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Geothermal Energy
Published in Robert Ehrlich, Harold A. Geller, John R. Cressman, Renewable Energy, 2023
Robert Ehrlich, Harold A. Geller, John R. Cressman
We have seen that geothermal plants emit negligible amounts of CO2, but for geothermal residential heating, the issue is less clear. Geothermal heating systems usually rely on heat pumps that extract heat from the ground and deliver it to a higher temperature, i.e., the interior of your house. Thus, they make heat flow the wrong way through the input of work. The COP of ground source heat pumps is usually above 4. The actual average COP tends to be somewhat lower than 4 when we include the energy needed to power the water pumps. Let us assume a COP of 3—meaning that the heat supplied is three times the electrical energy used to power the compressor.
Modular Systems for Energy Conservation and Efficiency
Published in Yatish T. Shah, Modular Systems for Energy Usage Management, 2020
White Oak Modular is one of the leading builders of energy-efficient homes in the United States. This company is proficient in the installations of solar electric panels to power home and geothermal heating and cooling systems. Combining both solar and geothermal systems allows to have free heating and cooling [38]. The solar panels generate all of the electricity needed to run the geothermal system. During sunny days, one generates more electricity than one uses, and this results in net surplus of energy. Geothermal heating and cooling systems use the 56° temperature of the earth to heat or cool your home, using a fraction of the energy used by a conventional system. While conventional furnaces and boilers burn fuel to generate heat, geothermal systems use electricity to simply move heat from the earth into your home during winter and transferring it out of your home and back into the ground during summer. The most efficient fuel-burning heater can reach efficiencies around 95% but a geothermal heating system can move up to four units of heat for every unit of electricity needed to power the system, resulting in a practical equivalence of over 400% efficiency [38].
Modelling HVAC and renewable energy plant and control
Published in Jan L.M. Hensen, Roberto Lamberts, Building Performance Simulation for Design and Operation, 2019
The interaction between the ground and the adjacent atmospheric environment, along with the superior thermal capacity of the ground, are such that fluctuations in ground temperatures are always reduced in amplitude compared to the fluctuations in dry-bulb temperature. Making use of the ground’s relatively high thermal capacity, compared to either the air or typical building fabrics, is correspondingly thermodynamically advantageous when it comes to possible sources or sinks for heat pump systems. This is one of the main reasons for the abiding interest in geothermal heating and cooling using heat pumps (ground source heat pumps) as potentially one of the most efficient means of heating and/or cooling buildings.
Modeling of vertical ground heat exchangers
Published in International Journal of Green Energy, 2021
Seama Koohi-Fayegh, Marc A. Rosen
A geothermal heating and cooling system consists of three main components: a heat pump, an underground heat exchanger and a distribution system such as air ducts. The cost of the system is roughly proportional to the heat exchanger size. Therefore, there is an incentive to evaluate peak monthly and daily loads and average annual loads to design the heat exchanger as small as possible to meet the required heat transfer for system operation. The heat exchanger performance is influenced by several factors: the structural and geometric configuration of the heat exchanger, the ground temperature distribution, soil moisture content and its thermal properties, groundwater movement and possible freezing in soil. Thus, appropriate and validated tools are needed, with which the thermal behavior of GHEs can be assessed and optimized, considering technical and economic aspects.
A comprehensive review of geothermal energy evolution and development
Published in International Journal of Green Energy, 2019
M. Soltani, F. Moradi Kashkooli, A.R. Dehghani-Sanij, A. Nokhosteen, A. Ahmadi-Joughi, K. Gharali, S.B. Mahbaz, M.B. Dusseault
Geothermal heating for buildings can be integrated with other forms of renewable energy to increase savings. The European Center for Public Law in Greece uses two groundwater heat pumps for the building’s main heating needs and air handling units with solar mixing boxes to provide the building with ventilation, Figures 11–12 (Karagiorgas, Mendrinos, and Karytsas 2004), Field data collected during a winter test day shows the important role renewable energy was able to play in the building’s energy consumption (Figure 13).