- A passive cooling system, integrating radiative and convective cooling, was tested for a test cell in Sde-Boqer, Israel. The system was based on circulating water from a pond on the roof of the cell through a system of radiators, which removed energy from the system by nocturnal long wave radiation and convective losses. The water flowing through the system kept the radiators relatively warm, thus increasing radiative losses and eliminating convective gains. Wind screens were not necessary in this case. The radiators also served as a shading device over the roof during the day.