Desinging of Parabolic Solar Water Heater Technical and Dimensional Specifications Using Genetic Algorithm
Abstract
Calculating technical and dimensional specifications of a solar water heater through a simple model has always been a challenge. Nowadays such designs are being conducted by experiment more than calculations. Developing a capable model in order to simulate the thermal behavior of the collector and storage tank temperature with low computational load during its use in simulation and low error is required here. Recently such a thermal model for parabolic solar water heaters has been developed by adapting the fully mixed model of the storage tanks to consider the influence of storage tank inner box (Zahirnia at el., 2011); however, a process should still be presented to estimate appropriate technical and dimensional specifications of the solar water heater according to the customer needs and manufacturing and environmental conditions. In this paper, this process is presented. The designing idea is the same as the idea of identifying unknown parameters of a grey-box model. The only difference between these two ideas is that in identifying unknown parameters of a model experimental data are required, while in the presented designing method desired behavior of the device is expressed by a target diagram. Here as a simplifying assumption the target diagram is assumed to be a linear one depicted according to the customer needs. This linear target diagram is then modified along with the designing process. Applying an optimization method (genetic algorithm (G.A.) technique is used here), storage tank temperature in the simulated model is converged to the target diagram with minimum possible error. The set of numbers that G.A. has used in the simulated model to gain this minimum error are considered as the desired technical and dimensional specifications of the solar water heater. The results obtained demonstrate the viability of the proposed designing process.