Study of a silica gel-water-based three-bed dual-mode adsorption cooling cycle

The design and operation of a three-bed mass recovery silica gel-water-based adsorption cooling cycle has been outlined along with the performance evaluation of the system. The system can operate in a dual mode, either single-stage mode or two-stage mode, without any change of its physical configuration. The cycle time of the system is optimized to maximize the specific cooling power (SCP) using the particle swarm optimization (PSO) method. It is evident that in a single-stage operation mode the proposed system can effectively utilize a low-grade heat source as low as 55°C along with a coolant at 30°C, whereas a two-stage mode can utilize a heat source as low as 45°C. The optimal performance of the system with a single-stage operation mode is compared with the optimal performance of a two-stage operation mode. Accordingly, the coefficient of performance (COP) of the system in a single-stage operation mode is found to be higher than that of the two-stage operation mode over the whole range of heat source temperatures. However, the SCP of the single-stage cycle is observed to be lower to some extent than the two-stage mode. The system can be operated in a single-stage operation mode when the regeneration temperature remains between 60 and 90°C, and in a two-stage mode when the available regeneration temperature lingers between 45 and 60°C.