Energetic, hygrothermal and financial performance of chilled earth panels versus common AC split units

Abstract

Cooling energy consumption is projected to increase dramatically as a consequence of climate change and economical development. As itself a driver of climate change and social inequality, it is of fundamental importance to recognize the necessity of sustainable and affordable cooling systems. Clay cooling panels are gaining importance because of their energy efficiency, flexible operation and compatibility with natural ventilation. Simulations have been conducted with TRNSYS interfaced through TRNLizard to assess the energetic and hygrothermal performance of clay panels compared to the common AC split units. These are the most common cooling systems in residential settings, due to their low upfront cost and easy installation. Simulations have been set to represent a residential building in the city of Milan. The results show that clay radiant panels do indeed have an advantageous energetical and hygrothermal performance. This is mainly due to their flexible setpoint temperatures and the hygrothermal behavior, which eliminates the risk of condensation and makes them compatible with natural ventilation. The combination with natural ventilation improves the energy consumption further but not greatly. The passive effect of clay on comfort could not be depicted with the current Moisture Buffer Model. With an improved model, energy efficiency might be even higher. All in all, clay radiant cooling does represent a valid alternative to AC split units for the studied location. Further hurdles to promote their diffusion are the upscaling of production and the easing of installation to reduce their cost.