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This dissertation, An Optimization Model for a Solar Hybrid Water Heating and Adsorption Ice-making System by King-ho, Yeung, 楊景豪, was obtained from The University of Hong Kong (Pokfulam, Hong Kong) and is being sold pursuant to Creative Commons: Attribution 3.0 Hong Kong License. The content of this dissertation has not been altered in any way. We have altered the formatting in order to facilitate the ease of printing and reading of the dissertation. All rights not granted by the above license are retained by the author. Abstract: Abstract of thesis entitled An Optimization Model for a Solar Hybrid Water Heating and Adsorption Ice-making System Submitted by YEUNG KING HO for the degree of Master of Philosophy at the University of Hong Kong in October 2003 This thesis reports on a theoretical investigation of a solar hybrid adsorption system. The heart of this system is an adsorber, which is immersed in a tank filled with water heated directly by evacuated-tube solar collector during the daytime. The hot water is drained in the evening and used for domestic purposes, and is replaced with cold water. This cools the adsorption bed, and adsorption and refrigeration continue simultaneously almost throughout the night. The process ceases on the following morning, when natural sunlight becomes available to heat the collector again. The main features of the solar hybrid adsorption system are: (i) employment of an adsorber manifold to enhance the heat transfer efficiency of the adsorbent bed; (ii) use of a newly-developed activated carbon fibre (instead of the commonly-used activated carbon) as the adsorbent, to improve the adsorption capacity and regenerability of the adsorbent; and (iii) use of a new type of double-glazed evacuated-tube collector to eliminate convection and conduction heat transfer losses. iThe operation of the system is explained in detail, and the processes are illustrated on a Clapeyron diagram. The performance of the system was thoroughly analyzed. (1) Collector analysis was performed evaluate the thermal performance of the collector by determining the solar radiation energy received, overall heat loss coefficient, and transmittance-absorptance product of the system. (2) Heat transfer analysis of the water tank and adsorbent bed was carried out to predict their temperature as a function of time for a given set of parameters. Adsorption equilibrium behavior was also modeled to determine how much adsorption took place, and the heat of desorption in the adsorbent bed at the end of each cycle was also evaluated. (3) Design optimization was carried out to determine the optimal amounts of water and adsorbent for given collector area. The effects of various dimensions of the adsorber manifold on system performance were also studied. (4) The interplay of the main operational parameters (condensing temperature, adsorption temperature and evaporating temperature) was studied and an optimal solution determined. A computer model was developed to predict the hybrid system performance in terms of refrigeration capacity and overall system efficiency (including adsorption cooling and domestic water heating). Simulation results indicated that the optimal mass of water and adsorbent for an evacuated-tube collector with an exposed area of 2 m were 25 kg and 50 kg respectively. The simulated results are validated against recently published theoretical and experimental results in respect of a similar hybrid adsorption ice-maker working on the same principle. The study demonstrates that the modifications to existing non-conventional adsorption refrigeration systems iidescribed above can increase efficiency by about 11 % to 15 %. It also provides insights into the influence of cycle time on system performance. An abstract of exactly 451 words iii DOI: 10.5353/th_b2963243 Subject

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