Experimental study on a low energy radiant-capacitive heating and cooling system

The aim of this study is to assess the thermal performance of a low-energy Radiant-Capacitive Heating and Cooling System composed of a radiant-capacitive heating and cooling module, a sky radiator/solar collector and a thermal energy storage (water tank), operating mainly with natural energy sources. The system combines different passive strategies, namely: nocturnal radiative cooling for summer or warm periods of the year, solar heating when required, increase of thermal mass indoors with thermal activation of an indoor hydronic radiator. Experimental results are shown for the system in its cooling mode, carried out with small test cells in Curitiba, Brazil. For summer months, the system was capable of reducing the outdoor mean by on average 1.2 K with a peak temperature drop of 4 K. Corresponding offsets for the daily maxima were 5.2 K and 8.9 K, respectively. Mean cooling potential of the system, obtained in a side-by-side temperature comparison between an experimental cell with the implemented system and a control cell, resulted in daily values of up to 220 Wh/m(2)day. The net cooling power of the radiator during pumping hours at nighttime showed average values between 32 W/m(2) and 53 W/m(2), with maximum values reaching 84.5 W/m(2). (c) 2021 Elsevier B.V. All rights reserved.