Coefficient of Performance Stabilisation in Ground Source Heat Pump Systems

Wołoszyn, Jerzy; Gołaś, Andrzej

doi:10.13044/j.sdewes.d5.0173

Cited by 8 publications

(7 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Notwithstanding their higher costs due to the drilling required [9], vertical systems are typically the preferred setup due to the fact that ground temperatures get increasingly stable with depth [10,11]. One popular layout of a vertical ground heat exchanger system consists of a pair of parallel pipes connected at the bottom by a U-shaped connector installed inside a borehole with a typical diameter of 100-150 mm and depths of up to 200 m [12], although borehole depths of between 50 m and 150 m are the most commonly used [13].…”

Section: The Ground Source Heat Pump-a Short Reviewmentioning

confidence: 99%

The Effect of Shank-Space on the Thermal Performance of Shallow Vertical U-Tube Ground Heat Exchangers

Vella¹,

Borg²,

Micallef³

2020

Energies

View full text Add to dashboard Cite

One parameter that may affect the performance of a ground source heat pump is the shank-space, the center-to-center distance between the two branches of a vertical U-tube used in a ground heat exchanger. A 3D steady-state computational fluid dynamics (CFD) model of a U-tube ground heat exchanger was used to investigate the influence of varying shank-space on the thermal performance of two isolated vertical shallow U-tubes, one 20 m deep and the other 40 m deep, given that most existing research focuses on systems making use of deeper boreholes. The models adopt an innovative approach, whereby the U-junction at the bottom of the U-tube is eliminated, thus facilitating the computational process. The results obtained show that, although the temperature drop across the U-tube varies for different shank-spaces and is lowest and highest for the closest and the widest shank-spaces, respectively, this temperature drop is not linear with increases in shank-space, and the thermal performance improvement drastically diminishes with increasing shank-space. This indicates that, for shallow U-tubes, the temperature drop is more dependent on the length of the pipework.

show abstract

Section: The Ground Source Heat Pump-a Short Reviewmentioning

confidence: 99%

The Effect of Shank-Space on the Thermal Performance of Shallow Vertical U-Tube Ground Heat Exchangers

Vella¹,

Borg²,

Micallef³

2020

Energies

View full text Add to dashboard Cite

show abstract

“…The article (Wołoszyn, 2017) theoretically studies the energy efficiency of horizontal ground heat exchangers system with simultaneous use of the sub-surface humidification system, through which it is possible to automatically control the soil humidity (and hence its temperature conductivity), which is in close proximity to the heat exchangers. The authors note that conducting a full-scale experiment is very expensive, while three-dimensional numerical simulation takes a lot of time, so the modified quasi-3D heat transfer model (Wołoszyn, 2013;Wołoszyn, 2016) is used to greatly simplify the investigation process.…”

Section: Analysis Of Recent Research and Publicationsmentioning

confidence: 99%

“…It is believed that a promising way to solve this problem is the appliance of new energy-saving technologies that use alternative renewable energy sources. The utilization of low-grade ground heat as the direction of alternative energy has been actively developed abroad (Wołoszyn, 2017;Benli, 2013;Chiasson, 2010;Soni, 2015).…”

Section: Introductionmentioning

confidence: 99%

The Research Ways to Increase the Energy Efficiency of Ground Heat Exchangers by Means of Mathematical Simulation

Koviazin¹,

Pozhuyev²,

Mikhailutsa³

et al. 2020

Rural Development 2019

View full text Add to dashboard Cite

The scientific and methodological basis for increasing the efficiency of geothermal ventilation, making it possible to use thermal energy of the Earth's surface layers for cooling (heating) an incoming air stream are created. Mathematical modeling is performed based on the equations of hydrodynamics, heat transfer and thermal conductivity, along with a computational experiment carried out using the finite volume method. A mathematical model of the process of heat exchange between the flow of air in a heat exchanger and a soil mass is developed. This model describes a relationship between efficiency indicators of the horizontal ground heat exchanger and its performance parameters, and also natural climatic conditions. The determination of thermal fields in incoming cooled air and a soil mass at various depth locations of the horizontal ground heat exchanger is performed. The relationship between thermal efficiency and operation time of the horizontal heat exchanger, located at different depths, is proved. The energy comparison of a horizontal ground heat exchanger, located at different depths, with a vertical one, is made. he depth of the horizontal heat exchanger has been established, for which the loss of thermal energy in comparison with the vertical is insignificant (less than 7.5%). The operating time was determined, starting from which there are practically no differences in the level of thermal energy for all the studied models (> 10 7 s). The developed mathematical model allows to predict the energy efficiency indicators of a horizontal ground heat exchanger on the basis of its performance parameters and natural climatic conditions, that makes possible determining the economically optimal depth of the heat exchanger location under specific conditions.

show abstract

“…A Swiss study [9] found that Carbon dioxide (CO2) emission of a bivalent wastewater heat pump system is 22% of an oil-fired heating system. Zhao et al [15] showed that the heating Coefficient of Performance (COP) is about 4.3, and the cooling COP is about 3.5 in actual operating conditions which is comparable to the COP of a ground source heat pump [16,17].…”

Section: Introductionmentioning

confidence: 96%

Enhanced Pollution Removal with Heat Reclamation in a Small Hungarian Wastewater Treatment Plant

Somogyi¹,

Sebestyén²,

Kovács³

et al. 2018

J. sustain. dev. energy water environ. syst.

View full text Add to dashboard Cite

The aim of the research is to outline the possibilities of utilizing waste heat in small municipal wastewater treatment plants. The facility, which was chosen as case-study, accepts about 2,300 m 3 of raw sewage daily. In wintertime the wastewater temperature decreases to 10-14 °C which results in lower nitrification capacity based on measurement and validated model results. The excess heat of the wastewater would serve to increase the temperature of the aeration tank in order to enhance the microbiological activity and thus the efficiency of pollutant removal. The amount of reusable waste heat is calculated and with the help of dynamic simulation the effluent quality was determined to compare it with the original results. Increasing the temperature by 6 °C in the aerated tank, ammonium removal could be improved by 61%. This way not only the heat, but the nutrient pollution could be mitigated, too.

show abstract

Coefficient of Performance Stabilisation in Ground Source Heat Pump Systems

Cited by 8 publications

References 16 publications

The Effect of Shank-Space on the Thermal Performance of Shallow Vertical U-Tube Ground Heat Exchangers

The Effect of Shank-Space on the Thermal Performance of Shallow Vertical U-Tube Ground Heat Exchangers

The Research Ways to Increase the Energy Efficiency of Ground Heat Exchangers by Means of Mathematical Simulation

Enhanced Pollution Removal with Heat Reclamation in a Small Hungarian Wastewater Treatment Plant

Contact Info

Product

Resources

About