Thermo-economic analysis of a low-cost greenhouse thermal solar plant with seasonal energy storage

Reduction of greenhouse gas emissions is today mandatory to limit the increase of ambient temperature. This paper provides a numerical study of a thermal solar plant using a seasonal dual-media sensible heat thermal energy storage system for supplying the total energy demand of a greenhouse located in the South of Italy, avoiding the use of the gas boiler. The aim of the work is to assess the technical and economic performance of a low-cost pit storage system, made of gravel and water, placed under the greenhouse to save surface. The study provides an original analysis of the charging and discharging phases during one year of operation on the basis of the real hourly heating demand and on real weather data. A sensitivity analysis of the levelized cost of heat is carried on with respect to the solar-collector area and to the storage-pit volume. The analysis shows that a minimum-cost design solution exists to cover 100% of the heat demand with an estimated levelized cost of heat of 153.3 EUR/MWh. The results demonstrate that dual-media thermal energy storage systems with solar thermal collectors represent a viable solution for reducing the environmental impact of greenhouses.

Automated summary

This paper presents a numerical study of a thermal solar plant using a seasonal dual-media sensible heat thermal energy storage system to supply the energy demand of a greenhouse in Italy. A low-cost pit storage system made of gravel and water was evaluated for its technical and economic performance. The study analyzed the charging and discharging phases based on real heating demand and weather data, and conducted a sensitivity analysis of the cost of heat with respect to collector area and storage volume. The results demonstrate the feasibility of dual-media thermal energy storage systems with solar collectors in reducing greenhouse emissions.