Dedicated outdoor air system with pre-heating and method for same

Abstract

An energy exchange system is provided that may include a heater configured to be disposed within a supply air flow path. A first pre-heater is configured to be upstream from the heater within the supply air flow path and configured to pre-heat the supply air with a first liquid that circulates through the first pre-heater. A boiler may be operatively connected to the first pre-heater and configured to heat the first liquid. The system may also include a second pre-heater configured to be upstream from the heater within the supply air flow path. A heat transfer device may be operatively connected to the heater and the second pre-heater. The heat transfer device is configured to receive flue gas from the heater and transfer heat from the flue gas to a second liquid within the heat transfer device.

1 . An energy exchange system comprising:
 an energy recovery device configured to be disposed within supply and exhaust air flow paths;   at least one first pre-heater configured to be positioned within one or both of the supply and exhaust air flow paths, wherein the at least one pre-heater comprises one or more coils configured to circulate a first liquid that is configured to transfer heat to air within the one or both of the supply and exhaust air flow paths; and   at least one boiler operatively connected to the at least one first pre-heater, wherein the at least one boiler is configured to heat the first liquid.   
     
     
         2 . The energy exchange system of  claim 1 , wherein the at least one first pre-heater is configured to be upstream of the energy recovery device within the supply air flow path. 
     
     
         3 . The energy exchange system of  claim 1 , further comprising a heater configured to be downstream of the energy recovery device within the supply air flow path. 
     
     
         4 . The energy exchange system of  claim 3 , wherein the at least one first pre-heater is configured to be positioned within the supply air flow path. 
     
     
         5 . The energy exchange system of  claim 1 , wherein the at least one boiler comprises a main tank configured to retain the first liquid, and a heating element configured to heat the first liquid. 
     
     
         6 . The energy exchange system of  claim 1 , wherein the at least one first pre-heater comprises multiple first pre-heaters configured to be positioned within the supply air flow path. 
     
     
         7 . The energy exchange system of  claim 6 , wherein the multiple pre-heaters are operatively connected to the at least one boiler. 
     
     
         8 . The energy exchange system of  claim 7 , wherein the at least one boiler comprises multiple boilers, wherein the each of the multiple boilers is operatively connected to one of the multiple first pre-heaters. 
     
     
         9 . The energy exchange system of  claim 1 , further comprising:
 at least one second pre-heater configured to pre-heat air within one or both of the supply and exhaust air flow paths;   a heater configured to be disposed within the supply air flow path, wherein the heater is configured to generate flue gas; and   a heat transfer device operatively connected to the heater and the at least one second pre-heater, wherein the heat transfer device is configured to receive energy from the flue gas from the heater and transfer heat from the flue gas to a second liquid within the heat transfer device, and wherein the second liquid is configured to be channeled to the at least one second pre-heater so that heat is transferred from the second liquid to supply air within the supply air flow path before the supply air encounters the energy recovery device.   
     
     
         10 . The system of  claim 9 , wherein the heater is configured to be downstream from the energy recovery device within the supply air flow path. 
     
     
         11 . The system of  claim 9 , wherein the heater is configured to be upstream from the energy recovery device within the supply air flow path. 
     
     
         12 . The system of  claim 9 , wherein the at least one first pre-heater is configured to be positioned with the supply air flow path. 
     
     
         13 . The system of  claim 9 , further comprising one or more of pipes, tubes, conduits, or plenum connected between the heat transfer device and the heater, wherein the flue gas is configured to pass from the heater to the heat transfer device via the one or more of pipes, tubes, conduits, or plenum. 
     
     
         14 . The system of  claim 1 , wherein the energy exchange system is a Dedicated Outdoor Air System (DOAS). 
     
     
         15 . The system of  claim 1 , wherein the energy recovery device is one or more of an enthalpy wheel, a sensible wheel, a desiccant wheel, a plate heat exchanger, a plate energy exchanger, a heat pipe, or a run-around loop. 
     
     
         16 . The system of  claim 1 , wherein the one or more coils are configured to be disposed within or around a portion of the supply air flow path. 
     
     
         17 . The system of  claim 1 , further comprising at least one return air duct configured to fluidly connect the supply air flow path with the exhaust air flow path. 
     
     
         18 . The system of  claim 1 , further comprising at least one bypass duct configured to be disposed within the supply air flow path, wherein the at least one bypass duct is configured to bypass at least a portion of the supply air around one or both of the at least one first pre-heater or the energy recovery device. 
     
     
         19 . A method of operating an energy exchange system having a supply air flow path that allows supply air to be supplied to an enclosed structure and an exhaust air flow path that allows exhaust air from the enclosed structure to be exhausted to the atmosphere, the method comprising:
 heating a first liquid within an internal chamber of a boiler;   pumping the first liquid from the boiler to at least one first pre-heater disposed within one or both of the supply air flow path and the exhaust air flow path;   pre-heating air within the one or both of the supply air flow path and the exhaust air flow path with the first liquid within the at least one first pre-heater; and   pumping the first liquid from the at least one first pre-heater back to the boiler.   
     
     
         20 . The method of  claim 19 , further comprising:
 capturing flue gas generated by a heater;   channeling the flue gas to a heat transfer device;   transferring heat from the flue gas to a second liquid within the heat transfer device;   circulating the second liquid to at least one second pre-heater disposed within one or both of the supply air flow path and the exhaust air flow path; and   transferring heat within the second liquid to the air within one or both the supply air flow path and the exhaust air flow path.   
     
     
         21 . The method of  claim 20 , further comprising venting the flue gas from the heat transfer device after heat from the flue gas has been transferred to the second liquid within the heat transfer device. 
     
     
         22 . The method of  claim 20 , further comprising recirculating the second liquid back to the heat transfer device after the heat within the second liquid has been transferred to the supply air. 
     
     
         23 . The method of  claim 20 , further comprising passing the pre-heated air to an energy recovery device. 
     
     
         24 . The method of  claim 20 , further comprising bypassing at least a portion of the air around the at least one first pre-heater. 
     
     
         25 . A Dedicated Outdoor Air System (DOAS) comprising:
 a heater configured to be disposed within a supply air flow path;   a first pre-heater configured to be upstream from the heater within the supply air flow path, wherein the first pre-heater is configured to pre-heat the supply air through heat transfer with a first liquid that circulates through the first pre-heater; and   a boiler operatively connected to the first pre-heater, wherein the boiler is configured to heat the first liquid.   
     
     
         26 . The DOAS of  claim 24 , further comprising:
 a second pre-heater configured to be upstream from the heater within the supply air flow path; and   a heat transfer device operatively connected to the heater and the second pre-heater, wherein the heat transfer device is configured to receive flue gas from the heater and transfer heat from the flue gas to a second liquid within the heat transfer device, and wherein the second liquid is configured to be channeled to the second pre-heater so that heat is transferred from the second liquid to supply air within the supply air flow path.