The procedure for solving for the top loss coefficient using Equations 6.4.1 through 6.4.7 is necessarily an iterative process. First a guess is made of the unknown cover temperatures, from which the convective and radiative heat transfer coefficients between parallel surfaces are calculated. With these estimates, Equation 6.4.7 can be solved for the top loss coefficient.
The top heat loss is the top loss coefficient times the overall temperature difference, and since the energy exchange between plates must be equal to the overall heat loss, a new set of cover temperatures can be calculated. Beginning at the absorber plate, a new temperature is calculated for the first cover. This new first cover temperature is used to find the next cover temperature, and so on. For any two adjacent covers or plate, the new temperature of plate or cover j can be expressed in terms of the temperature of plate or cover i as