scholarly journals Component sequence and thermal mass effects on the transient thermal performance of concrete walls

2021 ◽  
Vol 2069 (1) ◽  
pp. 012091
Author(s):  
B Salehpour ◽  
M Ghobadi ◽  
T Moore ◽  
H Ge
Keyword(s):  
Thermal Resistance ◽  
Energy Use ◽  
Energy Savings ◽  
Mass Effect ◽  
Heat Fluxes ◽  
Thermal Mass ◽  
Concrete Walls ◽  
Heating And Cooling ◽  
Concrete Form ◽  
Transient Thermal

Abstract The increased requirements of buildings to reduce energy use have highlighted the importance of accounting for all factors that influence energy use in buildings. One consideration that requires further study in the envelope design of concrete-based wall assemblies is the placement of the thermal mass layer. In this study, two thermally massive walls, Insulated Concrete Form (ICF) and tilt-up walls, with the same thermal resistance but different sequencing of layers are investigated. In addition, a wall made of a homogeneous insulation layer with an identical thermal resistance was considered to further investigate the thermal mass effect on the potential for energy savings. Results of the numerical simulations performed using COMSOL Multiphysics® software indicate that, for the transient scenarios investigated, thermal mass can contribute to shifting and dampening peak heating and cooling loads, as well as saving energy. Also, less intense fluctuations were observed in the heat fluxes when considering the ICF wall. Energy savings during the primary seasons (i.e. winters in Montreal and summers in Miami) are found to be marginal but the existence of a thermally massive layer considerably reduced the demands during secondary seasons i.e. summers in Montreal and winters in Miami.

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 Comparison Evaluations of VRF and RTU Systems Performance on Flexible Research Platform

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Je-hyeon Lee ◽  
Piljae Im ◽  
Jeffrey D. Munk ◽  
Mini Malhotra ◽  
Min-seok Kim ◽  
...  
Keyword(s):  
Energy Use ◽  
Energy Savings ◽  
Thermal Conditions ◽  
The United States ◽  
Energy Performance ◽  
Coefficient Of Performance ◽  
Part Load ◽  
Variable Air Volume ◽  
Heating And Cooling ◽  
Load Conditions

The energy performance of a variable refrigerant flow (VRF) system was evaluated using an occupancy-emulated research building in the southeastern region of the United States. Full- and part-load performance of the VRF system in heating and cooling seasons was compared with a conventional rooftop unit (RTU) variable-air-volume system with electric resistance heating. During both the heating and cooling seasons, full- and part-load conditions (i.e., 100%, 75%, and 50% thermal loads) were maintained alternately for 2 to 3 days each, and the energy use, thermal conditions, and coefficient of performance (COP) for the RTU and VRF system were measured. During the cooling season, the VRF system had an average COP of 4.2, 3.9, and 3.7 compared with 3.1, 3.0, and 2.5 for the RTU system under 100%, 75%, and 50% load conditions and resulted in estimated energy savings of 30%, 37%, and 47%, respectively. During the heating season, the VRF system had an average COP ranging from 1.2 to 2.0, substantially higher than the COPs of the RTU system, and resulted in estimated energy savings of 51%, 47%, and 27% under the three load conditions, respectively.

scholarly journals Thermal mass and the effects on heating and cooling demands – an experimental study of an exposed concrete floor

2020 ◽  
Vol 172 ◽  
pp. 03004
Author(s):  
Alessandro Nocente ◽  
Steinar Grynning
Keyword(s):  
Energy Demand ◽  
Energy Use ◽  
Positive Impact ◽  
Thermal Mass ◽  
Wooden Floor ◽  
Heating Systems ◽  
Heating And Cooling ◽  
Experimental Campaign ◽  
Office Rooms ◽  
Positive Effect

The increase of thermal mass in buildings is discussed as a useful measure for reducing the energy demand for heating and cooling while contributing to improve the internal comfort. Several studies confirmed its positive effect, but few conducted a solid comparative measurement campaign and rarely in comparative conditions. The present work reports the results of an extensive comparative campaign in a test cell facility, where the internal conditions are measured in two identical rooms. One of the rooms was equipped with a large concrete mass while the other was constructed with a thin wooden floor. Measurements were conducted for circa a month, divided in four phases. The internal temperature of the two rooms was kept within typical boundaries of actual office rooms by a water-based cooling and heating systems. The energy demand of both heating and cooling was measured. Occupancy was simulated by a mannequin and by the lighting, both active only in office hours. The results demonstrated a positive impact of the thermal mass on the energy use. Since the test rooms are highly insulated, the energy use associated to cooling was dominant. During the experimental campaign, a reduction of up to 44% of the energy demand due to cooling was registered.

scholarly journals Heating and cooling requirement of an office building and urban rooftop greenhouse

2021 ◽  
Author(s):  
Andrea Vickers
Keyword(s):  
Food Security ◽  
Energy Consumption ◽  
Urban Agriculture ◽  
Energy Savings ◽  
Simulation Software ◽  
Office Building ◽  
Thermal Mass ◽  
Heating And Cooling ◽  
Several Variables ◽  
Potential Impact

Urban agriculture is an important step towards food security in cities where rooftop space is abundant, and underused. This research addresses the potential impact of adding a rooftop greenhouse to a six storey, detached office building on the total heating and cooling energy consumption of both structures operated year‐round, using IES‐VE simulation software. Several variables including the level of insulation between the office building and greenhouse, additional thermal mass, the greenhouse envelope and greenhouse internal loads were tested to observe trends that suggest an impact on the system’s conditioning energy due to the presence of the greenhouse. Overall, it was found to be most likely that the greatest energy savings for an integrated office building and rooftop greenhouse would be achieved with the highest resistance greenhouse envelope possible, which may be limited by the light needs of plants grown in the greenhouse, and incorporation of thermal mass in the greenhouse.

scholarly journals Thermochromic Paints on External Surfaces: Impact Assessment for a Residential Building through Thermal and Energy Simulation

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 1912 ◽  
Author(s):  
Vasco Granadeiro ◽  
Margarida Almeida ◽  
Tiago Souto ◽  
Vítor Leal ◽  
João Machado ◽  
...  
Keyword(s):  
Energy Use ◽  
Energy Savings ◽  
Residential Buildings ◽  
Residential Building ◽  
Cost Effective ◽  
Physical Models ◽  
Indoor Temperature ◽  
Heating And Cooling ◽  
Step Transition ◽  
Linear Manner

This work addresses the effect of using thermochromic paints in residential buildings. Two different thermochromic paint types were considered: One that changes properties through a step transition at a certain temperature, and another that changes properties in a gradual/linear manner throughout a temperature range. The studied building was a two-floor villa, virtually simulated through a digital model with and without thermal insulation, and considering thermochromic paints applied both on external walls and on the roof. The performance assessment was done through the energy use for heating and cooling (in conditioned mode), as well as in terms of the indoor temperature (in free-floating mode). Three different cities/climates were considered: Porto, Madrid, and Abu Dhabi. Results showed that energy savings up to 50.6% could be reached if the building is operated in conditioned mode. Conversely, when operated in free-floating mode, optimally selected thermochromic paints enable reductions up to 11.0 °C, during summertime, and an increase up to 2.7 °C, during wintertime. These results point out the great benefits of using optimally selected thermochromic paints for obtaining thermal comfort, and also the need to further develop stable and cost-effective thermochromic pigments for outdoor applications, as well as to test physical models in a real environment.

Design and Performance of the Van Geet Off-Grid Home

2004 ◽  
Vol 126 (2) ◽  
pp. 738-743 ◽  
Author(s):  
C. Dennis Barley ◽  
Paul Torcellini ◽  
Otto Van Geet
Keyword(s):  
Computer Simulation ◽  
Energy Efficient ◽  
Performance Monitoring ◽  
Energy Use ◽  
Energy Savings ◽  
Energy Performance ◽  
Hot Water ◽  
Domestic Water ◽  
Heating And Cooling ◽  
And Performance

The Van Geet home near Denver, Colorado, demonstrates the successful integration of energy conservation measures and renewable energy supply in a beautiful, comfortable, energy-efficient, 295-m23,176-ft2 off-grid home in a cold, sunny climate. Features include a tight envelope, energy-efficient appliances, passive solar heating (direct gain and Trombe wall), natural cooling, solar hot water, and photovoltaics. In addition to describing this house and its performance, this paper describes the recommended design process of (1) setting a goal for energy efficiency at the outset, (2) applying rules of thumb, and (3) using computer simulation to fine-tune the design. Performance monitoring and computer simulation are combined for the best possible analysis of energy performance. In this case, energy savings are estimated as 89% heating and cooling (compared to 95 MEC), 83% electrical, and nearly 100% domestic water heating. The heating and cooling energy use is 8.96kJ/°Cs˙days˙m20.44Btu/°Fs˙days˙ft2.

scholarly journals Evaluating the impact of different pipe arrangements on the thermal performance of thermo-active piles

2020 ◽  
Vol 205 ◽  
pp. 05006
Author(s):  
Ryan Y. W. Liu ◽  
Eleonora Sailer ◽  
David M. G. Taborda ◽  
David M. Potts
Keyword(s):  
Thermal Performance ◽  
Energy Use ◽  
Near Field ◽  
Heat Fluxes ◽  
Far Field ◽  
Low Carbon ◽  
Finite Element Analyses ◽  
Heating And Cooling ◽  
The Impact ◽  
Evolution With Time

Thermo-active piles are widely utilised for low carbon heating and cooling, and their uses are further encouraged in cities where there are obligations for developments larger than a certain threshold to generate a portion of their estimated energy use on site in a renewable manner. It is therefore important to model accurately the thermal performance of the designed thermo-active piles to ensure that such obligations are complied with. In this paper, the thermal performance of a thermo-active pile is quantified by the evolution with time of the power that can be harnessed from the pile, obtained from 3D thermo-hydro-mechanically coupled finite element analyses which include the simulation of a hot fluid flowing through heat exchanger pipes. Different pipe arrangements are considered in this study, in order to demonstrate the potential gains in efficiency arising from the installation of multiple U-loops within the pile. Furthermore, detailed analysis of the heat fluxes resulting from pipe-pile-soil interaction is carried out, illustrating the contribution of the different components of the system (concrete, near-field and far-field) to the overall storage of thermal energy.

Experimental Study on Load Bearing Capacity of Cement Stabilized Unburnt Clay Bricks

2021 ◽  
Author(s):  
J.Z. Mohamed ◽  
◽  
K.A.B.P. Kuruppu ◽  
Keyword(s):  
Energy Use ◽  
Cost Savings ◽  
Thermal Mass ◽  
Clay Material ◽  
Clay Brick ◽  
Load Bearing Capacity ◽  
Clay Bricks ◽  
Masonry Construction ◽  
Heating And Cooling ◽  
The World

Clay brick is one of the most widely used conventional materials in the masonry construction throughout the world. Despite living in cement age, bricks still have a defined space in our societies. Clay bricks are good for construction activities in dry zones because of its better thermal insulation and moisture control properties. With around 39 percent of the home’s energy use going towards maintaining a pleasant temperature, it has become increasingly important to build a home that will minimize the energy required for heating and cooling, from both a cost savings and sustainability perspective [1]. Bricks made with clay material can be the better option to neutralize the above condition since bricks offer superior thermal mass.

Optimization of Thermal Mass in Commercial Building Applications

1990 ◽  
Vol 112 (4) ◽  
pp. 273-279 ◽  
Author(s):  
M. Judson Brown
Keyword(s):  
Energy Savings ◽  
Thermal Storage ◽  
Office Building ◽  
Base Case ◽  
Thermal Mass ◽  
Commercial Building ◽  
Heating And Cooling ◽  
Initial Cost ◽  
Heavy Construction ◽  
Cooling Loads

Based on results from a one-year intensive monitoring project of a Northern New York commercial building with energy-conserving design features, a thermal storage project was undertaken to optimize the design of a thermal mass storage system for a moderately sized commercial building and transfer the technology to the commercial building sector. A generic commercial building design of 27,000 square feet (2508 m2) was selected for the optimization project. Several different types of thermal mass designs were considered as potentially practical for a commercial building. These included a “sandmass” design such as the mass incorporated in the previously monitored commercial building mentioned above, a foundation slab of sufficient thickness to serve as a significant building thermal mass, and the use of poured cement in interior wall and floor construction. Five different office building thermal designs were selected which represented various thermal storage features and two different building insulation levels (R10 and R20). Energy performance of the five thermal designs was modeled in building energy simulations using DOE 2.1C (Department of Energy 2.1C) energy simulation code. Results of the simulations showed a reduction in peak heating and cooling loads would be experienced by the HVAC equipment. The reduction in peak heating and cooling loads was anticipated because thermal mass within a building serves to average peak heating and cooling loads due to the capacity of the thermal mass to store and release heat from all building heat sources over a period of time. Peak heating loads varied from 1972 kBtuh (578 kW) for the R-10 light construction base case to a minimum of 980 kBtuh (287 kW) for the R-20 heavy construction sandmass storage case. Peak cooling loads dropped from 772 kBtuh (226 kW) for the R-20 light construction case to 588 kBtuh (172 kW) for the R-20 heavy construction sandmass storage case. Results of the simulations also showed annual energy savings for the high thermal mass designs. Energy savings varied from 20 percent [16.0 kBtu/ft2 (50 kWh/m2)] for the R-10 high thermal mass design in comparison to its base case to 18 percent [12.2 kBtu/ft2 (39 kWh/m2)] for the R-20 high thermal mass design in comparison to its base case. The annual energy savings are due to the ability of the thermal mass to absorb heat from all sources of heat generation (lights, occupancy, solar, and auxiliary) during occupied periods and release the heat during unoccupied periods. An optimized thermal design was developed based on results from the DOE 2.1C simulations. The initial cost for the optimized thermal storage design is lower than the initial costs for light construction office buildings, since the lower initial cost of the down-sized HVAC system for the optimized thermal storage design more than offsets the increased cost of wall and floor systems incorporated in the optimized design. Annual energy savings are realized from the high thermal mass system in both cooling and heating modes due to the interaction of building HVAC systems operation in the simulated 27000 ft2 (2508 m2) office building. Annual operating savings of $3781 to $4465 per year are estimated based on simulation results.

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