Optimization and Performance Study of Residential Centralized Solar Domestic Hot Water System

Solar fraction is an important index to evaluate the energy saving effect of solar hot water system. However, the practical operation indicates that it has some limitations and fails to achieved anticipate result of energy saving if use it only. Therefore, the centralized solar hot water system of residential area in Tianjin is studied, the mathematical model of the heat-collecting unit, heat-supply unit and heat-using unit were established, and the mathematical model of the whole system is formed. MATLAB language was used to write the calculation procedures based on the above model, providing support for the research of system optimization and performance. And the performance index of the system is applied to simulated calculation. Based on the results of the simulation, the system performance in the whole year, the effect of water consumption and the control strategies on the operation performance of this system are studied. Four parameters, solar fraction, solar energy utilization, efficient replacement ratio of foil energy, system heat dissipation ratio has been proposed as system performance evaluating index, and the strategy of reducing the water cycling time properly is put forward. (C) 2019 The Authors. Published by Elsevier Ltd.