Date of Award
Civil and Environmental Engineering
Greenhouse, Heating Demand, Seasonal Thermal Energy Storage, Solar Collector
There is currently a global effort to reduce dependency on carbon-based fuels and move towards more sustainable practices utilizing renewable energy sources. This is in part due to the detrimental effects to the environment and climate change caused by the procurement and combustion of these fuels. Buildings account for a significant portion of global final energy use for heating and cooling purposes. This work focuses on the agricultural greenhouse sector in a cold climate, where significant heating demands are present and are typically met by utilizing significant amounts of natural gas. The heating demand of these structures is examined as well as sustainable generation concepts that have the potential to reduce this dependency on carbon-based fuels. Chapter II investigates the potential of closed greenhouse systems in a cold climate, where active cooling is implemented and the heat removed is stored for later use. It is determined that the annual cooling demand is equal to or greater than the heating demand in each of the cold climates examined and the use of a high-insulating cover material would be most suitable due to the significant reduction in annual heating demand. Chapter III analyses the ability of a large-scale solar collector system to cover a significant portion of the greenhouse heating demand during the summer months. It is determined that a solar collector system with total area of ~575 m2 is able to cover 97% of the heating demand during the month of July and approximately 27% of the annual demand of a 0.4 hectare greenhouse. By replacing natural gas CO2 equivalent emissions are reduced by about 95 tonnes/ year and a payback period of about 10 years is achievable with carbon tax at a rate of $200/ tonne of CO2 equivalent emissions. Finally, Chapter IV simulates the performance of a large-scale solar collector system with seasonal thermal energy storage (STES), where year-round heat is supplied by the system. High and low-temperature systems are able to cover approximately 64% of the annual heating demand and achieve a system coefficient of performance of about 21.7 and 2.9, respectively. The systems are able to reduce CO2 equivalent emissions by ~220 tonnes / year and a payback period of about 7 years is achievable with a 70% subsidy and carbon tax at a rate $200/ tonne of CO2 equivalent emissions.
Semple, Lucas Macrae, "Heating Energy Demands and Sustainable Generation Concepts for Agricultural Greenhouses" (2017). Electronic Theses and Dissertations. 6015.