Available online 25 January 2013 Publication year: 2013 Source:Building and Environment
The pandemic H1N1 2009 (p-H1N1) spreading worldwide has led to severe morbidity and mortality. This study aimed to quantify the impacts on disease control by applying various control strategies for p-H1N1 in an elementary school indoor setting. Indoor disease transmissibility was explored by a general Wells-Riley equation. To better contain influenza outbreak, a multi-control measure model was developed. A non-extinction branching process was presented to quantify the indoor epidemic probability for seasonal influenza and p-H1N1. The infection risk, quantum generation rate (quanta d−1), basic reproduction number (R0), generation time (d), and asymptomatic infectious proportion (%) were, respectively, estimated to be 0.020 (95% CI: 0.010 – 0.043), 494 (140 – 1292), 3.30 (0.75 – 11.47), 3.54 (3.15 – 3.99), and 15 (8 – 59) for p-H1N1. By implementing all non-engineering interventions, seasonal influenza could be well controlled, whereas for p-H1N1, engineering and non-engineering control measure combinations were effective for complete outbreak containment. Indoor epidemic probability of p-H1N1 increases with increments in R0 and introductions of infected individual. The proposed control strategies combined with non-engineering and engineering interventions could effectively control p-H1N1 outbreak. A multi-control measure model developed here could be implemented in more complex infectious circumstances. Our study can be incorporated into the relationship among influenza virus, host, and indoor environment for better understanding the complex dynamics of environmental processes and to achieve optimal indoor control measures.
Highlights
► Optimal control measures can be achieved in an elementary school. ► General multi-control measure model can be used in complex infectious conditions. ► Epidemic probability model captures the idea of alterations in indoor epidemic. ► Complex interactions among virus, host, and indoor environment can further be studied.
Available online 29 January 2013 Publication year: 2013 Source:Building and Environment
The development of a reliable and validated model can facilitate the widespread application of ultra-violet photocatalytic oxidation (UV-PCO) for indoor air treatment and purification in building mechanical ventilation systems. This paper reports the development of a time-dependent model for predicting the performance of an in-duct PCO air cleaner under the conditions relevant to the actual applications. The model was developed by integrating light scattering model, reaction kinetic model, mass balance as well as optional ozonation model. The comprehensive model incorporates the influences of properties of light sources and catalyst, reactor geometry, mass transfer parameters, kinetic parameters, operational conditions, as well as ozonation effect. These parameters can be estimated easily from experiments and/or empirical equations. The UV-PCO model and UV-PCO model combined with ozonation model were validated with experimental results for fiberglass fibers coated with TiO2 (TiO2/FGFs) air filters under different conditions. There was good agreement between the prediction made by the model and the experiment results. It was also demonstrated that the developed model can be applied to predict the UV-PCO performance for carbon cloth fibers loaded with TiO2 (TiO2/CCFs) air filters.
Highlights
► A reliable two-phase based time-dependent UV-PCO model was developed. ► The comprehensive model incorporated the influences of various parameters. ► Ozonation model was proposed to describe the VOCs removal in the reaction with ozone. ► There was good agreement between the model predictions and the experiment results. ► The model can be applied to predict UV-PCO performance for different air filters.
April 2013 Publication year: 2013 Source:Building and Environment, Volume 62
This research has the goal of determining, comparing and substantiating the actual outcome of using sustainable practices, from a financial and environmental comfort point of view. The selected context was of interest due to the challenge of quality sustainable construction at controlled costs, meant for inhabitants of the Portuguese cooperative housing, due to its economical implications and especially its social ones. Two case studies of cooperative housing developments built in Portugal are presented, the first with characteristics of traditional construction and the second including sustainable building features. With these examples, it is intended to demonstrate that it is possible to build below cost limits imposed by law in order to substantially reduce energy consumption costs for heating and cooling as well as for domestic water heating. So, calculations of energy savings in indoor heating and cooling, as well as for domestic water heating are presented in this article for two specific situations: first, for a standard comfort use of housing, as opposed to a situation of real consumption of housing developments as obtained by monitoring carried out for one year in the same dwellings studied for standard comfort. The causes that lead to a substantial decrease in energy consumption in the building of sustainable construction are also described, as a starting point to the improvement of future cooperative housing. Finally are presented, for each of the two situations, calculations of the payback period of investment, according to the specific incremental cost in sustainable construction and the benefits in reducing consumptions. The results show an effective contribution to the improvement of the environment and environmental comfort, due to sustainable construction.
Highlights
► How to use efficient insulation on a small overcost basis. ► How to strongly decrease heating energy cost with very efficient insulation. ► Efficient solar collectors and DHW gas heaters reduce energy consumption up to 70%. ► Simple payback period of efficient construction estimated 2.3–24 years.
March 2013 Publication year: 2013 Source:Building and Environment, Volume 61
Exposure to indoor chemical air pollutants is expected to increase potentially the chance of developing cancer. Ambient levels of carbonyl (formaldehyde, acetaldehyde, acrolein and acetone) and BTEXs (benzene, toluene and xylenes) compounds were monitored at 210 residential homes in Xicheng district, Beijing, during the period of November–December 2009. The indoor concentrations of formaldehyde, acetaldehyde, acrolein, acetone, benzene, toluene and xylenes were in the range of 0.2–213.4 μg m−3, 0.7–140.9 μg m−3, 0.1–25.2 μg m−3, 0.3–102.1 μg m−3, 1.0–47.5 μg m−3, 1.3–552.6 μg m−3 and 0.2–150.6 μg m−3, respectively. Average concentrations of formaldehyde, acetaldehyde, acrolein, acetone, benzene, toluene and xylenes were 21.8 μg m−3, 16.3 μg m−3, 2.8 μg m−3, 10.7 μg m−3, 9.0 μg m−3, 32.1 μg m−3 and 12.3 μg m−3, respectively. The individual samples were mostly lower than the Chinese guideline values except formaldehyde and toluene, which showed higher values in 91 and 29 samples. Statistical analysis and I/O (indoor concentration/outdoor concentration) ratio results showed that the main sources of formaldehyde, acetaldehyde, benzene and toluene at homes with renovation age <5 years were organic solvents used in adhesives and decoration materials. Meanwhile, outdoor emission factors may have an impact on acetone, acrolein and xylenes concentrations of indoor air at different homes, and on formaldehyde, acetaldehyde, benzene and toluene concentrations of indoor air at homes with renovation age >5 years. Our results also showed that higher cancer risks for human exposure to formaldehyde, acetaldehyde and benzene than previous studies in Guangzhou and Hangzhou, China with one exception.
Highlights
► Levels of carbonyls and BTEXs were monitored at 210 homes in Xicheng district, Beijing. ► The main sources of carbonyls and BTEXs for newly decoration home were organic solvents used in adhesives. ► The indoor concentrations of carbonyls and BTEXs were also influenced by outdoor emissions.
March 2013 Publication year: 2013 Source:Building and Environment, Volume 61
Indoor air humidity is an important factor influencing air quality, human comfort, energy consumption of buildings and the durability of building materials. As a result, the aim of this study is to put forward a numerical approach for conjugate thermo-solutal-convection and condensation of humid air phenomena in rooms. The numerical model pertinence is thoroughly analyzed using experimental data for ventilated enclosures (isothermal conditions, cold air supply, hot air supply and specific study of water vapour condensation on a cold glazed wall). Consequently, we first describe the experimental set-up (the test cell), focussing particularly on the elements concerning the humidification system and condensation qualification system, especially added for this study. This is followed by the numerical model description. The approach is essentially based on the computational fluid dynamics technique, adding a convection–diffusion conservation equation of water vapour to the basic equations for a turbulent non-isothermal air flow. In addition, detailed presentation of water vapour surface and volume condensation modelling is given. The results from our work can find a direct applicability in several fields: residential and commercial buildings (thermal comfort and energy consumption), museums and industry (microclimate control and technological conditions), vehicles (freezing prediction on the windshield).
Highlights
► Comprehensive thermo-solutal-convection CFD model for humid air in rooms. ► In addition: water vapour surface and volume condensation modelling. ► Experimental validation based on full scale test cell (ventilated enclosure). ► Focus on the experimental humidification and condensation qualification systems. ► Analysed cases: isothermal/cold/hot air supply; condensation on glazed walls.
March 2013 Publication year: 2013 Source:Building and Environment, Volume 61
Photocatalysis is a promising technique for remediation of indoor air pollution. This study focuses on the enhancement of the effectiveness of the photocatalytic process by the introduction of artificial roughness on the interior reactor surface. Artificial roughness elements on the catalytic surface could enhance the turbulence intensity close to the catalytic surface. The enhanced turbulence intensity would translate to an increased in the mass transfer of airborne contaminants to the catalyst surface, improving the efficiency of photocatalysis.Air flow properties in a model photoreactor channel with transverse rib roughness on the wall are investigated by the “realizable k–epsilon (k–ε)” model. The investigation includes different shapes, sizes, and arrangements of the roughness elements for determining the maximum enhancement of turbulence intensity in the photoreactor channel. The optimum roughness has been determined to be an isosceles triangle shape with the bottom angle (α) equal to 75°, the relative height (e/h) equal to 0.05, and the pitch ratio (p/e) equal to 10. An experimental study was also carried out, which verified that the photocatalytic reactor performance for indoor air cleaning is significantly improved by a roughness pattern on catalyst surface compared to a reactor with a smooth catalyst surface.
Highlights
► The study focuses on the effectiveness of the photocatalytic process. ► A rough surface enhances wall turbulence and convective mass transfer. ► Photocatalytic reactor performance is greatly improved by rough catalyst surface. ► The paper presents analysis of turbulence intensity by CFD modeling. ► The experimental measurements are also carried out.
April 2013 Publication year: 2013 Source:Building and Environment, Volume 62
To study transient mass transfers inside buildings equipped with ventilation systems, reduced-scale experiments have been performed by applying the scaling down methodology developed for studying isothermal airflows in a steady or a transient state [1]. Transient tests have been carried out both on simplified cases considered for the validation of the methodology and on two reference industrial configurations representative of real industrial facilities. In this article, focus is made on transient results obtained on simplified and reference industrial cases subjected to wind and internal overpressure effects. The main objectives are firstly to identify the internal transient airflow behaviour, compared with Helmholtz oscillated phenomena underlined from natural ventilation studies, secondly to analyse the pollutant containment of reference industrial configurations subjected to wind and/or internal overpressure effects due to an accident, and finally to check the ability of the SYLVIA code to model these transient phenomena.
Highlights
► Transient flows in ventilation systems were experimentally and numerically studied. ► Helmholtz oscillations have been characterized depending on branch characteristics. ► The ventilation system inertia can often be negligible for industrial cases studied. ► Wind turbulence can lead to unsteady losses of the containment inside buildings. ► The Sylvia code has been validated for taking into account transient flow phenomena.
Available online 4 February 2013 Publication year: 2013 Source:Building and Environment
A framework was developed for integrating indoor environmental quality (IEQ) into life cycle assessment (LCA). The framework includes three main impact types: 1) chemical-specific impacts directly comparable to conventional life cycle impact assessment (LCIA) human health categories, 2) non-chemical health impacts, and 3) productivity/performance impacts. The first part of the framework related to contaminant specific impacts was explored using a green university building as a case study, while the remaining categories will be the subject of future work. Results showed that including IEQ aspects in whole-building LCA revealed LCIA internal impacts in some categories comparable to external impacts. For human health respiratory effects, building-specific indoor impacts from the case study were 12% of global external impacts in conventional LCA. Building-specific indoor cancer toxicity impacts were greater than external impacts by an order of magnitude, and building-specific indoor noncancer toxicity impacts were lower than external impacts by an order of magnitude. Although internal impacts were greater than external impacts in one category - cancer toxicity, the source of the contamination in the other two categories - respiratory effects and noncancer toxicity - was related to intake of outdoor air. The findings of this study underscore the importance of filtration or other treatment of mechanically supplied outdoor or recirculated indoor air, as well as control of pollution from indoor sources such as building materials or cleaning products. These findings may support the use of green building rating systems which include acknowledgment of the aforementioned IEQ-related features.
Highlights
► We outline a framework for including whole-building IEQ effects in LCA. ► We explore the portion of the framework pertaining to internal chemical impacts. ► We use a case study of a LEED Gold academic building to illustrate application. ► Internal impacts were comparable to or greater than external impacts. ► Internal human health impacts should be included in whole-building LCA.
Available online 4 February 2013 Publication year: 2013 Source:Building and Environment
The climate in cities differs significantly from those found in the surrounding area. These differences results from modifications of the Earth’s surface that alters the disposition of “natural energy balance” at a micro-scale and the concentration of activities that results in anthropogenic emissions that change the composition of the atmosphere. These urban effects have distinctive temporal and spatial properties with different impacts on building energy performance depending on their purpose which are rarely accounted for.This paper examines performance implications of a change-of-use (from office to residential) in the context of the UK government’s proposal to encourage regeneration and to meet housing needs. However, the diurnal occupation and activity patterns of these uses are distinct. For office buildings, with daytime occupation, focus is on the diurnal heating cycle driven by solar energy gains to which internal energy sources must be added. For residential buildings occupation and activity are primarily associated with the diurnal cooling period, and lower levels of activity that results in a primary heating need. This paper highlights the link between the timing of the urban climate effects, the urban setting and energy performance in a typical city street, where buildings are currently designed for commercial use. It employs London’s current and projected climate to simulate heating and cooling demands. By studying the role of urban form and its implications on the suitability of a buildings function we find that a ‘form first’ approach should be considered in the early design stages over the standard ‘fabric first’ approach.
Highlights
► The value of the thermal interdependence between modern building groups. ► Urban climate implications when buildings undergo a change of use. ► building group performance examined in relation to mean H/W ratio. ► building group performance examined in relation to the nocturnal UHI. ► Street H/W ratio as a common descriptor to link urban disciplines.
April 2013 Publication year: 2013 Source:Building and Environment, Volume 62
After decades of intense research, the effects of light on the circadian system have been proved to exist. By studying the relationship between human physiology and light, research has also advanced to the point that there is the belief that these effects will be in future regulated by Standards. Establishing a direct connection among the fundamental radiometric, the traditional photometric and the new circadian approach to lighting becomes a fundamental step for introducing new concepts to lighting practitioners.This theoretical paper has the aim to propose a correlation between the traditional approach to lighting design with the new and still not definitely defined circadian approach by means of a photometric to circadian correlation factor. By this way, once the circadian efficiency function will be experimentally determined, technicians will be able to evaluate also from a numerical point of view the impact of lighting on the circadian system, adding health considerations to the traditional design process.
Highlights
► Approach to circadian photometry based on CIE definition of photometric quantities. ► Correlation between photometric approach to lighting design and circadian approach. ► A definition of circadian metrics in parallel to traditional photometric quantities. ► Conversion factors between luminous and circadian quantities are presented.
April 2013 Publication year: 2013 Source:Building and Environment, Volume 62
This study develops a new methodology to investigate the particle residence time in indoor environment with the Lagrangian modeling. So far, the particle residence time has been only developed in terms of the Eulerian-based advection-diffusion approach, which is easy to use but is only valid for the transport of fine, neutrally buoyant, non-inertial particles that exactly follow indoor airflows. However, for practical indoor air pollution problems, there exists a wide range of particle sizes. To extend the engineering application range of the particle residence time, a new Lagrangian-based approach, which adopts the kernel concentration estimation method, is herein proposed to model the particle residence time in indoor environment. This new approach can transfer Lagrangian particle trajectories into an Eulerian form of particle concentrations at a given point, and thus provide the mean particle residence time. The commonly used Eulerian-based advection-diffusion approach is also considered for numerical comparison. Two representative particle sizes of 10-μm coarse particles and 1-μm fine particles are input into the two approaches to investigate the effect of particle size on the mean particle residence time. The simulated results indicate that this new Lagrangian approach can give more reasonable prediction on the particle residence time than the Eulerian-based advection-diffusion approach.
Highlights
► The new Lagrangian approach is developed to evaluate the particle residence time. ► The Eulerian advection-diffusion approach is included for numerical comparison. ► Two particle sizes are input into the two approaches to compare the difference. ► The new Lagrangian approach well predicts the particle residence time.
April 2013 Publication year: 2013 Source:Building and Environment, Volume 62
It is important to accurately model person-to-person particle transport in mechanical ventilation spaces to create and maintain a healthy indoor environment. The present study introduces a hybrid DES-Lagrangian and RANS-Eulerian model for simulating transient particle transport in enclosed environments; this hybrid model can ensure the accuracy and reduce the computing cost. Our study estimated two key time constants for the model that are important parameters for reducing the computing costs. The two time constants estimated were verified by airflow data from both an office and an aircraft cabin case. This study also conducted experiments in the first-class cabin of an MD-82 commercial airliner with heated manikins to validate the hybrid model. A pulse particle source was applied at the mouth of an index manikin to simulate a cough. The particle concentrations versus time were measured at the breathing zone of the other manikins. The trend of particle concentrations versus time predicted by the hybrid model agrees with the experimental data. Therefore, the proposed hybrid model can be used for investigating transient particle transport in enclosed environments.
Highlights
► A hybrid model was proposed for modeling transient particle transport indoors. ► Two key time constants for the hybrid model were estimated and verified. ► Experiment was conducted in an MD-82 aircraft cabin to validate the hybrid model.
April 2013 Publication year: 2013 Source:Building and Environment, Volume 62
Based on the recent emergence of Controlled Radiator Valve (CRV) components, the paper considers the research, development, application and benefits of a modern control methodology to improve the heating efficiency of domestic dwellings. In particular, the problem of efficient temperature control, is formulated as a model predictive control scheme employing a parameter matching technique. A key contribution of the paper is the development of an on-line modelling method, which, in contrast to previously reported techniques, requires no prerequisite knowledge of the thermodynamic behaviour of a given controlled zone and a training period of only 48 h. Moreover, it is shown that excellent performance is obtained without the normal requirements for measurements of site weather or input from other external sources of weather data, thereby reducing system cost and complexity. The proposed techniques are applied in a controlled zone using a BS EN 442 oil filled heat emitter, whose input power is closely controlled using a PWM power converter within an instrumented test cell, and also in an occupied dwelling. Results demonstrated MPC can be implemented in a dwelling with minimal perquisite modelling and still achieve set point tracking when compared to more conventional solutions resulting in an energy saving of up to 22%.
Highlights
► We compared 2nd order to 5th order parameter matched models to zone heating response. ► We implemented MPC using recursively parameter matched models in a test cell. ► We implemented MPC using recursively parameter matched models in a dwelling. ► Recursive modelling is suitable for use with MPC controlling fluid filled heat emitters. ► PWM output does not reduce performance of MPC controller using recursive modelling.
Available online 6 February 2013 Publication year: 2013 Source:Building and Environment
The use of building materials modified with photocatalytic components is constantly growing, due to an increased need for efficient purification strategies to improve air quality in industrial and urban areas. Yet, few works are available on the actual behavior of photocatalysts integrated in supporting materials, in this case concrete, and on the alteration of their properties in time. This work focuses on mechanical and durability aspects of TiO2-containing photocatalytic concrete by examining mutual influences between TiO2 and concrete components, and their evolution with the material aging. Experimental tests showed that concrete rheological properties decreased by adding TiO2; mechanical resistance also decreased slightly, in spite of the filler effect expected from the addition of a nanopowder. On the other hand, carbonation decreased the material photocatalytic efficiency compared to the freshly cast specimens: this was ascribed to variations of pore solution chemistry and possible shielding effects produced by calcium carbonate precipitation.
Graphical abstract
Highlights
► Photocatalytic concrete specimens were cast by admixing TiO2 nanopowders to concrete. ► TiO2 reduces workability and compressive strength, accelerates carbonation. ► Carbonation reduces photocatalytic efficiency of TiO2. ► Need for a model describing the influence of weathering on TiO2 efficiency.
Available online 6 February 2013 Publication year: 2013 Source:Building and Environment
We look critically at the principal graphs relating thermal comfort indoors to the climate, and compare the metrics used for the climate; an exponential running mean of the mean outdoor temperature proves better than either the historic monthly mean or the current outdoor temperature. Using the SCATs and the ASHRAE RP-884 databases of field-studies we develop a method to derive a standard sensitivity to indoor temperatures change. People are more sensitive to temperature change within a single working-day than previously thought. This sensitivity is used to estimate the comfort temperatures and to establish a curve relating the probability of discomfort to the temperature-difference from the current optimum. Using the standard sensitivity, a reliable estimate of comfort temperature can be made from a small batch of data, and from batches whose summary statistics alone are known. This extends the quantity of available data from which to form the relation between indoor comfort and the climate. We draw on an extensive database of such summary statistics. Using this information the graphs relating the temperature for comfort indoors and the climate are updated. Bands are given within which the comfort temperatures are likely to lie, both for the free-running mode of operation and for the heated-or-cooled mode. The underlying mechanism of the relation between climate and indoor comfort is discussed. The data show that it is possible to design buildings to operate in the free-running mode so as to be comfortable when the prevailing mean outdoor temperature lies within the range 10-30°C.
Highlights
► An extensive database of summary statistics confirms general pattern of relation. ► Best metric for outdoor temperature an exponential running mean with alpha 0.8/day. ► People more sensitive to within-day temperature changes than thought (0.5votes/K). ► Graph of comfort temperature versus outdoor temperature is steeper (0.53/K). ► Free-running mode possible if mean outdoor temperature between 10 and 30oC.
Available online 8 February 2013 Publication year: 2013 Source:Building and Environment
This paper analyses the dispersion of the exhaled contaminants by humans in indoor environments, with special attention to the exhalation jet and its interaction with the indoor airflow pattern in both mixing and displacement ventilation conditions.The way in which three different numerical boundary conditions for the exhalation flow (one time-dependent and two steady conditions) predict that contaminant dispersion is also analysed. The first boundary condition is a time-dependent sinusoidal function, which is the most realistic condition (Test a), and it is used to validate the numerical model with experimental data obtained from a previous study. The second one (Test b) maintains the momentum of the exhalation flow and the third (Test c) uses the maximum exhalation velocity.The objectives of this study are to increase knowledge regarding the exhaled contaminant distribution under different environmental conditions and to validate whether a steady boundary condition of the exhalation flow may simulate human breathing in an effective and accurate way. The results show a very good agreement of the numerical results obtained for Test a and the experimental data. This fact confirms the use of numerical simulation as a powerful tool to predict the contaminant distribution exhaled by a human. The numerical tests with steady boundary conditions for the exhalation flow require a transitory resolution procedure and the predictions provided by these models display some discrepancies with respect to Test a. These differences are evaluated by comparing the penetration length and vertical ascendance values for the different tests.
Graphical abstract
Highlights
► We examined the dispersion of exhaled contaminants generated by human breathing. ► The solution may be time-dependent even with steady boundary conditions. ► A zone of elevated contaminant concentration is formed in the upper face area. ► Any constant exhalation will be incapable of predicting the previous highlight. ► We do not recommend substituting sinusoidal exhalation for another stationary one.
Available online 9 February 2013 Publication year: 2013 Source:Building and Environment
The simultaneous cooling in the dehumidification of an internally cooled process is quite different from an adiabatic process that uses liquid desiccant. In the present study, the operating performance of an internally cooled process was examined through both experimental tests and simulation analysis. An internally cooled dehumidifier made of stainless steel was designed, and experimental results in different working conditions were analyzed using a lithium bromide (LiBr) aqueous solution. The moisture removal rate, dehumidifying efficiency, and volume mass transfer coefficient were adopted as indices to evaluate the performance. The effects of the inlet parameters on these performance indices were investigated. The predicted results by the numerical model agreed well with the experimental results. The validated model was then utilized to predict the performance of the entire internally cooled/heated air handling system, in which low regeneration temperature could be realized. An internally cooled/heated system driven by the exhaust heat of heat pump was then proposed, and COP was in the range of 4.2-6.5.
Highlights
► Experiments on an internally cooled dehumidifier are carried out using LiBr. ► Effects of tw,in, and on the dehumidifying performance are investigated. ► Theoretical model for an internal cooled/heated system is built and validated. ► An internally cooled/heated system driven by the heat pump is analyzed.
Available online 9 February 2013 Publication year: 2013 Source:Building and Environment
External Thermal Insulation Composite Systems – ETICS are, now-a-days, quite common in European buildings, used both in new constructions and refurbishment. Unfortunately, ETICS can have serious problems of biological growth causing the cladding defacement. It is known that biological growth is due to high values of surface moisture content, which results mostly from surface condensation and wind-driven rain. If the drying process is not sufficiently fast, the surface moisture content remains high for longer periods and consequently increases the risk of biological growth.This paper presents the results of a detailed experimental study that was carried out by the Building Physics Laboratory of Porto University (UP), in order to assess the hygrothermal behaviour of façades covered with ETICS, namely to evaluate the influence of orientation on surface humidification, by external condensation and by wind-driven rain. A building located in UP campus, with its four façades facing the cardinal directions, was monitored during one year. The exterior surface parameters under study were temperature, long wave radiation, wind-driven rain and relative humidity. The exterior climate was also measured to evaluate surface condensation.
Highlights
► A test campaign was carried out to assess the hygrothermal behaviour of ETICS. ► The influence of orientation on surface water content was evaluated. ► The parameters assessed were temperature, lw radiation, WDR and relative humidity. ► Orientation has major influence on surface condensation and WDR. ► The drying process has a key role of in the surface water content.
Available online 15 February 2013 Publication year: 2013 Source:Building and Environment
The mean radiant temperature is one of the six main variables responsible for the thermal sensation of the man exposed in a particular thermal environment (indoor and outdoor). Its measurement is not direct and is usually carried out by means of different methodologies and instruments whose general details and accuracy requirements are reported in the ISO Standard 7726. This paper deals with a critical review on the typical measurement methodologies combined with a comparative analysis of the metrological performances exhibited by the more common practice instruments on the market. To this purpose a special room-test has been designed aiming to reproduce the typical microclimatic conditions can be encountered in workplaces both in summer and in winter conditions. The effect of the measurement methodology and used instruments on the thermal comfort (global and local) and the thermal stress assessment has been finally discussed. Obtained results show that the use of different instruments consistent with ISO Standard 7726 requirements results in values of the mean radiant temperature compatible with each other, but the consequences on thermal environment assessment appear often ambiguous. Obtained results have focused the need for starting an in-depth discussion on the measurements’ protocols and the instruments leading to a possible reduction of the required accuracy levels reported in the ISO Standard 7726.
Highlights
► We have investigated the measurement methods of the mean radiant temperature. ► Measurements have been carried out in a test room reproducing moderate conditions. ► The method based on the angle factors is reliable. ► The method based on the net radiometer is often not compliant with other methods. ► The assessment of both global and local comfort can become quite random.
