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 GEOTHERMAL ENERGY OF THE REPUBLIC OF SRPSKA AND HYDROCHEMICAL ASPECTS OF ITS EXPLORATION AND EXPLOITATION

2018 ◽  
Vol 4 (7) ◽  
Author(s):  
Andrijana Stevanović ◽  
Boban Jolović
Keyword(s):  
Renewable Energy ◽  
Geothermal Energy ◽  
Renewable Energy Sources ◽  
Energy Resource ◽  
Geothermal Gradient ◽  
Heat Pumps ◽  
Electricity Production ◽  
Thermal Waters ◽  
The Republic ◽  
Banja Luka

One of the most used renewable energy sources worldwide is geothermal energy. Itrepresents the heat, originated by natural processes happen in the Earth interior. The hot springsphenomena are the most frequent natural manifestation of geothermal activity.Geothermal potentiality of some area can be estimated based on geothermal gradient. Geothermalgradient is a conductive terrestrial parameter that represents the degree of increasing of the Earthtemperature vs. depth. It is usually expressed in ⁰C/m or ⁰C/km. Different areas have differentthermal gradients and thus different geothermal potential. Generally, higher geothermal gradientscorrespond to areas containing more geothermal energy.Geothermal characteristics of the territory of the Republic of Srpska are closely related to itscomplex geological setting. It is the reason why geothermal characteristics are different from areato area. Higher geothermal potentiality is recognised in the northern parts of the entity, in the firstorder in Semberija, Posavina and Banja Luka regions.The use of geothermal energy with different fluid temperatures can be considered throughthe Lindaldiagram, who firstly proposed acomprehensive scale with appropriate temperatures for differentuses. High temperature fluids are mostly used for electricity production and moderate and lowtemperature fluids for the direct use.Despite the fact that the territory of the Republic of Srpska hasfavourable geothermal properties, utilization of this kind of renewable energy resource isinadequate. Especially indicative are data about the use of geothermal energy by heat pumps (inbad sense) in comparison with praxis of developed countries.Chemical composition of thermal waters plays very important role and can be used in itsexploration stage, for analyses of possibility of its use and for prediction of exploitation effects, aswell. This kind of renewable energyresource, highly ecologically recommended, must be consideredmore seriously in the future in the Republic of Srpska. Furthermore, it must be put into the energystrategic documentsin appropriate manner.

scholarly journals Nationwide Determination of Required Total Lengths of Multiple Borehole Heat Exchangers under Variable Climate and Geology in Japan

2021 ◽  
Vol 10 (4) ◽  
pp. 205
Author(s):  
Yoshitaka Sakata ◽  
Takao Katsura ◽  
Katsunori Nagano
Keyword(s):  
Thermal Conductivity ◽  
Heat Pump ◽  
Heat Exchangers ◽  
Sustainable Use ◽  
Practical Method ◽  
Pump System ◽  
Climate Conditions ◽  
Heat Pump System ◽  
Geological Conditions ◽  
Borehole Heat Exchangers

This study determined the required lengths of borehole heat exchangers (BHEs) in ground-source heat pump systems for heating/cooling a building (with 300 m2 of floor area) across Japan’s four main islands through a simulation approach. Hourly thermal loads were estimated in 10 km gridded cells based on the outside temperature and humidity. Three-dimensional estimates of ground thermal conductivity from our previous study at the depths of the BHEs were used. A 5-year system operation was simulated in a total of 4059 cells with 81 combinations of individual lengths and total numbers of BHEs to determine the shortest total length required to achieve sustainable use and targeted performance. The optimal combination of individual length and total number varied regionally due to climate conditions and locally among adjacent cells due to geological conditions. The total required lengths ranged widely from 78 to 1782 m. However, the lengths were less than 400 m in 85% of the cells. Additionally, cost-effectiveness in 69% of the cells was shown by reducing the total lengths to half or less of those in the practical method. The reduction could potentially increase the feasibility of heat pump system use in Japan. The total lengths were dependent on the heating/cooling loads approximately as secondary-polynomial functions, but the relations with the ground thermal conductivity were not clear.

scholarly journals Heat pumps in the future

2021 ◽  
Vol 345 ◽  
pp. 00004
Author(s):  
Tímea Gresz ◽  
Dávid Faragó ◽  
Péter Bencs
Keyword(s):  
Renewable Energy ◽  
Thermal Energy ◽  
Geothermal Energy ◽  
Fossil Fuels ◽  
Renewable Energy Sources ◽  
Heat Pumps ◽  
Current Situation ◽  
Energy Sources ◽  
Power Demand ◽  
The Everyday

It has been discovered long ago that geothermal energy can be used to substitute various types of fossil fuels. Heat pumps are devices that can transfer the earth’s thermal energy from a cooler to a warmer space. Their deployment would not only benefit large companies but could even reduce the everyday costs of individuals. Among their many advantages, possibly the most important one is that it is environmentally friendly. Their power demand can ideally be satisfied using other renewable energy sources. In this article, the current situation of heat pumps and geothermal energy in Hungary, Sweden and Germany are examined including incentives and grants. Afterwards, the current situation and operation of hybrid systems in Sweden and Egypt are studied.

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 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 Geothermal Boreholes in Poland—Overview of the Current State of Knowledge

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3251
Author(s):  
Tomasz Sliwa ◽  
Aneta Sapińska-Śliwa ◽  
Andrzej Gonet ◽  
Tomasz Kowalski ◽  
Anna Sojczyńska
Keyword(s):  
Heat Exchangers ◽  
Oil And Gas ◽  
Produced Water ◽  
Geothermal Water ◽  
Laboratory System ◽  
Water Production ◽  
Injection Wells ◽  
Geological Conditions ◽  
Geothermal Wells ◽  
Borehole Heat Exchangers

Geothermal energy can be useful after extraction from geothermal wells, borehole heat exchangers and/or natural sources. Types of geothermal boreholes are geothermal wells (for geothermal water production and injection) and borehole heat exchangers (for heat exchange with the ground without mass transfer). The purpose of geothermal production wells is to harvest the geothermal water present in the aquifer. They often involve a pumping chamber. Geothermal injection wells are used for injecting back the produced geothermal water into the aquifer, having harvested the energy contained within. The paper presents the parameters of geothermal boreholes in Poland (geothermal wells and borehole heat exchangers). The definitions of geothermal boreholes, geothermal wells and borehole heat exchangers were ordered. The dates of construction, depth, purposes, spatial orientation, materials used in the construction of geothermal boreholes for casing pipes, method of water production and type of closure for the boreholes are presented. Additionally, production boreholes are presented along with their efficiency and the temperature of produced water measured at the head. Borehole heat exchangers of different designs are presented in the paper. Only 19 boreholes were created at the Laboratory of Geoenergetics at the Faculty of Drilling, Oil and Gas, AGH University of Science and Technology in Krakow; however, it is a globally unique collection of borehole heat exchangers, each of which has a different design for identical geological conditions: heat exchanger pipe configuration, seal/filling and shank spacing are variable. Using these boreholes, the operating parameters for different designs are tested. The laboratory system is also used to provide heat and cold for two university buildings. Two coefficients, which separately characterize geothermal boreholes (wells and borehole heat exchangers) are described in the paper.

THE ROLE OF RENEWABLE ENERGY SOURCES IN REGIONAL TOURISM DEVELOPMENT

2009 ◽  
Vol 15 (1) ◽  
pp. 25-36
Author(s):  
Branko Blazevic
Keyword(s):  
Sustainable Development ◽  
Renewable Energy ◽  
Wind Power ◽  
Geothermal Energy ◽  
Renewable Energy Sources ◽  
Biomass Energy ◽  
Energy Sources ◽  
Regional Tourism ◽  
Regional Sustainable Development

In this paper, the author focuses on the fundamental hypothesis that the adoption of a concept of regional sustainable development and the use of renewable energy sources are preconditions to organising an acceptable regional tourism offering based on an eco-philosophy The renewable development of tourism regions is the basic framework for research regarding opportunities for introducing renewable energy sources such as hydro energy, wind power, solar energy, geothermal energy, and biomass energy. The purpose of this paper is to indicate the real opportunities that exist for substituting conventional energy sources with renewable ones and the role of renewables in regional development from economic, environmental and sociological viewpoints. It should also be noted that renewable energy sources have a strong regional importance and can contribute significantly to local employment.

scholarly journals Sustainable Development and Renewable Energy Sectors: Selected Indicators in European Union and Poland

2018 ◽  
Vol 18(33) (4) ◽  
pp. 250-258
Author(s):  
Anna Klepacka
Keyword(s):  
European Union ◽  
Renewable Energy ◽  
Raw Materials ◽  
Renewable Energy Sources ◽  
Main Tool ◽  
Heat Pumps ◽  
Solar Heating ◽  
Energy Sources ◽  
The European Union ◽  
European Union Countries

The aim of this article was to show the position of Poland in the renewable energy subsectors among the European Union countries. The research covered the areas of biomass, solar heating and heat pumps, showing the degree of their utilization, power required to drive the system and their production in 2016. The provided information was supplemented with a revenues per employee in thousand euros in chosen subsectors of renewable energy sources in the year 2016. The main tool for carrying out the set objective was the use of descriptive and comparative methods. The results of the survey demonstrated Poland’s prominent place in the sector of liquid biofuels (1st place in EU), thanks to the significant supply of raw materials as well as development perspectives in solar energy, which is confirmed by the world's statistics indicating a record number of photovoltaic installations fitted (PV).

Analyzing the Efficiency of Renewable Energy Sources in Terms of Electricity Generation

2021 ◽  
pp. 155-176
Author(s):  
Talip Arsu
Keyword(s):  
Renewable Energy ◽  
Geothermal Energy ◽  
Energy Supply ◽  
Electricity Generation ◽  
Renewable Energy Sources ◽  
Biomass Energy ◽  
Energy Sources ◽  
Data Envelopment ◽  
Efficiency Determination ◽  
Energy Supply Security

Electricity generation, one of the renewable energy sources (RES), delivers a solution for various problems such as energy efficiency, energy supply security, reducing foreign dependency, and especially, environmental concerns. However, the solutions provided for these problems bring along the question of which RESs are produced more effectively. Therefore, in this research, RESs used for electricity generation in Turkey were analyzed by using generation data to show which one is more effective. Bi-objective multiple-criteria data envelopment analysis (BiO-MCDEA) method, a goal programming-based efficiency determination method, was used for the efficiency analysis conducted for five years between the years of 2014 and 2018. As a result of the analysis, geothermal energy came into prominence as the most effective RES for all of the years included in the solution. Geothermal energy was followed by biomass energy, wind energy, hydroelectric, and solar energy, respectively.

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