Influence of Sand Concentration on Variation Characteristics of Aquifer Parameters under Groundwater Source Heat Pump Long-Term Operation

2013 ◽  
Vol 689 ◽  
pp. 551-555
Author(s):  
Song Qing Wang ◽  
Shi Jing He
Keyword(s):  
Heat Pump ◽  
Simulation Method ◽  
Confined Water ◽  
Seepage Velocity ◽  
Term Operation ◽  
Aquifer Parameters ◽  
Water Head ◽  
Variation Characteristics ◽  
Groundwater Source

The influence of sand concentration on variation characteristics of aquifer parameters, under groundwater source heat pump long-term operation, is theoretically analyzed through numerical simulation method. The present studies show that the sand concentration obviously affects the variations of the porosity and hydraulic conductivity, however, the variation of confined water head is affected inconspicuously. The variations of aquifer parameters are also related with the seepage velocity.

scholarly journals Finite element modeling of geothermal source of heat pump in long-term operation

2020 ◽  
Vol 154 ◽  
pp. 04003
Author(s):  
Elżbieta Hałaj
Keyword(s):  
Finite Element ◽  
Heat Source ◽  
Heat Pump ◽  
Heat Exchangers ◽  
Transport Model ◽  
Heat Pumps ◽  
Initial Temperature Distribution ◽  
Term Operation ◽  
Borehole Heat Exchangers

Heat pumps become more and more popular heat source. They can be an alternative choice for obsolete coal fired boilers which are emissive and not ecological. During heat pump installation designing process, especially for heat pumps with higher heating capacity (for example those suppling larger buildings), a simulation of heat balance of ground heat source must be provided. A 3D heat transport model and groundwater flow in the geothermal heat source for heat pump (GSHP) installation was developed in FEFLOW according to Finite Element Modelling Method. The model consists of 25 borehole heat exchangers, arranged with spacing recommended by heat pump branch guidelines. The model consists of both a homogeneous, non-layered domain and a layered domain, which reflected differences in thermal properties of the ground and hydrogeological factors. The initial temperature distribution in the ground was simulating according to conditions typical for Europe in steady state heat flow. Optimal mesh refinement for nodes around borehole heat exchangers were calculated according to Nillert method. The aim of this work is to present influence of geological, hydrogeological factors and borehole arrangement in the energy balance and long term sustainability of the ground source. The thermal changes in the subsurface have been determined for a long term operation (30 years of operation period). Some thermal energy storage applications have also been considered.

Study on the Influence of Shallow Groundwater Source Heat Pumps on Groundwater Quality in Weifang, China

2014 ◽  
Vol 641-642 ◽  
pp. 97-100
Author(s):  
Qiang Huang ◽  
Wei Ping Wang ◽  
Hai Yan Deng
Keyword(s):  
Groundwater Quality ◽  
Heat Pump ◽  
Shallow Groundwater ◽  
Heat Pumps ◽  
Total Hardness ◽  
Project Area ◽  
Research Objects ◽  
Groundwater Source ◽  
Change Curve

Selecting 4 shallow groundwater source heat pump (GSHP) projects as research objects in Weifang city of Shandong province, China, the groundwater quality in the project area was, observed and analyzed by sampling continuously. The results show that the concentrations of chloride and the total hardness are relatively stable, and there are no apparent changes; In the change curve of TDS in different kind of shallow GSHPs, the worse the sealing condition of the project, the more obvious the rising trend of TDS; The concentration of nitrate is generally on the rise, and the concentration of ammonia appears in the trend of first increased then decreased. Therefore, in the region, the shallow GSHPs are not completely free from contamination in the current technology conditions and the application should be controlled and managed strictly. The observation of shallow GSHPs still need be conducted in a long term.

scholarly journals Evaluation of long-term operation of combined system for heating the building and preparation of domestic hot water

2018 ◽  
Vol 46 ◽  
pp. 00018
Author(s):  
Dawid Taler ◽  
Rafał Pitry ◽  
Jan Taler
Keyword(s):  
Heat Source ◽  
Heat Pump ◽  
Summer Season ◽  
Hot Water ◽  
Buffer System ◽  
Generation Efficiency ◽  
Combined System ◽  
Term Operation ◽  
Measuring Period

The paper presents, the results of research on the operation and energy efficiency of a 186 kW gas-fired condensing boiler operating in a hybrid heat source system. The boiler co-operates with an 81.1 kW (electric) brine-to-water compressor heat pump, a 27.4 kW air-to-water heat pump and 6 flat solar collectors. A local, built-in, hybrid heat source is located in a public building and is intended to satisfy the building needs. The study was conducted over a period of 1 year - from 1 September 2014 to 31 August 2015. The gas-fired boiler operates in the heating buffer system all year round. The boiler performance is characterized both in the winter and in the summer season, in terms of the amount of heat produced and the heating power. The calculations results of the heat generation efficiency obtained in the measuring period are also presented

scholarly journals A varying comprehensive hydropower coefficient for medium/long-term operation of a single reservoir

2020 ◽  
Vol 51 (4) ◽  
pp. 686-698
Author(s):  
Wenting Gong ◽  
Pan Liu ◽  
Lei Cheng ◽  
He Li ◽  
Zhikai Yang
Keyword(s):  
Big Data ◽  
Hydropower Plant ◽  
Simulation Accuracy ◽  
K Value ◽  
Term Operation ◽  
Water Power ◽  
Hydropower Plants ◽  
Water Head ◽  
Study Results

Abstract In medium/long-term reservoir operation, the hydropower output is calculated from k × q × h, where q is the power discharge, h is the water head, and k is the comprehensive hydropower coefficient. k indicates the conversion efficiency from water power to electricity, however, it is standard practice to use a constant k. We developed a novel method to derive the varying k based on observed big data. The operational frequencies of different units for time (multiple periods) and space (multiple units) were accounted based on the observed big data from each unit, and then weights were obtained. Finally, k was derived by integrating the efficiency curves (hill charts) of the different units with their weights. The Three Gorges Project, China, was selected for a case study. Results indicated that: (1) the varying k value can improve hydropower simulation accuracy, (2) simulations using 10-day intervals have a higher accuracy for hydropower calculation than daily and monthly scales, (3) the evaluation of hydropower plant benefits is sensitive to k, and there is potential for producing more hydropower. These findings are highly relevant to the operation of hydropower plants and to the evaluation of medium/long-term hydropower generation for a hydropower plant.

scholarly journals Finite Element Modeling of Geothermal Source of Heat Pump in Long-Term Operation

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1341 ◽  
Author(s):  
Elżbieta Hałaj ◽  
Leszek Pająk ◽  
Bartosz Papiernik
Keyword(s):  
Heat Pump ◽  
Thermal Energy ◽  
Heat Exchangers ◽  
Thermal Recovery ◽  
Small Scale ◽  
Term Operation ◽  
Ground Source ◽  
Space Cooling ◽  
Borehole Heat Exchangers

Model simulation allows to present the time-varying temperature distribution of the ground source for heat pumps. A system of 25 double U-shape borehole heat exchangers (BHEs) in long-term operation and three scenarios were created. In these scenarios, the difference between balanced and non-balanced energy load was considered as well as the influence of the hydrogeological factors on the temperature of the ground source. The aim of the study was to compare different thermal regimes of BHEs operation and examine the influence of small-scale and short-time thermal energy storage on ground source thermal balance. To present the performance of the system according to geological and hydrogeological factors, a Feflow® software (MIKE Powered by DHI Software) was used. The temperature for the scenarios was visualized after 10 and 30 years of the system’s operation. In this paper, a case is presented in which waste thermal energy from space cooling applications during summer months was used to upgrade thermal performance of the ground (geothermal) source of a heat pump. The study shows differences in the temperature in the ground around different Borehole Heat Exchangers. The cold plume from the not-balanced energy scenario is the most developed and might influence the future installations in the vicinity. Moreover, seasonal storage can partially overcome the negative influence of the travel of a cold plume. The most exposed to freezing were BHEs located in the core of the cold plumes. Moreover, the influence of the groundwater flow on the thermal recovery of the several BHEs is visible. The proper energy load of the geothermal source heat pump installation is crucial and it can benefit from small-scale storage. After 30 years of operation, the minimum average temperature at 50 m depth in the system with waste heat from space cooling was 2.1 °C higher than in the system without storage and 1.6 °C higher than in the layered model in which storage was not applied.

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