Downhole heat exchangers

Journal Article · Wed Sep 01 04:00:00 EDT 1999 · Geo-Heat Center Quarterly Bulletin

OSTI ID:691514

Culver, G; Lund, J W ^[1]

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1. Oregon Inst. of Tech., Klamath Falls, OR (United States). Geo-Heat Center

The downhole heat exchanger (DHE) eliminates the problem of disposal of geothermal fluid, since only heat is taken from the well. The exchanger consists of a system of pipes or tubes suspended in the well through which clean secondary water is pumped or allowed to circulate by natural convection. These systems offer substantial economic savings over surface heat exchangers where a single-well system is adequate (typically less than 0.8 MWt, with well depths up to about 500 ft) and may be economical under certain conditions at well depths to 1500 ft. Several designs have proven successful; but, the most popular are a simple hairpin loop or multiple loops of iron pipe (similar to the tubes in a U-tube and shell exchanger) extending to near the well bottom. An experimental design consisting of multiple small tubes with headers at each end suspended just below the water surface appears to offer economic and heating capacity advantages. The paper describes design and construction details and New Zealand`s experience with downhole heat exchangers.

• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: FG01-99EE35098
• OSTI ID: 691514
• Journal Information: Geo-Heat Center Quarterly Bulletin, Journal Name: Geo-Heat Center Quarterly Bulletin Journal Issue: 3 Vol. 20; ISSN GCQBDW; ISSN 0276-1084
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
CONSTRUCTION
DESIGN
GEOTHERMAL WATER HEATING
GEOTHERMAL WELLS
HEAT EXCHANGERS
HEAT EXTRACTION
NEW ZEALAND
PERFORMANCE