Cooling method and apparatus

Abstract

A cooling method and apparatus which uses an absorption cycle with ammonia as the refrigerant and in which a generator ( 31,34 ) converts a liquid ammonia solution into ammonia gas or vapour for supply to a condenser ( 36 ) in which the ammonia gas or vapour is condensed into a liquid ammonia solution. The liquid ammonia solution is supplied to an evaporator ( 39 ) in which liquid ammonia is evaporated into ammonia gas or vapour to thereby absorb heat and an absorber ( 43 ) absorbs the ammonia gas or vapour back into an ammonia solution. The evaporator ( 39 ) includes a reservoir or bulb ( 40 ) which retains portion of the liquid ammonia solution which is converted back into an ammonia gas or liquid by exposure to ambient heat and returned to the condenser ( 36 ) for recycling.

1 . Cooling apparatus of the type which operates on an absorption cycle using ammonia as the refrigerant, said apparatus including a generator for supplying ammonia gas or vapour, a condenser for condensing the ammonia gas or vapour into a liquid ammonia solution, an evaporator in which liquid ammonia is evaporated into ammonia gas or vapour which thereby absorbs heat and an absorber for absorbing said ammonia gas or vapour into an ammonia solution and wherein said evaporator includes means for retaining a portion of said liquid ammonia received from said condenser for return and recycling through said apparatus. 
     
     
         2 . Cooling apparatus as claimed in  claim 1  wherein said reservoir comprises a recess or bulb at an end of the evaporator in which liquid ammonia can collect. 
     
     
         3 . Cooling apparatus as claimed in  claim 2  wherein said reservoir is provided at an end of said evaporator remote from the inlet thereto. 
     
     
         4 . Cooling apparatus as claimed in  claim 3  wherein a return line or pipe connects the reservoir to the condenser 
     
     
         5 . Cooling apparatus as claimed in  claim 4  wherein said return line or pipe is adapted to return ammonia collecting in the reservoir to the condenser inlet. 
     
     
         6 . Cooling apparatus as claimed in  claim 4  or  claim 5  wherein said return pipe or line is exposed to ambient heat such that liquid ammonia flowing in the return pipe or line is vaporised before returning to the condenser. 
     
     
         7 . Cooling apparatus as claimed in  claim 6  wherein said return pipe is in heat exchange contact with said evaporator. 
     
     
         8 . Air conditioning apparatus including cooling apparatus as defined in any one of the preceding claims, said air conditioning apparatus including means for circulating air over the evaporator. 
     
     
         9 . Air conditioning apparatus as claimed in  claim 8  wherein said circulating means comprise one or more fans. 
     
     
         10 . Air conditioning apparatus as claimed in  claim 9  wherein said generator of the cooling apparatus is adapted to be heated by solar energy. 
     
     
         11 . Air conditioning apparatus as claimed in  claim 10  and including a solar energy collector for supplying solar energy to said generator. 
     
     
         12 . Air conditioning apparatus as claimed in  claim 11  and including a heat exchanger is associated with the generator to transfer heat generated by solar energy to the generator. 
     
     
         13 . Air conditioning apparatus as claimed in any one of  claims 8  to  12  and including additional heating means for heating the or a further said generator. 
     
     
         14 . Air conditioning apparatus as claimed in  claim 13  wherein said further generator is arranged in parallel with the first generator, said further generator being adapted to be heated by said additional heating means. 
     
     
         15 . Air conditioning apparatus as claimed in  claim 14  wherein said additional heating means comprises one of a gas flame or electric heater. 
     
     
         16 . Cooling apparatus of the type which operates on an absorption cycle using ammonia as the refrigerant, said apparatus including at least a first generator for supplying ammonia gas or vapour, a condenser for condensing the ammonia gas or vapour into a liquid ammonia solution, an, evaporator in which liquid ammonia is evaporated into ammonia gas or vapour and absorbs heats heat and an absorber for absorbing said ammonia gas or vapour from said evaporator and wherein said first generator is heated directly or indirectly by a solar energy collector. 
     
     
         17 . Cooling apparatus as claimed in  claim 16  wherein said first generator or another generator arranged in parallel to the first generator is adapted to be heated selectively by a further heat source such as a gas powered heat source or electrically powered heat source. 
     
     
         18 . A method of cooling comprising the steps of
 converting a liquid ammonia solution into ammonia gas or vapour;   condensing said ammonia gas or vapour into a condensed ammonia solution;   evaporating said condensed ammonia solution to convert said liquid into ammonia gas of vapour and thereby absorb heat;   retaining a portion of condensed ammonia liquid in said evaporation step for reconversion into ammonia gas or vapour; and   absorbing said ammonia gas from said evaporator to convert said ammonia gas or vapour into a liquid ammonia solution for subsequent conversion into said ammonia gas or vapour.   
     
     
         19 . A method of cooling as claimed in  claim 18  wherein said liquid ammonia solution is converted into said ammonia gas or vapour by a solar heat source. 
     
     
         20 . A method of cooling as claimed in  claim 19  wherein said retained liquid is converted into ammonia gas or vapour under the influence of ambient heat.