Optimal design and operation of solar energy system with heat storage for agricultural greenhouse heating

Abstract

A significant challenge of agricultural greenhouses is their high energy demand which is mainly satisfied by fossil fuels resulting in climate change impacts. In this paper, a joint design-operation linear optimization framework for a solar energy system with heat storage is developed to fulfill the agricultural greenhouse heating load. The energy system consists of solar collector, backup boiler, and short-long term heat storages. The developed framework is applied to reach minimum-cost solution. Then, the effects of emission reduction policies, greenhouse cultivation scheduling, natural gas price, and investment cost scenarios are investigated. Furthermore, a multi-objective optimization is performed in terms of minimizing CO2 emissions and total annual cost using epsilon-constraint method. The optimal energy system due to the minimum-cost solution includes a 1065 m2 solar collector and a 1265 kW boiler in combination with 967 kWh and 25 MWh short-term and long-term heat storages, respectively. The 30 % carbon reduction policy results in a 70.5 % increase in solar collector area. The selected optimal solution of the Pareto front, which is the closest solution to the ideal point, has 35.3 % more annual cost and 89.5 % less CO2 emissions compared to the minimum-cost solution.