Ramp Wave Analysis of the Solid/Vapor Heat Pump

Abstract

A theramlly driven heat pump using a solid/vapor adsorption/desorption compression process in a vapor compression cycle is thermodynamically analyzed. The cycle utilizes a simple heat transfer fluid circulating loop for heating and cooling of two solid adsorbent beds. This heat transfer fluid loop also serves to transmit heat recovered from the adsorbing bed being cooled to the desorbing bed being heated. This heat recovery process greatly improves the efficiency of the single-stage solid/vapor adsorption process without the complication of a two-stage cycle. During the heating and cooling processes a thermal wave profile travels through the beds. Previous studies of this cycle used a square wave model to simulate the thermal wave front. This paper utilizes a more physically realistic ramp wave model to overcome the shortcomings of the square wave model. The ramp wave model is integrated into a thermodynamic cycle which provides detailed information on the performance of the beds as well as the COP and the heating and cooling outputs of the heat pump system. Significant cycle design and operating parameters are varied to determine their effect on cycle performance.

Review of Regenerative Adsorption Heat Pumps

“…The theoretical limit of heat recovery for a two-bed device is 50%, but the aforementioned 40% is the practical limit. 12 …”

High-efficient thermochemical sorption refrigeration driven by low-grade thermal energy

“…1-NH 3 ; 2-PbCl 2 (8/3.25); 3-BaCl 2 (8/0); 4-LiCl (4/3); 5-AgCl (3/1.5); 6-CaCl 2 (8/4); 7-SrCl 2 (8/1); 8-CaCl 2 (4/2); 5-CdCl 2 (6/2); 10-ZnCl 2 (6/2); 11-MnCl 2 (6/2); 12-FeCl 2 (6/2); 13-CoCl 2 (6/2); 14-MgCl 2 (6/2); 15-NiCl 2 (6/2). low-temperature bed due to the temperature difference during the switching process [13][14][15]23] . The decrease in heat consumption enhanced the working performance of sorption refrigerator.…”

“…Besides the basic intermittent sorption thermodynamic refrigeration cycle, many advanced sorption thermodynamic cycles have been proposed and investigated to improve the performance of sorption refrigeration system. The representative cycles mainly include the thermal wave sorption cycle [13] , the forced convection sorption cycle [14] , the cascading sorption cycle [15] , the mass recovery cycle [16] , the heat and mass recovery sorption cycle [17] , and the multi-stage sorption cycle [18] , etc. The above-mentioned sorption refrigeration cycles were conducted on the physical sorption working pairs,…”

Performance Analysis of a Double-effect Adsorption Refrigeration Cycle with a Silica Gel/Water Working Pair

“…Shelton et al [16] proposed a thermal wave cycle for an adsorption heat pump using a zeolite/ammonia combination. Wang [17] studied the performance of vapor recovery cycles using activated carbon/methanol as the adsorbent/refrigerant pair and indicated that the mass recovery cycle is effective for low regenerative temperatures.…”