scholarly journals A Method to Analyze the Performance of Geocooling Systems with Borehole Heat Exchangers. Results in a Monitored Residential Building in Southern Alps

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7407
Author(s):  
Marco Belliardi ◽  
Nerio Cereghetti ◽  
Paola Caputo ◽  
Simone Ferrari
Keyword(s):  
Heat Exchangers ◽  
Residential Buildings ◽  
Residential Building ◽  
High Energy ◽  
Heat Pumps ◽  
Space Heating ◽  
Geothermal Heat ◽  
Space Cooling ◽  
Efficient Alternative ◽  
Borehole Heat Exchangers

Geothermal heat is an increasingly adopted source for satisfying all thermal purposes in buildings by reversible heat pumps (HP). However, for residential buildings located in moderate climates, geocooling, that implies the use of geothermal source for cooling buildings without the operation of HP, is an efficient alternative for space cooling not yet explored enough. Geocooling allows two main benefits: to cool the buildings by high energy efficiencies improving summer comfort; to recharge the ground if space heating is provided by HP exploiting the geothermal source (GSHP). In these cases, geocooling allows to avoid the decreasing of the performances of the GSHP for space heating over the years. To explore these issues, a method has been developed and tested on a real case: a new residential building in Lugano (southern Switzerland) coupled with 13 borehole heat exchangers. The system provides space heating in winter by a GSHP and space cooling in summer by geocooling. During a 40 months monitoring campaign, data such as temperatures, heat flows and electricity consumptions were recorded to calibrate the model and verify the benefits of such configuration. Focusing on summer operation, the efficiency of the system, after the improvements implemented, is above 30, confirming, at least in similar contexts, the feasibility of geocooling. Achieved results provides knowledge for future installations, underlining the replication potential and the possible limits.

scholarly journals Experimental Hydration Temperature Increase in Borehole Heat Exchangers during Thermal Response Tests for Geothermal Heat Pump Design

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3461 ◽  
Author(s):  
Fabio Minchio ◽  
Gabriele Cesari ◽  
Claudio Pastore ◽  
Marco Fossa
Keyword(s):  
Heat Exchangers ◽  
Recovery Period ◽  
Early Period ◽  
Design Procedure ◽  
Thermal Response ◽  
Heat Pumps ◽  
Reliable Estimate ◽  
Geothermal Heat ◽  
Pump Design ◽  
Borehole Heat Exchangers

The correct design of a system of borehole heat exchangers (BHEs) is the primary requirement for attaining high performance with geothermal heat pumps. The design procedure is based on a reliable estimate of ground thermal properties, which can be assessed by a Thermal Response Test (TRT). The TRT analysis is usually performed adopting the Infinite Line Source model and is based on a series of assumptions to which the experiment must comply, including stable initial ground temperatures and a constant heat transfer rate during the experiment. The present paper novelty is related to depth distributed temperature measurements in a series of TRT experiments. The approach is based on the use of special submersible sensors able to record their position inside the pipes. The focus is on the early period of BHE installation, when the grout cement filling the BHE is still chemically reacting, thus releasing extra heat. The comprehensive dataset presented here shows how grout hydration can affect the depth profile of the undisturbed ground temperature and how the temperature evolution in time and space can be used for assessing the correct recovery period for starting the TRT experiment and inferring information on grouting defects along the BHE depth.

scholarly journals Towards Sustainable Energy Retrofitting, a Simulation for Potential Energy Use Reduction in Residential Buildings in Palestine

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3876
Author(s):  
Sameh Monna ◽  
Adel Juaidi ◽  
Ramez Abdallah ◽  
Aiman Albatayneh ◽  
Patrick Dutournie ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Energy Use ◽  
Energy Savings ◽  
Residential Buildings ◽  
Residential Building ◽  
Simulation Models ◽  
Water Heating ◽  
Heating And Cooling ◽  
Space Cooling ◽  
Cooling Loads

Since buildings are one of the major contributors to global warming, efforts should be intensified to make them more energy-efficient, particularly existing buildings. This research intends to analyze the energy savings from a suggested retrofitting program using energy simulation for typical existing residential buildings. For the assessment of the energy retrofitting program using computer simulation, the most commonly utilized residential building types were selected. The energy consumption of those selected residential buildings was assessed, and a baseline for evaluating energy retrofitting was established. Three levels of retrofitting programs were implemented. These levels were ordered by cost, with the first level being the least costly and the third level is the most expensive. The simulation models were created for two different types of buildings in three different climatic zones in Palestine. The findings suggest that water heating, space heating, space cooling, and electric lighting are the highest energy consumers in ordinary houses. Level one measures resulted in a 19–24 percent decrease in energy consumption due to reduced heating and cooling loads. The use of a combination of levels one and two resulted in a decrease of energy consumption for heating, cooling, and lighting by 50–57%. The use of the three levels resulted in a decrease of 71–80% in total energy usage for heating, cooling, lighting, water heating, and air conditioning.

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 Ground-Source Heat Pumps with Horizontal Heat Exchangers for Space Cooling in the Hot Tropical Climate of Thailand

Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1274 ◽  
Author(s):  
Arif Widiatmojo ◽  
Sasimook Chokchai ◽  
Isao Takashima ◽  
Yohei Uchida ◽  
Kasumi Yasukawa ◽  
...  
Keyword(s):  
Economic Growth ◽  
Heat Pump ◽  
Heat Exchangers ◽  
Life Cycle Cost ◽  
Heat Pumps ◽  
Ground Source Heat Pump ◽  
Ground Source Heat Pumps ◽  
Air Source Heat Pump ◽  
Ground Source ◽  
Space Cooling

The cooling of spaces in tropical regions, such as Southeast Asia, consumes a lot of energy. Additionally, rapid population and economic growth are resulting in an increasing demand for space cooling. The ground-source heat pump has been proven a reliable, cost-effective, safe, and environmentally-friendly alternative for cooling and heating spaces in various countries. In tropical countries, the presumption that the ground-source heat pump may not provide better thermal performance than the normal air-source heat pump arises because the difference between ground and atmospheric temperatures is essentially low. This paper reports the potential use of a ground-source heat pump with horizontal heat exchangers in a tropical country—Thailand. Daily operational data of two ground-source heat pumps and an air-source heat pump during a two-month operation are analyzed and compared. Life cycle cost analysis and CO2 emission estimation are adopted to evaluate the economic value of ground-source heat pump investment and potential CO2 reduction through the use of ground-source heat pumps, in comparison with the case for air-source heat pumps. It was found that the ground-source heat pumps consume 17.1% and 18.4% less electricity than the air-source heat pump during this period. Local production of heat pumps and heat exchangers, as well as rapid regional economic growth, can be positive factors for future ground-source heat pump application, not only in Thailand but also southeast Asian countries.

scholarly journals Finite element modeling of geothermal source of heat pump in long-term operation

2020 ◽  
Vol 154 ◽  
pp. 04003
Author(s):  
Elżbieta Hałaj
Keyword(s):  
Finite Element ◽  
Heat Source ◽  
Heat Pump ◽  
Heat Exchangers ◽  
Transport Model ◽  
Heat Pumps ◽  
Initial Temperature Distribution ◽  
Term Operation ◽  
Borehole Heat Exchangers

Heat pumps become more and more popular heat source. They can be an alternative choice for obsolete coal fired boilers which are emissive and not ecological. During heat pump installation designing process, especially for heat pumps with higher heating capacity (for example those suppling larger buildings), a simulation of heat balance of ground heat source must be provided. A 3D heat transport model and groundwater flow in the geothermal heat source for heat pump (GSHP) installation was developed in FEFLOW according to Finite Element Modelling Method. The model consists of 25 borehole heat exchangers, arranged with spacing recommended by heat pump branch guidelines. The model consists of both a homogeneous, non-layered domain and a layered domain, which reflected differences in thermal properties of the ground and hydrogeological factors. The initial temperature distribution in the ground was simulating according to conditions typical for Europe in steady state heat flow. Optimal mesh refinement for nodes around borehole heat exchangers were calculated according to Nillert method. The aim of this work is to present influence of geological, hydrogeological factors and borehole arrangement in the energy balance and long term sustainability of the ground source. The thermal changes in the subsurface have been determined for a long term operation (30 years of operation period). Some thermal energy storage applications have also been considered.

Thermal Performance of Parabolic Trough Collector for Cooling Applications in Residential Buildings in UAE

2016 ◽  
Author(s):  
Fadi A. Ghaith ◽  
Haseeb-ul-Hassan Razzaq
Keyword(s):  
Thermal Performance ◽  
Carbon Dioxide Emissions ◽  
Residential Buildings ◽  
Residential Building ◽  
Parabolic Trough ◽  
Heating Source ◽  
Optimum Configuration ◽  
Space Cooling ◽  
Proposed Model ◽  
Optimum Solution

This paper addresses the potential of integrating Parabolic Trough Collectors (PTC) with a double-effect absorption chiller for the purpose of space cooling in residential buildings. The proposed model was designed such to provide a continuous cooling while in the absence of sun, the bio-mass heater was used as an auxiliary heating source. In this study, the thermal performance was investigated and a feasibility study was conducted in order to assess the system’s economic and environmental impacts. The obtained model was implemented on a case study represented by a four-floored residential building based in Dubai with a net cooling load requirement of 366 kW. The obtained results from the numerical simulation were analyzed to identify the optimum configuration in terms of feasibility and potential savings. It was found that a hybrid system with 40% solar contribution is the optimum solution compared to other alternatives. The proposed system achieved Annual Energy Consumption savings (AEC) of about 556061 kWh and a reduction by 69% in the annual operating costs. Moreover; the system reduced the Carbon-dioxide emissions by 344 tons/year. The payback period of the proposed system was found to be 2.42 years only.

Sign in / Sign up

Export Citation Format

Share Document