scholarly journals Residential Buildings’ Foundations as a Ground Heat Exchanger and Comparison among Different Types in a Moderate Climate Country

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6287
Author(s):  
Lazaros Aresti ◽  
Paul Christodoulides ◽  
Gregoris P. Panayiotou ◽  
Georgios Florides

Shallow Geothermal Energy Systems (SGESs) constitute Renewable Energy Systems (RES), which find application in the residential sector through the use of Ground Source Heat Pumps (GSHPs). GSHPs are associated with Ground Heat Exchangers (GHEs), whereby heat is gained/lost through a network of tubes into the ground. GSHPs have failed to flourish in the RES market due to their high initial costs and long payback periods. In this study, the use of Energy Geo-Structure (EGS) systems, namely, the foundation (or energy) piles and the foundation bed of a residential building in Cyprus, was computationally modeled in the COMSOL Multiphysics software. First, the single-houses’ trend in number of units and area in Cyprus was examined and a theoretically typical house with nearly Zero Energy Building (nZEB) characteristics was considered. The heating and cooling loads were estimated in the TRNSYS software environment and used as inputs to investigate the performance of the GSHP/GHE systems. Both systems were shown to exhibit steady performance and high Coefficient of Performance (COP) values, making them an alternative RES solution for residential building integration. Next, the systems were economically evaluated through a comparison with a convectional Air Source Heat Pump (ASHP) system. The economic analysis showed that the cost of the suggested conversions of the foundation elements into GHEs had short payback periods. Consequently, either using the foundation piles or bed as a GHE is a profitable investment and an alternative to conventional RES.

Energies ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2496 ◽  
Author(s):  
Laura Carnieletto ◽  
Borja Badenes ◽  
Marco Belliardi ◽  
Adriana Bernardi ◽  
Samantha Graci ◽  
...  

The design of ground source heat pumps is a fundamental step to ensure the high energy efficiency of heat pump systems throughout their operating years. To enhance the diffusion of ground source heat pump systems, two different tools are developed in the H2020 research project named, “Cheap GSHPs”: A design tool and a decision support system. In both cases, the energy demand of the buildings may not be calculated by the user. The main input data, to evaluate the size of the borehole heat exchangers, is the building energy demand. This paper presents a methodology to correlate energy demand, building typologies, and climatic conditions for different types of residential buildings. Rather than envelope properties, three insulation levels have been considered in different climatic conditions to set up a database of energy profiles. Analyzing European climatic test reference years, 23 locations have been considered. For each location, the overall energy and the mean hourly monthly energy profiles for heating and cooling have been calculated. Pre-calculated profiles are needed to size generation systems and, in particular, ground source heat pumps. For this reason, correlations based on the degree days for heating and cooling demand have been found in order to generalize the results for different buildings. These correlations depend on the Köppen–Geiger climate scale.


Author(s):  
Wahiba Yaïci ◽  
Evgueniy Entchev ◽  
Michela Longo

Abstract As the energy needed for heating and cooling involves a substantial amount (> 80%) of residential energy utilisation in Canada, there is a demand for ultra-efficient energy systems for heating, cooling, and power generation. Two efficient systems to assist these systems are ground-source heat pumps (GSHPs) and organic Rankine cycles (ORCs). Of particular interest, this paper presents the integration of these two systems in a parallel configuration. A transient simulation model developed in TRNSYS program has been utilised to simulate the thermal performance of the combined ORC-GSHP based microco/trigeneration system. This later supplies heating and cooling to the residential load during the heating mode as required, with the capability to switch to a charging mode, where the ORC unit is directly coupled to the ground heat exchanger (GHE), which operates as a thermal energy storage and provides energy to the GSHP. The feasibility of this combined system configuration as well as its comparison with a conventional GSHP system are investigated for use in residential application in Ottawa, Canada temperature conditions. Results disclosed that the proposed micro-cogeneration system had the operating hours and performance of the GSHP improved by the addition of the ORC unit, resulting in about 11.8% reduction in hours in the colder city of Ottawa. The COP (coefficient of performance) of the GSHP system sustained a much higher value overall due to the addition of the ORC system to maintain the GHE storage temperature. In terms of net energy reduction between the conventional GSHP system and the ORC-assisted one, results revealed that Ottawa had energy usage reduction of 82.0%, demonstrating that the addition of an ORC to provide heating and recharge the GHE of a GSHP system has many advantages that could be accomplished by the end-user.


Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2933
Author(s):  
Michele Bottarelli ◽  
Francisco Javier González Gallero

Installation costs of ground heat exchangers (GHEs) make the technology based on ground-coupled heat pumps (GCHPs) less competitive than air source heat pumps for space heating and cooling in mild climates. A smart solution is the dual source heat pump (DSHP) which switches between the air and ground to reduce frosting issues and save the system against extreme temperatures affecting air-mode. This work analyses the coupling of DSHP with a flat-panel (FP) horizontal GHE (HGHE) and a mixture of sand and phase change materials (PCMs). From numerical simulations and considering the energy demand of a real building in Northern Italy, different combinations of heat pumps (HPs) and trench backfill material were compared. The results show that PCMs always improve the performance of the systems, allowing a further reduction of the size of the geothermal facility. Annual average heat flux at FP is four times higher when coupled with the DSHP system, due to the lower exploitation. Furthermore, the enhanced dual systems are able to perform well during extreme weather conditions for which a sole air source heat pump (ASHP) system would be unable either to work or perform efficiently. Thus, the DSHP and HGHE with PCMs are robust and resilient alternatives for air conditioning.


2016 ◽  
Vol 138 (6) ◽  
Author(s):  
Byung Chang Kwag ◽  
Moncef Krarti

The application of thermo-active foundation (TAF) systems to heat and cool residential buildings is evaluated in this paper. First, a transient three-dimensional finite difference numerical model is developed for the analysis of thermo-active foundations. The numerical model predictions are then validated against experimental data obtained from laboratory testing. Using the validated numerical model, G-functions for TAFs are generated and integrated into whole-building simulation analysis program, energyplus. A comparative analysis is carried out to evaluate TAF systems compared to conventional ground-source heat pumps (GSHPs) to provide heating and cooling for multifamily residential buildings. In particular, the analysis compares the cost-effectiveness of TAFs and GSHPs to meet heating and cooling needs for a prototypical multifamily building in three U.S. climates. Due to lower initial costs associated to the reduced excavation costs, it is found that TAFs offer a more cost-effectiveness than GSHP systems to heat and cool multifamily residential buildings.


2017 ◽  
Vol 25 (03) ◽  
pp. 1750024 ◽  
Author(s):  
Samuel Boahen ◽  
Kwang Ho Lee ◽  
Soolyeon Cho ◽  
Jong Min Choi

Heating and cooling systems contribute greatly to the energy consumption and CO2 emissions of many countries. Ground source heat pumps (GSHP) are promising energy saving systems for residential, commercial or industrial heating or cooling purposes. A method to estimate the energy consumption and CO2 emission of GSHPs is therefore very eminent. This paper reviews the methodology to calculate the energy consumption and CO2 emission of GSHPs. The discussed methodology is then used to compare the energy consumption and CO2 emission of an open-loop and closed-loop GSHP using data from field test. It is observed that the open-loop GSHP saves 28% energy and reduces CO2 by 28% than the closed-loop GSHP in the cooling season. When used for both cooling and heating purposes in the year, the open-loop GSHP saves about 6% energy and reduces about 6% of CO2 emission than the closed-loop GSHP.


2013 ◽  
Author(s):  
Fabrizio Ferraro ◽  
Enrico Sciubba ◽  
Claudia Toro

The relatively low average conversion efficiency of air-conditioning systems and the recently imposed upper bounds to the final energy use in the heating and cooling of residential buildings suggest to consider new approaches to design less energy intensive systems. An integrated, exergy-based approach for the optimal matching of internal and external heating plants in building conditioning systems has been proposed — and its theoretical basis discussed — in a previous paper. The procedure allows the designer to obtain a pseudo-optimal integration of the building and its heating plant (heating element + primary energy supply system) and to identify, among a set of alternative solutions for the building under examination, the thermodynamically most efficient plant. The objective of this paper is to validate the method on a real building in order to demonstrate its practical applicability. The large “Chiostro Hall” (220 square meters, 1245 cubic meters) of the Engineering School of the University “Sapienza” of Roma has been employed as the benchmark. This is the main hall of the building, reconverted from a previously existing Renaissance structure, the old convent of San Lorenzo in Panisperna, which was in turn built on the ruins of a pre-christian roman basilica and of a portion of emperor Nero’s Domus Aurea. The hall consists of two semi-connected rooms, originally the Refectory of the old Convent, that are now used for public events, conferences and graduation ceremonies. This structure can be considered as a model case for similar halls in historical buildings, so that the guidelines deriving from the present study can be extended to other similar environments. The current heating elements are traditional radiators: in our simulations, they have been successively replaced by other elements such as floor and ceiling heating panels and fan coils. Each one of these configurations (the hall and its heating elements) has been modeled and simulated via a commercial CFD code to generate detailed thermal maps and to compute the actual thermal load. Different global “heating chains” were then modeled by coupling solar and hybrid photovoltaic-thermal (PV/T) panels with radiant panels and ground-source heat pumps with fan coils and radiant heating panels. Finally by means of a process simulator software each one of these configurations was analyzed to identify the one that provides the same comfort level with the least exergy use. The procedure also allows to calculate the savings obtained in terms of primary resources.


Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1383
Author(s):  
Abolfazl Rezaei ◽  
Bahador Samadzadegan ◽  
Hadise Rasoulian ◽  
Saeed Ranjbar ◽  
Soroush Samareh Abolhassani ◽  
...  

Designing district-scale energy systems with renewable energy sources is still a challenge, as it involves modeling of multiple loads and many options to combine energy system components. In the current study, two different energy system scenarios for a district in Montreal/Canada are compared to choose the most cost-effective and energy-efficient energy system scenario for the studied area. In the first scenario, a decentral energy system comprised of ground-source heat pumps provides heating and cooling for each building, while, in the second scenario, a district heating and cooling system with a central heat pump is designed. Firstly, heating and cooling demand are calculated in a completely automated process using an Automatic Urban Building Energy Modeling System approach (AUBEM). Then, the Integrated Simulation Environment Language (INSEL) is used to prepare a model for the energy system. The proposed model provides heat pump capacity and the number of required heat pumps (HP), the number of photovoltaic (PV) panels, and AC electricity generation potential using PV. After designing the energy systems, the piping system, heat losses, and temperature distribution of the centralized scenario are calculated using a MATLAB code. Finally, two scenarios are assessed economically using the Levelized Cost of Energy (LCOE) method. The results show that the central scenario’s total HP electricity consumption is 17% lower than that of the decentral systems and requires less heat pump capacity than the decentral scenario. The LCOE of both scenarios varies from 0.04 to 0.07 CAD/kWh, which is cheaper than the electricity cost in Quebec (0.08 CAD/kWh). A comparison between both scenarios shows that the centralized energy system is cost-beneficial for all buildings and, after applying the discounts, the LCOE of this scenario decreases to 0.04 CAD/kWh.


Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3876
Author(s):  
Sameh Monna ◽  
Adel Juaidi ◽  
Ramez Abdallah ◽  
Aiman Albatayneh ◽  
Patrick Dutournie ◽  
...  

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.


Author(s):  
Leon M. Headings ◽  
Gregory N. Washington

The goal of this research is to develop a framework for replacing conventional heating and cooling systems with distributed, continuously and electrically controlled, building-integrated thermoelectric (BITE) heat pumps. The coefficient of performance of thermoelectric heat pumps increases as the temperature difference across them decreases and as the amplitude of temperature oscillations decreases. As a result, this research examines how thermal insulation and mass elements can be integrated with thermoelectrics as part of active multi-layer structures in order to minimize net energy consumption. In order to develop BITE systems, an explicit finite volume model was developed to model the dynamic thermal response of active multi-layer wall structures subjected to arbitrary boundary conditions (interior and exterior temperatures and interior heat loads) and control algorithms. Using this numerical model, the effects of wall construction on net system performance were examined. These simulation results provide direction for the ongoing development of BITE systems.


Author(s):  
Xinli Lu ◽  
David R. Larson ◽  
Thomas R. Holm

Groundwater source heat pumps exploit the difference between the ground surface temperature and the nearly constant temperature of shallow groundwater. This project characterizes two areas for geothermal heating and cooling potential, Mason County in central Illinois and the American Bottoms area in southwestern Illinois. Both areas are underlain by thick sand and gravel aquifers and groundwater is readily available. Weather data, including monthly high and low temperatures and heating and cooling degree days, were compiled for both study areas. The heating and cooling requirements for a single-family house were estimated using two independent models that use weather data as input. The groundwater flow rates needed to meet these heating and cooling requirements were calculated using typical heat pump coefficient of performance values. The groundwater in both study areas has fairly high hardness and iron concentrations and is close to saturation with calcium and iron carbonates. Using the groundwater for cooling may induce the deposition of scale containing one or both of these minerals.


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