to the separator 13 by the action of the bubble pump 12 in the separator 13 the ammonia gas is separated from the weak ammonia solution and travels to the condenser 14 where heat is released to the air in duct 20 causing the ammonia gas to condense as liquid ammonia the latter passes through trap 15 into the evaporator where it is exposed to hydrogen gas the hydrogen environment lowers the vapour pressure of the liquid ammonia sufficiently to cause the ammonia to evaporate extracting heat from air in the duct 24 this produces cool dehumidified air for air conditioning purposes and pure water which exits from port 24 c and can be collected for use the ammonia gas and hydrogen mixture passes to the mixer 17 where the ammonia dissolves in the weakened solution from the separator 13 producing a more concentrated solution which flows into the heat exchanger 18 where it loses its heat to air within the duct 20 the concentrated solution then passes into the reservoir 19 and thence to the generator 11 whereupon the cycle is complete when the power of the sun becomes insufficient to retain the phase change material above 200 u00b0 c the latter starts to solidify and the latent heat of fusion maintains the generator 11 at a sufficient temperature to sustain the refrigeration cycle in this way the refrigeration mechanism can remain operational throughout the night or at least a sufficient part of it to ensure that cooling is maintained until the ambient temperature drops to an acceptable level a larger.