Modeling Radiative–Convective Panels for Nighttime Passive Cooling Applications

Abstract

Passive cooling by combined radiation–convection from black panels at night is a potential source of significant energy-efficient cooling for both homes and industry. Assessing the technology requires system models that connect cooling load, passive cooling technology performance, and changing weather conditions in annual simulations. In this paper, the performance of an existing analytical model for a passive cooling panel is validated using a full two-dimensional finite differences model. The analytical model is based on a solar hot water collector model but uses the concept of adiabatic surface temperature to create an intuitive, physically meaningful sink temperature for combined convection and radiation cooling. Simulation results are reported for cooling panels of different sizes and operating in both low temperature (comfort cooling) and high temperature (power plant) applications. The analytical model using adiabatic minimum temperature agrees with the high-fidelity finite differences model but is more practical to implement. This model and the validations are useful for the continued study of passive cooling technology, in particular, as it is integrated into system-level models of higher complexity.