Sustainable Low-cost Household Energy Systems: Solar Photovoltaic and Shallow Geothermal Systems

An innovative research, service, and teaching initiative led by the Engineering for Development (E4D) program at Mercer University focuses on education, applied research, and service that aims to improve environmental practices at the household level in Macon, Georgia, USA (including water and energy efficiency; re-use and recycling; and use of renewable energy technologies). It focuses on cost-effective solutions that are intended to improve the local environment while saving households money over the mediumand long-term, with key aspects incorporated into Mercer University’s environmental engineering curriculum. This paper focuses on sustainable design and implementation of low-cost renewable energy technologies, specifically low-cost solar photovoltaic systems and shallow geothermal heat pump systems, and use of these technologies in academic teaching. Social Marketing (‘marketing behavior change’) is central to the design and implementation of the initiative. A low-cost ’Solar Self-Supply’ starter solar photovoltaic kit was designed, constructed, and monitored over 4 years (2016-2020). This affordable, expandable system encourages local households to take advantage of recent drops in prices in photovoltaic panels, as well as partial federal subsidies for the entire cost of solar household systems. System design, construction, and testing results are discussed, as are project implementation strategies. The second form of low-cost renewable household energy studied is a shallow geothermal heating and cooling system, which utilizes manual well drilling to install a vertical loop, used in a split geothermal heat pump system. The largest cost component in shallow geothermal systems is the installation of the wells. Thus, using low-cost drilling options makes system installation more economically feasible for households. A preliminary design of the vertical loop was installed in a manually drilled well on Mercer University’s Macon campus and monitored in Spring 2018. Key technical, community development, and socio-economic aspects of the initiative have been incorporated into teaching in a senior and master’s level Green Engineering course at Mercer University.