Earth Tube Research Articles

Optimizing Windcatcher Designs for Effective Passive Cooling Strategies in Vienna’s Urban Environment

Urban overheating, intensified by climate change, poses a critical challenge in Central European cities, witnessing a rise in tropical days. Conventional mechanical cooling systems in buildings significantly contribute to carbon dioxide emissions, exacerbating global warming. In response, windcatchers—traditional Iranian natural cooling systems—emerge as a promising sustainable solution for contemporary architecture, even in non-arid climates. This research aims to evaluate windcatchers’ efficacy in improving building thermal comfort in Central European climates, focusing on Vienna’s urban environment. This study identifies optimal windcatcher designs by analyzing key variables: height variation, inlet dimensions, urban exposure, Building Management System (BMS) temperature thresholds, and integration with an earth tube system using Design Builder simulation software version 6. The findings reveal that a windcatcher standing at 2.5 m tall, with inlet dimensions of 0.9 m by 1.4 m, in an open, less densely populated urban setting, and with open valves when indoor temperatures surpass 22 °C, demonstrates the most effective reduction in cooling load. Moreover, both one-sided and two-sided windcatchers outperform conventional ventilation through openings. Additionally, combining a one-sided windcatcher with an earth tube system ensures efficient cooling even when exterior temperatures exceed 25 degrees Celsius. When augmented by a heat pump, this integrated system can provide heated ventilation.

A Review on Harnessing Nature's Heat with Earth Tube Heat Exchangers (ETHE)

This review paper presents a comprehensive review of recent advancements in Earth Tube Heat Exchanger. Through a meticulous examination of various scholarly papers, this review synthesizes and analyzes the significant contributions made by researchers in the field. Each paper reviewed offers unique insights and methodologies aimed at addressing key challenges and expanding the boundaries of knowledge in Earth Tube Heat Exchanger. This review provides a succinct summary of the methodologies employed, the findings obtained, and the implications of each study. The synthesis presented here underscores the diversity of approaches and the richness of ideas that characterize contemporary research in Earth Tube Heat Exchanger. From theoretical frameworks to empirical investigations, each paper contributes to a deeper understanding of the subject matter and suggests avenues for future exploration. By distilling the essence of each paper, this review serves as a valuable resource for scholars, practitioners, and students interested in gaining a nuanced understanding of the current state of research in Earth Tube Heat Exchanger. Furthermore, it highlights emerging trends, unresolved questions, and potential areas for further investigation, thereby fostering ongoing dialogue and innovation within the academic community. In conclusion, this review illuminates the collective efforts of researchers in advancing knowledge and addressing pressing issues within Earth Tube Heat Exchanger. It underscores the importance of interdisciplinary collaboration, critical inquiry, and methodological rigor in shaping the trajectory of future research endeavors.

A review on earth tube heat exchanger in heating and cooling systems

About 40% of the primary energy in the building sector is consumed for heating and cooling applications, where it started by relying on the use of sustainable energy sources through using an Earth tube heat exchanger (ETHE). ETHE is apparatus that works to transfer heat from ambient air to underground and vice versa which is used in heating and cooling applications. ETHE depends on undisturbed subsoil temperature, where the underground temperature doesn't change through the year at a certain depth. Ambient air passes through the buried heat exchanger in the ground and then cools down in summer and warms in winter. The good performance of this system depends on design efficiency. This paper reviews the experimental and numerical researches of ETHE which focuses on its design. The use of geothermal energy through ETHE leads to meeting energy demand and preserving the environment by reducing carbon dioxide emissions, which in turn affects the ozone.

Design of Ventilation Systems in a Single-Family House in Terms of Heating Demand and Indoor Environment Quality

In buildings with good-quality thermal insulation of external partitions, the main component of the building’s heat balance is the heat demand for ventilation. The reduction of this energy demand cannot be achieved at the expense of thermal comfort of the occupants and indoor air quality. The aim of this article is to analyze the impact of various ventilation strategy (natural and mechanical) on heating demand, thermal comfort, and CO2 concentration in a single-family house located in Poland. The benefits of using fans integrated with the earth tube were tested. The study was based on the numerical energy simulation of a multi-zone building model for the entire calendar year. Contam, EnergyPlus, and Python programs were used to perform calculations. The thermal model was validated on the results of temperature measurements in the building. To obtain the best solutions, the parameters of the systems considered have been optimized with the use of genetic algorithms. Various optimal parameters of the earth tube (diameter, length, and foundation depth) were obtained during this research. The highest number of thermal discomfort hours was obtained in the naturally ventilated building with automatic window opening. This system supplied to the rooms a large amount of cool outdoor air in winter and warm air in summer, causing instantaneous rapid fluctuations in indoor temperature. Supplementing the mechanical ventilation control system with CO2 concentration sensors resulted in a much higher amount of ventilation air supplied to the rooms compared to systems controlled only by temperature sensors, resulting in an increase in heat demand.

Modeling of Combined Earth Tube Heat Exchanger and Solar Photovoltaic with Blower for Maintaining a Hospital Ward

Modeling of Combined Earth Tube Heat Exchanger and Solar Photovoltaic with Blower for Maintaining a Hospital Ward

Theoretical Analysis to Enhance the Effectiveness of Earth Tube Heat Exchanger

The temperature of atmosphere fluctuating continuously because the changing of environment, due to global warming effect that is uncomfortable for human beings. For comfort zone of human being air conditioning is use in summer season and heater is use in winter season. There for air conditioning and heater required high grade energy as well as high maintenance cost. Now replacing these devices by Earth tube heat exchanger. Earth tube heat exchanger is a device which is producing cooling effects in summer season and heating effects in winter season by passing the ambient air through the pipes inside the ground or soil as a source or sink of heat. According to previous research (IJERTCONV5IS02011) the effect of temperature at a certain depth about 2 m to 5 m remain nearly same throughout the whole year. The temperature inside the earth surface is greater than the atmospheric temperature in winter and less than the summer. Till date many researchers have done extensive research on Earth tube heat exchanger. The present study on this paper, focus on variation of temperature in buried pipes and enhance the various parameters of Earth tube heat exchanger that is reduced the cost and energy consumption for same desired effect. And also replace the other pipe with PVC pipe at 1524mm (6 inches) internal diameter as a varying length and 250-watt blower is use to flow the air at 2-5 m/s.

Earth Tube Heat Exchanger

Abstract: Devices that utilise the ground as a wellspring of or sink for warming or cooling are called ground-to-air heat exchangers, ground pipe heat exchangers, or soil heat exchangers. Numerous concepts and experiments with EAHE have so far been developed and tested to determine the best parameter values to increase performance based on location and other variables. In this study, we will review the studies conducted so far from the viewpoint of performance evaluation considering the influence of various parameters such as construction materials, depth from the ground surface, wind speed, and pipe length.

Thermal performance optimization of a semi-nested building coupled with an earth-to-air heat exchanger using iterative Taguchi method

In this paper, a semi-nested building coupled with an earth-to-air heat exchanger is investigated to maintain indoor thermal comfort and reduce building energy consumption. Firstly, the computer models on the semi-nested building coupled with earth-to-air heat exchanger were developed under the TRNSYS environment. Secondly, the simulation results from the computer models were validated with experimental data from open literature. Finally, iterative Targuchi method was employed to find the optimal design values for the envelope properties and earth-to-air heat exchanger configurations. The optimal values of the design parameters were found to be A1 (window-to-wall ratio of 10%), B3 (triple-layer Low-E glazing window), C3(insulation thickness of 200 mm for external wall),D3 (concrete slab thickness of 250 mm for external wall), E3(absorption of solar radiation for external walls of 0.75), F3(absorption of solar radiation for the roof of 0.75),G5 (earth tube inner diameter and air gap of 300 mm and 400 mm, respectively), H2 (earth tube length of 50 m), and I3 (duct air velocity of 1.5 m/s).

A Review Paper on Computational Study of Earth Tube Heat Exchanger System

Abstract: Earth Tube heat exchanger can be proved as a better substitution to the space heating and HVAC problems that we face in our day to day lives. Earth tube heat exchangers can work in two phases, i.e. as a heater during winter seasons and as a cooler during summer season. ETHE can work more efficiently than traditional HVAC. This project concentrates on computational study of earth tube heat exchanger. The designing calculations were done for appropriate length and area of an earth tube heat exchanger. A model of ETHE was produced on basis of this calculations and dimensions obtained. The model was generated using Solidworks R2021 software. The ETHE model generated was then analysed for thermal stresses, distribution and other parameters. A CFD simulation of model for velocity and flow was carried on. The conclusions obtained show that ETHE works efficiently and can be used as a substitution for traditional HVAC. Keywords: Heating ventilation and air conditioning(HVAC), Earth tube heat exchanger(ETHE), Computational fluid Dynamics (CFD), Efficiently, Thermal stresses.

Reducing The Thermal Deviation Inside Greenhouses by Using Solar Heating and Earth Tube Heat Exchanger Systems

Reducing The Thermal Deviation Inside Greenhouses by Using Solar Heating and Earth Tube Heat Exchanger Systems

Heat Pump Design for Simultaneous Cooling Space and Heating Water Coupled with Earth-Tube Heat Exchanger as Secondary Heat Sink

A heat pump for simultaneous heating and cooling (HPS) is more efficient in energy and beneficial
 in use than a reversible heat pump which works in either direction to provide heating or cooling. A HPS is usually coupled with a thermal storage tank for possibly operating in 3 modes: heating mode, cooling mode, and simultaneous heating and cooling mode. To improve the HPS performance in heating mode or cooling mode, the HPS should be installed an auxiliary equipment in order to reject overheat in the system or to absorb supplemental heat into the system. This paper proposed a design of a HPS for cooling space and hot water production coupled with a horizontally shallow earth-tube heat exchanger as secondary heat sink for Thai residences in which the main components in the design are composed of the condenser and the earth tube heat exchanger. The coefficients of performance (COP) of the HPS were evaluated by the experiments. The results showed that it could work the best performance when it worked in simultaneous cooling and heating mode at the water flow rate of 6.0 L/min with the coefficient of performance (COP) of 6.3±3.1 %. The HPS had high efficiency and it worked continuously in cooling mode when it operated in the nighttime with the average COP of 4.3±14.5 %. However, an efficiency of the HPS was declined when heat gain in the conditioned room is significantly increased by high intensity of solar radiation in the daytime with the average COP of 2.5±14.5 %.
 HIGHLIGHTS
 
 Energy used for cooling or heating systems such as air-conditioning and hot water production is predominantly effect to total energy use in residential sector in many countries including Thailand
 A heat pump for simultaneous heating and cooling (HPS) for cooling space and hot water production coupled with thermal storage tank and a horizontally shallow earth-tube heat exchanger as secondary heat sink were designed for Thai residences
 This HPS could work the best performance when it worked in simultaneous cooling and heating mode
 For only cooling mode, this HPS worked continuously with high performance when it operated in the nighttime but in the daytime it still worked continuously with lower performance
 
 GRAPHICAL ABSTRACT

The Use of Key Enabling Technologies in the Nearly Zero Energy Buildings Monitoring, Control and Intelligent Management

The 2018 revision of the European Performance Building Directive (EPBD) requires that from the year 2020 onwards, all new buildings will have to be “nearly zero energy buildings”. It also further promotes smart building technologies, raising awareness amongst building owners and occupants of the value behind building automation. The European Commission also identified, in 2011, Key Enabling Technologies (KETs), which provide the basis for innovation in the EU. In the frame of the SUDOKET project, the Solar XXI building was used as a pilot case, as innovative integrated solutions and technologies are monitored and controlled. The objective of this paper is to validate a simulation of the laboratorial test room in EnergyPlus with data obtained experimentally and determine the impact of the control systems on energy needs and on thermal comfort. Two systems, in particular, were studied: the Building-Integrated Photovoltaic (BIPV) and the earth tubes. Once validated, the simulation of the test room without the systems was created, allowing their impact to be determined. The results show that, for the analysed periods, BIPVs reduced the heating consumption by 22% while also increasing thermal comfort, and the earth tube system would reduce the cooling needs by 97%.

Earth tube와 열전소자를 이용한 냉난방 겸용 습도 조절 유닛 성능에 관한 실험적 연구

Earth tube와 열전소자를 이용한 냉난방 겸용 습도 조절 유닛 성능에 관한 실험적 연구

Earth tube heat exchanger design for efficiency enhancement of PV panel

PV panel or Photovoltaic panels are semi-conducting materials to convert solar energy into electrical energy. According to the Standard Test Conditions, the best operating condition of the PV panel is at 25 °C. For countries like Saudi Arabia, Libya, Yemen and much other have atmospheric temperature of about 40 °C. At this temperature, the performance of the PV panel degrades. In this current paper a heat exchanger is designed numerically in exact dimensions to carry out thermal cooling of the PV panels, with motive to improve the performance of PV panels even at elevated temperatures. Aluminium pipe of 50 m long, 10 cm internal diameter with 40 fins/m length is selected for designing. This increases the efficiency of the panel and the convective heat transfer rate with lower pressure drop.

Bioclimatic design and low energy cooling systems at IER-UNAM

This article presents some strategies of bioclimatic design for hot-subhumid climate and of low energy cooling systems and how they have been implemented at the IER-UNAM buildings since 1985. Some of the experimental and numerical simulation projects carried out by the Energy in Buildings Group (GEE) are commented. Finally, the project for a new building for undergraduate students is presented, where passive and low energy strategies as night ventilation, evaporative cooling, radiative cooling and earth tube cooling are been evaluated.

省エネルギー配慮型庁舎の空調設備計画とエネルギーマネジメントの取り組み （第３報）地中熱ヒートポンプシステムとアースチューブの分析・評価

省エネルギー配慮型庁舎の空調設備計画とエネルギーマネジメントの取り組み （第３報）地中熱ヒートポンプシステムとアースチューブの分析・評価

CFD Analysis of Geothermal Heat Exchanger at Different Orientation

The main objective of present work to investigate the arrangements of piping system of earth tube heat exchanger for better thermal comfort. For these work CFD analysis on three different designs of earth tube heat exchanger for summer and winter session for Bhopal location have been performed. computational fluid dynamics analysis have been performed on earth tube heat exchanger using horizontal pipe at various air velocity such as 0.5m/sec, 1 m/sec, 2m/sec, 3m/sec, 4m/sec & 5m/sec for summer session, to get temperature distribution inside the earth tube heat exchanger. Results show that there are drop of temperature in summer session range from 318K to 296K and rise of temperature in winter session range from 288K to 296.7K. It has been observed from the results of computational fluid dynamic analysis that the earth tube heat exchanger using horizontal pipe gives better result as compared with vertical and inclined piping arrangement. So it is recommended that the earth tube heat exchanger using horizontal pipe arrangement may be used for better thermal comfort.

CONCEPTUAL DEVELOPMENT OF THE EARTH TUBE COOLING SYSTEM FOR A TALL BUILDING

ABSTRACT Earth tubes are earth-to-air heat exchangers that are frequently utilized in energy conscious low-rise buildings, but are scarcely reported for tall buildings. The feasibility of applying earth tube cooling to tall buildings in a hot summer and cold winter climate zone was studied in this paper. Firstly, the designed cooling load of a tall building was obtained from the energy simulation using the baseline and the modified models with applicable energy efficiency measures. Based on the load, the required cooling capacity, the overall section area and the effective length of the earth tube system was deduced from the heat transfer and fluid flow calculation analytically. Then the performance of the earth tube system was crosschecked and verified via the Computational Fluid Dynamics (CFD) simulation. In the CFD simulation, earth tubes with different diameters and lengths, as well as a full-scale earth tube model with surrounding soil above the depth of constant temperature, were investigated. The outlet air temperatures of the full-scale models were computed with the consideration of different axial distances between adjacent tubes. Meanwhile, multiple conceptual design schemes and the tunnel construction method for the earth tube system were proposed from the perspective of performance enhancement, constructability, efficiency and economy. It revealed that earth tube systems are conditionally feasible for some tall buildings if their design guidelines for climate, underground spaces, construction method, friction of tube interior surface, optimization of effective length and axial distance, as well as synergy with other energy efficiency measures are followed. Even the cooling capacity of earth tubes degrade with time due to the accumulated heat underground, but in a hot summer and cold winter climate zone it can still possibly produce cooled air for a tall building with a Floor Area Ratio of less than 7 effectively in summer.

An innovative concept building design incorporating passive technology to improve resource efficiency and welfare of finishing pigs

In conventionally-designed buildings for finishing pigs, extreme weather conditions can impact negatively on feed utilisation and animal welfare. The SPaTHE (Solar, Passive, Thermal, Heat Exchange) concept is an innovative, resource-efficient engineered building designed to provide an internal environment where finishing pigs can thrive. Passive design elements include solar shading and capture combined with integrated earth tubes to facilitate heat exchange with incoming fresh air to reduce extreme summer and winter internal temperatures. The SPaTHE specification was dynamically modelled and compared to an existing conventional finisher building operating in the UK. The same dimensions (18 m × 14 m) and build specification were used for each building, which was designed to hold 292 pigs from 20 to 100 kg liveweight. Results showed that pigs in the optimum configuration of conventional building form spent 661 fewer h y−1 in conditions 28 °C than with a standard building. Whereas with the SPaTHE design, during 2222 h y−1 the pigs were kept at optimum conditions between 19 °C to 22 °C. The model also estimated that the SPaTHE design would reduce the peak summer internal operative temperature by 3.4 °C when the external temperature was 28 °C, and increase the peak winter internal operative temperature by 1.2 °C when the external air temperature is −5.4 °C. Hence the concept design potentially provides an environment which more closely matches the needs of finishing pigs and thus may contribute to more sustainable food production systems.

アースチューブ併用自然換気システムの性能検証 : 第1報-自然換気解析とCFDの連成解析法の開発と再現性検証

アースチューブ併用自然換気システムの性能検証 : 第1報-自然換気解析とCFDの連成解析法の開発と再現性検証