Cooling Tower

Abstract

A method of operating an evaporative cooling tower includes contacting water with air in a cooling zone to cool the water and heat the air and cooling the heated air to condense water therefrom, thereby to reduce water loss from the cooling tower. Typically, the cooling of the heated air is by means of evaporative cooling employing a refrigerant.

1 . A method of operating an evaporative natural draught cooling tower which has upwardly moving air, the method including 
 contacting water with air in a cooling zone to cool the water and heat the air;    cooling the heated air by means of evaporative cooling provided by a compression refrigeration system or an absorption refrigeration system, with the refrigeration system including a condenser and an evaporator arranged in a circuit, the evaporator being at a low elevation inside the cooling tower to cool the upwardly moving air and remove water therefrom by condensation; and    above the level of cooling of the heated air, heating the upwardly moving dried air with the condenser, to promote the draught in the tower.    
     
     
         2 . The method as claimed in  claim 1 , in which the cooling tower employs filling with drift eliminators above the filling in the tower, the evaporator comprising one or more coils in or on one or more drift eliminators and the condenser comprising one or more coils in or on one or more drift eliminators located above the evaporator coil or coils.  
     
     
         3 . In a natural draught cooling tower of the type used for large scale water cooling as in the cooling of water used by thermal power stations, and which comprises a typically concrete hollow shell which is circular in plan view and has walls which are concave and parabolic in side view outline, the bottom of the tower being raised from ground level on stilts or the like to provide a circumferentially extending air inlet at its lower end and the tower containing filling at its lower end and a water distribution system for distributing water to be cooled onto the filling from which it drains into a reservoir under the tower while air circulates from the inlet up over the filling and out of the top of the tower by natural convection to cool the water, there is provided the method of operation which comprises, above the filling, cooling the upwardly moving air to condense water therefrom, thereby to reduce water loss from the tower at its top, and above the level of cooling of the upwardly moving air, heating the upwardly moving air to promote the draught in the cooling tower, the cooling of the upwardly moving air being by evaporative cooling provided by a compression refrigeration system or an absorption refrigeration system, with the refrigeration system including a condenser and an evaporator arranged in a circuit, the evaporator being located above the filling in the tower to cool the upwardly moving air and remove water therefrom by condensation, and the condenser being located above the evaporator to heat the upwardly moving air, which is dried air, to promote the draught in the tower.  
     
     
         4 . The method as claimed in  claim 3 , in which the cooling tower employs drift eliminators above the filling in the tower and the evaporator of the refrigeration circuit comprises one or more coils in or on one or more drift eliminators, and the condenser of the refrigeration circuit comprises one or more coils in or on one or more drift eliminators, located above the evaporator coil or coils.  
     
     
         5 . An evaporative cooling tower which includes a cooling zone for contacting water with air to cool the water and heat the air, and a refrigeration or cooling system for cooling the heated air from the cooling zone for condensing water therefrom, the refrigeration system being a compression refrigeration system for the evaporative cooling of the air by means of a refrigerant, the refrigeration system being an arranged to heat the cooled air at a level above that at which the refrigeration system cools said air.  
     
     
         6 . The cooling tower as claimed in  claim 5 , in which the refrigeration system comprises one or more cooling circuits, each comprising a condenser and an evaporator.  
     
     
         7 . The cooling tower as claimed in  claim 6 , which includes filling and drift eliminators, each evaporator comprising coils in or on one or more drift eliminators above the filling in the tower, and each condenser comprising coils in or on one or more drift eliminators above the filling, the condenser coils being at a higher level than the evaporator coils.  
     
     
         8 . The cooling tower as claimed in  claim 6 , in which each cooling circuit includes a compressor which is driven by a turbine and optionally via a gearbox, the gearbox, when present, being between the turbine and the compressor, and the turbine being driven by an incoming stream of water to be cooled as it enters the cooling tower.  
     
     
         9 . An evaporative cooling tower which includes a cooling zone for contacting water with air to cool the water and heat the air, and a refrigeration or cooling system for cooling the heated air from the cooling zone for condensing water therefrom, the refrigeration system being an absorption refrigeration system for the evaporative cooling of the air by means of a refrigerant, the refrigeration system being arranged to heat the cooled air at a level above that at which the refrigeration system cools said air.  
     
     
         10 . The cooling tower as claimed in  claim 9 , in which the refrigeration system comprises one or more cooling circuits, each comprising a generator, a condenser and an evaporator, with each circuit having its generator located outside the cooling tower.  
     
     
         11 . The cooling tower as claimed in  claim 9 , which includes filling and drift eliminators, each evaporator comprising coils in or on one or more drift eliminators above the filing in the tower, and each condenser comprising coils in or on one or more drift eliminators above the filling, the condenser coils being at a higher level than the evaporator coils.  
     
     
         12 . A natural draught cooling tower of the type used for large scale water cooling as in the cooling of water used by thermal power stations, and which comprises a typically concrete hollow shell which is circular in plan view and has walls which are concave and parabolic in side view outline, the bottom of the tower being raised from ground level on stilts or the like to provide a circumferentially extending air inlet at its lower end and the tower containing filling at its lower end and a water distribution system for distributing water to be cooled onto the filling from which it drains into a reservoir under the tower while air circulates from the inlet up over the filing and out of the top of the tower by natural convection to cool the water, the cooling tower further including a refrigeration system for cooling upwardly moving air in the tower above the filling, for condensing water therefrom,  
     
     
         13 . The cooling tower as claimed in  claim 12 , in which the refrigeration system is a compression refrigeration system for the evaporative cooling of the upwardly moving air by means of a refrigerant, the refrigeration system being arranged to heat the cooled upwardly moving air at a level above that at which the refrigeration system cools said air.  
     
     
         14 . The cooling tower as claimed in  claim 13 , in which the refrigeration system comprises one or more cooling circuits, each comprising a condenser and an evaporator.  
     
     
         15 . The cooling tower as claimed in  claim 14 , in which each evaporator comprises coils in or on one or mote drift eliminators above the filling in the tower, and each condenser comprises coils in or on one or more drift eliminators above the filling, the condenser coils being at a higher level than the evaporator coils.  
     
     
         16 . The cooling tower as claimed in  claim 15 , in which each cooling circuit includes a compressor which is driven by a turbine and optionally via a gearbox, the gearbox, when present, being between the turbine and the compressor, and the turbine being driven by an incoming stream of water to be cooled as it enters the cooling tower.  
     
     
         17 . The cooling tower as claimed in  claim 12 , in which the refrigeration system is an absorption refrigeration system for the evaporative cooling of the air by means of a refrigerant, the refrigeration system being arranged to heat the cooled upwardly moving air at a level above that at which the refrigeration system cools said air.  
     
     
         18 . The cooling tower as claimed in  claim 17 , in which the refrigeration system comprises one or more cooling circuits, each comprising a generator, a condenser and an evaporator, with each circuit having its generator located outside the cooling tower.  
     
     
         19 . The cooling tower as claimed in  claim 18 , in which each evaporator comprises coils in or on one or more drift eliminators above the filling in the tower, and each condenser comprises coils in or on one or more drift eliminators above the filling, the condenser calls being at a higher level than the evaporator coils.