Computational modelling of multiple-bed and thermal wave adsorption cycles is carried out in order to determine which method of heat recovery gives the superior trade off between coefficient of performance (COP) and power density (the power output per unit mass or volume of machine). The modelling is performed for the activated carbon-ammonia pair with a high power density plate heat exchanger type generator. It is discovered that multiple-bed cycles give a superior trade-off between COP and power density and are therefore recommended over thermal wave cycles. The principal application is considered to be a gas fired heat pump and it is found that the technology compares favourably with competing systems.