Taguchi and utility concept optimization of parabolic solar collector assisted ground coupled heat pump system for space heating applications.

In this paper optimization of operating parameters of a solar assisted ground coupled heat pump (SAGCHP) system is discussed for space heating application under Indian climatic conditions using Taguchi method and utility concept to achieve optimum COP of the SAGCHP system with minimum solar collector area and minimum ground heat exchanger length. Taguchi method is employed with lower the better concept to achieve minimum solar collector area and minimum GHX length whereas higher the better concept is used to obtain maximum COP. To achieve these objectives a mixed level L18(21,37) orthogonal array has been selected. The method is implemented for a 2 ton heating load application in winter season. Results obtained from 18 trial runs are analyzed using signal to noise ratio and ANOVA method. The best levels of contributing parameters for optimum solar collector area and GHX length obtained from Taguchi method are further optimized using the utility concept to obtain a single set of optimum parameters for maximum COP. The implementation of utility concept has resulted in 8.8% and 7.3% reduction in solar collector area and GHX length respectively and about 9.13% increase in COP of SAGCHP system compared to the values obtained by the Taguchi method.