EFFECTS OF ACID STRENGTH OF SOLID CATALYST ON COOLING RATE OF A CHEMICAL HEAT-PUMP WITH PARALDEHYDE DEPOLYMERIZATION

The paraldehyde chemical heat pump is combined with a chemical reactio n and a vapor-compression heat pump. The paraldehyde chemical heat pum p generates cold thermal energy with depolymerization of paraldehyde ( 2,4,6-trimethyl-trioxane). The cooling rate of the paraldehyde chemica l heat pump depends on the catalyst activity of the paraldehyde depoly merization. This study investigates the effect of the acid strength of the solid catalyst on the paraldehyde depolymerization rate, the cool ing rate, and the coefficient of performance of the heat pump. The aci d strength distribution of Amberlyst 15 E was measured for estimation of the catalyst activity of the paraldehyde depolymerization. The depo lymerization rate was measured with Amberlyst 15 E of modified acid st rength distribution. The high activity range of the acid strength is - 7.1 < pKa < -4.3 for the paraldehyde depolymerization with Amberlyst 1 5 E. The coefficient of performance, the cooling rate and the catalyst weight were estimated with the acid strength. The weight of the catal yst 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.