Reduced order dynamic model of the flat-plate solar collector

Abstract

Padé approximation techniques are applied to obtain a reduced order dynamic model for the partial differential system representing the dynamic behaviour of the flat-plate solar collector. According to a prespecified accuracy, the collector is divided into n sections. At any position along each section the reduced order dynamic model is decoupled second order state equation, the input of which is the output of the preceding section. Numerical solutions obtained from the reduced order dynamic model are in very close agreement with the exact solution. Moreover, the computational efforts as well as the computer storage requirements are considerably reduced in comparison with other methods. The results obtained from the dynamic model are compared with those based on a simple steady-state model. The comparison reveals that the steady-state expression may only be used for collectors having a low thermal inertia and a high fluid-stream heat capacity.