Page 95 - Analysis and Design of Energy Geostructures
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Energy geostructures 65
l. The purpose of using a heat pump to heat a built environment through energy
geostructures is:
i. To enhance the heat input that can be extracted from the ground
ii. To diminish the heat input that can be extracted from the ground
iii. To equilibrate the heat input that can be extracted from the ground
iv. None of the above
m. When an energy geostructure is cooled as a consequence of its geothermal opera-
tion, the building is:
i. Cooled
ii. Heated
iii. Heated and cooled
iv. None of the above
n. The rationale of using heat pumps is based on the thermodynamic prin-
ciple that fluids become warmer when they are compressed into a smaller
volume. The opposite is true for reversed heat pumps fluids become
cooler when they are expanded.
Simple heat pumps consist of four main devices: the evaporator, the
compressor, the condenser and the expansion valve.
o. The coefficient of performance, COP, is defined as
COP 5 Energy output after heat pump operation ½kW
Energy input for heat pump operation ½kW
The COP is a device parameter that defines how many units of heat
can be obtained using one unit of electricity.
p. The seasonal factor of performance is defined as a ratio between the
energy output usable from the energy system and the energy input of the
energy system. Compared to the coefficient of performance, this factor
includes not only the energy of the heat pump but also that of other
energy-consuming elements.
