The paraldehyde/acetaldehyde (Pa/A) chemical heat pump is used as a cooling system. The present study investigates depolymerization of paraldehyde for a chemical heat pump cycle. The depolymerization rate of paraldehyde was measured in a range from 286 K to 303 K on an acid resin catalyst (Amberlyst 15E). The rate determining step of the depolymerization is the paraldehyde ring-opening step on the catalyt. The depolymerization rate equation on the solid catalyst is described by the Langmuir-Hinshelwood kinetic model. The cooling rate of the Pa/A system at 286 K is estimated from the reaction rate equation. The cooling rate is 10 kW per unit catalyst-weight and higher than other CHPs. The coefficient of performance of the Pa/A system is 6.3.