Optimization of a weather-based energy system for high cooling and low heating conditions using different types of water-cooled chiller

A weather-based energy system consisting of a tri-generation unit, photovoltaics, and water-cooled chiller is proposed here for improving the energy and environmental performance. Together with capacities of other devices, the cooling ratio, and capacities of different types of chiller are optimized to find the ideal system configuration setting the energy and cost savings and renewable energy use as the objectives. In addition, daily and monthly operating modes with the optimal system composition are analyzed followed by a sensitivity analysis. The results show that increasing energy saving ratio improves the cost saving benefits, but the renewable energy penetration rate would decrease due to lower grid electricity consumption. The ideal system configuration in ratio optimization process has a higher gas turbine and chiller capacity resulting in higher performance than the system with capacity optimization process, or 2.7%, 1.6%, and 0.2%-unit higher of the considered indices. When increasing the specific cost of the chiller, cost saving ratio of the ideal system decreases, while the impacts on the energy savings and renewable energy use are lower. The analysis indicates that the price of grid electricity is the most sensitive factor, while the influence of carbon cost is slight.