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Are earth tube heat exchangers of interest when heating buildings?
Author(s) -
Gustafsson StigInge
Publication year - 1993
Publication title -
international journal of energy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.808
H-Index - 95
eISSN - 1099-114X
pISSN - 0363-907X
DOI - 10.1002/er.4440170705
Subject(s) - heat exchanger , tube (container) , environmental science , heat pump , earth (classical element) , copper in heat exchangers , heat recovery ventilation , renewable heat , heat spreader , waste heat , air source heat pumps , inlet , shell and tube heat exchanger , ventilation (architecture) , plate fin heat exchanger , plate heat exchanger , hybrid heat , waste management , mechanical engineering , engineering , physics , mathematical physics
It is a well‐known fact that the temperature of the soil, some metres below the surface, is relatively stable. If this heat could be utilized by use of an earth tube heat exchanger, significant benefits could occur when space heating for buildings is considered. The inlet ventilation air is then led through a long earth tube in which it will, depending on their relative temperatures, take up heat from, or leave heat to, the surrounding soil. In this paper two case studies are presented. The buildings of concern are sited in the vicinity of Linköping, about 200 km south of Stockholm, Sweden. One of the cases utilizes heat from the earth tube in an air‐to‐water heat pump, while the other uses an air‐to‐air heat exchanger. The studies show that the earth tubes only to a very low degree contribute to the need of added heat in order to achieve a desirable indoor climate. Hence, the extra cost for the tube will not be balanced by the decreased cost for space heating. This discouraging result may have depended on heat pipes that were too short or the fact that the difference in temperature between the passing air stream and the surrounding soil was too small.