Estimation of Transient Refrigeration Load in Potato Cold Store

摘要

An accurate estimation of cooling load is very important for selection of proper-sized refrigeration equipment. Therefore, the objective of this paper was to develop a software for estimating the refrigeration load for a given potato cold store under the prevailing conditions during transient cooling period. Various data as inputs to the program were obtained from a commercial cold store for throughout the transient cooling period of 60 days. From the analysis of the data collected, it has been found that in a particular day, the maximum load due to structural leakage occurred at 6.00 PM, while the maximum outdoor temperature was at 3.00 PM. The average structural heat leakage for the month of March and April were 25.44 and 25.65 kW, respectively. The heat loads due to lights and human beings were maximum during loading hours (5 PM to 9 AM), while heat output from fans was almost constant throughout the day. The average cooling load due to lights, fans, and human beings was 10.2 kW. The infiltration heat gain remained constant during the loading hours and was estimated to be 9.97 kW. The cooling load due to product and moisture phase transformation being increasing with the loading duration achieved a peak at the end of loading period, i.e. 30 days. The average values for product cooling load and moisture phase transformation were 100.35 and 22.25 kW, respectively. The peak of total refrigeration load was also at the 30th day with a value of 253.5 kW. The average refrigeration load during the transient cooling period was estimated to be 159.58 kW. The contributions from five major components of cooling load viz. heat leakage through structure; heat gain from infiltration of outdoor air; latent heat due to condensation and freezing of moisture on cooling coil; heat output from product during cool-down period and subsequent storage; and heat gain from lights, fans, motors and human occupancy, towards the total cooling load were about 16, 3,14, 63 and 4%, respectively.