22 May 2008
This paper presents the development of an energy efficient refrigeration system
for transportation purposes. The system stores the heat wasted during refrigeration cycles
and utilizes it for hot gas defrost process. A computer model is developed to design an
evaporator and a condenser and to determine heat storage size based on pre-determined
cooling condition. Simulations with the selected components were carried out to investigate
refrigeration system performance under various operating conditions during refrigeration and
defrost cycles. An experimental investigation on cooling capacity tests is performed on a
3,225 x 1,740 x 1,640 mm full-scale refrigerated box to validate the model. The evaporator
coil defrost process analysis provides quantitative information on the defrost energy
efficiency. The simulation values show a good agreement with the experimental results with
the deviation for cooling capacity and defrost time less than 7.5% and 13.8% respectively.
These results are important in order to avoid excessive parasitic load and temperature rise
inside the refrigerated container.