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Photocatalytic oxidation (PCO) has a great potential to eliminate various gaseous pollutants even at low concentrations. Numerous studies have been carried out to improve the effectiveness and performance of this technology. In addition, the development of appropriate models can enhance the understanding of reactor performance and the evaluation the intrinsic kinetic parameters that enable the scale up or re-design of more efficient large-scale photocatalytic reactors. This paper reviews recent research works on mathematical modeling of gas phase photocatalytic reactors and analyses different key factors that can enhance pollutants decomposition performance. First, the fundamental of the photocatalytic oxidation process and degradation reaction mechanism are briefly described. Then, to study kinetics of reaction, this paper focuses on Langmuir-Hinshelwood equation, which is by far the most common kinetic model that takes both adsorption and reaction processes into account. Moreover, an overall mass balance that contains advection, diffusion, and reaction rate terms, is analyzed to obtain a comprehensive mathematical model. In the end, the influence of key operating parameters (e.g. flow rate, catalyst surface area and porosity, and catalyst thickness) on the photocatalytic process and removal efficiency of the reactor are discussed. • Comprehensive literature review on mathematical modeling of photocatalytic oxidation of VOCs in the air is presented. • Fundamental of PCO process including mass transfer and degradation reaction mechanism are reviewed. • Analysis of key operating parameters affecting on PCO performance and on mathematical model is conducted. • A mass balance containing advection, diffusion and reaction rate equations can provide detailed modeling of PCO reactor. [ABSTRACT FROM AUTHOR]

Automated shading and integrated lighting control systems are being used in buildings for electrical energy savings and improve occupant's comfort. These systems facilitate effective utilization of useful daylight in interior spaces that benefit an occupant's health, well-being, and productivity by preventing glare and overheating while maintaining the adequate illuminance levels. The pragmatic procedure to implement open loop shading and integrated lighting control comprises three parts: (i) a reliable estimation of sky conditions on real-time basis, (ii) determining indoor daylight metrics using outdoor conditions, and (iii) incorporating the metrics in the blind and integrated lighting control techniques. This paper presents a review of experimental studies done on open-loop window shade and integrated lighting control strategies. The aim of this paper is to analyse the performance and feasibility of various daylight prediction methods and their application in controlling blinds and integrated lighting system. The review mainly focuses on simulation assisted open loop control techniques that employ real-time daylight estimation methods. The review identifies the current challenges, recommends areas for improvement, and provides significant scope for future research. The paper concludes that modified and improved open loop system are more competent as an alternative compared to the conventional methods for automated blind and lighting control systems. Advanced open-loop control systems along with calibrated simulations have the capability to reduce post commissioning errors, allow easy monitoring of the system and predict daylight more extensively. [ABSTRACT FROM AUTHOR]

Abstract Within building envelopes, air cavities behind a siding provide a feasible way to mitigate the moisture-related issues such as rain penetration and frost damage. However, for a common contact-applied siding system, the small gap directly attaching the siding with the wall sheathing greatly limits the drying functions of air cavity: capillary break, drainage, and ventilation drying. Moreover, the drying performance of the air cavities behind the siding remains unknown, and commonly a rectangular unicellular cavity is inexactly assumed to simplify investigating the hygrothermal performance of a siding system. After analyzing the irregular and complex configuration of air cavities composed of multiple same cavity cells, this paper develops a mathematical model based on the circuit diagram principle to quantify the air flow rate within the multicellular cavity behind a siding with respect to the air differential pressure and flow resistance. This model is then used to evaluate the drying performance of a siding system, which is found to be heavily dependent on the cavity depth between the siding and the wall sheathing. Further sensitivity analysis shows that the air flow rate within the cavity rapidly increases to a maximum value as the cavity depth increases, and then converges at a lower value. The cavity's air flow rate reaches its maximal value when the cavity depth is 48% of a siding panel projection, e.g., 0.31 in (7.8 mm) for a triple dutch lap vinyl siding. Based on the optimal cavity depth, several design improvements are proposed. Highlights • The real irregular and complex configuration of air cavities behind a siding, rather than a simplified rectangular cavity, is analyzed. • of Based on the circuit diagram principle, a mathematical model is developed to determine the air flow rate within the cavity behind a siding. • The air flow rate within a cavity reaches its maximal value when the cavity depth is 48% of a siding panel projection. • Several design improvements of traditional siding are proposed. [ABSTRACT FROM AUTHOR]

Abstract This paper works toward a goal of determining outlines of vortex zones occurring at the inlet of an exhaust hood and identifying the effect that a hood shape adjusted to these outlines may have on the local drag coefficient of the hood. A mathematical model and a computer program based on the discrete vortex method have been developed for computing velocity fields and boundaries of the first and second vortex zones occurring upon flow separation at inlet of a cone hood. First vortex zone outlines have been found to be geometrically similar even as exhaust hood flange length and angle vary. A computational experiment using the discrete vortex method and computational fluid dynamics techniques, supported by a laboratory experiment, has been carried out to determine the boundaries of the second vortex zone. It has been found that, even though flange length is not a factor for the second vortex zone, the characteristic dimensions of this zone depend on the hood flange tilt angle. Exhaust hood shaping has been assessed for its efficacy in reducing pressure losses at inlet of a circular exhaust hood. The effect of shaping the hood with the outlines of the first and/or second vortex zones has been found in terms of local drag coefficients at hood inlet expressed. Shaping by the outlines of the vortex zones of the most effective exhaust hood with a flange inclination angle of 90° makes it possible to reduce the local resistance coefficient by more than 10 times. Highlights • The algorithm for flow separation zones based on the vortex method has been improved. • The first vortex zone have been found to stay geometrically similar. • The second vortex zone and the relation of its dimensions have been determined. • Exhaust hood shaping has been assessed for its efficacy. • Local drag coefficient to decrease with shaped exhaust hoods. [ABSTRACT FROM AUTHOR]

The paper presents a control-oriented modeling approach for multi-zone buildings with mixed-mode cooling, based on the linear state-space representation with varying coefficient matrices. Key features are the time-variant thermal resistances, associated with the heat extraction due to airflow, calculated using an airflow network model. This approach was validated with experimental data collected in a two-zone test-building under four operation modes. A forward linear time-variant state-space (LTV-SS) model, developed based on first principles, was then used as a true representation of the building, to identify the parameters of a low-order LTV-SS gray-box model. The low-order model can predict the building thermal dynamics with sufficient accuracy with a root mean square error (RMSE) of 0.58 °C for the air and 1.08 °C for the area-weighted mean surface temperature in the south direct gain zone. Furthermore, the study develops a progressive refinement (ProRe) optimization method, following the multi-level optimization topology and branch and bound decision trimming strategy, to find sequences of binary (open/close) decisions for the motorized windows. Due to the significant improvement in computing time, the models and algorithms presented in this paper enable long-term simulation for MPC performance evaluation and implementation of predictive strategies in real controllers. [ABSTRACT FROM AUTHOR]

Abstract In this paper, support vector machine method is introduced to solve air balancing problem for ventilation systems and a novel non-iterative air balancing method is presented. The proposed method provides a well-formulated form of air balancing problem for air ventilation system by i) building a mathematical model for duct system based on steady-state pressure balance; ii) constructing a pressure prediction model based on the system model and theory of support vector machine; iii) identifying the significant model parameters by support vector machine regression supervised machine lssearning; and iv) determining the damper positions based on the formulated model. The performance of the method is validated experimentally in a duct testbed with five terminals. The results demonstrate that the method can achieve the desired values within 4.6% relative error and is a promising approach for air balancing. Highlights • A novel non-iterative air balancing method is presented. • The proposed method provides a well-formulated form of air balancing problem for air ventilation system. • The method can achieve the desired values within 4.6% relative error. [ABSTRACT FROM AUTHOR]

Abstract The estimation of a hazardous contaminant unknown source characteristics (i.e., rate and location) in a complex urban environment using efficient inverse modelling techniques is a challenging problem that involves advanced computational fluid dynamics combined with appropriate mathematical algorithms. In this paper we further assess our recently proposed inverse source term estimation method (Efthimiou et al., 2017, Atmos. Environ., 170, 118–129) by applying it in two wind tunnel experiments simulating atmospheric flow and tracer dispersion following a stationary release in realistic urban settings, namely Michelstadt and Complex Urban Terrain Experiment (CUTE). The method appears to be robust and to predict with encouraging accuracy the source location and emission rate for both wind tunnel experiments. Highlights • Evaluation of an inverse source term identification method. • Variational, 2-steps method: (1) source coordinates (2) emission rate estimation. • Successful validation through simulations of Michelstadt and CUTE wind tunnel experiments. • The performance of the method varies with the examined scenario. [ABSTRACT FROM AUTHOR]

The need for adequate instruments to support practitioners toward achieving sustainable and energy-efficient architectural and urban design has long been acknowledged. Motivated by identified shortcomings of building performance assessment tools for conceptual neighborhood-scale design, this paper proposes a novel workflow to enable practitioners to efficiently explore a space of design alternatives and compare them in terms of their energy and daylight performance. The workflow includes a multi-criteria optimization algorithm, which is coupled to a performance assessment engine based on predictive mathematical models. To get some insight on the potential added value for design and the usability of this approach in practice, the workflow has been implemented as a plug-in to an existing 3D modeling software and subsequently tested by practitioners during workshops, notably on real projects provided by the participants. Outcomes from the workshops, which include responses from the participants to a pre- and post-test survey, are presented. Results highlight the relevance of the proposed workflow for informing decisions about early-stage building massing on the basis of the considered performance criteria. Improvements envisioned for both the workflow and its implementation are highlighted and discussed. [ABSTRACT FROM AUTHOR]

Diffuser boundary condition is important for the accurate simulation of indoor environment. This paper analyzes the condition of keeping the coupling of mass and momentum boundary condition in CFD. A superficial density method is developed to describe the diffuser boundary condition for the simplified geometry of the diffuser. The present superficial density method is validated through the experimental data from IEA Annex-20 project. Good agreement is obtained between the computation and the experimental data. The present method can be easily implemented in the in-house code and commercial CFD software. [ABSTRACT FROM AUTHOR]

This paper introduces a concept called ”spatial-aware” source-term estimation (STE), which utilizes the acquired knowledge of how the forward model (FM) predictions compare against observations spatially to enhance the overall quality of source estimation. We evaluated the effectiveness of the proposed method against a wind tunnel experiment simulating low-stack plume dispersion in a building downwash environment with known source locations and varying building aspect ratios and building angles relative to wind direction, selected to achieve the balance of physical complexity and environmental controllability. Specifically, we adopted AERMOD as the FM, constructed spatially-resolved error models by comparing the FM predictions against measured concentrations for one configuration, referred to as the training case. Then the error models were applied to the rest of the configurations, referred to as test cases, for estimating emission rates. The results show that the spatial-aware STE can improve the estimation results, due to closer agreement between the error models and error distribution in terms of shapes and/or magnitudes. For example, using the vertical measurements around the H / W  = 1/2 building with wind direction perpendicular to the building as the training case and applying the spatially-resolved error models, the estimated emission rates for all test cases with same building aspect ratio differ from the true emission rate by less than 30%, compared to 63.2%–236% without applying any error models. We argue that parallel efforts, i.e., improving the accuracy of FMs and quantifying the FM performance are needed to further advance the science and applications of source estimation. [ABSTRACT FROM AUTHOR]

Abstract: The scenario modeling method empowers building managers by enabling comprehensive performance analysis in commercial buildings, but is currently limited to data from the building management domain. This paper proposes that Linked Data and Complex Event Processing can form the basis of an interoperability approach that would help to overcome technical and conceptual barriers to cross-domain scenario modeling. In doing so, this paper illustrates the cross-domain potential of scenario modeling to leverage data from different information silos within organizations and demonstrates how to optimize the role of a building manager in the context of his or her organization. Widespread implementations of cross-domain scenario models require a solution that efficiently manages cross-domain data acquisition and post processing underpinned by the principles of linked data combined with complex event processing. An example implementation highlights the benefits of this new approach. Cross-domain scenario models enhance the role of the building manager within an organization and increase the importance of information communicated by building managers to other organizational stakeholders. In addition, new information presented to stakeholders such as facilities managers and financial controllers can help to identify areas of inefficiency while still maintaining building function and optimized energy consumption. Two key challenges to implementing cross-domain scenario modeling are: the data integration of the different domains'' sources, and the need to process scenarios in real-time. This paper presents an implementation approach based on linked data to overcome interoperability issues, and Complex Event Processing to handle real-time scenarios. [Copyright &y& Elsevier]

Abstract: This research studies buoyancy-driven flow patterns in two series-connected chambers, which have the same height and a common divider. Theoretical analysis categories the ventilation modes of two series-connected chambers as the pull and push types of displacement ventilation, according to an extra resistance force of ventilation due to the unforced chamber. For the pull-type displacement ventilation, there is only a buoyant layer in the forced chamber and the extra resistance force is due to the additional upstream opening(s). This paper focuses on the steady-state push-type naturally displacement ventilation, when the forced chamber is located upstream in two series-connected chambers. For the push-type displacement ventilation, a two-layer stratification develops in both chambers, and the extra resistance force is not only due to the additional opening(s), but also the stratification in the downstream unforced chamber. This paper presents a derived theoretical model and analogous salt-bath experimental results, and shows reasonable agreement between them. Our results show that a different opening level on the unforced side wall changes the properties of both buoyant layers in two chambers. Among the openings on the unforced side wall, only those covered by the buoyant layer of the unforced chamber play the role of the exit, and the theoretical model only takes account of their parts for the push-type displacement ventilation. The effects on the opening area ratio of the unforced chamber and the same reduced area at a different opening location are also investigated in this study. [Copyright &y& Elsevier]

Abstract: The paper focuses on the assessment of greenhouse gas emissions produced by the walls of buildings according to their lifespan. These assessments take account of the construction, maintenance and end of life. The contribution of the utilization phase must be equivalent for all technical solutions for a given usage function. In the first part of the paper, the methodology is described by (1) considering a unit area of wall (i.e. 1 square metre), (2) determining a long service life, (3) choosing technical solutions in agreement with the specifications, (4) establishing the lifespan of each technical solution according to experts, (5) finding the corresponding greenhouse gas index from an appropriate database, and finally (6) modelling the evolution of these indicators with time. Several technical solutions (concrete, brick, stone, wood, aerated concrete) are considered and lifespans range from a few years to centuries. The results of this analysis suggest and quantify the important impact of lifespan on greenhouse gas emission indicators. For example, the best technical solution for a short lifetime can be the worst on a longer duration and vice versa. In the second part, since the lifespan of a product is very difficult to determine objectively, it is considered as a variable. The numerical results presented point out the need to revisit the current life cycle tools. [Copyright &y& Elsevier]

Abstract: Thermal properties (i.e. thermal conductivity and heat capacity) are important parameters that influence the temperature of building materials and thermal performance of built environment. These properties are required as fundamental inputs for modeling and simulating thermal behavior of built environment. Most existing methods for measuring thermal properties of building materials are based on 1-D steady-state heat transfer theory. The critical challenge for these methods has been the difficulty in achieving a 1-D heat flow condition for the testing specimen. A multi-dimensional transient method is needed to reduce the challenge and requirement on the testing specimen size and shape, and make it possible to accurately measure all the thermal properties from one single test. This paper first developed a multi-dimensional transient model and a practical tool to simulate the transient temperature at any location on a beam or cylinder specimen of any size subject to convection heat transfer. Case studies verified that this model can be used to, if the thermal properties are known, simulate the transient temperature at any location for a specimen of various shapes and sizes, and predict the time to reach a specified target temperature for mechanical and other testing. Secondly, this paper developed and validated partly by case studies on both asphalt and concrete materials a procedure for back-calculating the thermal properties of a specimen of various shapes and sizes. Thermal properties of novel building materials (various initiative cool materials such as porous concrete and high thermal resistance materials) can be easily measured with that procedure. [Copyright &y& Elsevier]

Abstract: The present paper presents a full procedure to develop an adaptive comfort model for South-East Asia. Meta-analysis on large number of observations from field surveys which were conducted in this region was employed. Standardization and bias control of the database were fully reported. Statistical tests of significance and weighted regression method applied in the analyses strengthened the reliability of the findings. This paper found a great influence of ‘Griffiths constant’ on the establishment of adaptive comfort equation and proposed an appropriate value. The adaptive comfort model generated is applicable to naturally ventilated building under hot and humid conditions of South-East Asia. The mean neutral comfort temperature (operative temperature, effective temperature, standard effective temperature) in naturally ventilated and air-conditioned building was compared and the differences have been discussed. The similar neutral standard effective temperature in both naturally ventilated and air-conditioned building proposes a new idea to implement SET* into building simulation tools to assess thermal comfort without the attention of building classification. Through the analysis, the effectiveness of behavioral adaptive actions on occupant''s thermal perception has been argued. The extended PMV-PPD model for hot humid conditions was examined and its applicability was recommended. Other comfort-related issues, the differences and similarities between various adaptive comfort models were also addressed. [Copyright &y& Elsevier]

Abstract: Computational fluid dynamics (CFD) has been introduced to indoor environment study for decades. Analysis of CFD results will first require the reach of a grid-independent CFD solution to eliminate the false information induced by numerical causes, e.g., grid and numerical scheme. Judging a grid-independent solution has been mostly experience-based, leading the necessity of developing an objective and easy-to-use criterion for grid independency evaluation. This paper presents a new approach to assessing the grid independency of CFD modeling for indoor environment applications. A normalized root mean square error (RMSE) index is developed from the grid convergence index (GCI) concept in literature to evaluate the overall differences of predicted results with varying grid resolutions. The paper further introduces the use of numerical viscosity analysis method to verify the grid-independent solution of a CFD analysis, which also provides fundamental insight into the grid-induced error in numerical solutions. Although initially developed for indoor environment applications, the proposed RMSE index along with the numerical viscosity analysis method can be applied to most general CFD studies and has great potential of being incorporated into commercial CFD software to provide user a more accurate and objective alternative of checking grid independency of CFD simulation. [Copyright &y& Elsevier]

Abstract: This paper presents the development of a new building physics and energy supply systems simulation platform. It has been adapted from both existing commercial models and empirical works, but designed to provide expedient exhaustive simulation of all salient types of energy- and carbon-reducing retrofit options. These options may include any combination of behavioural measures, building fabric and equipment upgrades, improved HVAC control strategies, or novel low-carbon energy supply technologies. We provide a methodological description of the proposed model, followed by two illustrative case studies of the tool when used to investigate retrofit options of a mixed-use office building and primary school in the UK. It is not the intention of this paper, nor would it be feasible, to provide a complete engineering decomposition of the proposed model, describing all calculation processes in detail. Instead, this paper concentrates on presenting the particular engineering aspects of the model which steer away from conventional practise. [Copyright &y& Elsevier]

Abstract: This paper presents a quasi-steady state heat and mass transfer green roof model that can be incorporated in different energy simulation software or calculation procedures. The model considers heat and mass transfer processes between the sky, plants, and substrate. This paper also presents new equations to calculate (1) substrate thermal conductivity for green roofs, (2) substrate resistance to calculate green roof soil evaporation, (3) and set of compiled stomatal resistance functions to calculate plants’ transpiration. The model is validated with robust experimental data that consists of surface temperatures, conduction heat flux, convection heat flux, net radiation and evapotranspiration. The data was obtained from laboratory experiments using a new “Cold Plate” apparatus set in an environmental chamber. The validation shows that the model predicts the heat and mass transfer accurately, except that it tends to underestimate peak evapotranspiration rates. [Copyright &y& Elsevier]

Abstract: Air distributions in commercial airliner cabins are crucial for creating a thermally comfortable and healthy cabin environment. This paper reviews the methods used in predicting, designing, and analyzing air distributions in the cabins, among which experimental measurements and numerical simulations are the two popular ones. The experimental measurements have usually been seen as more reliable although they are more expensive and time consuming. Most of the numerical simulations use Computational Fluid Dynamics (CFD) that can provide effectively detailed information. Numerous applications using the two methods can be found in the literature for studying air distributions in aircraft cabins, including investigations on more reliable and accurate models. The review in the paper shows that the studies using both experimental measurements and computer simulations are becoming popular. And it is necessary to use a full-scale test rig to obtain reliable and high quality experimental data. What’s more, the hybrid CFD models are found to be rather promising for simulating air distributions in airliner cabins. [Copyright &y& Elsevier]

Abstract: Maintaining positive pressure indoors with a mechanical ventilation system is a popular control method for preventing the entry of outdoor airborne particles. This paper analyzes the factors which affect the satisfied superfluous airflow rates of positive pressure control. Through modeling a large amount of cases with a validated model, the factors, e.g. temperature difference, outdoor wind velocity, effective air leakage gaps in the envelopes, the area of the air leakage and the room, were analyzed. Based on the theoretical model, a correlating equation to calculate the satisfied superfluous airflow rate was established by multiple full quadratic regressions. The correlating equation is simple for engineers or designers to use to determine the satisfied superfluous airflow rate. This paper also aims to find which method, pressure control or indoor air cleaning, costs less to prevent the same amount of outdoor-originated particles from entering indoor environments. Generally speaking, indoor air cleaning control method requires less supply airflow rate than positive pressure control method for reducing the concentration of indoor particles with outdoor origin. An exception for this is a situation with a very low indoor/outdoor particle concentration (I/O ratio) requirement. [ABSTRACT FROM AUTHOR]

Abstract: In building simulations it is common practice to use standardized occupant behavior and internal gains. Although this is a valid approach for designing systems, the probabilistic nature of these boundary conditions influences the energy demand and achieved thermal comfort of real systems. This paper analyzes the influence of occupant behavior on the energy performance and thermal comfort of a typical office floor equipped with a thermally activated building system (TABS). A multi-zone TRNSYS model with 10 adjacent zones per orientation for a typical moderate Belgian climate is set up. First, the energy performance and thermal comfort of thermally activated building systems (TABS) are compared with the performance of idealized cooling with standardized user behavior. TABS are able to deliver good thermal comfort but show to have a higher energy demand. Secondly, probabilistic occupant behavior was implemented in the TABS simulations. The influence of the occupancy rate, the shading device use and switching of the lights are analyzed by defining user profiles. It is shown that occupant behavior may have an important influence on the cooling demand and thermal comfort. However, as long as good solar protection is foreseen and operated in a correct way, TABS are able to cope with different user behavior modeled in this paper. In this case, normal daily stochastic processes do not considerably affect the cooling demand and thermal comfort during summer. [ABSTRACT FROM AUTHOR]

Abstract: As a passive cooling strategy to control increased surface temperatures and create cooler urban environments, we have developed a passive evaporative cooling wall (PECW) constructed of pipe-shaped ceramics that possess a capillary force to absorb water up to a level higher than 130 cm. The current paper presents a simulation system to predict and evaluate microclimatic modifying effects of PECWs in urban locations where PECW installation is under consideration at the design stage. This simulation system is composed of a CFD simulation tool and a 3D-CAD-based thermal simulation tool. Simulation methodology of coupling the two simulation tools was developed and described in this paper. Numerical models for simulating surface temperatures and evaporation of PECWs were proposed based on analysis results of experimental data. Validation of the proposed numerical models was confirmed by comparing simulated results with measured data. In order to demonstrate the applicability of the proposed simulation system, a case study was then performed to predict and evaluate the microclimate in a rest station where PECWs were assumed to be installed. Spatial distributions of air temperature, airflow, moisture and surface temperature in the rest station were simulated under a sunny weather condition in the summer of Tokyo. Furthermore, thermal comfort indexes (mean radiant temperature and new standard effective temperature) were used to evaluate thermal comfort in the human activity spaces of the rest station. Simulation results show that this simulation system can provide quantitative predictions and evaluations of microclimatic modifying effects resulting from the application of PECWs. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents an experimental study of indoor thermal environment near a full-scale glass facade with different types of shading devices under varying climatic conditions in winter. Interior glazing and shading temperature, operative temperature and radiant temperature asymmetry were measured for façade sections with roller shades and venetian blinds at different positions. Interior glass surface temperatures can be high during sunny days with low outdoor temperature. Shading systems significantly improved operative temperature and radiant temperature asymmetry during cold sunny days, depending on their properties and tilt angle. During cloudy days the impact was smaller, however the shading layers could still decrease the amount of heat loss through the façade. A transient building thermal model, which also calculates indoor environmental indices under the presence of solar radiation, was developed and compared with the experimental measurements. Part II of this paper uses this validated model with a transient, two-node thermal comfort model (including transmitted solar radiation) for assessment of indoor environmental conditions with different building envelope and shading properties, façade location and orientation. [Copyright &y& Elsevier]

Abstract: CFD (Computational Fluid Dynamics) is a useful tool to study air flow patterns in a room. Current CFD models are able to simulate air flow combined with temperature distributions and species distributions. In this paper a coupled CFD–HAM model is discussed. This model combines CFD with a HAM model (Heat, Air and Moisture) for hygroscopic materials. This coupled model is able to simulate air flow around a porous material and combines this with heat and moisture transport in the porous material. Validation with a small scale experiment in which gypsum board was used as a hygroscopic material showed good results. In this paper a further validation of the model is discussed based on a sensitivity analysis of some model parameters. Especially hygrothermal parameters like sorption isotherm and water vapour permeability proved to have a non negligible influence on the modelling outcome. Adding a hysteresis model showed improvement of the model during desorption. The model was also used to compare two modelling strategies. In one strategy the gypsum board was modelled as a uniform material, in a second approach the material was modelled as being layered. The difference between the two approaches showed to be negligible. [Copyright &y& Elsevier]

Abstract: Efficient and rational implementation of building stock CO2 emission reduction strategies and policies requires the application of comprehensive building stock models that have the ability to: (a) estimate the baseline energy demand of the existing building stock, (b) explore the technical and economic effects of different CO2 emission reduction strategies over time, including the impact of new technologies, and (c) to identify the effect of emission reduction strategies on indoor environmental quality. The aims of this paper are fourfold: (a) to briefly describe bottom-up and top-down methods and overview common bottom-up modelling techniques (statistical and building physics based), (b) to critically analyse the existing bottom-up building physics based residential energy models focusing on their purposes, strengths, and shortcomings, (c) to compare five building physics based bottom-up models focusing on the same building stock – UK case study, and (d) to identify the next generation of coupled energy–health bottom-up building stock models. This paper has identified three major issues which need to be addressed: a) the lack of publicly available detailed data relating to inputs and assumptions, as well as underlying algorithms, renders any attempt to reproduce their outcomes problematic, b) lack of data on the relative importance of input parameter variations on the predicted demand outputs, and c) uncertainty as to the socio-technical drivers of energy consumption – how people use energy and how they react to changes in their home as a result of energy conservation measures. [Copyright &y& Elsevier]

Abstract: The minimum size of subjects required for the research on human health, thermal comfort and productivity is a frequently asked question. In this paper the idea of power analysis, which helps to determine required sample size as well as to interpret research results, is introduced in order to promote good practice of power analysis in the context of human and building environment relationship research. How to calculate effect size from published article or experimental data is presented with plenty of examples. The effect sizes of several physiological and psychological measurements indicating the effect of indoor environment quality on human health, thermal comfort and productivity are presented, which could be worked as references when researchers planning their own studies. How to determine required sample size when planning a study and how to interpret the research results with power analysis are also illustrated step by step with samples. Finally how to make decisions when evaluating the study results is summarized. It is expected that these examples and the summary could help researchers to better apply power analysis in indoor environment quality (IEQ) studies. Some statistical terms used in this paper, such as power analysis, effect size, and t-test, etc., are explained in detail in the . [Copyright &y& Elsevier]

Wind pressure coefficients (Cp) are influenced by a wide range of parameters, including building geometry, facade detailing, position on the facade, the degree of exposure/sheltering, wind speed and wind direction. As it is practically impossible to take into account the full complexity of pressure coefficient variation, building energy simulation (BES) and Airflow network (AFN) programs generally incorporate it in a simplified way. This paper provides an overview of pressure coefficient data and the extent to which they are currently implemented in BES–AFN programs. A distinction is made between primary sources of Cp data, such as full-scale measurements, reduced-scale measurements in wind tunnels and computational fluid dynamics (CFD) simulations, and secondary sources, such as databases and analytical models. The comparison between data from secondary sources implemented in BES–AFN programs shows that the Cp values are quite different depending on the source adopted. The two influencing parameters for which these differences are most pronounced are the position on the facade and the degree of exposure/sheltering. The comparison of Cp data from different sources for sheltered buildings shows the largest differences, and data from different sources even present different trends. The paper concludes that quantification of the uncertainty related to such data sources is required to guide future improvements in Cp implementation in BES–AFN programs. [Copyright &y& Elsevier]

This paper aims at exploring quantitative methods that are appropriate for project location selection. One of the major considerations of whether to undertake a construction project is to determine if the location is valuable for investment. Location selection may be simply based on past experience, rudimentary, “gut-feeling”, or a combination of them. Alternatively, it may involve scientific methods. The paper introduces both deterministic and dynamic approaches and presents some of the basic quantitative methods, including data envelopment analysis model and binary integer linear program models, serving as a base for both academics and practitioners. To expand the contribution of the paper, illustrative examples are given. [Copyright &y& Elsevier]

This paper describes the combination of a physical pollutant model IAPPEM with a time activity profile, to create an air pollutant personal exposure model. A previous study has already demonstrated the capability of IAPPEM in predicting indoor Particulate Matter (PM) concentrations in a residential environment. The present work investigates personal exposure variability between individuals and, doors opened vs closed scenarios, by examining the movements of four individuals through the same dwelling. The results of the simulations highlight the distinction between personal exposure and indoor concentrations, providing computational validation to well-documented experimental differences that exist between indoor concentrations and personal exposure. Using IAPPEM, personal exposure is calculated according to the percentage contribution from the time spent in each room, illustrating that the periods of presence, in relation to the times of indoor source emission, are as important as the durations spent in each room. This study provides a comparison between two approaches for evaluating personal exposure: a time-weighted average and a time activity profile. The results showed that a time-weighted averaged profile is a poor substitute when compared with personal exposure calculated based on a time activity profile, as, in each simulated scenario, exposures were under-predicted using the time-weighted approach, in some cases by up to 135%. [ABSTRACT FROM AUTHOR]

In this paper, a mathematical model for predicting the departure duration of the first condensate droplet from a radiant ceiling surface was proposed on the basis of the condensation water mass. The simulation results indicate a dependence of condensation water mass on the apparent contact angle of the substrate, but almost in no relation with the surface temperature. The condensation water mass firstly increases with the increase of the apparent contact angle. It reaches a maximum weight of 522 g/m 2 at an apparent contact angle of 110°, and then decreases. A visualization experiment of condensation on a radiant ceiling panel with a conventional aluminum alloy surface was performed in a climate chamber to measure the departure duration of the droplet. The measured departure duration fluctuates due to the variance of apparent contact angle and the randomness of condensation process, but it decreases sharply with the sub-cooled degree (air dew point minus surface temperature). And the average departure duration is 10 h with a sub-cooled degree of 5 °C. The theoretical model is validated as the average relative biases between the experimental and theoretical results are within 25%. [ABSTRACT FROM AUTHOR]

This paper uses thermodynamics equilibrium theory to develop a mathematical model for dynamic thermal processes pertaining to rooms with a Chinese kang (a heatable brick bed). The model is developed through analysis of the dynamic thermal equilibrium of indoor air temperature and the temperature of interior and exterior surfaces of the building envelopes of rooms with a kang . It is developed and solved using a thermal reaction coefficient. Based on data from a field test, a simplified mathematical model of thermal processes in such a room is presented. The model only takes into account the radiation heat transfer between the exterior surface of the kang 's faceplate and the other interior surfaces of the building envelope, while ignoring the reciprocal radiation heat transfer between all other interior surfaces. A simplified mathematical model pertaining to the Chinese kang is also put forward. This model does not take into account the reciprocal radiation heat transfer between the interior surfaces of the Chinese kang . By combining these two models, the hourly values pertaining to indoor air temperature and exterior temperature of the kang 's faceplate can be predicted for different burning modes of the Chinese kang . MATLAB was used for calculating the target temperatures and solving the thermal reaction coefficient. The model was validated by error analysis and correlation analysis, the result of which shows that this mathematical model can accurately predict various characteristics concerning the temperatures in a room with a Chinese kang . [ABSTRACT FROM AUTHOR]

People can keep good thermal comfort when they participate in different intensity activities at a certain environment. But their thermal comfort changes greatly even with a slight change of activity intensity at other environment. It means that people's allowable fluctuation range of metabolic rate differs at different environments. Furthermore, the fluctuation ranges of thermal environment parameters also have different impacts on thermal comfort. Based on the body heat balance equation, this paper explored the influencing factors of the allowable fluctuation range of metabolic rate and the comfortable ranges of thermal environment parameters. The mathematical model between thermal environment parameters and the allowable fluctuation range of metabolic rate was established through the adoption of orthogonal experimental design test and multiple regression analysis. To verify the validity of theoretical results, questionnaire surveys were conducted in Changsha. The results showed that the air temperature is the most significant factors which affect the allowable fluctuation range of metabolic rate within the thermal comfort zone, the next are relative humidity and air velocity. There is a strong linear relationship between these three factors and the fluctuation range of metabolic rate. Combining the established model and questionnaire surveys, the comfortable ranges of temperature and relative humidity were obtained. These conclusions not only can provide a simple and feasible method to determine the allowable fluctuation range of metabolic rate in a given weather condition, but can also provide valuable references to set a standard for air-conditioning design parameters and indoor operating parameters according to different functional architectures. [ABSTRACT FROM AUTHOR]

Experimental measurement still plays an important role in indoor airflow study. To obtain three-dimensional and high-quality experimental data in building's indoor airflow study, Particle Tracking Velocimetry (PTV) and Particle Image Velocimetry (PIV) have been increasingly used. The accuracy and precision of measurement technologies is always a crucial issue. This paper first numerically compares the measuring performance of 3D PTV and typical 2D PIV algorithms on three laminar macro scale flows of known displacement, as a function of the particle tracking density defined as the ratio of mean particle spacing to mean particle displacement. Then, 3D PTV and 2D PIV results are compared using an experimental low-turbulence indoor airflow generated by a low-speed tailpipe. Results suggest that when the tracking density is smaller than two, 3D PTV generally cannot yield reliable measurement results. As the tracking density increases, 3D PTV has a better ability to measure larger displacement than PIV. [ABSTRACT FROM AUTHOR]

India is witnessing unprecedented growth trends in building construction, particularly office spaces. Indian offices are designed to operate at 22.5 ± 1 °C all year round to meet the stringent “Class A” specifications outlined by international standards in the absence of an India-specific comfort standard. This paper proposes an India Model for Adaptive Comfort – IMAC – based on the field surveys administered in 16 buildings in three seasons and five cities, representative of five Indian climate zones. A total of 6330 responses were gathered from naturally ventilated, mixed mode and air-conditioned office buildings using instantaneous thermal comfort surveys. Occupants in naturally ventilated Indian offices were found to be more adaptive than the prevailing ASHRAE and EN models would suggest. According to the IMAC model, neutral temperature in naturally ventilated buildings varies from 19.6 to 28.5 °C for 30-day outdoor running mean air temperatures ranging from 12.5 to 31 °C. This is the first instance where a study proposes a single adaptive model for mixed mode buildings asserting its validity for both naturally ventilated and air-conditioned modes of operation in the building, with neutral temperature varying from 21.5 to 28.7 °C for 13–38.5 °C range of outdoor temperatures. For air-conditioned buildings, Fanger's static PMV model was found to consistently over-predict the sensation on the warmer side of the 7-point sensation scale. [ABSTRACT FROM AUTHOR]

The dominant heat transfer between ceiling radiant cooling panels (CRCP) and indoor environment is the combined heat transfer of thermal radiation and natural convection. Currently, researchers usually discussed indoor radiation heat transfer under steady state conditions rather than non-steady state conditions. In this study, an experimental chamber was built to investigate the indoor parameter variations during the CRCP start-up process in summer, and a mathematical model was also established for further analysis of non-steady state radiation heat transfer. There was a concrete ceiling radiant cooling panel (C-CRCP) equipped in the chamber, and the panel was a concrete slab with pipes embedded in it. The experimental results showed that the temperature of the ceiling surface suddenly dropped after the C-CRCP started up, but the temperatures of the other inner surfaces and the indoor air decreased gradually with a similar trend. The radiant heat flux of the ceiling reached a trough rapidly, and then increased back to steady status step by step. Moreover, it took 7–9 h to nearly get steady status after the C-CRCP started up because of the thermal inertia and the thermal storage of concrete slab. The ratio of radiation heat transfer in the total heat transfer of the ceiling ranged from 40% to 60%. Based on the useful experimental data obtained in this C-CRCP system, a reliable start-up control strategy was also proposed in this paper. [ABSTRACT FROM AUTHOR]

This paper deals with the multi-input-multi-output (MIMO) control of an air handling unit (AHU) in an industrial heating ventilating and air conditioning (HVAC) system. The temperature and the relative humidity of the supply air have to be controlled simultaneously. Due to the nonlinear behavior of such a AHU it is difficult to achieve satisfactory performance over the whole operating range using linear control. Therefore in this work a model predictive control (MPC) strategy based on a network of local linear models is proposed. A detailed mathematical model referred to as “physical model” of the AHU is derived from physical laws and is verified by measurements. By proper excitation of the physical model, the local linear models are determined using the so called LoLiMoT (Local Linear Model Tree)-algorithm. The proposed concept is compared to a conventional PI control strategy and its performance is demonstrated in simulation as well as on a real world test plant. [ABSTRACT FROM AUTHOR]

Increasing size and complexity of indoor structures and increased urbanization has led to much more complication in urban disaster management. Contrary to outdoor environments, first responders and planners have limited information regarding the indoor areas in terms of architectural and semantic information as well as how they interact with their surroundings in case of indoor disasters. Availability of such information could help decision makers interact with building information and thus make more efficient planning prior to entering the disaster site. In addition as the indoor travel times required to reach specific areas in the building could be much longer compared to outdoor, visualizing the exact location of building rooms and utilities in 3D helps in visually communicating the indoor spatial information which could eventually result in decreased routing uncertainty inside the structures and help in more informed navigation strategies. This work aims at overcoming the insufficiencies of existing indoor modelling approaches by proposing a new Indoor Emergency Spatial Model (IESM) based on IFC. The model integrates 3D indoor architectural and semantic information required by first responders during indoor disasters with outdoor geographical information to improve situational awareness about both interiors of buildings as well as their interactions with outdoor components. The model is implemented and tested using the Esri GIS platform. The paper discusses the effectiveness of the model in both decision making and navigation by demonstrating the model's indoor spatial analysis capabilities and how it improves destination travel times. [ABSTRACT FROM AUTHOR]

This paper investigates by modeling and experimentation the dispersion of bacteria and performance of Upper Room Ultraviolet Germicidal Irradiation ( UVGI ) in spaces conditioned by combined chilled ceiling ( CC ) and mixed displacement ventilation ( DV ) system. The effects of gravitational settling and deposition were taken into account in mathematical modeling to reasonably simulate the transport of pathogen via expiratory droplets of all size ranges. The model was experimentally validated with and without the use of UVGI for different ventilation rates. Experiments were conducted in a CC/DV test room with a constant generation of Serratia marcescens , an extremely UV-susceptible microorganism to measure the airborne bacteria concentration in the room air and quantify the bacteria deposition on horizontal surfaces. The experimental bacteria colony forming units ( CFU ) count was used to validate a CFD model developed to predict the deposition of pathogen carriers. The mathematical model was then substantiated using the CFD predictions of pathogen concentration in the space for large carrying particles. The validated mathematical model was then used to study the effect of pathogen-carrying particle sizes on the microbiological indoor air quality. Results showed that the droplet size affects the value of maximal bacteria concentration and the height at which it occurs. Moreover, the UV disinfection rate achieved in the upper zone decreases from 88% to 78% when the size of pathogen-carrying particles increases from 2.5 μm to 20 μm meaning that greater percentage of bacteria are removed by deposition when bacteria is carried by large particles. [ABSTRACT FROM AUTHOR]

Knowledge regarding the characteristics of national building stocks is fundamental to understanding how the energy performance of the building stock can be improved. To facilitate large diversity and a number of buildings for such analyses, this paper presents a methodology by which national building stocks may be aggregated through archetype buildings. The methodology has been implemented and verified in four EU countries in regions with different climates, namely France, Germany, Spain and the UK. These countries account for about half of the final energy consumption of the EU-28 buildings. The analysis includes the residential and non-residential sectors (residential sector only for Germany). The number of archetypes per country has been defined according to different categories of building type, construction year, climate region and the main fuel source for heating purposes. The accuracy of the description is validated by simulating energy demand using the ECCABS Building Stock Model, and comparing the final energy demand modeled with corresponding statistical data. The total final energy demand calculated for these countries differs from available statistics by between −6% and +2%, which is considered satisfactory. The proposed description of the building stock is being used as a basis for analyzing the potential for and cost of energy conservation measures. [ABSTRACT FROM AUTHOR]

Adsorption-based air and water cleaning technologies have long been employed in various industrial applications, and several models have been developed to study their performance. This paper gives an overview of the existing sorbent-based gas filters models that have been used to predict a filter's performance for application in non-industrial buildings. The performance of existing models was investigated by comparing their predictions with experimental data of MEK and n-Hexane as a single-challenge gas for wide range of concentrations. A sensitivity analysis of models' parameters showed that the effective diffusivity has strong dependence on the concentration that is more noticeable for pore surface diffusion model. Considering the large discrepancies between the predicted and measured breakthrough curves at low concentrations using the pore diffusion model and the homogeneous-solid diffusion model, it is evident that further research is needed. [ABSTRACT FROM AUTHOR]

In Canada and USA, nearly 80 million students and teachers spend at least eight hours daily in schools that could be unhealthy and restrict their ability to learn. Despite this fact there is lack of adopting sustainability principles in school buildings. Even though life cycle assessment (LCA) and LEED® could serve as sustainability measurement tools, studies show that the integration of sustainability principles to LCA has not become standard practice yet. This paper presents an integrated LCA-LEED model that incorporates LCA into LEED and assigns corresponding LEED scores to achieve a high level of sustainability assessment, for the structure and envelope systems of Canadian school buildings. In this model, the selection of the most sustainable structure and envelope type for school buildings is done through the evaluation of three categories of the LEED rating system: energy and atmosphere, materials and resources, and LCA (incorporated under the innovation and design process category of LEED). Various options are tested by considering structures such as concrete, steel, masonry and wood, and envelope types such as precast panels, steel stud, wood stud and cavity wall. Energy simulation is performed by eQUEST® (version 3.64) program and LCA is performed by ATHENA® impact estimator. The results show that concrete and masonry buildings have high energy consumption and global warming potential during certain life cycle stages such as manufacturing, construction and demolition. However they have lower annual energy consumption and environmental impact during the operating stage, as well as for the overall life span. Concrete building with minimum insulation has obtained the highest total LEED score (19) followed by masonry (17), while steel and steel-masonry buildings have the least score (14). [ABSTRACT FROM AUTHOR]

Abstract: It is widely recognised that a major source of uncertainty in building performance simulation relates to occupancy and behavioural assumptions. This paper aims to assess the relative impact of lifestyle patterns, occupant-controlled window opening and shading use on indoor overheating risk levels in dwellings. The indoor thermal environment of a set of broadly representative archetypes of the London housing stock was simulated using dynamic thermal modelling. Two lifestyle patterns and four scenarios of window opening and shading use schedules were combined with multiple other varying parameters (building geometry and orientation, insulation levels, level of overshadowing by adjacent buildings), leading to a total of 27,648 modelled dwelling variants. It was found that the rankings obtained for dwellings occupied by a family with children at school and dwellings occupied by pensioners were broadly similar for all combinations of behaviour and the majority of overheating metrics. Lower ranking correlations were, however, observed between simple temperature-dependent window opening scenarios and a more sophisticated scenario of combined shading and night ventilation. This is an indication that shading and/or night cooling could modify indoor overheating risk significantly. The findings of the study add to a growing body of literature suggesting that the way inhabitants occupy and operate a building has a measurable impact on thermal discomfort and potentially the health risks associated with their exposure to high indoor temperatures. This should be taken into consideration in the design of retrofit interventions and public health strategies aiming to minimise such risks. [Copyright &y& Elsevier]

When simulating the hygrothermal behaviour of a building component, there are many inherently uncertain parameters. A probabilistic evaluation takes these uncertainties into account, allowing a more dependable assessment of the hygrothermal behaviour. However, this often necessitates many Monte Carlo simulations, which easily become computationally inhibitive. To overcome this time-expense problem, the hygrothermal model can be replaced by a metamodel, a much simpler mathematical model which aims at mimicking the original model with a strongly reduced calculation time. In this paper, a metamodel is developed to directly predict hygrothermal time series (e.g. temperature, relative humidity, moisture content), rather than single-valued derived performance indicators (e.g. maximum mould index), as these hygrothermal time series yield more information, and also allow the user to post-process the output as desired. So far, no metamodelling strategies able to tackle time series are available in the field of building physics. Because the hygrothermal response of a building component is highly non-linear and transient, this paper focuses on neural networks for time series, as they have proven successful in many other fields. The performance and training time of three popular types of networks (multilayer perceptron, recurrent neural network, convolutional neural network) is evaluated based on an application example of a massive masonry wall. The results indicate that only the recurrent and convolutional networks are able to capture the complex patterns of the hygrothermal response. Additionally, the convolutional network performed significantly better and was 10 times faster to train for the current application example, compared to the recurrent network. • A metamodel with a memory mechanism is required to accurately predict hygrothermal time series. • Recurrent neural networks and dilated causal convolutional networks are able to capture the complex patterns of the hygrothermal response. • To predict the relative humidity, dilated causal convolutional neural networks perform significantly better than recurrent neural networks. • Dilated causal convolutional networks are 10 times faster to train on the current example, compared to recurrent neural networks (LSTM, GRU). [ABSTRACT FROM AUTHOR]

Abstract: Rapid urbanization has emerged as the source of many adverse environmental effects and brings cities to a vulnerable situation under future climate challenges. Green roofs are proven to be an effective solution to alleviate these effects by field observations under a wide range of climate conditions. Recent advances in modeling urban land-atmosphere interactions provide a useful tool in capturing the dynamics of coupled transport of water and energy in urban conies, thus bridge the gap of modeling at city to regional scales. The performance of urban hydrological models depends heavily on the accurate determination of the input parameter space, where uncertainty is ubiquitous. In this paper, we use an advanced Monte Carlo approach, viz. the Subset Simulation, to quantify the sensitivity of urban hydrological modeling to parameter uncertainties. Results of the sensitivity analysis reveal that green roofs exhibit markedly different thermal and hydrological behavior as compared to conventional roofs, due to the modification of the surface energy portioning by well-irrigated vegetation. In addition, statistical predictions of critical responses of green roofs (extreme surface temperature, heat fluxes, etc.) have relatively weak dependence on climatic conditions. The statistical quantification of sensitivity provides guidance for future development of urban hydrological models with practical applications such as urban heat island mitigation. [Copyright &y& Elsevier]

Abstract: In ASHRAE Standard 55-2010, the comfort effects of elevated air movement are evaluated using the SET index as computed by the Gagge 2-Node model of whole-body heat balance. Air movement in reality has many forms, which might create heat flows and thermal sensations that cannot be accurately predicted by a simple whole-body model. This paper addresses two of such potential inaccuracies: 1) indoor airflows may affect only a portion of the body surface (e.g., above desktop), and the affected body surface might be variably nude (e.g., face) or clothed, 2) the turbulence intensity (TI) in some typical airstreams (e.g., those created by fans) might have a different impact on heat transfer than the TI implicit in 2-Node's single convective heat transfer coefficient. For both these issues, can a whole-body index like SET represent such a wide range of possible exposures to airflow? Measurements of thermal sensation were obtained from human subjects using face-level fans in warm environments. Previous laboratory studies of a range of airstream sources were also analyzed. The effects of turbulence intensity were examined with manikin tests. The results show that indices derived from the 2-Node model of whole-body heat balance are effective at predicting thermal sensation under most non-uniform air movement. In contrast, the PMV index underestimates cooling in warm conditions. Turbulence increases the cooling effect of air movement, but by amounts that might be neglected for most design purposes. [Copyright &y& Elsevier]

Abstract: Recent advances of information technology and the low cost of computing devices make it possible to collect end users' true thermal sensations at the building operation stage. This enables us to build personalized thermal comfort model from a new aspect. This paper proposes a data-driven method to describe the personalized thermal comfort in ordinary office environment. The model structure shows the condition of heat balance of human body, with four personalized coefficients estimated by on-line voting data. The adjustable coefficients provide the freedom to capture the personal differences in thermal comfort requirement. In contrast, the well-known PMV model is only an average model, which cannot reflect such differences. The model performance is evaluated by a field experiment study. A personal energy saving potential analysis is also presented as one of the applications. Both the experiment results and simulation results demonstrate the high accuracy of the data-driven model and the feasibility of the application in investigating personal energy saving potentials. [Copyright &y& Elsevier]

Abstract: Through a variable frequency drive (VFD), a variable air volume air handling system can significantly reduce supply fan power under partial load conditions. Typically, the VFD on a supply fan motor is modulated to maintain a supply air duct static pressure set point. The static pressure set point can be either constant or dynamically reset in response to different load conditions. In this paper, comprehensive mathematical models are established to describe the performance of a VFD-motor-fan system under three different static pressure control strategies: constant static pressure set point, static pressure reset by total airflow rate, and static pressure reset by highest zone demand. The total input power to the system, including the energy imparted into the air as well as the energy losses from the VFD, motor, and fan, are simulated and compared among the different static pressure reset strategies with different minimum airflow ratios. The simulation results show that more than 50% of electrical power savings can be realized by static pressure reset when the diversity of the zone thermal loads is moderate. In addition, although a lower minimum airflow ratio can result in more power savings, there were no significant power saving by reducing the minimum airflow ratio from 30% to 10% due to relatively high energy losses of the fan, motor and VFD at low load and speed conditions. Finally, experiments were carried out to demonstrate the performance comparison of three different control strategies. [Copyright &y& Elsevier]

Abstract: Human comfort is gaining importance in the recent decades. Mechanical air conditioners are conventional means of creating thermal comfort but they are energy intensive and hence harmful to ecological system. Therefore passive cooling can be adopted as a viable alternative to conventional cooling system. This paper reviews various passive cooling options available such as nocturnal radiation, geothermal, ventilation, evaporative, hydrogeothermal, deep ocean/lake, thermal insulation and shading along with their advantages, limitations, working principles and climatic dependence. The mathematical equations used for computing the performance of passive cooling systems have been discussed along with design and environmental parameters influencing the systems' performance. The usefulness of phase change materials, thermal mass and radiant cooling in passive cooling systems is also examined. Case studies containing experimental data and numerical predictions are discussed to provide options for building architects and infrastructure developers to adopt the appropriate passive cooling strategy. In addition, issues related to occupants' health and indoor air quality are also explained. A brief review of energy-efficient and eco-friendly solar cooling systems is also included. [Copyright &y& Elsevier]

Abstract: A human thermoregulation model called JOS-2 was developed based on the Stolwijk model and our previously developed (in 2002) JOS model. In this model, the whole body was idealized as 17 spherical or cylindrical body segments (Head, Neck, Chest, Pelvis, right and left Shoulders, right and left Arms, right and left Hands, right and left Thighs, right and left Legs, and right and left Feet). The Head segment consists of four layers—core, first layer, second layer, and skin—and the other segments consist of two layers—core and skin). All body segments have artery and vein blood pools. In addition, the limb segments have a detailed vascular system consisting of superficial veins and arteriovenous anastomoses (AVA). Thermoregulatory mechanisms such as vasoconstriction, vasodilation, perspiration, and shivering are considered. The physical parameters of this model, such as height, weight, sex, age, body fat percentage, basal metabolic rate, and cardiac index, can be changed. This paper describes the equations and coefficients as well as the model validation for stable, nonuniform, transient conditions. [Copyright &y& Elsevier]

Abstract: Many of the standards and codes related to watertightness of building components in use today have a long history and in most cases their roots were conceived decades ago. Irrespective of the broad spectrum of research on wind loads, rainfall and wind driven rain (WDR) intensity, little information is available concerning the scientific basis for watertightness test methods or performance criteria. This paper provides an overview of existing methodologies to establish test conditions and a critical review of calculation methods for wind and WDR loads on buildings, from the viewpoint of establishing test parameters for watertightness testing. The operative standard in the field of structural engineering is extended with a gust model to calculate wind loads for varying configurations, return periods and gust lengths, and model implications are discussed. A state-of-the-art on intensity–duration–frequency curves of horizontal rainfall intensity is given, and a new approach to accommodate conflicting models is presented. Furthermore, based on recent advances in WDR research, an adapted semi-empirical model is suggested to calculate extreme WDR intensities on building façades. For two locations boundary conditions for watertightness testing were calculated based on datasets extending over 10 years of 10-min averaged values. Finally, constraints and challenges in extreme value analysis in respect to cut-off values, fitting algorithms, goodness-of-fit (GOF) criteria and co-occurrence of rain and wind are discussed. [Copyright &y& Elsevier]