Cooling power enhancement for 2-D and 3-D CPC sky radiators

This paper describes the experimental results of the newly proposed 2-D and 3-D sky radiators. In order to enhance the performance of sky radiation cooling, the authors have proposed a compound parabolic concentrating (CPC) sky radiator with 2-D geometry and demonstrated that the CPC sky radiator has a greater cooling performance than the conventional flat plate one. In the present paper, optimal design of CPC reflector shape is made to enhance the cooling performance of the 2-D CPC sky radiator. Further, the CPC sky radiator with 3-D geometry is newly proposed and comparison is made between the 3-D and the 2-D CPC sky radiators for the cooling power under actual meteorological conditions. The experimental results demonstrate that the 3-D CPC sky radiator has by far the better cooling performance than the 2-D CPC sky radiator.