Development of Optimal Design of Solar Water Heating System by Using Evolutionary Algorithm

There are growing initiatives to promote renewable energy in Hong Kong, particularly for solar energy. In order to encourage wider application of centralized solar water heating system for high-rise residential buildings, it is important to pursue an optimal design to get significant energy-savings potential. In this regard, system optimization would be useful because it can relate to a number of design variables of the solar water heating system. The objective function is to maximize the year-round energy savings by using the solar heating against the conventional domestic electric heating. For the methodology of optimization, evolutionary programming, one of the paradigms of the evolutionary algorithm, was applied. From the optimization results, it is suggested that the solar collectors can be installed onto the external shading devices as an integrated architectural feature, since the optimal tilt angle is 21 deg and relatively flat. The optimal surface azimuth is southwest 16 deg, instead of due south. For the engineering design, both the optimal values of calorifier storage capacity and pump flow rate show that the calculations from normal design practice may not achieve an optimal performance.