Prediction of Long-Term Operational Conditions for Single-Well Groundwater Heat Pump Plants

1992 ◽  
Author(s):  
Stig Niemi Sørensen ◽  
Jan Reffstrup
Keyword(s):  
Heat Pump ◽  
Operational Conditions ◽  
Groundwater Heat Pump ◽  
Single Well

scholarly journals Study on the Long-Term Performance and Efficiency of Single-Well Circulation Coupled Groundwater Heat Pump System Based on Field Test

2021 ◽  
Vol 9 ◽  
Author(s):  
Ke Zhu ◽  
Yifan Zeng ◽  
Qiang Wu ◽  
Shengheng Xu ◽  
Kun Tu ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Heat Pump ◽  
Pump System ◽  
Groundwater Heat Pump ◽  
Heat Pump Unit ◽  
Single Well ◽  
Thermal Breakthrough ◽  
Long Term Performance ◽  
Term Performance

Although buildings are often heated and cooled by single-well circulation coupled groundwater heat pump systems, few studies have evaluated the long-term performance of these systems. Therefore, the present study investigated the performance of these systems by analyzing the efficiency and energy consumption using 4 years of operating data. The results indicate that the coefficient of performance (COP) of the system gradually decreases because of thermal breakthrough or an accumulation of cold. In addition, the sealing clapboards could effectively slow down thermal breakthrough. In addition, compared with the heating period, the COP of the heat pump unit (HPU) and system increases, and its energy consumption decreases in the cooling period. It was also found that partial heat loss occurs when water from the single-well circulation outlet penetrates the main pipeline. Moreover, the heat-exchange efficiency of a single HPU exceeds that of multiple HPUs, and the COP of a HPU decreases during operation with increasing indoor temperature. Accordingly, we improved the performance of system by increasing the underground heat storage. Herein, we focus on optimizing the system design during long-term operation, which includes taking steps such as lengthening the sealing clapboards, using insulated pipes, discharging the remaining water and adding intelligent control devices.

Investigation on the sustainability and efficiency of single-well circulation (SWC) groundwater heat pump systems

2019 ◽  
Vol 130 ◽  
pp. 656-666 ◽  
Author(s):  
Qiang Wu ◽  
Kun Tu ◽  
Haizhou Sun ◽  
Chaofan Chen
Keyword(s):  
Heat Pump ◽  
Groundwater Heat Pump ◽  
Single Well

The BSI indicator: preventing thermal interferences between groundwater heat pump systems

2020 ◽  
Author(s):  
Alejandro García-Gil ◽  
Miguel Ángel Marazuela ◽  
Miguel Mejías Moreno ◽  
Enric Vázquez-Suñè ◽  
Eduardo Garrido Schneider ◽  
...  
Keyword(s):  
Heat Pump ◽  
Energy Demand ◽  
Polynomial Regression ◽  
Energy Resource ◽  
Direct Calculation ◽  
Urban Environments ◽  
Geothermal Systems ◽  
Operational Conditions ◽  
Heating And Cooling ◽  
Groundwater Heat Pump

<p>Shallow geothermal systems are the most efficient and clean technology for the air-conditioning of buildings and constitutes an emergent renewable energy resource in the worldwide market. Undisturbed systems are capable of efficiently exchanging heat with the subsurface and transferring it to human infrastructures, providing the basis for the successful decarbonisation of heating and cooling demands of cities. Unmanaged intensive use of groundwater for thermal purposes as a shallow geothermal energy (SGE) resource in urban environments threatens the resources´ renewability and the systems´ performance, due to the thermal interferences created by a biased energy demand throughout the year. To ensure sustainability, scientifically-based criteria are required to prevent potential thermal interferences between geothermal systems. In this work, a management indicator (balanced sustainability index, BSI) applicable to groundwater heat pump systems is defined to assign a quantitative value of sustainability to each system, based on their intrinsic potential to produce thermal interference. The BSI indicator relies on the net heat balance transferred to the terrain throughout the year and the maximum seasonal thermal load associated. To define this indicator, 75 heating-cooling scenarios based in 23 real systems were established to cover all possible different operational conditions. The scenarios were simulated in a standard numerical model, adopted as a reference framework, and thermal impacts were evaluated. Two polynomial regression models were used for the interpolation of thermal impacts, thus allowing the direct calculation of the sustainability indicator developed as a function of heating-cooling ratios and maximum seasonal thermal loads. The BSI indicator could provide authorities and technicians with scientifically-based criteria to establish geothermal monitoring programs, which are critical to maintain the implementation rates and renewability of these systems in the cities.</p>

Clogging Problems in Groundwater Heat Pump Systems in Sweden

1988 ◽  
Vol 20 (3) ◽  
pp. 133-140 ◽  
Author(s):  
Annika Lindblad-Påsse
Keyword(s):  
Redox Potential ◽  
Heat Pump ◽  
Hydrogen Sulphide ◽  
Sludge Formation ◽  
Iron Bacteria ◽  
Iron Precipitation ◽  
Water Composition ◽  
Groundwater Heat Pump ◽  
And Control ◽  
System Knowledge

A number of groundwater heat pump systems have been investigated to determine the extent of problems caused by the chemistry of the groundwater used. The main purpose was to investigate sites using iron rich groundwater. Fifteen facilities were studied regularly for three years. Ten of these facilities had some kind of problem caused by iron precipitation. Four of the sites were rebuilt because of severe plugging due to iron sludge in wells, pumps and pipes. In all facilities with severe problems, iron bacteria were found. Low redox potential, indicated by hydrogen sulphide in the groundwater, seems to protect from iron bacteria. In some of the systems using groundwater with H2S the problems were corrosion and sludge formation caused by sulphur oxidizing bacteria. Rapid clogging was caused by aeration of the groundwater due to improper design of the system. Knowledge of the water composition, design of the systems to minimize aeration, and control of clogging turned out to be important factors to maintain operation safety.

Determination of optimal well locations and pumping/injection rates for groundwater heat pump system

Geothermics ◽  
2021 ◽  
Vol 92 ◽  
pp. 102050
Author(s):  
Dongkyu Park ◽  
Eunhee Lee ◽  
Dugin Kaown ◽  
Seong-Sun Lee ◽  
Kang-Kun Lee
Keyword(s):  
Heat Pump ◽  
Pump System ◽  
Heat Pump System ◽  
Groundwater Heat Pump ◽  
Injection Rates

scholarly journals Optimising the performance of a lab-scale tidal flow reed bed system treating agricultural wastewater

2004 ◽  
Vol 50 (8) ◽  
pp. 65-72 ◽  
Author(s):  
Y.Q. Zhao ◽  
G. Sun ◽  
C. Lafferty ◽  
S.J. Allen
Keyword(s):  
Tidal Flow ◽  
High Strength ◽  
Pollutant Removal ◽  
Inorganic Pollutants ◽  
Operational Conditions ◽  
Agricultural Wastewater ◽  
Major Route ◽  
Reed Bed ◽  
Ammoniacal Nitrogen Removal

A gravel-based tidal flow reed bed system was operated with three different strategies in order to investigate its optimal performance for the treatment of a high strength agricultural wastewater. According to the three strategies, individual reed beds were saturated and unsaturated with the wastewater for different periods while reasonably stable hydraulic and organic loadings were maintained. Experimental results demonstrated that the system produced the highest pollutant removal efficiencies with a relatively short saturated period and long unsaturated period, highlighting the importance of oxygen transfer into reed bed matrices during the treatment. Significant removals of some major organic and inorganic pollutants were achieved under all three operational conditions. Nitrification was not the major route of ammoniacal-nitrogen removal when the system was under high organic loading. Due to the filtration of suspended solids and the accumulation of biomass, gradual clogging of the reed bed matrices took place, which caused concerns over the long-term efficiency of the tidal flow system.

Experimental Study on the Drying Performance of the High Temperature Heat Pump Dryer

2012 ◽  
Vol 550-553 ◽  
pp. 3219-3223
Author(s):  
Xing Wang Zhu ◽  
Chun Xia Hu ◽  
Zhi Min Guo ◽  
Yu Gui Su
Keyword(s):  
High Temperature ◽  
Heat Pump ◽  
External Environment ◽  
Stable Operation ◽  
Obvious Effect ◽  
Electromagnetic Valve ◽  
Exhaust Temperature ◽  
Temperature Heat ◽  
High Temperature Heat Pump

In this paper，a high temperature heat-pump dryer and a corresponding semi-enclosed test drying room for using the dryer are built up respectively. While the average dry bulb of the external environment is 25°C and the relative humidity is 55%, the performance of the dryer is obtained when the dryer is running continuously for five hours. The results show that: the electromagnetic valve-capillary institution has an obvious effect on the lower the dryer exhaust temperature. It makes the suction temperature of compressor dropped 10 °C~15 °C, which can reduce the exhaust temperature and prevent compressor’s overheating. When the exhaust temperature keep at 100~110 °C, it can not only guarantee the temperature of wind coming from the dryer is high, but also can make sure the drying system’s long-term stable operation.

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