Page 94 - Analysis and Design of Energy Geostructures

64 Analysis and Design of Energy Geostructures

e. When dealing with energy tunnels, configurations involving pipes ori-
ented perpendicular or parallel to the axial direction of the tunnel can be
foreseen.
f. In designing the pipe layout for energy tunnels, energy walls and other energy
geostructures characterised by a significant heat exchange surface, a key aspect is
to obtain the lowest heat exchange surface for the selected energy geostructure
portion at the highest pressure drop and investment:
i. True
ii. False
g. Thermal insulation layers can be foreseen in energy tunnel, wall and slab applica-
tions to prevent heat exchange with either the airside or the groundside:
i. True
ii. False
h. What are the purposes of the heat exchange that can be established with energy
geostructures?
i. Heating and cooling of superstructures
ii. Prevent the icing of pavements and decks
iii. Production of hot water
iv. Production of electricity
i. Heat extraction: heat is extracted from the ground in the cool season to
heat the built environment, cooling the energy geostructure;
Heat injection: heat is injected in the ground in the warm season to
cool the built environment, heating the energy geostructure;
Heat extraction and heat injection: heat is extracted in the cool season to
heat the built environment and injected in the warm season to cool the built
environment, cooling and heating the energy geostructure, respectively;
Heat injection for storage purposes: heat (usually arising from thermal
solar panels) is injected in the ground (usually during the warm period)
for a successive use of the superstructure (usually during the cool period),
heating the energy geostructure.
j. Ground source heat pump systems comprise a primary and a secondary
circuit. The primary circuit includes the ground heat exchanger while
the secondary circuit characterises the built environment to be heated or
cooled. In between these two circuits, electrically driven machines such
as a heat pump or reversed heat pump can be employed.
k. How many circuits characterise the ground source heat pump system? To which
circuit do energy geostructures belong?
i. Two circuits. The primary
ii. Three circuits. The primary
iii. Two circuits. The secondary