Metal roofs are very common in many developing countries. Such roofs cool down quickly, during the nights, acting as an effective nocturnal radiator directly above the living space. However, during the daytime hours the indoor temperatures in buildings with such often uncomfortably hot. Installing inflammable, operable hinged interior insulation plates under the roof can reduce greatly the daytime heating without interfering too much with the cooling effect of such roofs during the nights. The effectiveness of storing the "cold energy" generated by the nocturnal radiant cooling for lowering the indoor air temperature during the daytime hours depends on availability of thermal storage in the interior space. The distribution of the mass inside the space affects the performance of the system. A model of this system (a test cell) was constructed and tested at UCLA. The main variable in the experimental series was the location (configurations) of the thermal mass. This mass is needed for utilization of the nocturnal cooling during the following hot daytime hours. This paper describes the performance of this system under different configurations of the thermal mass. In addition, the development of formulas that recreate the indoors maximum temperatures of a test cell with such a cooling system is described.
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