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Influence of infiltration on the energy losses in residential buildings in Amman
Abstract
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.
... In terms of architecture, the shape of the building and its compactness, the arrangement of rooms in the building, and its orientation are crucial [7]. With regard to construction, the influence of airtightness and building technology has been proved [8]. For technical equipment, the energy consumption is influenced by the heating, ventilation, and air conditioning systems used, the type of heating/cooling source, the presence of a building management system, and systems for automatic control and regulation. ...
... The regression equation adequately describes the results of the calculation if the F value is significantly greater than the tabular value F t at the significance level p and degrees of freedom f 1 and f 2 , in the analysis F t = F 0.05; 23;9 = 2.910 [60]. The calculated F value of model (8), developed for Wrocław, is 351.840, and for model (10), for Suwałki, F III = 434.465. For model (9), for Białystok, F II = 635.739 ...
... In a similar way, based on the obtained models (8) and (10) of the dependence of the usable energy demand for heating and ventilation of a single-family building on selected factors, mathematical descriptions of equally energy-efficient windows for Wrocław and Suwałki were created. Using appropriate algebraic simplifications of models (8) and (9), the mathematical descriptions of the recommended window parameters ensuring equal energy efficiency of windows have the following form: ...
Location is crucial when it comes to reducing the energy demand of buildings. Deterministic mathematical models of the energy demand of a single-family building were developed for the cities of Wrocław and Suwałki, representing the mild and severe climatic conditions of Poland, respectively, and compared with energy demand for Białystok, representing medium conditions. Models include the windows area, heat transfer coefficient, solar radiation transmittance of glazing, and orientation of windows. For medium conditions (Białystok), the energy demand is 18.3% higher than for mild conditions (Wrocław) and 7.3% lower than for severe climate conditions (Suwałki). Location does not influence the nature of the effect of the factors on energy demand, which increases with an increase in heat transfer coefficient and a decrease in window area, glazing solar radiation transmittance, and orientation change from north to south. The large impact of solar gains was proved. The optimisation procedure was performed and mathematical descriptions of recommended parameters were created to ensure the equivalent energy efficiency of windows for each orientation and location. For Bialystok, north-facing windows can have an area 1.32 times larger and south-facing windows 1.48 times smaller than east-facing windows to ensure a building’s energy demand remains constant.
... Air infiltration through the building envelope is one of main mechanisms that directly affect both the energy performance of buildings and the quality of the indoor environment [18], [19]. Air infiltration is a term commonly used 5 to designate uncontrolled and unintentional air flows through the building envelope, through holes, cracks, voids and unsealed joints. ...
... to system overdesign and uncertainty in building simulation. Air infiltration represents heat loss in winter and excessive daytime heat load in summer [19], and affects the performance of mechanical or hybrid ventilation systems. Infiltration may represent a significant fraction of untreated air entering buildings with mechanical extraction, even with purposively designed inlet devices, or where unbalance is created by pressure differences in other types of mechanical systems. ...
In this paper some of the recent developments and ongoing work at the Energy, Environment and Comfort research group of ADAI (Association for the Development of Industrial Aerodynamics), in the areas of Indoor Environmental Quality and Energy Efficiency in Buildings are presented. Summarily, it is showcased a state of the art of the Indoor Live Lab, developed at the Mechanical Engineering Department of the University of Coimbra.
The Indoor Live Lab (I2L) is a new platform for research and technology demonstration in Indoor Environmental Quality (IEQ). The main motivation for initiating this effort arose from the increasing necessity that researchers, educators and decision makers have for continuously available monitored data on all aspects of building functioning. This paper aims at presenting early developments at the I2L, as well as associated research projects which were at the centre of its creation. Firstly, the objectives of the I2L are presented. Secondly, ongoing research on both residential buildings and services buildings is exposed. After, the several IEQ parameters studies are discussed in particular. This is followed by the I2L description, location and specific features. Finally, a conclusion and future work section is presented.
... In Mediterranean regions, the impact of infiltration on the building heating and cooling energy demand ranged from 2.43 to 16.44 kWh/m 2 and 0.54 to 3.06 kWh/m 2 per year, respectively (Feijo-Munoz et al., 2019). In Amman, the building heat loss caused by infiltration accounted for approximately 10 % of the total heat loss (Hassouneha et al., 2012). Changes in air temperature and humidity affect the building energy demand by paths such as infiltration and heat conduction through the envelope. ...
... 38 According to a study of low-rise residential units in Amman, Jordan, air infiltration can account for 30% or more of the expenditures for heating and cooling. 39 In an urban setting, poor indoor air quality within a building is also caused by air intrusion. The wet outside air tends to condense around the crevices when it enters a colder environment. ...
Better insulation or material with low thermal conductivity is a crucial factor in new construction and retrofitting existing structures where energy efficiency is the objective. Effective energy savings need the careful selection of construction materials to accomplish this. For this purpose, in this research work, a typical residential flat is taken into account. Using the hourly analysis program (HAP 4.90) software, the cooling and heating load is determined. Eight influencing factors, including building orientation (A), overall heat transfer coefficient of wall (B), roof insulation material (C), roof insulation thickness (D), heat transfer coefficient of glass (E), window to wall ratio (F), air infiltration flow rate (G), and bypass factor of air-conditioner (H) at three levels, are chosen to optimize the cooling and heating load. An orthogonal L27 layout is considered for the optimization, and the cooling and heating load has been determined for each experimental attempt. At first using Taguchi method, ANOVA analysis is done separately for each response variable and later using GRA and TOPSIS based Taguchi analysis, multi-objective optimization has been done, and the results are compared with each other. By determining each factor’s percentage contribution to the cooling and heating load, the ANOVA approach is also used to identify the primary components that have a major impact on the cooling and heating load. The outcome demonstrates that A3B2C2D3E1F1G1H1 is the best possible combination of all eight variables, and overall heat transfer coefficient of wall is the most influencing parameter for the residential buildings.
... Air infiltration can represent 30 % or more of the cooling costs of a constructed space and contributes to problems of humidity, noise, dust and contaminants. To reduce the energy losses due to air infiltration, it is recommended to reduce the glazed area or implement windows that reduce the infiltration or exfiltration rate (Hassouneh et al., 2012). ...
The evaluation and results of a thermal balance is presented for a building located at latitude 18° N, in an intercultural university community in the "Sierra de los Tuxtlas" (Tuxtlas Mountains), southeast of Mexico. The case study corresponds to the main building of the Intercultural University of Veracruz "Las Selvas" which is able to house the library, a center for learning native languages and a computing. In order to maintain thermal comfort conditions in this space, the use of an air conditioning system is required, which works at its maximum capacity, implying high consumption of electrical energy, as well as important maintenance expenses. The objective of this work was to evaluate the thermal load of the building considering the American Society of Heating, Refrigeration and AirConditioning Engineers (ASHRAE) methodology in order to reduce the consumption of the electric energy required for the use of air conditioning, which is of vital importance in this tropical zone. In the first stage of evaluation, the following assumptions were considered: (a) the loads related to the glazed enclosures (radiation, conduction and infiltration of air), (b) the effect of the surface of the windows of the different orientations of the building and, (c) the use of solar control films to decrease heat gains. Special care was taken not to make alterations on the infrastructure of the physical space and to not compromise the external environment. In the building that was under evaluation it was found that by reducing the enveloped area of the north and south sections, heat can be minimized and the transmitted visible light required for the development of the occupants' activities is not affected. However, if the enveloped area on the west side is modified, visible light would be compromised. The use of solar control films provides significant benefits because the heat gained by radiation can be minimized by more than 60 %, this is achieved without obstruction the view to the outside nor the visible light required by the occupants to maintain an adequate performance in the development of their activities. If these strategies are implemented, the consumption of electrical energy can be reduced considerably.
... The second common factor is the infiltration rate of 0.1 ac/h, which is the minimum specified value. Previous research [112][113][114] also confirmed that the infiltration rate negatively correlates with HVAC energy consumption and thermal comfort in buildings. It is because the infiltration rate is an uncontrolled phenomenon and consistently blows cold air in the winter and hot air in the summer into the building, adding to the heating and cooling loads. ...
It is expected that heatwaves will strike more frequently and with higher temperatures with the continuation of global warming. More extreme heatwaves concurrent with disruptions in the cooling system can lead to significant overheating problems in buildings affecting occupants’ health, productivity, and comfort. This paper projects current and future heatwaves on an optimized nearly Zero-Energy terraced dwelling in Brussels, assuming the outage of the cooling system. Initially, a multi-objective optimization is performed considering 13 passive design strategies using the Genetic Algorithm (GA) based on the Non-dominated Sorting Genetic Algorithm 2 (NSGA-II) method. It is found that high ventilation rate, low infiltration rate, high insulation, high thermal mass, integration of green roof, and application of operable roller blinds are beneficial in reducing the final HVAC energy use up to 32% and enhancing thermal comfort up to 46%. Subsequently, three optimal solutions are selected and analyzed under the highest maximal temperature heatwaves detected during the 2001–2020, 2041–2060, and 2081–2100 periods. It is found that non of the optimal solutions are able to fully suppress overheating during heatwaves and the cooling system outage. The indoor operative temperatures reach more than 29 which can cause serious health issues for the occupants. The situation will be exacerbated in the future since an increase in maximum Heat Index (HI) between 0.28 °C and 0.49 °C, an increase in the maximum operative temperature between 1.34 °C and 2.33 °C, and a decrease in Thermal Autonomy (TA) between 17% and 28% are estimated. Finally, some recommendations are provided for practice and future research.
... The causal relationship between air infiltration and building energy losses is well-known among the building physics community (Kalamees, 2007), (Jokisalo et al., 2009), (Hassouneh et al., 2012), (Meiss and Feijó-Muñoz, 2015). Infiltration of unconditioned outdoor air is an important contributor to heat losses/gains in buildings, which for commercial facilities can constitute 25% of their total heating demand due to heat losses (Younes et al., 2012) while for industrial facilities it can represent as much as 40% of their total heating demand (Brinks et al., 2015). ...
Air curtains (ACs) are of interest in building applications to support energy efficiency and air quality by restricting heat and mass transport across continuously open entrances. Environmental conditions to which ACs are generally subjected, such as differences in temperature and pressure, induce loads on ACs that alter their flow pattern, hence can considerably influence their separation efficiency. Therefore, proper design and implementation of ACs demands detailed knowledge of the impact of these parameters both individually and combined. This is addressed here by a systematic evaluation of the AC separation efficiency under moderate environmental temperature (5 °C ≤ ΔT ≤ 25 °C) and pressure (1 Pa ≤ ΔP ≤ 8 Pa) difference conditions. RANS CFD simulations of an AC are conducted on verified computational grids, validated with experimental data and calibrated with field measurements. Results show a strong yet non-linear dependency of AC performance on environmental parameters and indicate there is an optimal separation efficiency (based on total mass transfer) in which competing effects between a given jet momentum flux on the one hand and cross-jet loads caused by temperature or pressure differences on the other hand are counterbalanced. Findings suggest to dynamically control the supplied AC jet momentum as a function of variable environmental conditions in order to continually deliver an optimal performance.
... These results demonstrate 7 the importance of these parameters in the energy consumption of buildings and in the ANN output. These 8 results are also in line with previous research which demonstrated the importance of these variables in 9 other similar applications (Hassouneh et al., 2012; Kwok and Lee, 2011; Probst, 2004; Shukuya and 10 Matsunawa, 1988; Wan and Yik, 2004). All of these parameters should therefore be considered in the 11 ANN for labelling purposes to assure its precision. ...
Surrogate models are an important part of building energy labelling programs, but these models still present low accuracy, particularly in cooling-dominated climates. The objective of this study was to evaluate the feasibility of using an artificial neural network (ANN) to improve the accuracy of surrogate models for labelling purposes. An ANN was applied to model the building stock of a city in Brazil, based on the results of extensive simulations using the high-resolution building energy simulation program EnergyPlus. Sensitivity and uncertainty analyses were carried out to evaluate the behaviour of the ANN model, and the variations in the best and worst performance for several typologies were analysed in relation to variations in the input parameters and building characteristics. The results obtained indicate that an ANN can represent the interaction between input and output data for a vast and diverse building stock. Sensitivity analysis showed that no single input parameter can be identified as the main factor responsible for the building energy performance. The uncertainty associated with several parameters plays a major role in assessing building energy performance, together with the facade area and the shell-to-floor ratio. The results of this study may have a profound impact as ANNs could be applied in the future to define regulations in many countries, with positive effects on optimizing the energy consumption.
The Qinghai-Xizang Plateau is characterized by a low-pressure and oxygen-deficient environment due to its high altitude, causing discomfort and major safety problems for the inhabitants. To address this, oxygen-enriched chambers can be used to alleviate the plateau reaction. However, little consideration has been given to air infiltration in these chambers, with a lack of information on the corresponding infiltration heat loss phenomenon. This paper addresses this by investigating the phenomenon of air flow in an oxygen-enriched chamber using experiments and simulations. The results highlight that when there is a difference in oxygen concentration between the interior and exterior of the chamber, mass transfer occurs due to both the molecular diffusion in addition to a flow due to the air density difference caused by the variation in concentration. Also, the simultaneous stack effect is roughly equivalent to 10 times the oxygen pressure, and the two pressure effects act in opposite directions. It is also noted that both the oxygen pressure and the stack effect decrease as the atmospheric pressure decreases. Overall, the oxygen-enriched chambers exhibit less infiltration in plateau areas with a low atmospheric pressure compared to plains areas with a relatively high atmospheric pressure. Finally, this study establishes formulas that can be used to calculate air infiltration rates in oxygen-enriched chambers. This study fills a gap in the existing literature regarding the air infiltration mechanism in oxygen-enriched chambers at high altitudes and low pressures, providing a theoretical foundation for improving indoor environments in the Qinghai-Xizang Plateau and other high-altitude regions.
Wind- and stack-interacted dwelling infiltration is a major factor influencing heating and cooling loads, indoor environmental quality, and indoor air quality (IAQ) in high-rise or multi-unit residential buildings (MURB). However, it is challenging to observe the real-time infiltration rates in an entire building using existing sensors. Therefore, this study proposes a virtual sensing method for dwelling infiltration rates in MURB. Virtual sensing is developed in situ for the target MURB by a hybrid modeling approach combining forward simulation and inverse estimation using the building life cycle. It mainly consists of (1) multi-zone airflow network modeling with design information, (2) model calibration with intrusive commissioning data, and (3) virtual sensing with nonintrusive operation data. The proposed method can observe the outdoor air infiltration rates across the envelope and the interzonal airflow rates at the entrance door by dwelling units. In the validation case, the hybrid modeling approach could determine the reliable infiltration rate (with 97.16% accuracy). In the application, all dwelling units were rated by the thresholds in terms of the heating loads and IAQ based on the virtual sensing results. We strongly recommend observing dwelling infiltration in each household using the proposed virtual sensing method.
Building envelope plays a crucial role in limiting the heat gains and affects the energy requirement for space cooling directly. To this end, building codes specify overall thermal transmittance values of the building envelope to address the building energy efficiency. However, these values do not consider the heat gains due to infiltration, which is a characteristic of the building envelope. With this context, the objective of this research is to measure the infiltration rates in apartments and propose an infiltration factor to revise the existing equation of the residential envelope transmittance value (RETV), recommended by the building code in India. Herein, the Blower door method is employed to measure the infiltration rates for a total of 20 air-conditioned apartments. Such a study, with the blower door method, has not been reported in India. The measurements show that the infiltration rates vary from 0.53 ACH to 1.63 ACH and are correlated with the window construction characteristics. Simulations are also carried out for estimating the impact of infiltration on the RETV with a calibrated energy model. The sensitivity analysis showed that the heat gain from infiltration accounted for 10% to 33% of the overall envelope heat gains. The infiltration factor is derived for different climate zones of India by carrying out a parametric study involving 3072 simulation cases. It was found that 1 ACH of infiltration contributes 5.46, 4.22, and 3.53 W/m² of RETV in hot-dry, composite and warm-humid climate respectively. A relationship between revised RETV and energy consumption is also established.
The present study described a design of a crossflow shell-and-tube heat exchanger with staggered tube array containing phase change material (PCM) to absorb the heat from the warm air stream ejected from building HVAC, and to release heat into the cold air stream entering building. A real scale prototype was constructed to validate the numerical model. The results showed consistent agreements between the modeling and experiment. Then, the numerical simulation was comprehensively used to study the effects of geometrical and operational parameters on the overall thermal performance, including the numbers of tube rows, operational time, and tube diameter. Furthermore, the study investigated the possible heat transfer enhancement using multiple melting temperatures in regions of tube array, and the use of dispersed highly conductive material in PCM. This PCM heat exchanger has potential of increasing the energy efficiency and saving overall energy cost.
Air flow measurement is a fundamental and important task for testing, adjusting, and balancing of HVAC system. However, it is difficult to carry out in the field due to the large size and weight of the flow meter. In this study, for the purpose of developing a small and portable flow meter, we proposed a different method of static pressure measurement and verified it experimentally. In the proposed method, static pressure difference was measured by inserting a tube inside the chamber before and after the nozzles. The results were compared with measurements according to the ANSI/ASHRAE standard. The results were in good agreement, indicating that the inserted tube method could be used for static pressure measurement of a portable flow meter. The proposed method eliminates the pressure tubes that are attached outside, which results in smaller size and easy handling.
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.
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.
Heating and air conditioning Amman: University of Jordan Renewable energy: Power for a sustainable future
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