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Fundamentals of energy transfer in buildings
Published in V.S.K.V. Harish, Amit Vilas Sant, Arun Kumar, Renewable Energy Integration with Building Energy Systems, 2022
V.S.K.V. Harish, Nayan Kumar Singh, Arun Kumar, Karan Doshi, Amit Vilas Sant
Apart from the external walls and roofs, windows and skylights are the key components of a building envelope, through which heat transfer takes place between the indoor space and outdoor space. Window glass is generally much thinner and more transparent as compared to the external walls, and therefore, solar radiation penetration occurs easily in windows. In fact, it dominates the heat gain or loss of a heated or air-conditioned space in the building.
Design and Health Considerations
Published in Traci Rose Rider, Margaret van Bakergem, Building for Well-Being, 2021
Traci Rose Rider, Margaret van Bakergem
There can be an inverse relationship between energy efficiency and indoor air quality, given that increased ventilation and fresh air – common strategies for elevating indoor air quality – requires more energy consumption for that added circulation. Similarly, a tighter building envelope, a strategy often cited for increasing energy efficiency, may actually contribute to harmful indoor air quality issues such as mold and chemical build up. However, there can be synergies between the two, such as increased insulation which helps not only to support energy efficiency but also to help the HVAC system better filter airborne particles like dust and spores from the indoor environment. The relationships between energy efficiency and air quality are very particular and nuanced and should be addressed thoroughly on a case-by-case basis.
House As a System
Published in Stan Harbuck, Donna Harbuck, Residential Energy Auditing and Improvement, 2021
The Thermal Boundary: The thermal boundary is essentially the insulation in the walls, attic, crawlspace, etc. of a home. Because it is made of insulation, the thermal boundary can be easily identified. Common insulation materials include cellulose, fiberglass, and vermiculite. Insulation acts as a resistor to heat flow or conductive heat loss through the building envelope, and limits heat flow between the inside and the outside of the house. Even small areas of missing insulation can make a big difference in the thermal boundary. Voids in insulation of only 7% can reduce the effective thermal resistance (R-value) by almost half. As an example, if there is a roughly 1000 ft² attic space above a home that is insulated to R-38, the affective R-value falls to 19 when only 70 ft² of insulation is removed.
Influential aspects on melting and solidification of PCM energy storage containers in building envelope applications
Published in International Journal of Green Energy, 2021
The building sector is considered as one of the most critical sectors in terms of energy consumption. Globally, buildings are responsible for 30–40% of national energy consumption and 40–50% of greenhouse gas emissions (Abd Rashid and Yusoff 2015). Building envelope is a critical key for maintaining building energy as it directly controls the heat energy between indoor and outdoor environments under hot and cold locations (Biswas et al. 2019)(Al-Yasiri, Al- Furaiji, and Alshara 2019). According to the International Energy Agency (IEA), most expenditures and investments in the building sector have been spent on building envelopes. Furthermore, envelope constructions and renovations worldwide are responsible for 36% and 39% of final building energy and energy-related CO2 emissions, respectively, in the year 2018 (International Energy Agency, UN Environment Programme 2019). Official global bodies and research centers have tended to adopt different methods to reduce energy consumption in buildings by implementing different strategies and technologies (Azuatalam et al. 2020)(International Energy Agency (IEA) 2013)(Luo et al. 2020). Researchers in the last few decades turned to incorporate phase change materials (PCMs) with building constructions thanks to their ability to manage the heat energy through the building envelope during phase transition and bridge between the supply and demand of energy (Madad, Mouhib, and Mouhsen 2018)(Zeinelabdein, Omer, and Gan 2018).
Determination of economical thermal insulation thickness for a building wall with two parallel structures
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2020
Jianen Huang, Henglin Lv, Wei Feng, Pei Qu, Zhaochen Huang
Building energy consumption accounts for approximately 40% of the total energy demands in many countries. The energy requirement for space heating and air conditioning is approximately 60% of the total energy consumption in buildings, which is the largest percentage of energy consumption (Kaynakli 2012). External wall thermal insulation can improve the thermal performance of a building envelope and effectively reduce the cooling and heating energy consumption of buildings. The thicker the thermal insulation is, the smaller the building cooling and heating load and the better the energy-saving effect. However, increasing thermal insulation thickness can result in an increased investment cost. Consequently, thermal insulation thickness should be determined by both the energy-saving effect and investment cost.
Application of passive measures for energy conservation in buildings – a review
Published in Advances in Building Energy Research, 2019
Farhad Amirifard, Seyed Amirhosain Sharif, Fuzhan Nasiri
The building envelope, especially its external walls, plays a significant role in energy conservation. In this sense, using a passive system, energy is stored during the daytime in the outer surfaces and this energy can be used to warm up the indoor at night. The heat storage capability of a building can be identified as its thermal mass, especially in passive solar spaces design techniques (Ozel & Pihtili, 2007; Reardon, McGee, & Milne, 2013). Therefore there must be integration between thermal mass and insulation place (to compensate the thermal bridges) to reach the high indoor thermal comfort condition. Many studies have been done to determine the optimum location of insulation. Thermal bridges essentially define the conditions in a building envelope in which thermal resistance varies considerably. Therefore, it causes a significant amount of heat gain (in summer) and heat loss (in winter) through the building envelope. One of the common ways is to put an insulation layer on different surfaces of the wall (inner surface, outer surface or in the middle) with different thicknesses and calculate the thermal mass capability of the wall by considering the maximum time lag and minimum decrement factor. In this sense, we provide an overview of the thermal mass and thermal bridge concepts.