TY - JOUR
T1 - Thermal response of energy foundations installed in unsaturated residual soils
AU - Reiter, Michael B.
AU - Morais, Thaise Da S.O.
AU - Tsuha, Cristina De H.C.
AU - Baser, Tugce
N1 - Funding Information:
Financial support provided by the Lemann Faculty Collaborative Research Grants at University of Illinois at Urbana Champaign, the State of São Paulo Research Foundation -FAPESP (Process 2014/14496-0), and the National Council for Scientific and Technological Development - CNPQ (Process 140143/2015-7 and 310881/2018-8) are greatly appreciated. The opinions are those of the authors alone and do not reflect the viewpoint of the sponsors.
Publisher Copyright:
© The Authors, published by EDP Sciences, 2020.
PY - 2020/11/18
Y1 - 2020/11/18
N2 - This study focuses on the thermal response of energy foundations with different piping geometries installed in unsaturated soil. Energy foundations are an efficient alternative to traditional space heating and cooling approaches and can reduce energy demand for air conditioning in Brazil, where unsaturated residual soil deposits are abundant. A three-dimensional numerical model for heat transfer and subsurface flow is first validated against field data from a thermal response test at the University of São Paulo. The model is then used to compare the performance of triple and quadruple U-tube piping geometries and helical piping geometries of equivalent length. The helical geometries resulted in initial less uniformly heated foundations and lower heat flux at the foundation boundary compared with the U-tubes, but the differences between the U-tube geometries and their equivalent length helices were less than 1°C. All piping geometries exhibited increased heat output as the length of heat exchanger piping increased. The infinite line source solution was compared with the model results. The infinite line source solution underestimated the thermal response of the system during the first 25-30 days and overestimated it afterwards.
AB - This study focuses on the thermal response of energy foundations with different piping geometries installed in unsaturated soil. Energy foundations are an efficient alternative to traditional space heating and cooling approaches and can reduce energy demand for air conditioning in Brazil, where unsaturated residual soil deposits are abundant. A three-dimensional numerical model for heat transfer and subsurface flow is first validated against field data from a thermal response test at the University of São Paulo. The model is then used to compare the performance of triple and quadruple U-tube piping geometries and helical piping geometries of equivalent length. The helical geometries resulted in initial less uniformly heated foundations and lower heat flux at the foundation boundary compared with the U-tubes, but the differences between the U-tube geometries and their equivalent length helices were less than 1°C. All piping geometries exhibited increased heat output as the length of heat exchanger piping increased. The infinite line source solution was compared with the model results. The infinite line source solution underestimated the thermal response of the system during the first 25-30 days and overestimated it afterwards.
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U2 - 10.1051/e3sconf/202020505021
DO - 10.1051/e3sconf/202020505021
M3 - Conference article
AN - SCOPUS:85097722108
SN - 2555-0403
VL - 205
JO - E3S Web of Conferences
JF - E3S Web of Conferences
M1 - 05021
T2 - 2nd International Conference on Energy Geotechnics, ICEGT 2020
Y2 - 20 September 2020 through 23 September 2020
ER -