Using a capillary mat as a shallow heat exchanger for a ground source heat pump system

Widiatmojo, Arif; Shrestha, Gaurav; Ishihara, Takeshi; Yasukawa, Kasumi; Uchida, Yoshiyuki; Yoshioka, Mayumi; Tomigashi, Akira

doi:10.1016/j.enbuild.2019.109684

Cited by 13 publications

(4 citation statements)

References 39 publications

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“…Благодаря равномерному и плотному прилеганию друг к другу параллельно расположенных трубок достигается большая поверхность теплопередачи. В результате чего, для функционирования системы в качестве отопительного прибора, возможно использование низких температур теплоносителя (25-45 °C) [7][8][9]. Теплопередача от матов преимущественно осуществляется благодаря инфракрасному излучению, маты нагревают стены, пол или потолок помещения изнутри, и тепло равномерно распределяется по всему помещению.…”

Section: рис 1 лаборатория ниу «мэи» по исследованию капиллярных сист...unclassified

Development of a digital twin of the heat network in various software

et al. 2022

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The purpose of this work is development of the heat transfer calculation method of a water low-temperature ceiling capillary heating system for heating rectangular rooms. Recently, such systems have become widespread due to their advantages over traditional heating devices: the use of a coolant with a low temperature potential, high heating speed rate of the internal air, low temperature gradient in the height of the room, absence of noticeable air masses movement and dust flows, ability to work in cooling mode. However, such systems are still incompletely studied, and constructive calculations or calculations of thermal and hydraulic modes are carried out according to formulas obtained empirically, thus, calculations do not always have high accuracy. The paper proposes a heat transfer process calculation method from the considered low-temperature heating system, which allows determination of the heat flow value with high accuracy. It`s revealed that in the considered configuration of the system location (on the ceiling), a significant proportion of heat transfer is infrared radiation, and the convective component is very small. Therefore, it was very important to accurately describe the radiant heat exchange by mathematical equations. The calculation of the radiant component of heat transfer was carried out with the theory of radiation view factors. Experimental test of the studying object was carried out to find the missing values, as well as to verify the results obtained using the proposed calculation method. The calculation results had a slight deviation from the results obtained experimentally (the error was 6 %).

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Section: рис 1 лаборатория ниу «мэи» по исследованию капиллярных сист...unclassified

Development of a digital twin of the heat network in various software

et al. 2022

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“…Satisfactory results are being obtained from the application of chemical energy accumulation systems using solar thermal panels, functioning with lithium chloride: their future is promising [32,33]. The same applies to absorption systems based on solar thermal panels and geothermal energy systems [34] in which the mats act as ground exchangers at shallow depth [35]. Other studies propose applications on landscaped roofs [36] or using seawater [37,38].…”

Section: Radiant Surface Conditioning Systems Based On Capillary Tube Matsmentioning

confidence: 99%

Radiant Floors versus Radiant Walls Using Ceramic Thermal Panels in Mediterranean Dwellings: Annual Energy Demand and Cost-Effective Analysis

Iribarren

Hien

Gutiérrez³

2021

Sustainability

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The present study focuses on the application of large-format thermal ceramic conditioning panels (TCPs) containing polypropylene (PPR) capillary tube mats in dwellings on the Mediterranean coast. The thermal and energy behaviours were examined once the underfloor heating was installed, and they were compared with an alternative wall application. The system was implemented in a single-family house located on the Spanish Mediterranean coast. After having monitored the house during a complete one-year cycle, the annual energy demand was quantified using the Design Builder tool. TCP panels applied to radiant floors reduced energy demand by 5.15% compared to the wall-layout alternative. Significant reductions in CO2 emissions were also achieved, as well as a 25.19% reduction in energy demand compared to convection systems. The incorporation of 24 m2 of solar thermal panels into the system, combined with solar cooling systems based on lithium chloride, was also analysed. A reduction in energy demand of 57.46% was obtained compared to all-air convection systems. Finally, the amortisation periods of the investments in TCP panels and solar panels were calculated and compared to a convection system. Underfloor TCP panels proved to be more cost-effective than a wall installation. The additional cost of EUR 21,844 could be amortised over approximately 14 years with the radiant underfloor TCP system, while the wall TCP would be amortised over 17.4 years.

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“…Ground heat conductivity reflects the heat physical properties of the soil and is related to soil density, water content, groundwater, and other factors [11] (Li et al, 2020); the borehole heat resistance reflects the heat transfer effect between the U-pipe and the borehole wall, and is related to factors such as backfill material, U-pipe material, U-pipe shapes, and distribution position. To improve the heat exchange efficiency, scholars have proposed many novel design methods to reduce the heat resistance, such as enhanced heat transfer pipes [14], enhanced heat transfer fluid [40], spiral cloth pipe [41], eccentric U-pipe [42], and others [43,44].…”

Section: Introductionmentioning

confidence: 99%

Thermo-Hydraulic Performance of U-Tube Borehole Heat Exchanger with Different Cross-Sections

et al. 2021

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For reducing the initial GSHP investment, the heat transfer efficiency of the borehole heat exchange (BHE) system can be enhanced to reduce the number or depth of drilling. This paper proposes a novel and simple BHE design by changing the cross-sectional shape of the U-tube to increase the heat transfer efficiency of BHEs. Specifically, in this study, we (1) verified the reliability of the three-dimensional numerical model based on the thermal response test (TRT) and (2) compared the inlet and outlet temperatures of the different U-tubes at 48 h under the premise of constant leg distance and fluid area. Referent to the circular tube, the increases in the heat exchange efficiencies of the curved oval tube, flat oval tube, semicircle tube, and sector tube were 13.0%, 19.1%, 9.4%, and 14.8%, respectively. (3) The heat flux heterogeneity of the tubes on the inlet and outlet sides of the BHE, in decreasing order, is flat oval, semicircle, curved oval, sector, and circle shapes. (4) The temperature heterogeneity of the borehole wall in the BHE in decreasing order is circle, sector, curved oval, flat oval, and semicircle shapes. (5) Under the premise of maximum leg distance, referent to the heat resistance of the tube with a circle shape at 48 h, the heat exchange efficiency of the curved oval, flat oval, semicircle, and sector tubes increased 12.6%, 17.7%, 10.3%, and 7.8%, respectively. (6) We found that the adjustments of the leg distance and the tube shape affect the heat resistance by about 25% and 12%, respectively. (7) The flat-oval-shaped tube at the maximum leg distance was found to be the best tube design for BHEs.

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Using a capillary mat as a shallow heat exchanger for a ground source heat pump system

Cited by 13 publications

References 39 publications

Development of a digital twin of the heat network in various software

Development of a digital twin of the heat network in various software

Radiant Floors versus Radiant Walls Using Ceramic Thermal Panels in Mediterranean Dwellings: Annual Energy Demand and Cost-Effective Analysis

Thermo-Hydraulic Performance of U-Tube Borehole Heat Exchanger with Different Cross-Sections

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