Experimental and thermodynamic investigation of the novel open desiccant cooling cycle

In this thesis study, two different heat exchanger structures were designed and fabricated from Cu-ETP material to evaluate the open-cycle sorption performance of microchannel heat exchanger structures and the applicability of CAU-10-H material to these structures and the dehumidification and regeneration performance. coated with the adsorbent material at thicknesses of 98 μm and 88 μm. A special technique for coating was used and homogenous distribution of the adsorbent to the heat transfer surfaces was achieved. Experimental sorption tests of these constructions were made on a specially designed test apparatus for these constructions. In addition, by creating a mathematical model of the system, the utilized material model, heat and mass transfer mechanisms are defined separately for both heat exchanger structures. The input data of the experimental studies were transferred to the model and the simulations were performed in order to validate the model. According to the results obtained, the data obtained from the simulation model showed good agreement with the experimental data. In both cases, it was determined that dehumidification energy efficiency and COP were higher at lower flow rates. The highest dehumidification energy efficiency was determined to be 86 % at the finned channel heat exchanger structure. A 20 % decrease in relative humidity caused a 7-8 % reduction in the dehumidification energy efficiency for the circular channel heat exchanger structure and a 7 % reduction for the finned channel heat exchanger. The regeneration energy efficiency does not exceed 25 % due to relatively small the absolute humidity difference and small amounts of the applied adsorbent material which are 1.75 g and 2.82 g for circular and finned channel heat exchanger structures, respectively. The selected 20 oC temperature for dehumidification was found to be sufficient considering the amount of water adsorbed and the calculated dehumidification rates. The capability of regeneration at 65 oC for CAU-10-H has shown that this material is the ideal adsorbent material for systems where low-temperature waste heat sources are available.