4023 — Parametric Study of a Silica Gel-Water Adsorption Refrigeration Cycle – The Influence of Thermal Capacitance and Heat Exchanger UA-Values on Cooling Capacity, Power Density, and COP

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The influence of heat exchanger UA-values (adsorber/desorber, evaporator, and condenser) is investigated for an adsorption chiller, with consideration given to the thermal capacitance of the adsorber/desorber by means of a lumped-parameter cycle simulation model developed by the authors and co-workers for the single-stage silica gel-water adsorption chiller. The closed-cycle-type chiller, for use in air conditioning, is driven by low-grade waste heat (85degC [185deg]) and cooled by water at 31degC [88degF]) and operates on relatively short cycle times (420 seconds adsorption/desorption; 30 second adsorber/desorber sensible cooling and heating). The results showed cycle performance to be considerably affected by the thermal capacitance and UA-value of the adsorber/desorber, which is attributed to the severe sensible cooling/heating requirements resulting from batched cycle operation. The model is also sensitive to the evaporator UA-value – but to a lesser extent. The condenser UA-value is the least sensitive parameter due to the working pair adsorption behaviour in the temperature range defined for desorption and condensation.

KEYWORDS: year 1997, Adsorption, chillers, refrigeration, absorption refrigeration, desiccants, heat exchangers, calculating, air conditioning, heat recovery, performance, heat loss, heat flow, heat transfer coefficient

Citation: ASHRAE Trans. 1997, Vol.103, Part 1, Paper number 4023, 139-148, figs., 1 tab., refs

Product Details

Published:
1997
File Size:
1 file , 1.1 MB
Product Code(s):
D-16357