scholarly journals Geothermal energy: shallow sources

2014 ◽  
Vol 126 (2) ◽  
pp. 25
Author(s):  
Ian Johnston
Keyword(s):  
Heat Pump ◽  
Geothermal Energy ◽  
Heat Pumps ◽  
Cooling Mode ◽  
Ground Source Heat Pumps ◽  
Heating And Cooling ◽  
Ground Source ◽  
Heating Mode ◽  
To Receive ◽  
Ground Energy

Below a depth of around 5 to 8 metres below the surface, the ground displays a temperature which is effectively constant and a degree or two above the weighted mean annual air temperature at that particular location. In Melbourne, the ground temperature at this depth is around 18°C with temperatures at shallower depths varying according the season. Further north, these constant temperatures increase a little; while for more southern latitudes, the temperatures are a few degrees cooler. Shallow source geothermal energy (also referred to as direct geothermal energy, ground energy using ground source heat pumps and geoexchange) uses the ground and its temperatures to depths of a few tens of metres as a heat source in winter and a heat sink in summer for heating and cooling buildings. Fluid (usually water) is circulated through a ground heat exchanger (or GHE, which comprises pipes built into building foundations, or in specifically drilled boreholes or trenches), and back to the surface. In heating mode, heat contained in the circulating fluid is extracted by a ground source heat pump (GSHP) and used to heat the building. The cooled fluid is reinjected into the ground loops to heat up again to complete the cycle. In cooling mode, the system is reversed with heat taken out of the building transferred to the fluid which is injected underground to dump the extra heat to the ground. The cooled fluid then returns to the heat pump to receive more heat from the building.

scholarly journals A European Database of Building Energy Profiles to Support the Design of Ground Source Heat Pumps

Energies ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2496 ◽  
Author(s):  
Laura Carnieletto ◽  
Borja Badenes ◽  
Marco Belliardi ◽  
Adriana Bernardi ◽  
Samantha Graci ◽  
...  
Keyword(s):  
Heat Pump ◽  
Energy Demand ◽  
Residential Buildings ◽  
Building Energy ◽  
Heat Pumps ◽  
Climatic Conditions ◽  
Ground Source Heat Pumps ◽  
Heating And Cooling ◽  
Energy Profiles ◽  
Ground Source

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.

scholarly journals BUILDINGS DESIGN INTEGRATION WITH GEOTHERMAL ENERGY SYSTEM TECHNOLOGIES AND AIR CONDITIONING APPLICATIONS

2020 ◽  
Vol 1 (2) ◽  
Author(s):  
Abeer Osama Radwan
Keyword(s):  
Geothermal Energy ◽  
Influence Factors ◽  
Energy System ◽  
Heat Pumps ◽  
Ground Source Heat Pumps ◽  
Human Thermal Comfort ◽  
Heating And Cooling ◽  
Ground Source ◽  
Modern Cities ◽  
Design Integration

Nowadays global warming and thermal islands in modern cities are spending much energy on heating and cooling spaces. Geothermal energy considered a renewable energy technology for space heating and cooling. The ground source heat pumps (GSHPs) are increasingly interested in their expressive potential to reduce fossil fuel consumption and hence reduce greenhouse gases. Geothermal energy used for both electricity generation and direct use, depending on the temperature and the chemistry of the resources. Recently, direct utilization has varied significantly, and there are several methods available for temperatures typically ranging from 4°C up to 80°C. (Lund J.W., 2012). This paper presents a comprehensive literature-based review of ground source heat pump technology, cooling, and heating applications buildings to achieve precisely human thermal comfort. Subsequently, propose the influence factors of the system components that would undoubtedly reflect on the optimal design of the building. As a result, achieve precisely an integrated building.

Development of design guidelines for thermo-active foundations

2017 ◽  
Vol 27 (6) ◽  
pp. 805-817 ◽  
Author(s):  
Byung C. Kwag ◽  
Moncef Krarti
Keyword(s):  
Heat Pump ◽  
Heat Pumps ◽  
Design Guidelines ◽  
Conventional Heating ◽  
Ground Source Heat Pump ◽  
External Energy ◽  
Geothermal Heat ◽  
Ground Source Heat Pumps ◽  
Heating And Cooling ◽  
Ground Source

Ground medium can be utilized as a direct energy source to heat and cool buildings. In particular, ground source heat pump systems take advantage of the year-round mild deep earth temperature without a significant reliance on any external energy sources. However, the high installation cost of ground source heat pumps associated with high drilling cost of vertical boreholes often make these systems less cost-effective compared to conventional heating and cooling systems. Thermo-active foundations can be a viable solution to reduce ground source heat pump high installation costs by embedding heat exchangers within building foundation structures. Compared to ground source heat pumps, only limited analyses and research studies have been reported for thermo-active foundations especially for the US climates. In particular, no specific design guidelines have been reported for thermo-active foundations especially for US climates. In this paper, a simplified design approach was developed and applied for specifying geothermal heat pump size and heat exchanger loop length to meet all or part of building heat and cooling thermal loads. The developed guidelines would thus provide a proper design guide for installation of thermo-active foundations for heating and cooling of both US residential and commercial buildings.

scholarly journals Experimental study of the performance of a vertical and a horizontal ground loops coupled to a ground source heat pump system

2021 ◽  
Author(s):  
Waleed S. Alzahrani
Keyword(s):  
Heat Pump ◽  
Ground Source Heat Pump ◽  
Cooling Mode ◽  
Pump System ◽  
Heat Pump System ◽  
Heating And Cooling ◽  
Ground Source ◽  
Vertical Ground ◽  
Set Up ◽  
Heating Mode

The performance of vertical and horizontal ground loops coupled to a Ground-Source Heat Pump (GSHP) was investigated under four different scenarios. For this purpose, an experimental set-up was designed and constructed at the Archetype Sustainable houses in Vaughan, Ontario, Canada. In the first two tests, the two vertical ground loops coupled to the GSHP were tested in heating, and cooling modes. In heating mode, the GSHP COP ranged between 2.7 and 3.15. In cooling mode, the GSHP performed better than the heating mode with COP range of 3.75 and 5.4. In the last two tests, two scenarios were tested to compare the horizontal and the vertical ground loops in cooling mode. In the first scenario, the ground loop flow was divided equally between the loops and the GSHP overall COP was 5.42. The last test used equal Reynolds number in both loops and the GSHP overall COP was 5.36.

scholarly journals Critical Review on Efficiency of Ground Heat Exchangers in Heat Pump Systems

2020 ◽  
Vol 2 (2) ◽  
pp. 204-224
Author(s):  
Adel Eswiasi ◽  
Phalguni Mukhopadhyaya
Keyword(s):  
Heat Pump ◽  
Thermal Efficiency ◽  
Volumetric Flow Rate ◽  
Heat Pumps ◽  
Injection Rate ◽  
Pipe Diameter ◽  
Low Carbon ◽  
Ground Source Heat Pumps ◽  
Heating And Cooling ◽  
Ground Source

Use of ground source heat pumps has increased significantly in recent years for space heating and cooling of residential houses and commercial buildings, in both heating (i.e., cold region) and cooling (i.e., warm region) dominated climates, due to its low carbon footprint. Ground source heat pumps exploit the passive energy storage capacity of the ground for heating and cooling of buildings. The main focus of this paper is to critically review how different construction and operation parameters (e.g., pipe configuration, pipe diameter, grout, heat injection rate, and volumetric flow rate) have an impact on the thermal efficiency of the vertical ground heat exchanger (VGHE) in a ground source heat pump (GSHP) system. The published literatures indicate that thermal performance of VGHEs increases with an increase of borehole diameter and/or pipe diameter. These literatures show that the borehole thermal resistance of VGHEs decreases within a range of 9% to 52% due to pipe configurations and grout materials. Furthermore, this paper also identifies the scope to increase the thermal efficiency of VGHE. The authors conclude that in order to enhance the heat transfer rate in VGHE, any attempt to increase the surface area of the pipe configuration would likely be an effective solution.

scholarly journals Experimental study of the performance of a vertical and a horizontal ground loops coupled to a ground source heat pump system

2021 ◽  
Author(s):  
Waleed S. Alzahrani
Keyword(s):  
Heat Pump ◽  
Ground Source Heat Pump ◽  
Cooling Mode ◽  
Pump System ◽  
Heat Pump System ◽  
Heating And Cooling ◽  
Ground Source ◽  
Vertical Ground ◽  
Set Up ◽  
Heating Mode

The performance of vertical and horizontal ground loops coupled to a Ground-Source Heat Pump (GSHP) was investigated under four different scenarios. For this purpose, an experimental set-up was designed and constructed at the Archetype Sustainable houses in Vaughan, Ontario, Canada. In the first two tests, the two vertical ground loops coupled to the GSHP were tested in heating, and cooling modes. In heating mode, the GSHP COP ranged between 2.7 and 3.15. In cooling mode, the GSHP performed better than the heating mode with COP range of 3.75 and 5.4. In the last two tests, two scenarios were tested to compare the horizontal and the vertical ground loops in cooling mode. In the first scenario, the ground loop flow was divided equally between the loops and the GSHP overall COP was 5.42. The last test used equal Reynolds number in both loops and the GSHP overall COP was 5.36.

scholarly journals Performance analysis of a two-stage variable capacity air source heat pump and a horizontal loop coupled ground source heat pump system

2021 ◽  
Author(s):  
Amir Alizadeh Safa
Keyword(s):  
Heat Pump ◽  
Ground Source Heat Pump ◽  
Outdoor Temperature ◽  
Cooling Mode ◽  
Two Stage ◽  
Pump System ◽  
Air Source Heat Pump ◽  
Ground Source ◽  
Variable Capacity ◽  
Heating Mode

The thermal performance of a new two-stage variable capacity air source heat pump (ASHP) and a horizontal ground loop ground source heat pump (GSHP) was investigated side-by-side at the Archetype Sustainable Twin Houses located in Toronto, Canada. The heat pumps were tested in cooling mode, as well as heating mode under extreme winter conditions. In cooling mode, the ASHP COP ranged from 4.7 to 5.7 at an outdoor temperature of 33 degrees C and 16 degrees C respectively, while the GSHP COP ranged from 4.9 (at an ELT of 8.5 degrees C and EST of 19.2 degrees C) to 5.6 (at an ELT of 12. 4 degrees C and EST of 17.8 degrees C). In heating mode, the ASHP COP ranged from 1.79 to 5.0 at an outdoor temperature of -19 degrees C and 9 degrees C respectively, while the GSHP COP ranged from 3.05 (at an ELT of 44.4 degrees C and an EST of 2.7 degrees C) to 3.44 (at an ELT of 41.5 degrees C and an EST of 5.48 degrees C) during the earlier winter test period. Data extrapolation and energy simulation was also performed to predict annual heat pump performance in Toronto as well as other Canadian regions.

scholarly journals Heat pump systems: A mini review

2021 ◽  
Vol 4 (2) ◽  
pp. 73-81
Author(s):  
Mohammad Omar Temori ◽  
František Vranay
Keyword(s):  
Heat Pump ◽  
Electricity Consumption ◽  
Cost Savings ◽  
Electrical Energy ◽  
Primary Energy ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Heating And Cooling ◽  
Ground Source ◽  
Reduce Electricity Consumption

In this work, a mini review of heat pumps is presented. The work is intended to introduce a technology that can be used to income energy from the natural environment and thus reduce electricity consumption for heating and cooling. A heat pump is a mechanical device that transfers heat from one environmental compartment to another, typically against a temperature gradient (i.e. from cool to hot). In order to do this, an energy input is required: this may be mechanical, electrical or thermal energy. In most modern heat pumps, electrical energy powers a compressor, which drives a compression - expansion cycle of refrigerant fluid between two heat exchanges: a cold evaporator and a warm condenser. The efficiency or coefficient of performance (COP), of a heat pump is defined as the thermal output divided by the primary energy (electricity) input. The COP decreases as the temperature difference between the cool heat source and the warm heat sink increases. An efficient ground source heat pump (GSHP) may achieve a COP of around 4. Heat pumps are ideal for exploiting low-temperature environmental heat sources: the air, surface waters or the ground. They can deliver significant environmental (CO2) and cost savings.

scholarly journals Ground Source Heat Pumps: Considerations for Large Facilities in Massachusetts

2020 ◽  
Author(s):  
Eric Wagner ◽  
Benjamin McDaniel ◽  
Dragoljub Kosanovic
Keyword(s):  
Co2 Emissions ◽  
Current System ◽  
Cost Benefit ◽  
Heating System ◽  
Heat Pumps ◽  
Ground Source Heat Pumps ◽  
Heating And Cooling ◽  
Ground Source ◽  
Industry Standards ◽  
Conventional Cooling

Ground-source heat pump (GSHP) systems have been implemented at large scales on several university campuses to provide heating and cooling. In this study, we test the idea that a GSHP system, as a replacement for an existing Combined Heat and Power (CHP) heating system coupled with conventional cooling systems, could reduce CO2 emissions, and provide a cost benefit to a university campus. We use the existing recorded annual heating and cooling loads supplied by the current system and an established technique of modeling the heat pumps and borehole heat exchangers (BHEs) using a TRNSYS model. The GSHP system is modeled to follow the parameters of industry standards and sized to provide an optimal balance of capital and operating costs. Results show that despite a decrease in heating and cooling energy usage and CO2 emissions are achieved, a significant increase in electric demand and purchased electricity result in an overall cost increase. These results highlight the need for thermal energy storage, onsite distributed energy resources and/or demand response in cases where electric heat pumps are used to help mitigate electric demand during peak periods.

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.

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