A dehumidification system including: a fluid-air heat exchanger including an external, air-side surface coated with desiccant material, wherein during an adsorption cycle fluid is passed through the heat exchanger at a temperature which causes water vapour to be removed from a stream of air permitted or forced across the heat exchanger; a means for permitting or forcing a stream of air across said heat exchanger during the adsorption cycle; and a means of heating the desiccant material during a regeneration cycle to cause adsorbed water to be removed from the desiccant material by vaporisation, thereby regenerating the desiccant material to a state which will allow the desiccant material to remove water vapour from a stream of air in a subsequent adsorption cycle; a means of cooling the desiccant material during the adsorption cycle in order to maintain said temperature within a range sufficient for water vapour to be removed from the stream of air wherein the means of cooling the desiccant material is the fluid-air heat exchanger wherein cooling is achieved by passing a cooling fluid through the fluid-air heat exchanger; an evaporative means that includes a volume of fluid wherein an evaporative cooling process includes permitting or forcing a volume of desiccated air across a surface area of the volume of fluid in the evaporative means, whereby the volume of air causes the temperature of said fluid to be lowered by evaporation; characterised in that the volume of fluid, having had its temperature reduced by the evaporative cooling process in the evaporative means is supplied to the fluid-air heat exchanger as cooling fluid and is used to cool the desiccant material during the adsorption cycle. a fluid-air heat exchanger including an external, air-side surface coated with desiccant material, wherein during an adsorption cycle fluid is passed through the heat exchanger at a temperature which causes water vapour to be removed from a stream of air permitted or forced across the heat exchanger; a means for permitting or forcing a stream of air across said heat exchanger during the adsorption cycle; and a means of heating the desiccant material during a regeneration cycle to cause adsorbed water to be removed from the desiccant material by vaporisation, thereby regenerating the desiccant material to a state which will allow the desiccant material to remove water vapour from a stream of air in a subsequent adsorption cycle; a means of cooling the desiccant material during the adsorption cycle in order to maintain said temperature within a range sufficient for water vapour to be removed from the stream of air wherein the means of cooling the desiccant material is the fluid-air heat exchanger wherein cooling is achieved by passing a cooling fluid through the fluid-air heat exchanger; an evaporative means that includes a volume of fluid wherein an evaporative cooling process includes permitting or forcing a volume of desiccated air across a surface area of the volume of fluid in the evaporative means, whereby the volume of air causes the temperature of said fluid to be lowered by evaporation; characterised in that the volume of fluid, having had its temperature reduced by the evaporative cooling process in the evaporative means is supplied to the fluid-air heat exchanger as cooling fluid and is used to cool the desiccant material during the adsorption cycle.