A semi-empirical model for studying the impact of thermal mass and cost-return analysis on mixed-mode ventilation in office buildings

2013 ◽  
Vol 67 ◽  
pp. 267-274 ◽  
Author(s):  
Haojie Wang ◽  
Qingyan Chen
Keyword(s):  
Empirical Model ◽  
Mixed Mode ◽  
Office Buildings ◽  
Thermal Mass ◽  
Semi Empirical ◽  
The Impact

On the interest of a semi-empirical model for the tooth friction coefficient in gear transmissions

2021 ◽  
pp. 135065012110521
Author(s):  
Romain Quiban ◽  
Nicolas Grenet De Bechillon ◽  
Thomas Touret ◽  
Pierre Navet ◽  
Yasser Diab ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Empirical Model ◽  
Gear Tooth ◽  
Stochastic Approach ◽  
Surface Finishing ◽  
Bulk Temperature ◽  
Friction Measurements ◽  
Two Parameters ◽  
Semi Empirical ◽  
The Impact

Accurate modelling of friction coefficient is of primary importance in efficiency, vibration and failure analyses of enclosed gear drives. After showing the influence of surface/lubricant interactions on friction, the authors used a semi-empirical model which can take all these aspects into account. Lubricant is modelled as an Eyring–Reynolds fluid and rough surfaces are described with two parameters via a stochastic approach. A specific two-disc machine is used to perform series of friction measurements on smooth and rough discs. Smooth discs allow to operate under full film lubrication and to measure a reference shear stress of lubricant, whereas rough discs reproduce gear tooth roughness and generate a representative value of friction on asperities. The purpose of this present paper is to describe calculations of this physical-based friction coefficient model and to present the experimental process. On the basis of new results, the impact of a surface finishing process is assessed as well as the consequence of calculating friction coefficient based on oil injection instead of local bulk temperature.

Research on CO2 Corrosion Rate Prediction of Gathering Pipelines Considering the Effect of Oil

2015 ◽  
Vol 737 ◽  
pp. 788-793 ◽  
Author(s):  
Yuan Peng Cheng ◽  
Zi Li Li ◽  
Qian Qian Liu
Keyword(s):  
Corrosion Rate ◽  
Empirical Model ◽  
Prediction Models ◽  
Mechanistic Model ◽  
Experimental Studies ◽  
Research Directions ◽  
Rate Prediction ◽  
Semi Empirical ◽  
The Impact ◽  
Sweet Corrosion

Experimental studies show that under special conditions, oils in corrosion environment have some inhibiting effect on CO2corrosion behavior of gathering pipelines. Oil wetting and corrosion product film are the great difference in existent rate prediction models of sweet corrosion. The progress of CO2corrosion rate prediction including empirical model, semi-empirical model, mechanistic model and artificial neural networks model considering the impact of oil in recent years are introduced in detail, the present problems and further research directions are also discussed.

scholarly journals A Semi-Empirical Model for Predicting Frost Properties

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 412
Author(s):  
Shao-Ming Li ◽  
Kai-Shing Yang ◽  
Chi-Chuan Wang
Keyword(s):  
Thermal Conductivity ◽  
Linear Programming ◽  
Numerical Model ◽  
Empirical Model ◽  
Quantitative Method ◽  
Predictive Ability ◽  
Dimensionless Temperature ◽  
Crystal Shape ◽  
Proposed Model ◽  
Semi Empirical

In this study, a quantitative method for classifying the frost geometry is first proposed to substantiate a numerical model in predicting frost properties like density, thickness, and thermal conductivity. This method can recognize the crystal shape via linear programming of the existing map for frost morphology. By using this method, the frost conditions can be taken into account in a model to obtain the corresponding frost properties like thermal conductivity, frost thickness, and density for specific frost crystal. It is found that the developed model can predict the frost properties more accurately than the existing correlations. Specifically, the proposed model can identify the corresponding frost shape by a dimensionless temperature and the surface temperature. Moreover, by adopting the frost identification into the numerical model, the frost thickness can also be predicted satisfactorily. The proposed calculation method not only shows better predictive ability with thermal conductivities, but also gives good predictions for density and is especially accurate when the frost density is lower than 125 kg/m3. Yet, the predictive ability for frost density is improved by 24% when compared to the most accurate correlation available.

Lighting energy performance determination in office environments through implementation of EN 15193-1 for Turkey

2021 ◽  
pp. 147715352098742
Author(s):  
FŞ Yilmaz
Keyword(s):  
System Design ◽  
Architectural Design ◽  
Office Buildings ◽  
Energy Requirements ◽  
System Control ◽  
Lighting System ◽  
Artificial Lighting ◽  
Design Alternatives ◽  
Lighting Energy ◽  
The Impact

Office buildings are building typologies where efficient and optimal use of lighting energy is crucial while providing comfortable visual environments. The purpose of this study is to explore the impact of diverse architectural design alternatives on lighting energy requirements and lighting energy saving possibilities through a case study. In this study, a total of 3888 design alternatives are investigated in a comparative way in terms of daylighting system design alternatives, artificial lighting system design scenarios, artificial lighting system control types and shading system control options. Introducing the adaptation process of the EN 15193-1:2017 standard for Turkey’s specific climatic and geographical conditions and considering diverse lighting design scenarios, results of this parametric study aim to underline the significance of architectural design strategies in office buildings for the reduction of lighting energy requirements.

scholarly journals A Fundamental Study on the Development of New Energy Performance Index in Office Buildings

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2064
Author(s):  
Jin-Hee Kim ◽  
Seong-Koo Son ◽  
Gyeong-Seok Choi ◽  
Young-Tag Kim ◽  
Sung-Bum Kim ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Energy Requirement ◽  
Energy Performance ◽  
Office Buildings ◽  
Light Transmittance ◽  
Wall Structure ◽  
Fundamental Study ◽  
Future Studies ◽  
U Value ◽  
The Impact

Recently, there have been significant concerns regarding excessive energy use in office buildings with a large window-to-wall ratio (WWR) because of the curtain wall structure. However, prior research has confirmed that the impact of the window area on energy consumption varies depending on building size. A newly proposed window-to-floor ratio (WFR) correlates better with energy consumption in the building. In this paper, we derived the correlation by analyzing a simulation using EnergyPlus, and the results are as follows. In the case of small buildings, the results of this study showed that the WWR and energy requirement increase proportionally, and the smaller the size is, the higher the energy sensitivity will be. However, results also confirmed that this correlation was not established for buildings approximately 3600 m2 or larger. Nevertheless, from analyzing the correlation between the WFR and the energy requirements, it could be deduced that energy required increased proportionally when the WFR was 0.1 or higher. On the other hand, the correlation between WWR, U-value, solar heat gain coefficient (SHGC), and material property values of windows had little effect on energy when the WWR was 20%, and the highest effect was seen at a WWR of 100%. Further, with an SHGC below 0.3, the energy requirement decreased with an increasing WWR, regardless of U-value. In addition, we confirmed the need for in-depth research on the impact of the windows’ U-value, SHGC, and WWR, and this will be verified through future studies. In future studies on window performance, U-value, SHGC, visible light transmittance (VLT), wall U-value as sensitivity variables, and correlation between WFR and building size will be examined.

scholarly journals Assessing the Energy Resilience of Office Buildings: Development and Testing of a Simplified Metric for Real Estate Stakeholders

Buildings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 96
Author(s):  
Paul Mathew ◽  
Lino Sanchez ◽  
Sang Hoon Lee ◽  
Travis Walter
Keyword(s):  
Regression Models ◽  
Health And Safety ◽  
Office Buildings ◽  
Extreme Weather Events ◽  
Economic Losses ◽  
Power Outage ◽  
Continuity Of Operations ◽  
Quasi Monte Carlo ◽  
Building Characteristics ◽  
The Impact

Increasing concern over higher frequency extreme weather events is driving a push towards a more resilient built environment. In recent years there has been growing interest in understanding how to evaluate, measure, and improve building energy resilience, i.e., the ability of a building to provide energy-related services in the event of a local or regional power outage. In addition to human health and safety, many stakeholders are keenly interested in the ability of a building to allow continuity of operations and minimize business disruption. Office buildings are subject to significant economic losses when building operations are disrupted due to a power outage. We propose “occupant hours lost” (OHL) as a means to measure the business productivity lost as the result of a power outage in office buildings. OHL is determined based on indoor conditions in each space for each hour during a power outage, and then aggregated spatially and temporally to determine the whole building OHL. We used quasi-Monte Carlo parametric energy simulations to demonstrate how the OHL metric varies due to different building characteristics across different climate zones and seasons. The simulation dataset was then used to develop simple regression models for assessing the impact of ten key building characteristics on OHL. The most impactful were window-to-wall ratio and window characteristics. The regression models show promise as a simple means to assess and screen for resilience using basic building characteristics, especially for non-critical facilities where it may not be viable to conduct detailed engineering analysis.

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