1. Introduction
Night sky cooling represents a method of passive cooling of buildings. It is based on the principle of heat radiation from hot surface of a solar panel against the cold night sky. Temperature of the night sky on the atmospheric boundary layer reaches 4 K [1]. This method of cooling is preferably applicable in dry climatic conditions because high air humidity absorbs heat radiated from the ground and therefore this heat is partially emitted back. According to previous studies [2,3], the efficiency of cooling collectors is affected not only by relative