scholarly journals Application and Design Aspects of Ground Heat Exchangers

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2134
Author(s):  
Luka Boban ◽  
Dino Miše ◽  
Stjepan Herceg ◽  
Vladimir Soldo
Keyword(s):  
Renewable Energy ◽  
Heat Exchangers ◽  
Geothermal Energy ◽  
Energy Demand ◽  
Design Parameters ◽  
Direct Expansion ◽  
Alternative Source ◽  
Ground Heat Exchangers ◽  
Point Of Interest ◽  
Constant Source

With the constant increase in energy demand, using renewable energy has become a priority. Geothermal energy is a widely available, constant source of renewable energy that has shown great potential as an alternative source of energy in achieving global energy sustainability and environment protection. When exploiting geothermal energy, whether is for heating or cooling buildings or generating electricity, a ground heat exchanger (GHE) is the most important component, whose performance can be easily improved by following the latest design aspects. This article focuses on the application of different types of GHEs with attention directed to deep vertical borehole heat exchangers and direct expansion systems, which were not dealt with in detail in recent reviews. The article gives a review of the most recent advances in design aspects of GHE, namely pipe arrangement, materials, and working fluids. The influence of the main design parameters on the performance of horizontal, vertical, and shallow GHEs is discussed together with commonly used performance indicators for the evaluation of GHE. A survey of the available literature shows that thermal performance is mostly a point of interest, while hydraulic and/or economic performance is often not addressed, potentially resulting in non-optimal GHE design.

scholarly journals Research on Fresh and Hardened Sealing Slurries with the Addition of Magnesium Regarding Thermal Conductivity for Energy Piles and Borehole Heat Exchangers

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 5119
Author(s):  
Tomasz Sliwa ◽  
Tomasz Kowalski ◽  
Dominik Cekus ◽  
Aneta Sapińska-Śliwa
Keyword(s):  
Thermal Conductivity ◽  
Renewable Energy ◽  
Heat Exchangers ◽  
Geothermal Energy ◽  
Cooling System ◽  
Renewable Energy Sources ◽  
Heat Pumps ◽  
Cement Slurry ◽  
Geological Conditions ◽  
Borehole Heat Exchangers

Currently, renewable energy is increasingly important in the energy sector. One of the so-called renewable energy sources is geothermal energy. The most popular solution implemented by both small and large customers is the consumption of low-temperature geothermal energy using borehole heat exchanger (BHE) systems assisted by geothermal heat pumps. Such an installation can operate regardless of geological conditions, which makes it extremely universal. Borehole heat exchangers are the most important elements of this system, as their design determines the efficiency of the entire heating or heating-and-cooling system. Filling/sealing slurry is amongst the crucial structural elements. In borehole exchangers, reaching the highest possible thermal conductivity of the cement slurry endeavors to improve heat transfer between the rock mass and the heat carrier. The article presents a proposed design for such a sealing slurry. Powdered magnesium was used as an additive to the cement. The approximate cost of powdered magnesium is PLN 70–90 per kg (EUR 15–20/kg). Six different slurry formulations were tested. Magnesium flakes were used in designs A, B, C, and magnesium shavings in D, E and F. The samples differed in the powdered magnesium content BWOC (by weight of cement). The parameters of fresh and hardened sealing slurries were tested, focusing mainly on the thermal conductivity parameter. The highest thermal conductivity values were obtained in design C with the 45% addition of magnesium flakes BWOC.

scholarly journals Thermal Performance Analyses of Multiborehole Ground Heat Exchangers

Geofluids ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-11
Author(s):  
Wanjing Luo ◽  
Changfu Tang ◽  
Yin Feng ◽  
Pu Miao
Keyword(s):  
Thermal Performance ◽  
Heat Exchangers ◽  
Geothermal Energy ◽  
Greenhouse Gas Emission ◽  
Energy Resource ◽  
Thermal Dissipation ◽  
Uniform Heat Flux ◽  
Fluid Temperature ◽  
Cooling Mode ◽  
Ground Heat Exchangers

Geothermal energy known as a clean, renewable energy resource is widely available and reliable. Ground heat exchangers (GHEs) can assist the development of geothermal energy by reducing the capital cost and greenhouse gas emission. In this paper, a novel semianalytical method was developed to study the thermal performance of multiborehole ground heat exchangers (GHEs) with arbitrary configurations. By assuming a uniform inlet fluid temperature (UIFT), instead of uniform heat flux (UHF), the effects of thermal interference and the thermal performance difference between different boreholes can be examined. Simulation results indicate that the monthly average outlet fluid temperatures of GHEs will increase gradually while the annual cooling load of the GHEs is greater than the annual heating load. Besides, two mechanisms, the thermal dissipation and the heat storage effect, will determine the heat transfer underground, which can be further divided into four stages. Moreover, some boreholes will be malfunctioned; that is, boreholes can absorb heat from ground when the GHEs are under the cooling mode. However, as indicated by further investigations, this malfunction can be avoided by increasing borehole spacing.

Efficient Ways of Turning to Account Geothermal Energy for Heating in Energy Efficient Buildings

2017 ◽  
Vol 21 ◽  
pp. 437-444 ◽  
Author(s):  
Raluca Paula Moldovan ◽  
Gheorghe Viorel Dragoș ◽  
Marina Verdeș ◽  
Vasilică Ciocan ◽  
Marius Costel Bălan ◽  
...  
Keyword(s):  
Heat Exchangers ◽  
Energy Efficient ◽  
Geothermal Energy ◽  
Energy Demand ◽  
Negative Impact ◽  
Heat Pumps ◽  
Economic Framework ◽  
Energy Efficient Buildings ◽  
Optimum Solution ◽  
Heating Energy Demand

Within the present context of the effects of climate changes upon the environment, social and economic framework, but also of the trend of population growth and urban development, ensuring a sustainable, competitive and secure energy development will be possible, primarily, by reducing the negative impact of buildings upon the environment, improving energetic and ecological performances of systems and buildings envelope and promoting renewable sources of energy. In this sense, the paper analyzes, in dynamic simulation regime, performant solutions to reduce the energy consumption for heating energy efficient buildings and greenhouse gas emissions, by harnessing geothermal energy through the use of heat pumps and earth-to-air heat exchangers. The case study starts from an energy efficient building, analyzing the dynamic thermal behavior of the building and then various configurations of earth-to-air heat exchangers in terms of heating potential. For the selection of the optimum solution in terms of coverage of the heating energy demand, different systems combining heat pumps and earth-to-air heat exchangers are studied.

scholarly journals Low Enthalpy Geothermal Resources for Local Sustainable Development: A Case Study in Poland

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5010 ◽  
Author(s):  
Aleksandra Szulc-Wrońska ◽  
Barbara Tomaszewska
Keyword(s):  
Thermal Conductivity ◽  
Low Temperature ◽  
Heat Pump ◽  
Heat Exchangers ◽  
Geothermal Energy ◽  
Alternative Energy ◽  
Heat Output ◽  
Empirical Formulas ◽  
Ground Source Heat Pumps ◽  
Ground Heat Exchangers

Many regions in Poland face the problem of air pollution. These regions include, though are not exclusive, to health resorts, an important element of the healthcare industry. Poor air quality is mainly associated with the domestic sector, which is dominated by individual solid fuel and coal boilers. One option for reducing emissions is to use alternative energy sources for heating purposes. Therefore, the paper presents an analysis into the possibility of using low enthalpy (low temperature) geothermal energy in health resort areas. The main purpose of the article is to estimate the potential of soil and water as the lower source for a heat pump. The article presents analyses of geological and hydrogeological conditions based on which the thermal parameters of the rock mass were determined, which were thermal conductivity and unit heat output for 1800 operating hours per year. The calculated values were used to perform a spatial analysis of the data and create maps of the average thermal conductivity for horizontal ground heat exchangers (HGHE) to a depth of 2 and 10 m and vertical ground heat exchangers (VGHE) in depth ranges up to 30, 60, and 90 m. The heating power of the intakes, located in the research area, were estimated using empirical formulas. In addition, a detailed analysis of the physicochemical parameters of groundwater in terms of the requirements indicated by four heat pump manufacturers is presented. The results of the presented research makes it possible to assess the potential of low-temperature geothermal energy and to characterize the suitability of the selected location for the use of HGHE, VGHE, and wells. As a result, the discussed area was found to have a high potential for the use of ground source heat pumps and a moderate potential for the use of low-temperature systems based on groundwater.

scholarly journals Future of renewable energy in India for sustainable development

2022 ◽  
Vol 8 (4) ◽  
pp. 242-244
Author(s):  
S Ravichandran ◽  
R M Madhumitha Sri ◽  
Mahrukh Mehraj ◽  
Chundru Sowmya
Keyword(s):  
Sustainable Development ◽  
Renewable Energy ◽  
Wind Energy ◽  
Geothermal Energy ◽  
Energy Demand ◽  
Solar Power ◽  
Renewable Energy Sources ◽  
Energy Sources ◽  
Tidal Power ◽  
Energy Consumptions

Renewable energy (wind energy, solar power, geothermal energy and tidal power) is the inexhaustible energy resulted from contineous regeneration. The main features of renewable energy is that it can be obtained without damaging the environment. It has been found that renewable energy sources have the ability to give solutions to environmental related problems being faced by mankind. India is highly populated country on this planet and has more energy demand. The renewable energy is one of the major options to meet this quality. Today, renewable energy account for 37% of India’s most energy consumptions. In this paper, efforts have been made to discuss the future of renewable energy of our country.

scholarly journals PEMBUATAN BIOETANOL DARI KUPASAN KENTANG (Solanum tuberosum L.) DENGAN PROSES FERMENTASI

Jurnal Kimia ◽  
2016 ◽  
Author(s):  
Devi Esteria Hasianna Purba ◽  
Iryanti Eka Suprihatin ◽  
A.A.I.A. Mayun Laksmiwati
Keyword(s):  
Gas Chromatography ◽  
Renewable Energy ◽  
Solanum Tuberosum ◽  
Acid Hydrolysis ◽  
Sulphuric Acid ◽  
Solanum Tuberosum L ◽  
Alternative Source ◽  
Hydrolysis Process ◽  
Potato Peels ◽  
Detoxification Process

Ethanol fermented from potato peels is proposed as one alternative source of renewable energy called bioethanol. In this research bioethanol was produced through four stages namely acid hydrolysis, detoxification, fermentation and distillation. The acid hydrolysis process was carried out using sulphuric acid at 100oC for 60 minutes. The detoxification process was carried out by adding NH4OH into the hydrolyzate prior to fermentation. Distillation was performed up to 100oC and the distillate with the BP of 78-84oC was determined for its ethanol content using gas chromatography. The ethanol produced from 5 grams of dried potato peels through fermentation for 4, 5, 6, and 7 days 3.54%; 4,85%; 5,35%; and 6.15% respectively.

scholarly journals Techno-Economic Analysis of a Novel Hydrogen-Based Hybrid Renewable Energy System for Both Grid-Tied and Off-Grid Power Supply in Japan: The Case of Fukushima Prefecture

2020 ◽  
Vol 10 (12) ◽  
pp. 4061 ◽  
Author(s):  
Naoto Takatsu ◽  
Hooman Farzaneh
Keyword(s):  
Renewable Energy ◽  
Energy Demand ◽  
Renewable Energy Sources ◽  
Economic Assessment ◽  
Energy System ◽  
Modeling Framework ◽  
Integrated Simulation ◽  
Hybrid Renewable Energy System ◽  
Renewable Energy System ◽  
Hybrid Renewable Energy

After the Great East Japan Earthquake, energy security and vulnerability have become critical issues facing the Japanese energy system. The integration of renewable energy sources to meet specific regional energy demand is a promising scenario to overcome these challenges. To this aim, this paper proposes a novel hydrogen-based hybrid renewable energy system (HRES), in which hydrogen fuel can be produced using both the methods of solar electrolysis and supercritical water gasification (SCWG) of biomass feedstock. The produced hydrogen is considered to function as an energy storage medium by storing renewable energy until the fuel cell converts it to electricity. The proposed HRES is used to meet the electricity demand load requirements for a typical household in a selected residential area located in Shinchi-machi in Fukuoka prefecture, Japan. The techno-economic assessment of deploying the proposed systems was conducted, using an integrated simulation-optimization modeling framework, considering two scenarios: (1) minimization of the total cost of the system in an off-grid mode and (2) maximization of the total profit obtained from using renewable electricity and selling surplus solar electricity to the grid, considering the feed-in-tariff (FiT) scheme in a grid-tied mode. As indicated by the model results, the proposed HRES can generate about 47.3 MWh of electricity in all scenarios, which is needed to meet the external load requirement in the selected study area. The levelized cost of energy (LCOE) of the system in scenarios 1 and 2 was estimated at 55.92 JPY/kWh and 56.47 JPY/kWh, respectively.

scholarly journals Low enthalpy geothermal energy: borehole heat exchangers (BHE). Geological and geothermal supervision during active construction in support of the energy certification of buildings - ESBE certification plan

2012 ◽  
Author(s):  
Lorenzo Cadrobbi ◽  
Fioroni Daniele ◽  
Alessandro Bozzoli
Keyword(s):  
Energy Conservation ◽  
Heat Exchangers ◽  
Energy Efficient ◽  
Geothermal Energy ◽  
Energy Requirements ◽  
Effective Coverage ◽  
Correct Execution ◽  
Environmental Technologies ◽  
Borehole Heat Exchangers ◽  
Ongoing Monitoring

This article draws on the experience matured while working with low-enthalpy geothermic installations both in the design and executive phase as well as ongoing monitoring, within the scope of energy conservation as it relates to building and construction. The goal is to illustrate the feasibility of adopting the ESBE certification protocol (Certification of Energy Efficient Low-Enthalpy Probes) aimed at optimizing the harnessing of local geothermic resources to satisfy the energy requirements of a building, measured against the initial investment. It is often the case, in fact, that during the course of a construction project for a given low-enthalpy installation, we verify incompa tibilities with the local geologic and geothermic models, which, if inadequate during construction, can compromise the proper functioning of the installation and its subsequent operation. To this end, the ESBE method, which adheres to the governing environmental regulations, and which takes its cue from technical statutes within the sector, permits us to validate via verification, simulations and tests, the geothermic field probes used in construction in an objective and standardized manner, thereby joining and supporting the most recent protocols for energy certification of buildings (LEED 2010, CASACLIMA 2011, UE 20120/31 Directive). ESBE certification operates through a dedicated Certifying Entity represented by the REET unit (Renewable Energies and Environmental Technologies) of FBK (Bruno Kessler Foundation) of Trento. The results obtained by applying the ESBE method to two concrete cases, relative to two complex geothermic systems, demonstrate how this protocol is able to guarantee, beyond the correct execution in the field of geothermic probes, an effective coverage of the energy requirements of the building during construction adopting the best optimization measures for the probes in keeping with the local geological and geothermic model.

scholarly journals A Sizing Method for PV–Battery–Generator Systems for Off-Grid Applications Based on the LCOE

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1988
Author(s):  
Ioannis E. Kosmadakis ◽  
Costas Elmasides
Keyword(s):  
Renewable Energy ◽  
Energy Demand ◽  
Renewable Energy Sources ◽  
Temporal Distribution ◽  
Electrical Energy ◽  
Optimal Number ◽  
Diesel Generator ◽  
Levelized Cost Of Electricity ◽  
Sufficient Power ◽  
Battery Energy

Electricity supply in nonelectrified areas can be covered by distributed renewable energy systems. The main disadvantage of these systems is the intermittent and often unpredictable nature of renewable energy sources. Moreover, the temporal distribution of renewable energy may not match that of energy demand. Systems that combine photovoltaic modules with electrical energy storage (EES) can eliminate the above disadvantages. However, the adoption of such solutions is often financially prohibitive. Therefore, all parameters that lead to a functionally reliable and self-sufficient power generation system should be carefully considered during the design phase of such systems. This study proposes a sizing method for off-grid electrification systems consisting of photovoltaics (PV), batteries, and a diesel generator set. The method is based on the optimal number of PV panels and battery energy capacity whilst minimizing the levelized cost of electricity (LCOE) for a period of 25 years. Validations against a synthesized load profile produced grid-independent systems backed by different accumulator technologies, with LCOEs ranging from 0.34 EUR/kWh to 0.46 EUR/kWh. The applied algorithm emphasizes a parameter of useful energy as a key output parameter for which the solar harvest is maximized in parallel with the minimization of the LCOE.

Sign in / Sign up

Export Citation Format

Share Document