2019/07/29 by Baker, T. H. W., Frederking, R. M. W., Hoffman, D. R.
#chambre froide #stabilité thermique #thermal stability #walk in refrigerators
paper · doi:10.4224/40000599
The performance characteristics of two cold rooms operating since 1954 were evaluated with regard to temperature distribution throughout the rooms and temperature stability. One room is approximately 9 x 13 x 10 ft high, and the other is 10 x 12 x 10 ft high. Each room is conditioned with a 3.5 ton capacity compressor. An auxiliary compressor is shared between the two rooms as a standby and to operate during defrost periods. Each room has two evaporator units to serve as extra capacity during draw down and as the alternate during defrosting of the coils. Temperature control is achieved by varying the electrical reheat input at a constant refrigeration capacity. The thermal performance was evaluated by measuring the temperature at 30 locations with the rooms using copper-constantan thermocouples attached to a Kaye data logger. The room temperatures studied ranged from -5 to -40 degrees C. The thermal performance established may be summaried as follows: 1. control ranges from 0 to -40 degrees C. 2. air temperature fluctuations anywhere in the rooms is plus or minus 0.1 degrees C. 3. temperature variation at different locations is about 1 degree C. 4. relative humidity is between 35 and 40 per cent. 5. three to five hours are necessary for the room temperature to stabilize. 6. erratic thermal performance occurs during the monthly defrost cycle.