Abstract
Residential refrigerator designs have improved significantly over the recent years to achieve the required federal minimum energy standard and match with consumer expectations. Designers have been able to use innovative design features and components; however, evaporator designs have lagged in performance improvement due to the need to properly manage frost and maximize the freezer interior volume. Rotating Heat Exchangers (RHX) provide an innovative solution that addresses both of these concerns. The rotation of the fins results in continuous disruption to the boundary layer, hence reducing the overall thermal resistance. Thus, for the same capacity, the heat transfer area can be greatly reduced. Furthermore, the rotation inhibits frost growth on the fins and reduces the time and frequency of defrosting. In this paper, we present an experimental evaluation of the RHX in a benchtop refrigerant loop system showing results for different operating configurations. Cooling capacity, cooling COP, and overall energy consumption are investigated. High-speed imaging is also used to capture frost growth patterns over time on the RHX fins in the presence and absence of rotation. The results show that the rotating heat exchanger evaporator is capable of meeting the 100 W capacity requirement of residential refrigerators, while offering the potential of significant reduction in defrost energy consumption.