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Energy Rating Windows for Residential Buildings
Abstract
The present paper describes an example of an energy rating windows for residential buildings in Jordan. It focuses on the thermal properties of the available windows in the market in Jordan. Windows have a great effect on the heating and cooling requirements costs of a building, and the comfort level experienced by its occupants. Windows are considered the weakest link in a building envelope for heat gain in the summertime and heat loss in the wintertime. A survey on the most common windows that are used in residential buildings has been carried out. The label of the window describes the type of window, and rates it for many factors such as U-Factor, SHGC, and visible light transmittance. The output of the present work can give the home owners an opportunity to choose the appropriate window for the building taking into consideration thermal performance of the window and its impact on the cooling and heating load of the building. The energy performance of the building and the choice of energy efficient window are dependent on glazing type, number of glazing, frame materials, interior and exterior, shading, and window orientation. Therefore, it is very important to take into consideration all options when determining which energy-efficient window is best and most cost-effective for your needs both now and in the future. The most important reason to select energy efficient windows is to reduce the annual coast of heating and cooling of the buildings. This makes good sense for the most building owners and it also contributes in the efforts to reduce the bad impacts of the non-renewable energy use.
... It is obvious that the original glass increased the electricity cost, while the implementation of any new types helped decrease the buildings' expenses by up to 50%. Type (2) showed the best performance, followed by type (1), and then by type (3). ...
This paper deals with energy efficient glass in office buildings in Amman city. The objectives of this study are to understand the role of efficient glass in reducing lighting, heating, and cooling demands and the amount savings to achieve. In addition, to suggest main guidelines to follow when designing glazed office buildings for architects and stakeholders. Evaluation of thermal and daylighting performances for a glazed building in Amman was performed by Ecotect and some equations. The reductions in lighting, heating, and cooling loads and energy cost were evaluated through a comparative simulation among three glass types considering four optical and thermal variables; U-Value, Visual Light Transmission (VLT), Solar Heat Gain Coefficient (SHGC), and Solar Coefficient (SC). Results show that the basic factors to enhance buildings energy behavior are: building location and the availability of the solar radiation at the selected location. In addition to the building orientation and glass optical and thermal properties. The energy efficiency of buildings increase when the building orientation is between 125°- 235°, and the installed glass has U-Value less than 1.5 Wm2/k, VLT between (20-50)%, SHGC and SC less than 0.2. The implementation of these properties reduced the building electricity cost for lighting, heating, and cooling by (45-53)%.
... A large proportion of this energy is used for thermal comfort in buildings (Yang, 2012). One area where energy used could be reduced within the building and construction industry is through the use of natural ventilation (Hassouneh et al., 2010). Apart from natural ventilation, the use of zero energy to provide comfort within indoor spaces has its health benefits (Wolkoff, 2012). ...
For environmental evaluation of building operational energy, greenhouse and acidic gases are typically used as appropriate measures. This approach can lead to the loss of additional information concerning other carbon fuel-relevant impacts, such as carcinogenic substances, fossil fuels, and land users. The objective of this study is to analyze three different environmental levels of evaluation: (1) carbon dioxide (CO2) emission (inventory), (2) environmental impacts (midpoint), and (3) environmental damage (endpoint). A simple building module (3×4×3m) facing east, north, south, and west was studied. Eco-Indicator 99 (EI99), a comprehensive damage-oriented lifecycle impact assessment method, was used. Coal was the primary fuel used for electricity production. For each of the three evaluations, an unpaired two-tailed t-test was used to determine the differences between all pairings of the module in the four cardinal orientations. On the basis of inventory and midpoint evaluations, separate optimization of building technology variables is required for each of the cardinal directions; these results were not confirmed by endpoint evaluation. The study informs designers regarding the appropriateness of midpoint evaluation of EI99 (in addition to the CO2 measure) and the need for operational energy consumption to be evaluated from an environmental point of view.
Windows are considered as the major source of heat loss in winter and heat gain in summer. Air infiltration has a major effect on perceived performance of the window. The present paper describes the influence of infiltration on the energy balance for residential buildings. A comparison between fixed fenestration and other types of fenestration systems has been carried out. Air infiltration can account for 30% or more of a home's heating and cooling costs and contribute to problems with moisture, noise, dust, and entry of pollutants. A survey on the most common types of windows used in residential buildings is made. Calculations have been carried out using self developed simulation software.Results show that the clever choice of glazing can save energy and some types of glazing are more efficient in a specific direction than others. The rate of air infiltration depends on many factors, the most important being the size, location of holes in the thermal envelope and the difference in temperature between inside and outside. A better sealed, ventilated and insulated building envelope will save energy and reduce the negative impacts on the environment caused by fossil fuel. Horizontal sliders generally have the worst air infiltration performance of all window types. Beyond the sliding surfaces of the double hung, these windows have frames designed for sash removal. These features, along with necessary provisions for drainage, make it impossible to seal these windows as tightly as a double hung while casement and fixed offer excellent air infiltration performance.
Biodiesel emulsions are considered as the propitious alternative fuels for diesel engines. The need of biodiesel emulsion fuels for the diesel engines is to curtail the dependency on the fossil fuels in context to the world energy oil crisis. Henceforth, the present study provides a tangible pathway to prepare and to ameliorate the biodiesel emulsion fuel on incorporating potential alumina nanoparticles. The biodiesel emulsion fuel is prepared by emulsification technique comprising of 83% of jatropha biodiesel, 15% of water, and 2% of surfactants (Span80 and Tween80) with the aid of a mechanical agitator. The prepared biodiesel emulsion fuel is mixed with the alumina nanoparticles in the mass fractions of say 25, 50, and 100 ppm with the help of an ultrasonicator. The whole investigation is carried out in a constant speed diesel engine in three phases using jatropha biodiesel, jatropha biodiesel emulsion fuel, and alumina nanoparticle blended jatropha biodiesel emulsion fuels. The experimental results revealed a substantial enhancement in the performance and a reduction in harmful emissions for the biodiesel emulsion fuels compared to those of neat biodiesel. In addition, the incorporation of nanoparticles in the biodiesel emulsion fuel has also revealed an incremental better performance and reduced emissions than that of biodiesel emulsion fuel and biodiesel. Furthermore, the significance of shorten ignition delay effect associated with the nanoparticle blended biodiesel emulsion fuels has been investigated and asserted upon conducting a hot-plate evaporation study.
This paper describes the development efforts of RESFEN3.1, a PC-based computer program for calculating the heating and cooling energy performance and cost of residential fenestration systems. The development of RESFEN has been coordinated with ongoing efforts by the National Fenestration Rating Council (NFRC) to develop an energy rating system for windows and slqdights to maintain maximum consistency between RESFEN and NFRC's planned energy rating system. Unlike previous versions of RESFEN, that used regression equations to replicate a large database of computer simulations, Version 3.1 produces results based on actual hour-by-hour simulations. This approach has been facilitated by the exponential increase in the speed of personal computers in recent years. RESFEN3.1 has the capability of analyzing the energy performance of windows in new residential buildings in 52 North American locations. The user describes the physical, thermal and optical properties of the windows in each orientation, solar heat gain reductions due to obstructions, overhangs, or shades; and the location of the house. The RESFEN program then models a prototypical house for that location and calculates the energy use of the house using the DOE-2 program. The user can vary the HVAC system, foundation type, and utility costs. Results are presented for the annual heating and cooling energy use, energy cost, and peak energy demand of the house, and the incremental energy use or peak demand attributable to the windows in each orientation. This paper describes the capabilities of RESFEN3.1, its usefulness in analyzing the energy performance of residential windows and its development effort and gives insight into the structure of the computer program. It also discusses the rationale and benefits of the approach taken in RESFEN in combining a simple-to-use graphical front-end with a detailed hour-by-hour ''simulation engine'' to produce an energy analysis tool for the general public that is user-friendly yet highly accurate.
A user friendly and simple program implementation of an energy-rating tool for windows is presented in this chapter. The program takes hourly climate data of direct and diffuse radiation, and temperature into account. The building is reduced to one parameter, the balance temperature that defines if solar throughput is useful or not. This means that the energy efficiency of different windows can be compared without having access to detailed information about the building but still the type of building is taken into account. Window in-data are the total solar energy transmittance (g-value), the thermal leakage (U-value), and the type of coating for prediction of angle dependence characteristics. Output can be presented as saved energy compared to a selected base case window, for instance, an uncoated double-glazed unit. The model can be used for energy rating for both heating and cooling, and to take into account different type of buildings such as buildings with high or low-cooling requirements.
A general computer simulation model, ψ, for predicting average hourly diffuse solar radiation, developed and tested for Amman, Jordan, is presented in this paper. This model is based on three simple components with a control function ψ that can be switched on ( ψ = 1) or off ( ψ = 0) or set at half way position between on and off ( ψ = 0.5), The three components which constitute the ψ model are a normal distribution, a half-sine wave, and a polynomial of the fourth degree. These are individually tested as separate models. It is determined that none of them is alone adequately acceptable for the tested data. It is found that for an error of 1% or less, the polynomial model - although it is the best of the three - represents the data for only 18 hours of the year or 10% of the time while the ψ model represents 53 hours or about 29% of the time. The acceptability of the three models increases with an increase of the upper limit of error. If the error is 10% or less the polynomial model represents the data for 92 hours or about 51% of the time of the year compared with 122 hours or about 68% of the time of the year representable by the ψ model. It is also shown that the ψ model can represent the data for up to 92.4% of the time if the two early morning and the two late afternoon hours are neglected.
The influence of windows on the energy balance of apartment buildings in Amman is investigated by using self developed simulation software (SDS) based on the ASHRAE tables for solar heat gain calculation and coaling load factor for latitude 32°, where Amman city is located. The calculations of energy saving are made to find out the influence of windows on the energy balance of apartment buildings in Amman. Also, the present investigation aimed to study the energy performance of windows of an apartment building in Amman in order to select the most energy efficient windows that can save more energy and reduce heating load in winter, the percentage of saving energy and saving fuel and money through time.Variations of type of glazing using eight types of glazing (clear glass, types A, B, C, D, E, F, and G) are made to find out the most appropriate type of glazing in each direction. Also the orientation of window is changeable in the main four directions (N, S, E and W). The area of glazing varies also in different orientation to find the influence of window area on the thermal balance of the building. The results show that if energy efficient windows are used, the flexibility of choosing the glazed area and orientation increases.It has been found that choosing a larger area facing south, east and west can save more energy and decrease heating costs in winter using certain types of glazing such as glass type A and clear glass, while decreasing the glazing area facing north can save money and energy. However, it has been found that the energy can be saved in the north direction if glass type B has been used. In the apartment building, it is found that certain combination of glazing is energy efficient than others. This combination consists of using large area of glass type A in the east, west and south direction, and glass type B in the north direction or reducing glazing area as possible in the north direction.
As measured solar radiation data for all parts of Jordan are not available, they have to be estimated using correlation relations and models. This paper presents, for the first time, values of solar radiation over Jordan as estimated from these relations. Measurements of global solar irradiance on a horizontal surface and sunshine duration at nine meteorological stations in Jordan are correlated and used for prediction of the regression coefficients of an Angstrom type correlation relation at these stations and others which only have records of sunshine duration. Regional regression coefficients are obtained and used for prediction of global solar irradiance. The agreement with measurements is better than 5% and 1% on monthly and yearly basis respectively. Estimation of diffuse solar irradiance by Page's and also Liu and Jordan's correlations, as well as the direct beam component are also performed and the results are examined and presented. The abundance of solar energy in Jordan is evident from the daily average global solar irradiance which ranges between 5 and 7 kWh/m2. A correlation of Angstrom type of the form: H/Ho = 0.448+0.203 S/So is found suitable for Jordan with correlation coefficient r = 0.93.
An efficient way of determining some of the glazing related variables is described, thus enabling thermal performance to be considered easily at the early design stage when inexpensive measures of heating and cooling can be advocated and tested. L'auteur présente une méthode efficace pour la détermination des variables liées aux vitrages. Cette méthode permet de réfléchir à la performance thermique dès les premiers stades de la conception, au moment o[ugrave] il est encore possible de précondiser et de tester des moyens peu coÛteux de chauffage et de climatisation.
The substantial progress in the science and technology of vacuum glazing that has occurred over the past few years is reviewed. Vacuum glazing up to 1 m × 1 m in size has been produced with an air-to-air, mid-device thermal conductance as low as 0.90 W m−2 K−1, compared with 1.3 W m−2 K−1 for high performance double glazing. The mechanical tensile stresses in vacuum glazing due to pressure and temperature differentials are well understood, and appear to be tolerably small. The internal vacuum is high, and extremely stable over long times at moderate temperatures. The likely cost of volume production of vacuum glazing should be only slightly greater than for high performance double glazing.
With worldwide energy cost rising significantly, there has been a pressing need to reduce the burning of fossil fuels and subsequently energy consumption. This, coupled with the prospect of global warming threatening human habitation, has made countries including Singapore more conscious and aware of the energy problem at hand. This paper deals with smart window, a double glazing unit where one pane consists of a high-performance heat reflective glass and the other coated with low-emissivity (low-e) coating. This combination of glazing provides optimum energy efficiency and a high level of daylight transmission with minimal reflectance. A study is made on the benefits derived from smart window done on a hypothetical 20-storey building. This encompasses a description of its quantitative impact on cooling load, energy consumption and energy savings achieved as compared with other forms of glazing. Following this, a detailed life cycle costing is done to determine the economic benefits attained from this type of glazing. The reduction of atmospheric pollutants as a result of using smart window is also analysed, and the future application of the glazing in hot and humid climates is discussed. In conclusion, it is observed that the smart window meets the technical and economic targets set, thus making it a viable long-term investment for high-rise commercial buildings.
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