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Building-energy Performance Gap
A building-energy performance gap is a disparity between the energy consumption predicted in the design stage of a building and the energy use in actual operation. It can have many causes. Classification of factors that contribute to the performance gap The performance gap is mainly due to uncertainties. Uncertainties are found in any “real-world” system, and buildings are no exception. As early as 1978, Gero and Dudnik wrote a paper presenting a methodology to solve the problem of designing subsystems (HVAC) subjected to uncertain demands. After that, other authors have shown an interest in the uncertainties that are present in building design; uncertainties in building design/construction can be classified into three groups: # Environmental. Uncertainty in weather prediction under changing climate; and uncertain weather data information due to the use of synthetic weather data files: (1) use of synthetic years that do not represent a real year, and (2) use of a synthetic year t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HVAC
Heating, ventilation, and air conditioning (HVAC) is the use of various technologies to control the temperature, humidity, and purity of the air in an enclosed space. Its goal is to provide thermal comfort and acceptable indoor air quality. HVAC system design is a subdiscipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics, and heat transfer. " Refrigeration" is sometimes added to the field's abbreviation as HVAC&R or HVACR, or "ventilation" is dropped, as in HACR (as in the designation of HACR-rated circuit breakers). HVAC is an important part of residential structures such as single family homes, apartment buildings, hotels, and senior living facilities; medium to large industrial and office buildings such as skyscrapers and hospitals; vehicles such as cars, trains, airplanes, ships and submarines; and in marine environments, where safe and healthy building conditions are regulated with respect to temperature and humidity, using ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermal Bridge
A thermal bridge, also called a cold bridge, heat bridge, or thermal bypass, is an area or component of an object which has higher thermal conductivity than the surrounding materials, creating a path of least resistance for heat transfer.Gorse, Christopher A., and David Johnston (2012). "Thermal bridge", in ''Oxford Dictionary of Construction, Surveying, and Civil Engineering''. 3rd ed. Oxford: Oxford UP, 2012 pp. 440-441. Print. Thermal bridges result in an overall reduction in thermal resistance of the object. The term is frequently discussed in the context of a building's thermal envelope where thermal bridges result in heat transfer into or out of conditioned space. Thermal bridges in buildings may impact the amount of energy required to heat and cool a space, cause condensation (moisture) within the building envelope, and result in thermal discomfort. In colder climates (such as the United Kingdom), thermal heat bridges can result in additional heat losses and require addition ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
U-value
In the context of construction, the R-value is a measure of how well a two-dimensional barrier, such as a layer of insulation, a window or a complete wall or ceiling, resists the conductive flow of heat. R-value is the temperature difference per unit of heat flux needed to sustain one unit of heat flux between the warmer surface and colder surface of a barrier under steady-state conditions. The ''R-value'' is the building industry term for thermal resistance "per unit area." It is sometimes denoted RSI-value if the SI units are used. An R-value can be given for a material (e.g. for polyethylene foam), or for an assembly of materials (e.g. a wall or a window). In the case of materials, it is often expressed in terms of R-value per metre. R-values are additive for layers of materials, and the higher the R-value the better the performance. The U-factor or U-value is the overall heat transfer coefficient and can be found by taking the inverse of the R-value. It is a property ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Passivhaus
"Passive house" (german: Passivhaus) is a voluntary standard for energy efficiency in a building, which reduces the building's ecological footprint. It results in ultra-low energy buildings that require little energy for space heating or cooling. A similar standard, MINERGIE-P, is used in Switzerland. The standard is not confined to residential properties; several office buildings, schools, kindergartens and a supermarket have also been constructed to the standard. The design is not an attachment or supplement to architectural design, but a design process that integrates with architectural design. Although it is generally applied to new buildings, it has also been used for refurbishments. In 2008, estimates of the number of passive house buildings around the world ranged from 15,000 to 20,000 structures. In 2016, there were approximately 60,000 such certified structures of all types worldwide. The vast majority of passive structures have been built in German-speaking countrie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Time-use Survey
A time-use survey is a statistical survey which aims to report data on how, on average, people spend their time. Objectives The objective of the Time-Use survey is to identify, classify and quantify the main types of activity that people engage in during a definitive time period, e.g. a year, a month, etc. Many surveys are used for calculation of unpaid work done by women as well as men in particular locality. File:Time spent on activities on an average day, by sex, Sweden, OWID.svg File:Time spent on domestic work, per day, men vs women, OWID.svg File:Time spent on free time activities, per day, men vs women, OWID.svg File:Time spent on gainful work-study, per day, men vs women, OWID.svg File:Time spent on leisure, per day, men vs women, OWID.svg File:Time spent on leisure, social, and associative life per day, OWID.svg File:Time spent on meals and personal care, per day, men vs women, OWID.svg File:Time spent on paid work or study, per day, men vs women, OWID.svg File:Tim ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Energy Efficiency
Energy efficiency may refer to: * Energy efficiency (physics), the ratio between the useful output and input of an energy conversion process ** Electrical efficiency, useful power output per electrical power consumed ** Mechanical efficiency, a ratio of the measured performance to the performance of an ideal machine ** Thermal efficiency, the extent to which the energy added by heat is converted to net work output or vice versa ** Luminous efficiency, a measure of how well a light source produces visible light ** Fuel efficiency, the efficiency of converting potential energy in a fuel into kinetic energy ** Energy efficiency in transportation, the fuel economy of various modes of transportation ** Energy-efficient landscaping, a type of landscaping designed for the purpose of conserving energy * Efficient energy use, minimizing the amount of energy used for a given, constant energy service * Energy conservation, reducing energy consumption by using less of an energy service See ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
