Application of slurry of finely powdered adsorbent in LiBr solution was proposed as a means to enhance the performance of lithium bromide/water absorption heat pump. The effect of the slurry on the performance was analyzed by the heat and mass transfer model in the case where a film of the slurry or the solution flows down the surface of the heat transfer plate in the absorber and the generator of the heat pump system. In the open system analysis for the absorber and the generator, temperatures of the slurry and the solution rose remarkably in the inlet zone of the absorber due to the large heat transfer resistance between cooling water and the slurry or solution compared with the water vapor absorption rate. The LiBr concentration in the slurry was higher in the absorber and lower in the generator than that in the solution without adsorbent. In the closed loop system analysis where the slurry or the solution circulates between the absorber and the generator, the refrigeration energy output of 280 K was enhanced over 10% by employing the slurry when the waste heat source of 360 K and cooling water of 290 K were used. These analyses revealed that LiBr adsorbed on the adsorbent is desorbed when the solution absorbs water vapor in the absorber, thus acting as a buffer against dilution of the solution and thereby raising performance of the heat pump. If a fine powder of activated carbon of under 100 mu m was suspended as adsorbent in the solution, the equilibrium adsorption amount of LiBr was proportional to the concentration in the solution, and the equilibrium adsorption parameter was 1.5 equivalent to that used in the analysis.