an Air Conditioning (HVAC) system  16   b  are shown in  FIG. 2 . The wall fan  14  is mounted to an external wall  13  of the room  12   a  and the HVAC system  16   b  resides in or proximal to the room  12   b . The wall fan  14  may be mounted to any external wall, and is preferably mounted to an open window. The HVAC system  16   b  may be in either room, in a utility closet, in an attic, or on a roof of the temperature controlled area  10 . An HVAC thermostat  17  normally controls the operation of the HVAC system  16   b . Ducting  22  connects the HVAC  16   b  to vents  24   a  and  24   b  in the rooms  12   a  and  12   b  respectively providing either heated or cooled air. While an HVAC  16   b  using ducting and vents is shown, those skilled in the art will recognize that various heating and cooling systems are known, and such systems are intended to come within the scope of the present invention. 
     A control panel  26  may be mounted to the wall fan  14 , be part of the wall fan  14 , or mounted at any convenient location in the area  10 . The control panel  26  allows a user to select heating or cooling and the desired temperatures Tl and Th. An outdoor temperature sensor  28   a  measures outdoor temperature To and in indoor temperature sensor measures an indoor temperature Ti. The temperatures Tl, Th, To, and Ti are all provided to a processor  50  (see  FIG. 3 ). The processor  50  determines if the wall fan  14  should be energized or de-energized, and if the HVAC  16   b  should be de-energized or energized, based on the method of  FIGS. 3 and 5 . The control panel  26 , sensors  28   a  and  28   b , wall fan  14  and HVAC  16   b  may be connected by wires  30   a ,  30   b , and  32 . In a partially or totally wireless embodiment, some or all of the signals may be transmitted, for example, an antenna  18   a  connected to the processor  50  may transmit control signals  20  to a second antenna  18   b  electrically connected to the HVAC  16   b.    
       FIG. 3  shows a heating method according to the present invention. The method includes: setting heating mode and a low temperature Tl and a high temperature Th at step  100 ; measuring an outdoor temperature To and an indoor temperature Ti at step  102 ; comparing To and Ti at step  104 ; If To is not greater than Ti at step  104 , de-energize the wall fan and energize the temperature control unit at step  112 , waiting a period of time P at step  114 , and then repeating measuring the outdoor temperature To and the indoor temperature Ti, otherwise, if To is greater than Ti (i.e., can use outdoor air to heat the room), if Tl is less than Ti and Ti is less than Th at step  106 , energizing the wall fan and de-energizing the temperature control unit at step  108  or alternatively de-energizing the wall fan and energizing the temperature control unit at step  110 , and after the period of time P at step  114 , again measuring the outdoor temperature To and the indoor temperature Ti and repeating steps  104  through  110 . The temperature Tl is a lower preferred indoor temperature and the temperature Th is a higher preferred indoor temperature. 
       FIG. 4  shows the method of  FIG. 3  controlling a wall fan in heating mode. In interval A Ti is between Tl and Th, and To is greater than Ti, so the wall fan is energized to take advantage of the outdoor air to heat the room. During interval B Ti is greater than Th, or To is less than Ti and the wall fan is de-energize and a heater or HVAC system is energized. During interval C Ti remains between Tl and Th and To is greater than Ti, so the wall fan is energized to take advantage of the outdoor air to heat the room. During interval D To is less than Ti and the wall fan is de-energized and a heater or HVAC system is energized. During interval E, Ti remains between Tl and Th and To is greater than Ti, so the wall fan is energized to take advantage of the outdoor air to heat the room. 
       FIG. 5  shows a heating method according to the present invention. The method includes: setting cooling mode and the lower temperature Tl and the higher temperature at step  200 ; measuring an outdoor temperature To and an indoor temperature Ti at step  202 ; comparing Ti and To at step  204 ; If Ti is not greater than To at step  204 , di energize the wall fan and the energize the temperature control unit at step  212 , waiting a period of time P at step  214 , and then repeating measuring the outdoor temperature To and the indoor temperature Ti, otherwise, if Ti is greater than To (i.e., can use outdoor to cool the room), if Tl is less than Ti and Ti is less than Th at step  206 , energize the wall fan ON and de-energize the temperature control unit at step  208  or alternatively de-energize the wall fan and energize the temperature control unit at step  210 , and after the period of time P at step  214 , again measuring the outdoor temperature To and the indoor temperature Ti and repeating steps  204  through  210 . 
       FIG. 6  shows the method of  FIG. 5  controlling a wall fan in cooling mode. In interval F, either To is greater than Ti or Ti is greater than Th, so the wall fan is de-energized. During interval G, Ti is between Tl and Th, and To is less than Ti so the wall fan is energized to take advantage of cooler outdoor air. During interval H, either Ti is less than Tl or To is greater than Ti, so the wall fan is de-energized. During interval I, Ti is between Tl and Th, and To is less than Ti so the wall fan is energized to take advantage of cooler outdoor air. During interval J, To is greater than Ti, so the wall fan is de-energized. 
     A circuit according to the present invention for controlling the wall fan  14  and HVAC is shown in  FIG. 7 . The control panel  26 , sensors  28   a  and  28   b , wall fan  14  and HVAC  16   b  may be connected by wires or be wireless, for example Bluetooth, communications. 
     While the invention herein disclosed has been described by means of specific embodiments and applications thereof, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope of the invention set forth in the claims.