Solar Energy, Renewable Energy, Geothermal System, Net-Zero Energy Building
Buildings consumed 40% of the energy and represented 40% of the carbon emissions in the United States. This is more than any other sector of the U.S. economy, including transportation and industry. About 24% of all energy used in the nation is for space heating, cooling and water heating in buildings. Enhancing building efficiency represents one of the easiest, most immediate and most cost effective ways to reduce carbon emissions. One of energy efficient and environment friendly technologies with potentials for savings is Ground Source Heat Pump (GSHP) system. On the other hand, solar energy is considered as an unlimited and an environment friendly energy source, which has been widely used for solar thermal and solar power applications.Â This paper presents a laboratory test facility for a solar powered ground source heat pump system. The ultimate technical goal is to apply the solar powered ground source heat pump into a net-zero energy building, where all the electricity consumption will be covered by an integrated on-site solar PhotovoltaicsÂ (PV)Â panels and battery system. The added-on benefits from this solar powered GSHP include but not limited to: 1) help further reduce electricity peak demand and 2) help further reduce greenhouse emissions. In this test rig, a Â¾ - ton water-to-air GSHP is connected to two 60-feet deep wells.Â A group of solar PV panels of 1.12KW is connected to a battery bank, which is used to power the GSHP and a 0.27KW DC powered well pump. During the daytime, solar PV panels convert solar photons into electrical energy which will be stored into the battery bank. Whenever the GSHP system is on demand, the battery bank will provide the power. This test rig also has a comprehensive performance monitoring and data acquisition system. Well groundwater temperatures, refrigerant temperatures, air temperatures, water flow rates, etc. are all real-time monitored, trended and stored.Â In addition, an on-site weather station is installed to measure outside air temperature, relative humidity, wind speed and direction, and solar radiation. The details for the design and layout of this solar powered GSHP, together with the monitoring and data acquisition system will be introduced in this paper. In addition, the preliminary data collected from a testing of a cooling mode operation will be presented to illustrate the benefits of the proposed system. Finally, the feasibility of the application of the system will be discussed in the paper.