Air Cooling Unit For Data Centers

Abstract

An air handling unit utilizing a humidifier in conjunction with a heat exchanger to provide a means for free cooling recirculating return air with evaporatively cooled outside air. A first air stream comprising outside air can be circulated through the evaporative humidifier and a first portion of the energy recovery heat exchanger, while a second air stream comprising recirculated inside air can be circulated through a second portion of the heat exchanger. The outside air will be humidified as it circulates through the humidifier, thereby cooling the outside air to its adiabatic saturation temperature. The heat exchanger will cool the recirculating inside air with the evaporatively cooled outside air.

1 . An air handling unit for conditioning air, comprising:
 a. A humidifier positioned in a first air stream for humidifying the first air stream; and   b. A heat exchanger positioned partially in the first air stream and partially in a second air stream, the heat exchanger capable of transferring heat from the second air stream to the first air stream.   
     
     
         2 . The air handling unit of  claim 2 , wherein the first air stream comprises outside air, and wherein the second air stream comprises recirculated inside air. 
     
     
         3 . The air handling unit of  claim 2 , wherein the humidifier cools the first air stream up to its adiabatic saturation temperature. 
     
     
         4 . The air handling unit of  claim 3 , wherein the heat exchanger is positioned partially within a first air duct and partially within a second air duct. 
     
     
         5 . The air handling unit of  claim 4 , wherein the humidifier is positioned within the first air duct. 
     
     
         6 . The air handling unit of  claim 6 , wherein the humidifier is positioned within a separate air duct connected to the first air duct. 
     
     
         7 . The air handling unit of  claim 4 , wherein the first air stream flows through the first air duct, and wherein the second air stream flows through the second air duct. 
     
     
         8 . The air handling unit of  claim 7 , wherein the heat exchanger comprises a first portion positioned within the first air duct, and a second portion positioned within the second air duct. 
     
     
         9 . The air handling unit of  claim 8 , further comprising a supply fan for circulating the cooled second air stream within a conditioned space. 
     
     
         10 . The air handling unit of  claim 9 , further comprising an exhaust fan for discharging the humidified first air stream from the air handling unit. 
     
     
         11 . The air handling unit of  claim 10 , further comprising a mechanical cooling device positioned in the second air stream for further cooling the second air stream before the second air stream is recirculated by the supply fan within the conditioned space. 
     
     
         12 . The air handling unit of  claim 11 , wherein the first air duct comprises an outside air inlet and an exhaust air outlet, and wherein the second air duct comprises a return air inlet and a supply air outlet. 
     
     
         13 . The air handling unit of  claim 12 , wherein the supply fan circulates the second air stream successively through the return air inlet, the second portion of the heat exchanger, the mechanical cooling device, and the supply air outlet. 
     
     
         14 . The air handling unit of  claim 13 , wherein the exhaust fan circulates the first air stream successively through the outside air inlet, the humidifier, the first portion of the heat exchanger, and the exhaust air outlet. 
     
     
         15 . The air handling unit of  claim 15 , further comprising a plurality of dampers for controlling the flow of air in the air handling unit. 
     
     
         16 . The air handling unit of  claim 7 , wherein the heat exchanger is a heat pipe, the heat pipe comprising a cold deck portion and a hot deck portion, wherein the cold deck portion is positioned within the first air duct, and wherein the hot deck portion is positioned within the second air duct. 
     
     
         17 . The air handling unit of  claim 7 , wherein the heat exchanger is a heat wheel. 
     
     
         18 . The air handling unit of  claim 7 , wherein the humidifier is an evaporative humidifier. 
     
     
         19 . The air handling unit of  claim 3 , wherein there is substantially no exchange of moisture between the first air stream and the second air stream. 
     
     
         20 . The air handling unit of  claim 3 , wherein the dew point of the second air stream remains substantially unchanged. 
     
     
         21 . An air handling unit for conditioning air, comprising:
 a. a humidifying means positioned in a first air stream for humidifying the first air stream up to its adiabatic saturation temperature; and   b. A heat exchanger positioned partially within the first air stream and partially within a second air stream, the energy recovery heat exchanger cooling the second air stream using the humidified first air stream, wherein there is substantially no exchange of moisture between the first air stream and the second air stream.   
     
     
         22 . The air handling unit of  claim 21 , wherein the humidifying means is selected from the group consisting of an evaporative humidifier, an ultrasonic humidifier, a spray mist humidifier, a steam vaporizer, a drum style humidifier, and a disc wheel style humidifier. 
     
     
         23 . The air handling unit of  claim 21 , wherein the heat exchanger is selected from the group consisting of a heat pipe, a heat wheel, and a fixed-plate exchanger. 
     
     
         24 . A data center comprising:
 a. a conditioned space housing electronic equipment;   b. an air handling unit for conditioning the air in the conditioned space, the air handling unit comprising:
 i. a humidifier positioned in a first air stream, the humidifier capable of cooling the first air stream up to its adiabatic saturation temperature by humidifying the first air stream; and 
 ii. A heat exchanger positioned partially within the first air stream and partially within a second air stream, the energy recovery heat exchanger cooling the second air stream using the humidified first air stream; 
   c. an exhaust fan positioned in the first air stream for discharging the humidified first air stream from the air handling unit; and   d. a supply fan positioned in the second air stream for circulating the second air stream within the conditioned space.   
     
     
         25 . The data center of  claim 24 , wherein the heat exchanger is positioned partially within a first air duct and partially within a second air duct. 
     
     
         26 . The data center of  claim 25 , wherein the first air stream flows through the first air duct, and wherein the second air stream flows through the second air duct. 
     
     
         27 . The air handling unit of  claim 26 , wherein there is substantially no exchange of moisture between the first air stream and the second air stream. 
     
     
         28 . The air handling unit of  claim 26 , wherein the dew point of the second air stream remains substantially unchanged. 
     
     
         29 . A method for cooling a conditioned space, comprising:
 a. Providing an air handling unit for conditioning the air in the conditioned space, the air handling unit comprising a humidifier and a heat exchanger, the heat exchanger defining a first portion and a second portion;   b. Circulating an outside air stream successively through the humidifier and the first portion of the heat exchanger;   c. Circulating an inside air stream through the second portion of the heat exchanger to cool the inside air stream; and   d. Supplying the inside air stream to the conditioned space.   
     
     
         30 . The method of  claim 29 , wherein the circulated inside air is further cooled by a mechanical cooling device before the circulated inside air is supplied to the conditioned space.