Abstract
It is sure the solar collector is the heat apparatus of a solar energy system. However, it is not the internal combustion engine but is the heat exchanger generally speaking. Therefore, the characteristics of the collector should be shown in heat transmission coefficient K, and sol-air temperature SAT as the primary site temperature of it. This paper explains the measuring methods and their results of SAT and K of both flat and glass tube vacuum type collectors. The strong point of this paper is to measure SAT by observing the temperature inside of the tube of empty collector, which is called as SAT meter. The method to determine every coefficient which want to presume SAT preliminary is described. Also, it is explained to use SAT meter in field is much better than to use η index of solar collector which has been world widely used nowadays, because η sometimes lead men misunderstanding, and is not convenient to control the system.
