Modeling and Design of Building-Integrated Thermoelectrics

2011 ◽  
Author(s):  
Leon M. Headings ◽  
Gregory N. Washington
Keyword(s):  
Thermal Response ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Conventional Heating ◽  
Net Energy ◽  
Arbitrary Boundary ◽  
Heating And Cooling ◽  
Temperature Oscillations ◽  
Wall Structures ◽  
And Control

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.

Dynamic Simulation of Organic Rankine Cycle-Assisted Ground-Source Heat Pump Based Micro-Cogeneration System in Cold Climates: A Case Study in Canada

2021 ◽  
Author(s):  
Wahiba Yaïci ◽  
Evgueniy Entchev ◽  
Michela Longo
Keyword(s):  
Storage Temperature ◽  
Organic Rankine Cycle ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Net Energy ◽  
Combined System ◽  
Ground Source Heat Pumps ◽  
Heating And Cooling ◽  
Ground Source ◽  
Cogeneration System

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.

scholarly journals Optimum Design and Control of Heat Pumps for Integration into Thermohydraulic Networks

2020 ◽  
Vol 12 (22) ◽  
pp. 9421
Author(s):  
Maximilian Sporleder ◽  
Max Burkhardt ◽  
Thomas Kohne ◽  
Daniel Moog ◽  
Matthias Weigold
Keyword(s):  
Optimum Design ◽  
Net Present Value ◽  
Programming Model ◽  
Thermal Storage ◽  
Heat Pumps ◽  
Conventional Heating ◽  
Mixed Integer ◽  
Storage Tanks ◽  
Heating And Cooling ◽  
And Control

Germany has become one of the leading players in the transformation of the electricity sector, now having up to 42% of electricity coming from renewable sources. However, the transformation of the heating sector is still in its infancy, and especially the provision of industrial process heating is highly dependent on unsustainable fuels. One of the most promising heating technologies for renewable energies is power-to-heat, especially heat pump technology, as it can use renewable electricity to generate heat efficiently. This research explores the economic and technical boundary conditions regarding the integration of heat pumps into existing industrial thermohydraulic heating and cooling networks. To calculate the optimum design and control of heat pumps, a mixed-integer linear programming model (MILP) is developed. The model seeks the most cost-efficient configuration of heat pumps and stratified thermal storage tanks. Additionally, it optimizes the operation of all energy converters and stratified thermal storage tanks to meet a specified heating and cooling demand over one year. The objective function is modeled after the net present value (NPV) method and considers capital expenditures (costs for heat pumps and stratified thermal storage tanks) and operational expenditures (electricity costs and costs for conventional heating and cooling). The comparison of the results via a simulation model reveals an accuracy of more than 90%.

scholarly journals Factors Shaping A/W Heat Pumps CO₂ Emissions—Evidence from Poland

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1576
Author(s):  
Piotr Jadwiszczak ◽  
Jakub Jurasz ◽  
Bartosz Kaźmierczak ◽  
Elżbieta Niemierka ◽  
Wandong Zheng
Keyword(s):  
Air Quality ◽  
Power System ◽  
Heat Pump ◽  
Heat Pumps ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Conventional Heating ◽  
Additional Stress ◽  
The European Union ◽  
Energy Mix

Heating and cooling sectors contribute to approximately 50% of energy consumption in the European Union. Considering the fact that heating is mostly based on fossil fuels, it is then evident that its decarbonization is one of the crucial tasks for achieving climate change prevention goals. At the same time, electricity sectors across the globe are undergoing a rapid transformation in order to accommodate the growing capacities of non-dispatchable solar and wind generators. One of the proposed solutions to achieve heating sector decarbonization and non-dispatchable generators power system integration is sector coupling, where heat pumps are perceived as a perfect fit. Air source heat pumps enable a rapid improvement in local air quality by replacing conventional heating sources, but at the same time, they put additional stress on the power system. The emissions associated with heat pump operation are a combination of power system energy mix, weather conditions and heat pump technology. Taking the above into consideration, this paper presents an approach to estimate which of the mentioned factors has the highest impact on heat pump emissions. Due to low air quality during the heating season, undergoing a power system transformation (with a relatively low share of renewables) in a case study located in Poland is considered. The results of the conducted analysis revealed that for a scenario where an air-to-water (A/W) heat pump is supposed to cover space and domestic hot water load, its CO2 emissions are shaped by country-specific energy mix (55.2%), heat pump technology (coefficient of performance) (33.9%) and, to a lesser extent, by changing climate (10.9%). The outcome of this paper can be used by policy makers in designing decarbonization strategies and funding distribution.

Preliminary Feasibility Study of Groundwater Source Geothermal Heat Pumps in Mason County and the American Bottoms Area, Illinois

2014 ◽  
Author(s):  
Xinli Lu ◽  
David R. Larson ◽  
Thomas R. Holm
Keyword(s):  
Ground Surface ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Weather Data ◽  
Single Family ◽  
Geothermal Heat ◽  
Geothermal Heating ◽  
Heating And Cooling ◽  
Groundwater Source ◽  
Mason County

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.

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 Characterization of the Effects of Borehole Configuration and Interference with Long Term Ground Temperature Modelling of Ground Source Heat Pumps

2021 ◽  
Author(s):  
Ying Lam E. Law ◽  
Seth B. Dworkin
Keyword(s):  
Fast Food ◽  
High Efficiency ◽  
Separation Distance ◽  
Heat Pumps ◽  
Ground Temperature ◽  
Conventional Heating ◽  
Ground Source Heat Pumps ◽  
Heating And Cooling ◽  
Ground Source

Ground source heat pumps (GSHPs) are an environmentally friendly alternative to conventional heating and cooling systems because of their high efficiency and low greenhouse gas emissions. The ground acts as a heat sink/source for the excess/required heat inside a building for cooling and heating modes, respectively. However, imbalance in heating and cooling needs can change ground temperature over the operating duration. This increase/decrease in ground temperature lowers system efficiency and causes the ground to foul—failing to accept or provide more heat. In order to ensure that GSHPs can operate to their designed conditions, thermal modelling is required to simulate the ground temperature during system operation. In addition, the borehole field layout can have a major impact on ground temperature. In this study, four buildings were studied—a hospital, fast-food restaurant, residence, and school, each with varying borehole configurations. Boreholes were modeled in a soil volume using finite-element methods and heating and cooling fluxes were applied to the borehole walls to simulate the GSHP operation. 20 years of operation were modelled for each building for 2x2, 4x4, and 2x8 borehole configurations. Results indicate that the borehole separation distance of 6 m, recommended by ASHRAE, is not always sufficient to prevent borehole thermal interactions. Benefits of using a 2x8 configuration as opposed to a 4x4 configuration, which can be observed because of the larger perimeter it provides for heat to dissipate to surrounding soil were quantified. This study indicates that it is important to carefully consider ground temperature during the operation of a GSHP. Borehole separation distances, layout, and hybridization should be studied to alleviate ground fouling problems.

Annual pattern of the coefficient of performance considering several heat pump types and its environmental consequences

2014 ◽  
Vol 5 (2) ◽  
pp. 173-179
Author(s):  
T. Buday ◽  
Gy. Szabó ◽  
I. Fazekas ◽  
M. Paládi ◽  
Sz. Szabó ◽  
...  
Keyword(s):  
Heat Pump ◽  
Water Source ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Conventional Heating ◽  
Temperature Pattern ◽  
Ground Source Heat Pump ◽  
Environmental Consequences ◽  
Ground Source ◽  
Heating Mode

Heating with the use of ambient energy by heat pumps is a very effective way to reduce CO2 emission. However, efficiency, economic and environmental advantages depend on the type of the heat pump and the temperature of the source, the latter usually changes during the heating season. The aim of the paper is to give the annual pattern of the COP and emission as a function of the typical source temperature pattern, moreover yearly summarized energetic and emission values are also added in the case of air source, water source and ground source heat pump systems, compared to some conventional heating mode.

scholarly journals Practical study on heat pump enhancement by the solar energy

2021 ◽  
Vol 288 ◽  
pp. 01069
Author(s):  
Omar Abdulhadi Mustafa Almohammed ◽  
Farida Mizkhatovna Philippova ◽  
Fouad Ibrahim Alhajj Hassan ◽  
Nail Farilovich Timerbaev ◽  
Anatoliy Anatolyevich Fomin
Keyword(s):  
Heat Exchanger ◽  
Solar Energy ◽  
Heat Pump ◽  
Technical College ◽  
Heat Pumps ◽  
Coefficient Of Performance ◽  
Laboratory Model ◽  
Additional Heat ◽  
Heating And Cooling ◽  
Positive Effect

The heat pumps system is one of the most remarkable system that is widely used around the world, their capacity is different according to necessity. The energy consumption in those systems will limit their effectiveness. This study will try to prove the positive reactance of the new changes (the additional heat exchanger) on the heat pump work, where the power consumption will reduce about (13-17%). The study includes the experimental results of the laboratory model, which has been manufactured in the laboratories of the technical college of Mosul/Northern technical university-Iraq. The model consists of the heat pump that was improved by using the additional heat exchanger, its duty is to heat the refrigerant before entering the compressor, by using solar energy. The results of this work prove the positive effect of the additional heat exchanger, on the coefficient of performance of the heat pump, in both modes of heating and cooling. The conclusions are useful to the industries that deal with heat pumps.

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 Characterization of the Effects of Borehole Configuration and Interference with Long Term Ground Temperature Modelling of Ground Source Heat Pumps

2021 ◽  
Author(s):  
Ying Lam E. Law ◽  
Seth B. Dworkin
Keyword(s):  
Fast Food ◽  
High Efficiency ◽  
Separation Distance ◽  
Heat Pumps ◽  
Ground Temperature ◽  
Conventional Heating ◽  
Ground Source Heat Pumps ◽  
Heating And Cooling ◽  
Ground Source

Ground source heat pumps (GSHPs) are an environmentally friendly alternative to conventional heating and cooling systems because of their high efficiency and low greenhouse gas emissions. The ground acts as a heat sink/source for the excess/required heat inside a building for cooling and heating modes, respectively. However, imbalance in heating and cooling needs can change ground temperature over the operating duration. This increase/decrease in ground temperature lowers system efficiency and causes the ground to foul—failing to accept or provide more heat. In order to ensure that GSHPs can operate to their designed conditions, thermal modelling is required to simulate the ground temperature during system operation. In addition, the borehole field layout can have a major impact on ground temperature. In this study, four buildings were studied—a hospital, fast-food restaurant, residence, and school, each with varying borehole configurations. Boreholes were modeled in a soil volume using finite-element methods and heating and cooling fluxes were applied to the borehole walls to simulate the GSHP operation. 20 years of operation were modelled for each building for 2x2, 4x4, and 2x8 borehole configurations. Results indicate that the borehole separation distance of 6 m, recommended by ASHRAE, is not always sufficient to prevent borehole thermal interactions. Benefits of using a 2x8 configuration as opposed to a 4x4 configuration, which can be observed because of the larger perimeter it provides for heat to dissipate to surrounding soil were quantified. This study indicates that it is important to carefully consider ground temperature during the operation of a GSHP. Borehole separation distances, layout, and hybridization should be studied to alleviate ground fouling problems.

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