The paraldehyde chemical heat pump is combined with a chemical reaction and a vapor-compression heat pump. The paraldehyde chemical heat pump generates cold thermal energy with depolymerization of paraldehyde (2,4,6-trimethyl-trioxane). The cooling rate of the paraldehyde chemical heat pump depends on the catalyst activity of the paraldehyde depolymerization. This study investigates the effect of the acid strength of the solid catalyst on the paraldehyde depolymerization rate, the cooling rate, and the coefficient of performance of the heat pump. The acid strength distribution of Amberlyst 15 E was measured for estimation of the catalyst activity of the paraldehyde depolymerization. The depolymerization rate was measured with Amberlyst 15 E of modified acid strength distribution. The high activity range of the acid strength is -7.1 < pKa < -4.3 for the paraldehyde depolymerization with Amberlyst 15 E. The coefficient of performance, the cooling rate and the catalyst weight were estimated with the acid strength. The weight of the catalyst can be reduced to 0.05 g with 1.6 g.s(-1) of the flow rate in the system when the cooling rate and COP are 0.9 kW and 6, respectively.