System performance of a deep borehole heat exchanger

Köhl, Thomas; Brenni, Renzo; Eugster, Walter

doi:10.1016/s0375-6505(02)00031-7

Cited by 187 publications

(94 citation statements)

References 2 publications

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“…For lowering the weight of column and creating buoyancy effect, borehole needs to be filled with water or drilling mud. Other disadvantage is lack of heat insulation, this phenomenon is excluding use of conventional steel pipes in DBHE, what was confirmed by many studies around Europe [24,25].…”

Section: Single Steel Coaxial Inner Columnmentioning

confidence: 87%

The application of Vacuum Insulated Tubing in Deep Borehole Heat Exchangers

Śliwa

Kruszewski

Assadi

et al. 2017

drill

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Section: Single Steel Coaxial Inner Columnmentioning

confidence: 87%

The application of Vacuum Insulated Tubing in Deep Borehole Heat Exchangers

Śliwa

Kruszewski

Assadi

et al. 2017

drill

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“…Furthermore, less desirable geological conditions might produce exceptional heat production if the thermal loading is cyclic instead of steady. For example, Kohl et al 2002 observed 40 °C production temperatures from a 2133 m deep 3.0 °C /100 m BHE in Weggis, Switzerland.…”

Section: Discussionmentioning

confidence: 99%

“…(Kohl et al 2002) Heat pump 40 2,300 0.8-1.75 1 Entering Water Temperature (outlet temp from abandoned well heat exchanger)…”

Section: (Kohl Et Al 2000)mentioning

confidence: 99%

Reuse of abandoned oil and gas wells for geothermal energy production

2017

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This paper presents an investigation on the suitability of abandoned wells in California for Enhanced Geothermal Systems (EGS) and low temperature deep Borehole Heat Exchanger (BHE) applications. The study identifies three counties characterized by high numbers of abandoned wells, medium to high crustal heat flows (75-100 mW/m 2 ), and suitable sedimentary geology: Santa Clara, Monterey, and Santa Barbara. Thermal gradients range between 4 and 7.3°C /100 m and enable access to the bottom hole temperatures between 40-73 °C for an average 1,000 m deep well. These rock temperatures are sufficient for low-temperature direct use EGS such as district heating, greenhouse heating, and aquaculture. Abandoned wells reuse mitigation of drilling costs and the documented lithology both reduce the risk associated with EGS.However, hydraulic fracturing of loosely to moderately consolidated sedimentary rock in transitional stress regimes remains one limitation to the EGS conversion of these abandoned wells. The feasibility of deep BHE applications within abandoned oil and gas wells is demonstrated here by a mathematical model. Predictions show that outlet fluid temperatures >40°C can be achieved for 1,000 m deep wells in regions with temperature gradients >7 °C /100 m.

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“…Under this condition, heat extraction via circulation in a wellbore has been proposed as a means of geothermal power generation or for direct use applications (Kohl, Brenni, and Eugster 2002;Lund 2003).…”

Section: Wellbore Heat Exchanger Concept and Descriptionmentioning

confidence: 99%

“…This report describes the physical and numerical aspects of the wellbore heat exchanger model. Kohl et al (2002) analyzed the operation of a 2,302-m (7,552.5-ft)-deep borehole heat exchanger at Weggis, Switzerland, which was being used for space heating and domestic hot water purposes. They concluded that the heat exchanger was not being operated at optimal conditions, and that the produced thermal energy rate could be increased from the present value of 40 kW (136.5e+3 BTU/h) to 180 kW (614.2e+3 BTU/h) by optimizing the circulation rate.…”

mentioning

confidence: 99%

Parametric Sensivity Study of Operating and Design Variables in Wellbore Heat Exchangers

Shook¹,

Nalla²,

Mines³

et al. 2004

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This report documents the results of an extensive sensitivity study conducted by the Idaho National Engineering and Environmental Laboratory. This study investigated the effects of various operating and design parameters on wellbore heat exchanger performance to determine conditions for optimal thermal energy extraction and evaluate the potential for using a wellbore heat exchanger model for power generation. Variables studied included operational parameters such as circulation rates, wellbore geometries and working fluid properties, and regional properties including basal heat flux and formation rock type. Energy extraction is strongly affected by fluid residence time, heat transfer contact area, and formation thermal properties. Water appears to be the most appropriate working fluid. Aside from minimal tubing insulation, tubing properties are second order effects.On the basis of the sensitivity study, a best case model was simulated and the results compared against existing low-temperature power generation plants. Even assuming ideal work conversion to electric power, a wellbore heat exchange model cannot generate 200 kW (682.4e+3 BTU/h) at the onset of pseudosteady state. Using realistic conversion efficiency, the method is unlikely to generate 50 kW (170.6e+3 BTU/h). iv v ACKNOWLEDGMENTSThe authors wish to thank DOE for funding this project; Raymond LaSala, whose interest in evaluating the feasibility of wellbore heat exchangers motivated this critical study; John Finger from Sandia National Laboratories for his valuable contributions; and our program manager, Joel Renner, for providing support and suggestions for this project.

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System performance of a deep borehole heat exchanger

Cited by 187 publications

References 2 publications

The application of Vacuum Insulated Tubing in Deep Borehole Heat Exchangers

The application of Vacuum Insulated Tubing in Deep Borehole Heat Exchangers

Reuse of abandoned oil and gas wells for geothermal energy production

Parametric Sensivity Study of Operating and Design Variables in Wellbore Heat Exchangers

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