Effect of Operating Conditions on the Performance of Two-Bed Closed-Cycle Solid-Sorption Heat Pump Systems

Abstract

The effect of two operating parameters, the regeneration temperature and the ambient temperature, on the performance of two-bed, closed-cycle solid-sorption heat pumps is investigated. The results show that increasing the regeneration temperature can improve both the COP and cooling capacity, and the effect on cooling capacity is more significant than the COP. Increasing the regeneration temperature from 180°C to 260°C, the cooling capacity increases by 50 percent and the COP improves 20 percent. When the ambient temperature drops, the system performance increases significantly. When the ambient temperature decreases by 10°C from the design point of 35°C, the COP and cooling capacity increases by 50 percent and 40 percent, respectively. Also, the bed cycling speed should be increased to achieve the optimum system performance when the regeneration temperature is higher or the ambient temperature becomes lower.

Modelling and Optimization of an Adsorption Cooling System for Automotive Applications

“…Several dynamic models can be found in the literature [7,9,20,. Most of the proposed models have been used to investigate conventional double-bed adsorption cooling systems [7,20,[37][38][39][40][41][42][43][44][45][46][47][48][49][50]63]. Some of the dynamic models found in the literature have already been validated with experimental data [7, 37-39, 42, 44, 48-54, 63].…”

“…Differences among the aforementioned models generally occur in the simplifying assumptions, numerical resolution method, components design and application of the modelled system. The majority of researchers propose zero-dimensional models [7, 9, 37-44, 49, 51, 52, 63] while some have focused on onedimensional models [45, 55-57, 61, 64] and others on two-dimensional models [20,46,47,50,54,[58][59][60]62]. Three-dimensional models can also be found in the literature [48,53].…”

“…Some of the above dynamic models [20,37,42,44,49,50,56,57,59,61,62] assume that thermodynamic equilibrium exists between the adsorbent and adsorbate. Therefore, it is assumed that there exists no resistance to mass transfer between the adsorbate and the adsorbent.…”

“…Alam et al [46,47,49], Zheng et al [50] and Voyiatzis et al [55] introduced a non-dimensional switching frequency, which is inversely proportional to the cycle time, to find the optimum design and/or operating conditions of a system.…”

“…Zheng et al [50] have studied the effect of the switching speed on the performance of a double-bed activated carbon-ammonia adsorption heat pump.…”