Performance evaluation of a three-bed adsorption chiller employing an advanced mass recovery process with different cycles

Abstract

In this thesis, performance evaluation of a three-bed adsorption chiller employing an advanced mass recovery process with different cycles has been numerically investigated. In the present numerical solution, the heat source temperature variations are taken from 500C to 90°C for both cycle (cycle1 and cycle2) and along with coolant inlet temperature at 30°C and the chilled water inlet temperature at 14°C. Silica gel-water is chosen as adsorbent-refrigerant pair. In the new strategy, if any one bed is connected with the evaporator during pre-heating or pre-cooling time then it will give better performance than that of existing system. In this strategy, mass recovery process also occurs in all bed. In operational strategy1, the configuration of beds in the three-bed chiller with mass recovery are taken as uniform in size, but in operational strategy2, the configuration of Hex3 is taken as half of Hex1 or Hex2. A cycle simulation computer program is constructed to analyze the influence of operating conditions (hot and cooling water temperature) on COP (Coefficient of Performance), CC (Cooling Capacity) and chilled water outlet temperature. The performances in terms of Cooling Capacity (CC) and Coefficient of Performances (COP) are compared with those of conventional two-bed mass recovery scheme. Results show that the optimum COP values are obtained for hot water inlet temperature at 850C along with the coolant and chilled water inlet temperature are at 300C and 140C, respectively. It is also seen that the Cooling Capacity (CC), Coefficient of Performances (COP), and chiller efficiency can be improved up to 34%, 15% and 46% (for cycle1) and 5%, 13.8% and 31.5% (for cycle2) respectively than that of the conventional mass recovery cycle if heat source temperature is considered to be 850C. Finally, the performances in terms of Cooling Capacity (CC) and Coefficient of Performance (COP) are compared with those of conventional three-bed without mass recovery scheme. The COP and CC increased by 11.25% and 51.12%, respectively, and the optimal time of mass recovery is 40s.