Efficiency analysis of borehole heat exchangers as grout varies via thermal response test simulations. (September 2017)

• Record Type: Journal Article
• Authors: Sliwa, T.; Rosen, M.A.
• Is Part Of: Geothermics. Volume 69(2017:Sep.)
• Page Start: 132
• Page End: 138
• Publication Date: 2017-09
• Subjects: Borehole heat exchanger -- Geoenergetics -- Thermal response test -- Borehole grout -- Energy efficiency; Hydrogeology -- Periodicals; Geothermal resources -- Periodicals; Énergie géothermique -- Périodiques; GEOTHERMAL ENGINEERING; GEOTHERMAL ENERGY; GEOTHERMAL EXPLORATION; Geothermal resources; Hydrogeology; Periodicals; Electronic journals; 621.44
• DOI: 10.1016/j.geothermics.2017.05.004
• Languages: English
• ISSNs: 0375-6505

Abstract

Highlights: We model numerically thermal response tests. Various constructions of borehole heat exchangers are analyzed. Numerous thermal conductivities of grout are considered. Laboratory thermal response tests are also performed. Abstract: Grout is normally used in borehole heat exchangers, in part for separating different water layers. Grout can also enhance heat transfer with the ground when it has high thermal conductivity. In this article, thermal response test results from simulations of borehole heat exchangers are presented. The work is undertaken to enhance understanding and predictions of the heat transfer effectiveness and energy efficiency of borehole heat exchangers as grout varies. The following borehole heat exchanger types are considered: coaxial, single U-tube and double U-tube. The results quantitatively describe the effect of grout on energy efficiency and indicate if it is reasonable to incur the higher costs of using grouts of high thermal conductivity to enhance borehole heat exchanger performance.