Building heat load reduction method and apparatus

Abstract

A building heat load reduction system is provided having a series of spray nozzles located on a building roof that are connected to a cooling liquid supply. A temperature sensor on the roof is connected to a controller and, depending upon the heat on the roof, supplies liquid coolant to the spray nozzles which sprays the liquid coolant onto the roof. A moisture sensor on the roof or in the roof drain provides a signal to the controller so that once the top of the roof is wet, the sprinkler is shut down so that excess water is not wasted. A liquid coolant/surfactant mixing system is provided which mixes a surfactant with the cooling liquid to provide enhanced cooling. The surfactant causes the liquid coolant being sprayed to have a smaller droplet size which creates a relatively higher specific surface area for the water droplets.

1 . A building heat load reduction system, comprising:
 a series of spray nozzles located on a building roof that are connected to a cooling liquid supply;   a control valve connected between the cooling liquid supply and the spray nozzles;   a temperature sensor on the roof;   a controller, the temperature sensor and the control valve being connected to the controller such that depending upon a temperature of the roof, the controller opens the control valve to supply liquid coolant to the spray nozzles which spray the liquid coolant onto the roof;   a liquid sensor on the roof or in a roof drain and connected to the controller to provide a signal to the controller so that once a predetermined amount of cooling liquid is on the roof, the controller closes the control valve.   
     
     
         2 . The building heat load reduction system according to  claim 1 , further comprising a liquid coolant/surfactant mixing system located between the control valve and the spray nozzles that mixes a surfactant with the cooling liquid to provide enhanced cooling. 
     
     
         3 . The building heat load reduction system according to  claim 1 , further comprising where said liquid coolant is water. 
     
     
         4 . The building heat load reduction system according to  claim 1 , further comprising where said liquid coolant is a mixture of water and one or more surfactant. 
     
     
         5 . The building heat load reduction system according to  claim 1 , further comprising having a salinity/surfactant sensor located on the roof to detect the concentration of the surfactant in water located on the roof once the roof has been re-wetted. 
     
     
         6 . The building heat load reduction system according to  claim 5 , further comprising having the residual surfactant be reactivated by the additional liquid sprayed from the spray nozzles. 
     
     
         7 . The building heat load reduction system according to  claim 2 , further comprising having with the water delivered from the building water source into said mixing system. 
     
     
         8 . The building heat load reduction system according to  claim 2 , further comprising having said mixing system being a mixing tank. 
     
     
         9 . The building heat load reduction system according to  claim 8 , further comprising having said mixing tank being an in-line mixing arrangement which uses internal fins and a venturi effect. 
     
     
         10 . The building heat load reduction system according to  claim 8 , further comprising having said mixing tank having mixing implements located in the tank. 
     
     
         11 . The building heat load reduction system according to  claim 8 , further comprising having a tank outlet from the mixing tank that leads to the cooling liquid supply pipe. 
     
     
         12 . The building heat load reduction system according to  claim 8 , further comprising having a surfactant supply tank connected to the mixing tank by a surfactant supply line. 
     
     
         13 . The building heat load reduction system according to  claim 12 , further comprising having a pump located along the surfactant supply line and connected to the controller. 
     
     
         14 . The building heat load reduction system according to  claim 13 , further comprising having the controller controlling the pump to provide a desired amount of surfactant from the surfactant supply tank to the mixing tank. 
     
     
         15 . The building heat load reduction system according to  claim 1 , further comprising having the liquid sensor being a volumetric flow sensor. 
     
     
         16 . The building heat load reduction system according to  claim 1 , further comprising having the liquid sensor being a float sensor. 
     
     
         17 . The building heat load reduction system according to  claim 1 , further comprising having the spray nozzles and the cooling liquid supply being supported by supports. 
     
     
         18 . The building heat load reduction system according to  claim 17 , further comprising having said supports being A-frames. 
     
     
         19 . The building heat load reduction system according to  claim 1 , further comprising having the spray nozzles arranged in a pattern that fully covers the roof with said coolant. 
     
     
         20 . The building heat load reduction system according to  claim 1 , further comprising having the heat from the building transferred to the cooling liquid droplets sprayed onto the roof causing said liquid droplets to vaporize removing heat from the roof and reducing the heat load on the building.