scholarly journals The Significance of Sky Temperature in the Assessment of the Thermal Performance of Buildings

2020 ◽  
Vol 10 (22) ◽  
pp. 8057 ◽  
Author(s):  
Aiman Albatayneh ◽  
Dariusz Alterman ◽  
Adrian Page ◽  
Behdad Moghtaderi
Keyword(s):  
Air Temperature ◽  
Thermal Performance ◽  
Assessment Tool ◽  
Real Data ◽  
Building Design ◽  
Accurate Estimation ◽  
Brick Veneer ◽  
Simulation Error ◽  
Sky Temperature ◽  
The Impact

Energy-efficient building design needs an accurate way to estimate temperature inside the building which facilitates the calculation of heating and cooling energy requirements in order to achieve appropriate thermal comfort for occupants. Sky temperature is an important factor for any building assessment tool which needs to be precisely determined for accurate estimation of the energy requirement. Many building simulation tools have been used to calculate building thermal performance such as Autodesk Computational Fluid Dynamics (CFD) software, which can be used to calculate building internal air temperature but requires sky temperature as a key input factor for the simulation. Real data obtained from real-sized house modules located at University of Newcastle, Australia (southern hemisphere), were used to find the impact of different sky temperatures on the building’s thermal performance using CFD simulation. Various sky temperatures were considered to determine the accurate response which aligns with a real trend of buildings’ internal air temperature. It was found that the internal air temperature in a building keeps either rising or decreasing if higher or lower sky temperature is chosen. This significantly decreases the accuracy of the simulation. It was found that using the right sky temperature values for each module, Cavity Brick Module (CB) Insulated Cavity Brick Module (InsCB), Insulated Brick Veneer Module (InsBV) and Insulated Reverse Brick Veneer Module (InsRBV), will result in 6.5%, 7.1%, 6.2% and 6.4% error correspondingly compared with the real data. These errors mainly refer to the simulation error. On the other hand using higher sky temperatures by +10 °C will significantly increase the simulation error to 16.5%, 17.5%, 17.1% and 16.8% and lower sky temperature by +10 °C will also increase the error to 19.3%, 22.6%, 21.9% and 19.1% for CB, InsCB, InsBV and InsRBV modules, respectively.

scholarly journals Alternative Method to the Replication of Wind Effects into the Buildings Thermal Simulation

Buildings ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 237
Author(s):  
Aiman Albatayneh ◽  
Dariusz Alterman ◽  
Adrian Page ◽  
Behdad Moghtaderi
Keyword(s):  
Air Temperature ◽  
High Performance ◽  
Real Data ◽  
Wind Effect ◽  
Wind Effects ◽  
Energy Assessment ◽  
Wind Simulation ◽  
Brick Veneer ◽  
Equal Capacity ◽  
Simulation Time

To design energy-efficient buildings, energy assessment programs need to be developed for determining the inside air temperature, so that thermal comfort of the occupant can be sustained. The internal temperatures could be calculated through computational fluid dynamics (CFD) analysis; however, miniscule time steps (seconds and milliseconds) are used by a long-term simulation (i.e., weeks, months) that require excessive time for computing wind effects results even for high-performance personal computers. This paper examines a new method, wherein the wind effect surrounding the buildings is integrated with the external air temperature to facilitate wind simulation in building analysis over long periods. This was done with the help of an equivalent temperature (known as Tnatural), where the convection heat loss is produced in an equal capacity by this air temperature and by the built-in wind effects. Subsequently, this new external air temperature Tnatural can be used to calculate the internal air temperature. Upon inclusion of wind effects, above 90% of the results were found to be within 0–3 °C of the perceived temperatures compared to the real data (99% for insulated cavity brick (InsCB), 91% for cavity brick (CB), 93% for insulated reverse brick veneer (InsRBV) and 94% for insulated brick veneer (InsBV) modules). However, a decline of 83–88% was observed in the results after ignoring the wind effects. Hence, the presence of wind effects holds greater importance in correct simulation of the thermal performance of the modules. Moreover, the simulation time will expectedly reduce to below 1% of the original simulation time.

scholarly journals User Thermal Comfort in Historic Buildings: Evaluation of the Potential of Thermal Mass, Orientation, Evaporative Cooling and Ventilation

2020 ◽  
Vol 12 (22) ◽  
pp. 9672
Author(s):  
Mamdooh Alwetaishi ◽  
Ashraf Balabel ◽  
Ahmed Abdelhafiz ◽  
Usama Issa ◽  
Ibrahim Sharaky ◽  
...  
Keyword(s):  
Thermal Comfort ◽  
High Altitude ◽  
Air Temperature ◽  
Thermal Performance ◽  
Indoor Air ◽  
Computer Modelling ◽  
Evaporative Cooling ◽  
Comfort Level ◽  
Thermal Mass ◽  
The Impact

The study investigated the level of thermal comfort in historical buildings located at a relatively high altitude in the Arabian Desert of Saudi Arabia. The study focused on the impact of the use of thermal mass and orientation on the level of thermal performance at Shubra and Boqri Palaces. Qualitative and quantitative analyses were used in this study, including a questionnaire interview with architecture experts living at the relatively high altitude of Taif city, to obtain data and information from local experts. The computer software TAS EDSL was used along with on-site equipment, such as thermal imaging cameras and data loggers, to observe the physical conditions of the building in terms of its thermal performance. The study revealed that the experts’ age and years of experience were important aspects while collecting data from them during the survey. The use of thermal mass had a slight impact on the indoor air temperature as well as the energy consumption, but it helped in providing thermal comfort. Use of ventilation can improve thermal comfort level. Evaporative cooling technique has a considerable impact on reducing indoor air temperature with 4 °C drop, improving the thermal comfort sensation level. The novelty of this work is that, it links the outcomes of qualitative results of experts with field monitoring as well as computer modelling. This can contribute as method to accurately collect data in similar case studies.

scholarly journals Effective Adaptive Kalman Filter for MEMS-IMU/Magnetometers Integrated Attitude and Heading Reference Systems

2012 ◽  
Vol 66 (1) ◽  
pp. 99-113 ◽  
Author(s):  
Wei Li ◽  
Jinling Wang
Keyword(s):  
Kalman Filter ◽  
Linear Models ◽  
Dynamic Performance ◽  
Real Data ◽  
Operating Conditions ◽  
Measurement Unit ◽  
Accurate Estimation ◽  
Reference Systems ◽  
Adaptive Kalman Filter ◽  
The Impact

To improve the computational efficiency and dynamic performance of low cost Inertial Measurement Unit (IMU)/magnetometer integrated Attitude and Heading Reference Systems (AHRS), this paper has proposed an effective Adaptive Kalman Filter (AKF) with linear models; the filter gain is adaptively tuned according to the dynamic scale sensed by accelerometers. This proposed approach does not need to model the system angular motions, avoids the non-linear problem which is inherent in the existing methods, and considers the impact of the dynamic acceleration on the filter. The experimental results with real data have demonstrated that the proposed algorithm can maintain an accurate estimation of orientation, even under various dynamic operating conditions.

CFD Modelling Strategies for the Simulation of Roughness Effects on Friction and Heat Transfer in Additive Manufactured Components

2020 ◽  
Author(s):  
Lorenzo Mazzei ◽  
Riccardo Da Soghe ◽  
Cosimo Bianchini
Keyword(s):  
Heat Transfer ◽  
Surface Roughness ◽  
Thermal Performance ◽  
Accurate Estimation ◽  
Real Surface ◽  
Cfd Modelling ◽  
Roughness Effects ◽  
Modelling Strategies ◽  
The Impact ◽  
Grain Roughness

Abstract It is well-known from the literature that surface roughness affects significantly friction and heat transfer. This is even more evident for additive manufactured (AM) components, which are taking an increasingly important role in the gas turbine field. However, the exploitation of numerical approaches to improve their design is hindered by the lack of dedicated correlations and CFD model developed for such high roughness conditions. Usually the additive manufactured components are simulated considering the surfaces as smooth or applying an equivalent sand-grain roughness (ks) that results in a velocity shift in the boundary layer. However, determining a priori the most appropriate value of ks is challenging, as dozens of correlations are available, returning scattered and uncertain results. The aim of this work is to benchmark some existing modelling strategies (among which the equivalent sand grain roughness) and test a numerical approach capable of narrowing the existing gap between simulated and tested thermal performance of additive manufactured devices. The technology enabler is represented by higher-fidelity CFD simulations accounting for the impact of real surface roughness on pressure drop and heat transfer. At this purpose, an existing literature model for rough walls has been implemented in ANSYS Fluent and tested on a variety of AM mini-channels so as to determine the best-fitting values of ks and corrected wetted surface ratio Scorr that match the experimental data in terms of friction factor and Nusselt number. Knowing also the measured roughness descriptors of each component, it has been possible to derive valuable guidelines for an effective exploitation of CFD on additive manufactured components, thus allowing a more accurate estimation of the thermal performance in additive manufactured components.

An Alternative Approach to the Simulation of Wind Effects on the Thermal Performance of Buildings

2018 ◽  
Vol 1 (1) ◽  
pp. 35-44 ◽  
Author(s):  
Aiman Albatayneh ◽  
Dariusz Alterman ◽  
Adrian Page ◽  
Behdad Moghtaderi
Keyword(s):  
Air Temperature ◽  
Thermal Performance ◽  
Real Data ◽  
Wind Effect ◽  
Convection Heat ◽  
Equivalent Temperature ◽  
Wind Effects ◽  
Alternative Approach ◽  
Existing Housing ◽  
Simulation Time

The new method described in this paper incorporates the wind effect surrounding the buildings into the external air temperature by the use of an equivalent temperature (called here Tnatural) which produces the same rate of convection heat loss like that with the wind effects included. The internal air temperature of the building can be then calculated using this new external air temperature Tnatural.. Simulations using this approach were compared with the real data from four existing housing test modules incorporating a range of walling systems, resulted in an accurate, representative analysis as well as a significantly reducing simulation time.

Systematic design assessment techniques for solar buildings

1980 ◽  
Vol 295 (1414) ◽  
pp. 379-401 ◽  
Keyword(s):  
Thermal Performance ◽  
Computer Aided Design ◽  
Energy Demand ◽  
Dominant Role ◽  
Building Design ◽  
Short Wave ◽  
Wave Radiation ◽  
Accurate Estimation ◽  
Design Assessment ◽  
Input Variables

Solar building design involves the systematic study of complex interrelationships between the interacting temporal patterns of solar energy supply and energy demand within buildings. Variations in weather exercise a dominant role. Peak energy demands and solar supply tend to be antiphase. While the temporal matches between such dynamic inputs and outputs can be improved by the introduction of appropriate thermal storage, the building fabric itself acts as a capacitance phase regulator. It is necessary to be able to model the solar inputs and weather dependent energy losses dynamically to predict thermal performance. A team in the Department of Building Science, University of Sheffield, has been studying how to automate the complex climatological design assessment of passive and active solar buildings with the use of interactive computer aided design techniques with associated graphics. This paper describes the various approaches developed for the detailed modelling of the relevant climatic input variables. A report is made of the techniques developed to generate systematic short wave radiation data for vertical and inclined surfaces for different types of weather. The analysis is based on types of day — sunny, average and overcast. Work on the accurate estimation of the magnitude of the associated weather variables affecting heat transfer in the external environment is also reported — these studies cover air temperature, wind speed and long wave radiation exchanges. The outputs of this climatological analysis provide inputs into detailed thermal analysis programmes developed to predict different aspects of solar building thermal performance.

scholarly journals Sustainability at an Urban Level: A Case Study of a Neighborhood in Dubai, UAE

2021 ◽  
Vol 13 (8) ◽  
pp. 4355
Author(s):  
Sundus Shareef ◽  
Haşim Altan
Keyword(s):  
United Arab Emirates ◽  
Thermal Performance ◽  
Environmental Sustainability ◽  
Assessment Tool ◽  
Computer Software ◽  
Green Building ◽  
Building Design ◽  
The United States ◽  
Design Variables

The United Arab Emirates is witnessing enormous growth and the sustainability attitude has become one of the most important priorities in this development. This paper aims to optimize the environmental sustainability of the Emirate of Dubai communities by adopting an existing community as a case study. The investigation of the case study is looking at sustainability levels that consists of two major factors in neighborhood sustainable design, such as livability and thermal performance. The strategy of enhancing and optimizing the communities’ sustainability starts with an approach to the applicable modifications and solutions to the existed community master planning, where the modifications cover the two main urban design variables; (a) building design, and (b) open and landscape areas. The effect of the adopted scenarios is analyzed to find the improvement in environmental and thermal performance. The study has adopted two computer software packages, namely CityCAD and Integrated Environmental Solutions—Virtual Environment (IES-VE), to undertake the assessments. Furthermore, factors of urban sustainability are evaluated using the United States Green Building Council (USGBC)’s Leadership in Energy and Environmental Design (LEED) neighborhood assessment tool. The results have shown that the environmental sustainability levels can be increased after the adoption of certain suggested scenarios, in order to mitigate the likely weakness indicated in the livability aspects, covering land-use diversity, accessibility, transportation system, green and landscape areas, and energy efficiency, and the case study community can be turned toward “Sustainable Community” by implementing recommended actions and modifications.

Computational fluid dynamics assessment for the thermal performance of double-skin façades in office buildings under hot climatic condition

2020 ◽  
Vol 42 (1) ◽  
pp. 45-61
Author(s):  
Daeung Danny Kim
Keyword(s):  
Saudi Arabia ◽  
Energy Consumption ◽  
Thermal Performance ◽  
Climatic Condition ◽  
Building Design ◽  
Weather Situation ◽  
Double Skin ◽  
Shading Device ◽  
The Impact ◽  
Double Skin Facades

In general, a double-skin façade has been used to reduce energy consumption as well as to improve thermal performance in buildings as a buffer space between indoors and outdoors. The goal of this study is to undertake pre-normative research to provide information for developing a comprehensive double-skin façade system under the climatic condition in Saudi Arabia. To pursue this goal, the characteristics associated with the double-skin façade system are identified. In addition, the impact of various configurations on the thermal performance of the double-skin façades is evaluated under the weather situation in Saudi Arabia. Computational double-skin façade models are created by computational fluid dnamics simulation to assess the thermal performance of the various configurations such as cavity geometry and the use of a shading device. As a result, the variation of the opening size has a significant impact on the temperature in the cavity of the double-skin façade. For the air velocity in the cavity, the variation of the opening size and cavity depth is less sensitive. Moreover, the use of a shading device has an impact on the temperature drop in the cavity of the double-skin façade. Practical application: Generally, many studies have investigated the efficiency of double-skin façade applications due to its beneficial aspects. However, a few buildings have adopted double-skin façades to their envelopes. With a substantial growing demand for building industry in Saudi Arabia, double-skin façade applications to building design can be a solution for reducing building energy consumption. The present study investigates the thermal performance of double-skin façades under hot climates in Saudi Arabia and it can provide information for building stakeholders to develop proper double-skin façade systems

scholarly journals Incorporation of the equilibrium temperature approach in a Soil and Water Assessment Tool hydroclimatological stream temperature model

2017 ◽  
Author(s):  
Xinzhong Du ◽  
Narayan Kumar Shrestha ◽  
Darren L. Ficklin ◽  
Junye Wang
Keyword(s):  
Heat Transfer ◽  
Air Temperature ◽  
Assessment Tool ◽  
Stream Water ◽  
Swat Model ◽  
Equilibrium Temperature ◽  
Reaction Rates ◽  
Stream Temperature ◽  
Temperature Model ◽  
The Impact

Abstract. Stream temperature is an important indicator for biodiversity and sustainability in aquatic ecosystems. The stream temperature model currently in the Soil and Water Assessment Tool (SWAT) only considers the impact of air temperature on stream temperature, while the hydroclimatological stream temperature model developed within SWAT model considers hydrology and the impact of air temperature in simulating the water-air heat transfer process. In this study we propose using the equilibrium temperature approach to model complex heat transfer processes at the water-air interface, which reflects the influences of air temperature, solar radiation, wind speed and stream water depth on the heat transfer process. The thermal capacity of the streamflow is modelled by the variation of the stream water depth. An advantage of this equilibrium temperature model is the simple parameterization, with only two added parameters to model the heat transfer processes. The equilibrium temperature model is applied and tested in the Athabasca River Basin (ARB) in Alberta, Canada. The model is calibrated and validated at five stations throughout different parts of the ARB for which high-frequency observed stream temperature data are available. The results indicate that the equilibrium temperature model provided better and more consistent performances for the different regions of the ARB with the values of Nash-Sutcliffe Efficiency (> 0.67) greater than those of the original SWAT model and the hydroclimatological model. Overall, the equilibrium temperature model uses existing SWAT meteorological data as input, can be calibrated using fewer parameters and less effort, and has an overall better performance for the simulation of daily stream temperatures. Thus, it can be used as an effective tool for predicting the change in stream temperature regimes under varying hydrological and meteorological conditions. In addition, the impact of the stream temperature simulations on chemical reaction rates and concentrations was tested. The results indicate that the improved performance of the stream temperature simulation could significantly affect chemical reaction rates and the simulated concentrations and the equilibrium temperature model could be a potential tool to model stream temperature for water quality simulations.

The Impact of High-Rise Residential Building Design Parameters on the Thermal and Energy Performance: A Literature Review

2019 ◽  
Vol 4 (11) ◽  
pp. 81
Author(s):  
Lobna Elgheriani ◽  
Brian Cody
Keyword(s):  
Thermal Performance ◽  
Residential Buildings ◽  
Publishing House ◽  
Residential Building ◽  
Building Design ◽  
Energy Performance ◽  
Design Parameters ◽  
Future Research ◽  
High Rise ◽  
The Impact

Nowadays, high-rise buildings are developing very fast to cater to the increase in demand in major urban cities. This phenomenon has contributed to several environmental problems in both construction and operation. High-rise buildings design parameters seem to lack contextual environmental consideration. Evaluating the impact of such design parameters is a practical approach to enhance the overall energy and thermal performance. Existing research gaps are distinguished based on this review. Future research directions are also proposed through a methodological scheme to investigate comparatively, the effects of different geometric factors on both thermal and energy performance, specifically in the high-rise residential buildings with consideration to different climatic regions. Keywords: Energy Performance; Thermal Performance; High-rise Buildings; High-rise Residential BuildingseISSN: 2398-4287 © 2019. The Authors. Published for AMER ABRA cE-Bs by e-International Publishing House, Ltd., UK. This is an open access article under the CC BYNC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Peer–review under responsibility of AMER (Association of Malaysian Environment-Behaviour Researchers), ABRA (Association of Behavioural Researchers on Asians) and cE-Bs (Centre for Environment-Behaviour Studies), Faculty of Architecture, Planning & Surveying, Universiti Teknologi MARA, Malaysia.DOI: https://doi.org/10.21834/e-bpj.v4i11.1717

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