Center for the Built Environment

Cooling demands are a major driver of energy consumption in buildings, and is mostly performed using systems based on the refrigeration cycle, an energy and cost intensive process. To investigate the potential of eliminating the refrigeration cycle from a building design in Californian climates, we created a single zone EnergyPlus model that uses a high thermal mass radiant system as the primary conditioning system, and that meets California’s energy code requirements. On the cooling design day, we randomly selected the start and number of hours of radiant system operation, lighting and plug load power densities, and occupant density for a set of models to determine the supply water temperature (SWT) that maintained comfortable temperatures. About 67% of tested models required SWT at or above 18 °C indicating that high thermal mass radiant systems have a high potential to use less energy and lower cost cooling devices like evaporative cooling towers in most California climates.