ABSTRACT. The design of an entrance for a temperature-controlled space is always a conflict between operators, who would prefer a completely unrestricted access, and the needs of temperature control, which would prefer no doors or openings. The positioning and design of entrances are often decided on ease of use criteria with temperature control and interaction with the refrigeration system as a secondary consideration. The present study investigate experimentally the effect of door dimensions on warm air infiltration rates into a cold store. A laboratory scale model consists of a prefabricated sandwiched panel room of inside dimensions (1.5 x 1.5 x 2) m with two doors is prepared. The room is operated with a suitable refrigeration unit to achieve the required storage temperature. Experiments are conducted at 0 oC and -10 oC to simulate the conditions of chilled and frozen conditions respectively. The tracer gas technique was used for measuring CO2 concentration inside the model during the tests. The results show that as the opening time of the cold room door increases the air infiltration rate and heat load due to infiltration decreases. However the amount of air infiltration in (m3) increases during the opening period, and the CO2 concentration inside the room decreases gradually. A recovery time of ≈ 35 minutes is required for the machine to regain an initial storage temperature of -10 oC while the door size parameter (A* = door area / room volume) A* = 0.1792 m-1. Having different door sizes for the room each for its suitable purpose can reduce energy consumption. The height of the door is important factor on air infiltration into the room while having double area doesn’t mean double value of air infiltration into the room. |
