Defining the coefficient of heat transfer for heating and hybrid photovoltaic solar collectors

The coefficient of heat transfer α is one of the basic parameters of hybrid and heating solar collectors. It is used to define heat losses in collectors resulting from the convection heat exchange with the environment. The main aim of the present paper is to suggest a method for defining the coefficients αequ experimentally - by means of an analytical approach towards the problem. As a result from the experimental investigation and numerical calculation, the coefficient αequ of a hybrid PV/T-S solar collector has been defined. The suggested solution is free of mathematical complexity while giving at the same time opportunities for defining the coefficient αequ precisely enough for practical applications. (author)