Active energy exchange effect between building and rooftop greenhouse for energy saving, part 2: Energy consumption reduction scenario development

Carbon reduction is a vital target in the building and agricultural sectors. By 2050, the building and agricultural sectors need to reduce carbon emissions by 88 % and 37 %, respectively. Therefore, in this study, the conditions for reducing the combined energy load of the building and rooftop greenhouse were analysed using the CFD and BES model validated, to provide evidence-based operational scenarios that maximise the synergistic energy exchange between rooftop greenhouses and buildings. The structural symbiosis achieved by locating the greenhouse on the building roof and analysing its operation using passive scenarios was done. In addition, energy savings achieved by exchanging surplus energy, such as air heat and moisture in buildings and greenhouses according to various conditions, were analysed as active scenarios. Consequently, it was found that the energy-saving effect was highest when the wall insulation between rooftop greenhouses and buildings was low, when cooling in the rooftop greenhouse was used on summer nights, and when unused heat was exchanged between the rooftop greenhouse and building in winter. When applying passive and active scenarios in the standard weather data for Korea, energy law is annually saved by 4.33 kWh/m 2 and 1.81 kWh/m 2 , respectively for the building and rooftop greenhouse. It resulted in that 2.09 CO 2 /m 2 and 0.88 CO 2 /m 2 , respectively were saved for the building and rooftop greenhouse per year. • Dynamic energy coupling of rooftop greenhouse and building with crop loads. • Operational strategies based on insulation, cooling, and ventilation scenarios. • Contribution of RTG–building integration to energy reduction in both sectors.