Performance study and life-cycle cost analysis of a ground-source heat-pump system in a commercial building in Norway

High-performance systems are a prerequisite for profitable borehole thermal-energy storage. This paper presents performance measures for a system operating at a seasonal performance factor of 4.5 and evaluates the life-cycle costs of the actual and alternative system configurations. Compared to systems using dry cooling and electric or district heating the as-built system represents a profitable investment with internal rates of return of respectively 4.9% and 5.9% over a 50-year life cycle. Consequently, ambient-temperature borehole thermal-energy storage is economically competitive in North-European climates at current prices.Performance study and life-cycle cost analysis of a ground-source heat-pump system in a commercial building in NorwaypublishedVersio

DigiMon Final Report

"DigiMon Final Report” summarizes the ACT DigiMon project. The overall objective of the DigiMon project was to “accelerate the implementation of CCS by developing and demonstrating an affordable, flexible, societally embedded and smart Digital Monitoring early-warning system”, for monitoring any CO2 storage reservoir and subsurface barrier system, receiving CO2 from fossil fuel power plants, oil refineries, process plants and other industries.DigiMon Final ReportpublishedVersio

Energi fra overflatevann i Norge - kartlegging av økonomisk potensial

På oppdrag for NVE har NGI i samarbeid med COWI AS gjennomført en kartlegging av potensialet for å utnytte overflatevann til oppvarmingsformål ved hjelp av varmepumper. Undersøkelsen viser at potensialet for å bruke overflatevann (sjøvann, innsjøvann og elvevann) til oppvarmingsformål er betydelig. Av rapporten fremgår det imidlertid at dette energipotensialet i stor grad overlapper grunnvarmepotensialet. Tilleggspotensialet som energi fra overflatevann utgjør er følgelig forholdsvis beskjeden

Quantification of time-varying groundwater flow in boreholes in fractured crystalline rock using long-term distributed temperature sensing

Quantification of groundwater flow is an important factor for several applications, such as water supply, boreholes for energy extraction/storage and drainage and flood prevention projects. In this study, distributed temperature sensing (DTS) with fibre-optics has been combined with energy calculations to estimate the time-varying groundwater flow in fractures in four stand-alone boreholes at Åkneset in Norway. The method captures the natural, undisturbed time-variation of the groundwater flow as no tracers or pumps were used. Compared with temperature profile measurements using a probe, long-term distributed temperature sensing (from several weeks) gives a profound understanding of the hydrogeological conditions for a site. One example of how long-time measurements enhance this understanding is that they provide information about the sources of the groundwater flow: For some fractures, the groundwater estimations showed no correlation with meteorological data, indicating that these fractures are fed from deeper regional flow, with relatively large response times. In other fractures, the temporal variations in estimated groundwater flow showed high correlation (>0.60) with precipitation or temperature, with 1.4–9.0 days delay. This indicates that these fractures are fed mainly from precipitation and snow melting. The correlation with weather conditions at the surface also indicates that the method gives a true time-variation of groundwater flow. The results from the study show that DTS can be a useful tool to quantify groundwater flow in boreholes made for energy and monitoring (e.g., in tunnels). The method could be further improved by injection of heat along the entire borehole length, which has been done before. This would be similar to a thermal response test, which is an important pre-investigation for borehole thermal energy storage

Synergy Between CO2 Storage and Utilization of Geothermal Energy : A case study from Longyearbyen, Svalbard

Upprättat; 2013; 20151106 (samtav

Quantification of time-varying groundwater flow in boreholes in fractured crystalline rock using long-term distributed temperature sensing

Quantification of groundwater flow is an important factor for several applications, such as water supply, boreholes for energy extraction/storage and drainage and flood prevention projects. In this study, distributed temperature sensing (DTS) with fibre-optics has been combined with energy calculations to estimate the time-varying groundwater flow in fractures in four stand-alone boreholes at Åkneset in Norway. The method captures the natural, undisturbed time-variation of the groundwater flow as no tracers or pumps were used. Compared with temperature profile measurements using a probe, long-term distributed temperature sensing (from several weeks) gives a profound understanding of the hydrogeological conditions for a site. One example of how long-time measurements enhance this understanding is that they provide information about the sources of the groundwater flow: For some fractures, the groundwater estimations showed no correlation with meteorological data, indicating that these fractures are fed from deeper regional flow, with relatively large response times. In other fractures, the temporal variations in estimated groundwater flow showed high correlation (>0.60) with precipitation or temperature, with 1.4–9.0 days delay. This indicates that these fractures are fed mainly from precipitation and snow melting. The correlation with weather conditions at the surface also indicates that the method gives a true time-variation of groundwater flow. The results from the study show that DTS can be a useful tool to quantify groundwater flow in boreholes made for energy and monitoring (e.g., in tunnels). The method could be further improved by injection of heat along the entire borehole length, which has been done before. This would be similar to a thermal response test, which is an important pre-investigation for borehole thermal energy storage

Quantification of time-varying groundwater flow in boreholes in fractured crystalline rock using long-term distributed temperature sensing

Quantification of groundwater flow is an important factor for several applications, such as water supply, boreholes for energy extraction/storage and drainage and flood prevention projects. In this study, distributed temperature sensing (DTS) with fibre-optics has been combined with energy calculations to estimate the time-varying groundwater flow in fractures in four stand-alone boreholes at Åkneset in Norway. The method captures the natural, undisturbed time-variation of the groundwater flow as no tracers or pumps were used. Compared with temperature profile measurements using a probe, long-term distributed temperature sensing (from several weeks) gives a profound understanding of the hydrogeological conditions for a site. One example of how long-time measurements enhance this understanding is that they provide information about the sources of the groundwater flow: For some fractures, the groundwater estimations showed no correlation with meteorological data, indicating that these fractures are fed from deeper regional flow, with relatively large response times. In other fractures, the temporal variations in estimated groundwater flow showed high correlation (>0.60) with precipitation or temperature, with 1.4–9.0 days delay. This indicates that these fractures are fed mainly from precipitation and snow melting. The correlation with weather conditions at the surface also indicates that the method gives a true time-variation of groundwater flow. The results from the study show that DTS can be a useful tool to quantify groundwater flow in boreholes made for energy and monitoring (e.g., in tunnels). The method could be further improved by injection of heat along the entire borehole length, which has been done before. This would be similar to a thermal response test, which is an important pre-investigation for borehole thermal energy storage.acceptedVersio

Digital Monitoring of Co2 Storage Projects (Digimon)

With an overall objective to “accelerate the implementation of CCS by developing and demonstrating an affordable, flexible, societally embedded and smart Digital Monitoring early-warning system”, the DigiMon project aims to combine different technologies for monitoring CO2 storage into a uniform system. The project includes qualification of critical system components, integration of the components and embedding the system in a societal context.publishedVersio

Lessons learned after one-year of use of a highly efficient neighbourhood in Norway

2020Park is an innovative installation in Stavanger, Norway. This installation provides heating and cooling via a ground source heat pump (GSHP). The system combines eight 220m deep boreholes, with an air to brine heat exchanger and the heat from cooling 15 square meters of thermal photovoltaic cells (PVT). The GSHP has a rated coefficient of performance ranging from 2.8 to over 4 and can deliver 120kW of water-based heating at temperatures 50-60°C.The system is designed to deliver heating and, in reverse operation, cooling to offices, a playing ground, a supermarket and some shops. Analysing measured data of one year of operation, this system shows a clear discrepancy between available heat for ground storage and required heating during cold periods. Due to the imbalance between needs, one would expect the temperature in the ground to drop and thus the temperature of the brine at the inlet of the heat pump. By using the extra heat sources, the inlet temperature to the GSHP is relatively constant and thus the system operates mostly in constant conditions yielding constant system COP. This solution is very interesting for highly efficient buildings and neighbourhood with unbalanced demands.publishedVersio