Rates of thermal water discharge from the hot water geothermal system beneath the Steamboat Hills in Western Nevada, USA

The concurrent development of the Steamboat Hills geothermal area for power production and the adjacent alluvial aquifers for drinking water in Washoe County, Nevada, necessitates a good understanding of the hydrogeologic connection between these water resources. The problem is that adequate characterization of the subsurface geologic structure is not possible with existing geologic data. This need prompted us to construct a detailed 3D representation of the subsurface geologic structure based on 2.75D forward modeling of 11 gravity and aeromagnetic profiles constrained by geologic data and physical (density, magnetic susceptibility, remanent magnetic) properties. Potential-fields modeling results provided greater definition of the alluvial basins, and when combined with well-log data, yield an overall basin volume surrounding Steamboat Hills that is 64% greater than the volume derived from well-log data alone. A representation of the geothermal reservoir, consisting of altered granodiorite and metamorphic rocks, illustrates that the flow of thermal water is fault controlled. The model also suggests that thermal water may upflow along an unexplored fault flanking western Steamboat Hills. North-trending faults that conduct thermal water from the geothermal system to the alluvial aquifer appear to be zones of altered volcanics that produce subtle aeromagnetic anomalies.

Download Full-text

Biofilm Forming Bacteria during Thermal Water Reinjection

Geofluids ◽

10.1155/2017/9231056 ◽

2017 ◽

Vol 2017 ◽

pp. 1-7 ◽

Cited By ~ 2

Author(s):

Máté Osvald ◽

Gergely Maróti ◽

Bernadett Pap ◽

János Szanyi

Keyword(s):

Thermal Water ◽

Oxygen Demand ◽

Geothermal System ◽

Biological Processes ◽

Geothermal Systems ◽

The Past ◽

Surface System ◽

Buffer Tank ◽

Physical And Chemical ◽

Phenol Index

Reinjection of heat-depleted thermal water has long been in the center of scientific interest in Hungary regarding around 1000 operating thermal wells. While the physical and chemical aspects of reinjection have partly been answered in the past years, the effects of biological processes are still less known. We carried out our investigations in the surface elements of the Hódmezővásárhely geothermal system which is one of the oldest operating geothermal systems in Hungary. About one-third of the used geothermal water has been reinjected since 1998 by two reinjection wells at the end of the thermal loops. During the operation, plugging of the surface system was experienced within a few-day-long period, due to biological processes. The goal of our research was to find the dominant species of the microbial flora and to make a proposal to avoid further bacterial problems. We found that the reinjected, therefore the produced, water’s chemical oxygen demand, phenol index, and BTEX composition basically determine the appearing flora on the surface. When the concentration of these compounds in the thermal water is significant and residence time is long enough in the buffer tank, certain bacteria can be much more dominant than others, thus able to form a biofilm which plugs the surface equipment much more than it is expected.

Download Full-text

Revised hydrogeological model of the hydrothermal system Waiwera (New Zealand)

10.5194/egusphere-egu21-12196 ◽

2021 ◽

Author(s):

Andreas Grafe ◽

Thomas Kempka ◽

Michael Schneider ◽

Michael Kühn

Keyword(s):

Water Management ◽

New Zealand ◽

Water Level ◽

Hot Water ◽

Hydrogeology Journal ◽

Natural State ◽

Geothermal System ◽

Geological Model ◽

Species Transport ◽

Study Region

The geothermal hot water reservoir underlying the coastal township of Waiwera, northern Auckland Region, New Zealand, has been commercially utilized since 1863. The reservoir is complex in nature, as it is controlled by several coupled processes, namely flow, heat transfer and species transport. At the base of the aquifer, geothermal water of around 50&#176;C enters. Meanwhile, freshwater percolates from the west and saltwater penetrates from the sea in the east. Understanding of the system&#8217;s dynamics is vital, as decades of unregulated, excessive abstraction resulted in the loss of previously artesian conditions. To protect the reservoir and secure the livelihoods of businesses, a Water Management Plan by The Auckland Regional Council was declared in the 1980s [1]. In attempts to describe the complex dynamics of the reservoir system with the goal of supplementing sustainable decision-making, studies in the past decades have brought forth several predictive models [2]. These models ranged from being purely data driven statistical [3] to fully coupled process simulations [1]. Our objective was to improve upon previous numerical models by introducing an updated geological model, in which the findings of a recently undertaken field campaign were integrated [4]. A static 2D Model was firstly reconstructed and verified to earlier multivariate regression model results. Furthermore, the model was expanded spatially into the third dimension. In difference to previous models, the influence of basic geologic structures and the sea water level onto the geothermal system are accounted for. Notably, the orientation of dipped horizontal layers as well as major regional faults are implemented from updated field data [4]. Additionally, the model now includes the regional topography extracted from a digital elevation model and further combined with the coastal bathymetry. Parameters relating to the hydrogeological properties of the strata along with the thermophysical properties of water with respect to depth were applied. Lastly, the catchment area and water balance of the study region are considered. The simulation results provide new insights on the geothermal reservoir&#8217;s natural state. Numerical simulations considering coupled fluid flow as well as heat and species transport have been carried out using the in-house TRANSport Simulation Environment [5], which has been previously verified against different density-driven flow benchmarks [1]. The revised geological model improves the agreement between observations and simulations in view of the timely and spatial development of water level, temperature and species concentrations, and thus enables more reliable predictions required for water management planning. [1] K&#252;hn M., St&#246;fen H. (2005): &#160; &#160; &#160; Hydrogeology Journal, 13, 606&#8211;626, &#160; &#160; &#160; https://doi.org/10.1007/s10040-004-0377-6 [2] K&#252;hn M., Altmannsberger C. (2016): &#160; &#160; &#160; Energy Procedia, 97, 403-410, &#160; &#160; &#160; https://doi.org/10.1016/j.egypro.2016.10.034 [3] K&#252;hn M., Sch&#246;ne T. (2017): &#160; &#160; &#160; Energy Procedia, 125, 571-579, &#160; &#160; &#160; https://doi.org/10.1016/j.egypro.2017.08.196 [4] Pr&#228;g M., Becker I., Hilgers C., Walter T.R., K&#252;hn M. (2020): &#160; &#160; &#160; Advances in Geosciences, 54, 165-171, &#160; &#160; &#160; https://doi.org/10.5194/adgeo-54-165-2020 [5] Kempka T. (2020): &#160; &#160; &#160; Adv. Geosci., 54, 67&#8211;77, &#160; &#160; &#160; https://doi.org/10.5194/adgeo-54-67-2020

Download Full-text

Geothermal System Study Case near Bucharest

E3S Web of Conferences ◽

10.1051/e3sconf/201911106058 ◽

2019 ◽

Vol 111 ◽

pp. 06058

Author(s):

Galina Prică ◽

Lohengrin Onuțu ◽

Grațiela Țârlea

Keyword(s):

Thermal Response ◽

Hot Water ◽

Geothermal System ◽

System Study ◽

Accurate Calculation ◽

Good Efficiency ◽

Efficient System ◽

One Step ◽

Study Case ◽

Geological Formations

The article shows a study case of a geothermal system near Bucharest. In the paper it is shown that for a good efficiency of a geothermal system for heating and air conditioning, it is important to follow a few steps. One step is a very accurate calculation of the heat and cold load. In the next step it is important to use a specific equipment to obtain the Thermal Response Test (TRT) of geological formations crossed by the borehole. TRT is helpful in providing information related to the evolution of the soil temperature while introducing a thermal load. All information that can be obtained or calculated from the TRT will provide how the climate system will function in time and its efficiency. Furthermore, the effective thermal conductivity and thermal resistance of the well will be determined, extremely important parameters in designing the correct length of the geoheat exchanger. The article used specific software to simulate the evolution of parameters in time, for soil and heat pump. Earth Energy Design offer information for the number of needed boreholes, the depth and the yearly evolution of the soil’s temperature in time for the system etc. Following all these main steps, finally a very efficient system can be designed, that can ensure the heating and produce hot water for the consumption of a house, office building or of other destination buildings.

Download Full-text

A Compact and Fast Temperature-Response Heat Pump Water Heater

ASME 1997 Turbo Asia Conference ◽

10.1115/97-aa-026 ◽

1997 ◽

Cited By ~ 5

Author(s):

B. J. Huang ◽

F. H. Lin

Keyword(s):

Heat Pump ◽

Water Discharge ◽

Temperature Response ◽

Control Device ◽

Hot Water ◽

Water Heater ◽

Supply Tank ◽

Heat Pump Water Heater ◽

Temperature Recovery ◽

Line Switching

A compact and fast temperature-response heat pump water heater was designed using multiple tanks and a sequential control device. The supply tank was heated as a priority by a freon-line switching device to increase the temperature recovery speed. A dual-tank prototype with 100-liter capacity was built and tested. The experimental results show that the time for temperature recovery of the supply tank from 42°C to 54°C reaches 10–20 minutes and COP reaches 2.0–3.0 during various seasons. The prototype tests show that an energy saving around 50%–70% as compared to the electrical water heater can be obtained. The hot water discharge efficiency of the heat pump is 0.912.

Download Full-text

Hybrid Energy Thermal Water Pump for Producing Hot Water from a Shallow Well in Thailand

Journal of Energy Engineering ◽

10.1061/(asce)ey.1943-7897.0000278 ◽

2016 ◽

Vol 142 (3) ◽

pp. 04015023

Author(s):

Panusak Moonsri ◽

Janthana Kunchornrat ◽

Pichai Namprakai

Keyword(s):

Thermal Water ◽

Hot Water ◽

Water Pump ◽

Hybrid Energy

Download Full-text

Performance Analysis of Single-Well Enhanced Geothermal System for Building Heating

The Scientific World JOURNAL ◽

10.1155/2020/7927052 ◽

2020 ◽

Vol 2020 ◽

pp. 1-8

Author(s):

Haijun Liang ◽

Xiaofeng Guo ◽

Tao Gao ◽

Lingbao Wang ◽

Xianbiao Bu

Keyword(s):

Volume Flow Rate ◽

Water Reservoir ◽

Hot Water ◽

Heat Extraction ◽

Geothermal System ◽

Enhanced Geothermal System ◽

Artificial Reservoir ◽

Reservoir Volume ◽

Thermal Output ◽

Single Well

Deep borehole heat exchanger (DBHE) technology does not depend on the existence of hot water reservoir and can be used in various regions. However, the heat extraction from DBHE can hardly be improved due to poor thermal conductivity of rocks. Here, a single-well enhanced geothermal system (SWEGS) is proposed, which has a larger heat-exchange area of artificial reservoir created by fracturing hydrothermal technology. We find that, due to heat convection between rocks and fluid, the extracted thermal output for SWEGS is 4772.73 kW, which is 10.64 times of that of DBHE. By changing the injection water temperature, volume flow rate, and artificial reservoir volume, it is easy to adjust the extracted thermal output to meet the requirement of building thermal loads varying with outdoor air temperature. Understanding these will enable us to better apply SWEGS technology and solve the fog and haze problem easily and efficiently.

Download Full-text

A Study on Improving the Coefficient of Performance by Comparing Balancing Well and Standing Column Well Heat Exchange Systems

Sustainability ◽

10.3390/su122410445 ◽

2020 ◽

Vol 12 (24) ◽

pp. 10445

Author(s):

Myungkwan Lim ◽

Kyoungbin Lim ◽

Changhee Lee

Keyword(s):

Thermal Conductivity ◽

Heat Exchanger ◽

Effective Thermal Conductivity ◽

Water Discharge ◽

Underground Water ◽

Coefficient Of Performance ◽

Geothermal System ◽

Heat Accumulation ◽

Heating And Cooling ◽

Discharge Water

This study proposed a technology to improve the performance characteristics and coefficient of performance (COP) of a geothermal system by fundamentally preventing underground water discharge and maintaining a constant temperature of the underground heat exchanger composed of bleed discharge water that utilizes two balancing wells using cross-mixing methods. Using the standing column well (SCW) and cross-mixing balancing well underground heat exchanger, we compared and analyzed the effective thermal conductivity characteristics and COP characteristics during heating and cooling modes. Consequently, the cross-mixing balancing well underground heat exchanger exhibited more effective thermal conductivity than the SCW underground heat exchanger, with a high COP. Therefore, suggesting the performance was improved using groundwater flow rather than SCW. The comparison and analysis results of the effective heat map characteristics using the results of the SCW and balancing well system showed that the heating operation for the SCW underground heat exchanger had better thermal conductivity characteristics than the cooling operation. In addition, regarding a balancing well underground heat exchanger, the cooling operation exhibited superior thermal conductivity characteristics. Thus, the performance was considered to have improved due to the flow of activated groundwater in the ground and the rapid heat transfer without heat accumulation.

Download Full-text

A New Performance Estimate Method for Design of Storage-Type Domestic Electrical Water-Heaters Based on the CFD Simulation

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.129-131.463 ◽

2010 ◽

Vol 129-131 ◽

pp. 463-466

Author(s):

Li Li Zhao ◽

Zhi Jun Zhang ◽

Shi Wei Zhang

Keyword(s):

Water Temperature ◽

Cfd Simulation ◽

Cold Water ◽

Discharge Rate ◽

Water Discharge ◽

Hot Water ◽

New Method ◽

Dynamics Simulation ◽

Water Heater ◽

Water Heaters

The 3D physical model of the electrical water heater was built. The water-heater performance was resolved by computer fluid dynamics simulation (CFD). The heater performance is characterized by a new method rather than that the discharge efficiency, extraction efficiency and fraction of heat recoverable. The new method is based on the constant discharge water temperature and rate for end user, 5L/min and 43°C that include the hot water from EWH and cold water from outside EWH. But the water discharge rate from EWH was variable as the water temperature discharge from EWH was variable. Compared with the traditional method, it is more close to the user using reality condition.

Download Full-text

RESISTIVITY, SELF‐POTENTIAL, AND INDUCED‐POLARIZATION SURVEYS OF A VAPOR‐DOMINATED GEOTHERMAL SYSTEM

Geophysics ◽

10.1190/1.1440400 ◽

1973 ◽

Vol 38 (6) ◽

pp. 1130-1144 ◽

Cited By ~ 83

Author(s):

A. A. R. Zohdy ◽

L. A. Anderson ◽

L. J. P. Muffler

Keyword(s):

Geothermal Field ◽

Induced Polarization ◽

Hot Water ◽

Thermal Waters ◽

Geothermal System ◽

Electrical Soundings ◽

Lateral Extent ◽

High Concentrations ◽

Lake Deposits ◽

Self Potential

The Mud Volcano area in Yellowstone National Park provides an example of a vapor‐dominated geothermal system. A test well drilled to a depth of about 347 ft penetrated the vapor‐dominated reservoir at a depth of less than 300 ft. Subsequently, 16 vertical electrical soundings (VES) of the Schlumberger type were made along a 3.7‐mile traverse to evaluate the electrical resistivity distribution within this geothermal field. Interpretation of the VES curves by computer modeling indicates that the vapor‐dominated layer has a resistivity of about 75–130 ohm‐m and that its lateral extent is about 1 mile. It is characteristically overlain by a low‐resistivity layer of about 2–6.5 ohm‐m, and it is laterally confined by a layer of about 30 ohm‐m. This 30‐ohm‐m layer, which probably represents hot water circulating in low‐porosity rocks, also underlies most of the survey at an average depth of about 1000 ft. Horizontal resistivity profiles, measured with two electrode spacings of an AMN array, qualitatively corroborate the sounding interpretation. The profiling data delineate the southeast boundary of the geothermal field as a distinct transition from low to high apparent resistivities. The northwest boundary is less distinctly defined because of the presence of thick lake deposits of low resistivities. A broad positive self‐potential anomaly is observed over the geothermal field, and it is interpretable in terms of the circulation of the thermal waters. Induced‐polarization anomalies were obtained at the northwest boundary and near the southeast boundary of the vapor‐dominated field. These anomalies probably are caused by relatively high concentrations of pyrite.

Download Full-text