Abstract: A method of transferring heat from a low temperature reservoir to a high temperature reservoir in which a two bed adsorption system is used. An adsorbable component is desorbed from a first bed of a reversible adsorbent previously saturated with the adsorbable component and the heat required is transferred to the bed from a low temperature reservoir in heat-exchange relationship with the bed of adsorbent. The adsorbable component is then adsorbed on a second bed of a reversible adsorbent and the heat released is transferred to a high temperature reservoir in heat-exchange relationship with the bed. In order for the system to operate continuously the mode of operation of the first and second bed of reversible adsorbent must be periodically reversed.