A chiller for chilling a quantity of fluid of the type comprising an adsorbent for receiving and adsorbing under pressure a quantity of gas, the desorption of gas from the adsorption causing a reduction in temperature of the adsorbent and adsorbate which acts to chill the fluid, wherein the chiller comprises one or more thin-walled vessels for placement in direct thermal contact with the fluid to be chilled, each vessel comprising two thin sheets of substantially similar size and shape, joined together around the peripheral edges thereof so as to form a cavity therebetween for containing the adsorbent. Preferably, heat transfer means are provided to ensure efficient transfer of heat between the surface of the body of adsorbent and the adsorbent therewithin.