Novel solid oxide fuel cell system integrating adsorption cooling, heating, and carbon dioxide fertilization for greenhouse tomato production

Abstract

Fuel cells have been widely used for power sources in the power plant, building, and transportation sectors, while few attempts have been made to use fuel cells for agriculture. Heating costs make up a high proportion of agricultural operating costs, and fossil fuels are the primary fuels used, which affects agricultural income according to changes in international oil prices. This study proposes a novel solid oxide fuel cell(SOFC) system integrates adsorption cooling, heating, and carbon dioxide fertilization for greenhouse tomato production. To confirm the superiority of the proposed system (Case 3) in terms of efficiency, its energy consumption is compared with that of the reference systems (cases 1 and 2). Case 1 uses only the air-cooled scroll chiller while Cases 2 and 3 utilize both the air-cooled scroll chiller and the adsorption chiller as a heating and cooling device for the horticulture. In order to reduce the energy consumption for the horticulture thermal management, electrical and thermal energy required for the adsorption chiller are supplied by the SOFC. Case 3 supplied SOFC exhaust gas to fertilize carbon dioxide in horticulture for photosynthesis of the tomato. To determine the heating and cooling loads for horticulture, horticulture energy modeling has been developed based on target temperature, weather data, and tomato evapotranspiration using TRNSYS®. The total power consumption in Case 3 is reduced by up to 12 % during the heating season compared to Case 1, but it increases by up to 6.2 % during the cooling season. For Case 2, there is a savings of 9.8 % during the heating season but an increase of up to 4.1 % during the cooling season compared to Case 1. The study contributes to reduction of the energy consumption for the greenhouse crops production. This finally results in the significant reduction of the carbon emission and the enhancement of the economics in agricultural field.