Performance Study of a Hybrid Heat Pump Dryer based on Numerical Analysis and Experimental Set-up

Seafood, especially sea cucumbers and oysters are an expensive delicacy in several Asian countries. Traditional sun-drying of these products takes 3 to 4 days and fetches a lower market price. Modern industrial drying machines used for seafood drying are unable to dry sea cucumbers and oysters without texture and color degradation as they are delicate, temperature-sensitive and have longer drying time. An economical drying system that does not cause texture or color degradation is the heat pump drying system and is commonly applied for agriculture and fabric drying. In this study, the heat pump technology is applied to develop two hybrid dryer models (bottom discharge and front discharge) to dry shellfish and sea cucumbers in large scale for storage and transportation. Each model is tested in a laboratory-scale with wet sponges as input material for its dehumidification capacity and the power consumed to attain the target dryness. The front discharge model is found to have rapid drying capability and economy. Computational fluid dynamic tools are used to study the hot air flow behavior and flow uniformity inside the drying chamber. The front discharge model showed smooth uniform flow over the trays with fewer losses in the flow velocity. The front discharge model with higher drying rate, lower power consumption and uniform airflow distribution over the trays is chosen for the industrial-scale design.