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SUMMARY:Heat Exchanger Anchors for Thermo-active Tunnels
DTSTART:20130214T170000
DTEND:20130214T180000
DTSTAMP:20260916T120407Z
UID:c809c7c097ba24f2a0f060e2837aa5b083f552e4777cdcd9f4cf5130
CATEGORIES:Conferences - Seminars
DESCRIPTION:Thomas Mimouni\nShallow geothermal power represents an importa
 nt energy resource for the heating and cooling of the buildings. Due to re
 latively low temperature levels\nencountered at shallow depths in soils\, 
 heat pumps are required to process the extracted heat\, forming the so cal
 led ground source heat pump system.\nDifferent types of heat exchangers wi
 th the ground have been developed in order to optimize the heat exchanges\
 , and recent advances suggest that applying the concept of energy geostruc
 tures to tunnel structures could be efficient.\nThe present study investig
 ates the potential of using tunnel anchors and nails as heat exchangers wi
 th the surrounding soil. Two main structures of shallow tunnels were inves
 tigated. A cut and cover tunnel\, whose diaphragm walls are maintained wit
 h long anchors\, was modeled first. Thermal influence of the soil surface 
 and unsaturated conditions were taken into account. Nevertheless\, mechani
 cal implications of the heat extraction on the cut and cover tunnel were n
 eglected because of the low mechanical confinement observed on the structu
 re. Then\, an urban bored tunnel was investigated. Only saturated conditio
 ns were\nconsidered and the thermal influence of the surface was neglected
  but mechanical implications of the heat exploitation were quantified beca
 use of the high confinement of the bored tunnel body induced by the soil w
 eight.\nDifferent types of heat production cycles were tested in various s
 oil conditions. The heat extraction was based on the external air temperat
 ure to represent a simplified building heat demand. All the exploitation c
 ycles were optimized to reach a temperature threshold in the ground while 
 avoiding freezing. Next\, comparisons between extracted and retrieved heat
  for the different cycles allowed drawing an optimum exploitation method.
LOCATION:GCD0 386\, EPFL
STATUS:CONFIRMED
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