Tiberiu Catalina

The present study reports by experimental measurements the levels of volatile organic compounds (VOC) and radon concentrations in two high school classrooms. The difference between the two classrooms abbreviated as S7 and S8 is the presence of a mechanical ventilation system in one of them (S8). The topic is of high importance as the indoor air quality (IAQ) can affect the health and learning performance of the pupils. VOC and RADON have a substantial weight of IAQ and a study of theirs level can help us to better understand at what levels the children are exposed daily. The two mentioned classroom have suffered recently a massive renovation. The classroom with the ventilation system was mounted with variable flow of fresh air, while the other one relies only on natural ventilation by opening the windows. In S8 several test were done for different fresh air ventilation rates. The conclusions were that in the classroom S7 there were measured high levels of VOC and radon, higher than the maximum admissible which is a serious problem. On the other hand, in the classroom S8 for all the different air rates the values were very low, thus creating a healthy and comfortable environment for the learning process. In this article we raise again the problem of lack of a mechanical ventilation system in all Romanian schools. Due to thermal rehabilitation of the buildings the building is air sealed with negative impact on the introduced fresh air. Moreover, the high number of occupants in the classroom and the renovation of classroom have negative influence on all indoor pollutants levels. The only solution to these problems is a correct design of a school or to install other ways to mechanically introduce the fresh air.

Usually air permeability is measured for a specific building only once: either when the building construction is was just finished or when the building is already in use. In this paper we present a novel aspect. We researched if there is any variation of the building permeability during its construction. We followed the evolution of the building airtightness during the construction of a passive house carrying out permeability measurements in two different phases: (1) airtight construction but not finished and without HVAC, and (2) finished construction with HVAC. For each phase, we used a blower door experiment stand to measure the airflow at different indoor-outdoor pressure differences in two conditions (depressurization and pressurization). We obtained air change rate at 50Pa well below the maximum limit characteristic to passive house. However an intriguing result was found: the measured permeability for the finished building is slightly bigger than the measured permeability for the unfinished building. On one side the better finishing of the walls and windows lead to an airtightness improvement, but on the other side the new HVAC wall penetrations and HVAC terminals (inlets and exhausts) lead to an airtightness aggravation just enough to turn over the improvement brought by the better state of building finishing.

Achieving high acoustic quality in meeting rooms is important for intelligibility therefore several measures are needed especially in reflective high volume rooms. This article tackles the method and the solution to renovate a complex enclosure. The study is divided in multiple stages: development of the 3D room model exported in ODEON acoustic software, validation of the actual condition of the room with measurements, proposing and analysing different acoustic ceiling tiles and finally selecting the optimum solution based on the cost and efficacy in reducing the reverberation time (RT). The measured RT was four times higher (3.45 sec at f=1kHz) than the recommended value (0.9 sec at f=1kHz). The numerical simulation results were in accordance with the experimental measurements with errors of less than 0.2 sec. Using the difference between the RT obtained with the acoustic measures and the optimum RT we were able to calculate an efficiency that was later on compared with the cost of the solution. As a conclusion, due to a large diversity of acoustic ceiling types with different prices and sound absorption coefficients it is important, especially for complex room geometries, to run simulations and to perform a cost-efficiency analysis.

Climate change has become a fundamental concern for scientific researchers, architects and engineers, and requires improving the
performance of the sectors responsible for city and building infrastructure. Burning fossil fuels to produce electricity and heat are the
biggest cause of climate change and emissions and represent one third of total greenhouse gas emissions. Thus, buildings become
responsible for improving the external environment, either by construction phases, rehabilitating process or by maintaining process. In
Romania the building sector is the main contributor to gas emission and most of the residential multi-storeys constructions are buildings
from the communist period built using standardized projects. In Romania one the main goals are the thermal rehabilitation of buildings
and construction of apartments especially in the inner circle of the capital. However, the renovation measures are very basic and do not
target actual/future EU legislation that imposes the Nearly Zero Energy Building (NZEB) standard for the buildings. To overcome and
to provide an alternative to both correct refurbishment and creation of new apartments the OVER 4 prototype was developed. These
prototypes are modules of apartments where multiple bioclimatic strategies were implemented to minimize the energy consumption.
Using the Passive House Project Planning (PHPP) the module was 3D created and simulated to reach the optimal architecture for both
well-being of residents and the energy balance.

The aim of our study is to vary different energy parameters to observe their influences on the annual heating needs of a building apartment. Multiple cases of thermal resistances, glazing areas and orientations have been analyzed by using dynamic simulations. We wanted to check the importance of accurate data of the building envelope thermal resistances on the heating demand. It was found then small errors (0,25÷0,3 m 2 K/W) on the thermal resistance can have a large impact on the heating demand (from 5% to 25%). The use of standard thermal resistances values based on the age/structure are a good solution to reduce the errors and will contribute to a clearer and more correct comparison of buildings energy consumptions. Rezumat Scopul studiului nostru este de a varia diferiți parametri ai anvelopei unei cladiri pentru a observa influența lor asupra consumului de energie pentru incalzire. Au fost studiate mai multe cazuri in care a fost variata rezistența termica, suprafata vitrata și...

Nowadays, the enhancement of the existing building stock energy performance is a priority. To promote building energy renovation, the European Committee asks Member States to define retrofit strategies, finding cost-effective solutions. This research aims to investigate the relationship between the initial characteristics of an existing residential buildings and different types of retrofit solutions in terms of final/primary energy consumption and CO2 emissions. A multi-objective optimization has been carried out using experimental data in DesignBuilder dynamic simulation tool.

This article presents a numerical and experimental campaign for the measurements and prediction of the sound pressure levels inside an office space. The measurements were realized in multiple points and the analysis was realized for all frequency range (31 Hz to 8 kHz). The main source of noise was found to be the HVAC system and improvements to it were needed. A complex 3D model was created for simulation purposes and to test several noise proof solutions. The initial simulations were first validated with the experimental data and afterwards a soundproof solution was simulated. This study shows how a complex indoor space geometry can be simulated and validated with experimental data.

The purpose of this article is the assessment of energy efficiency and indoor air quality for a single-family house located in Cluj-Napoca County, Romania. The studied house is meant to be an energy-efficient building with thermal insulation, low U-value windows, and a high efficiency boiler. Increasing the energy efficiency of the house leads to lower indoor air quality, due to lack of natural ventilation. As the experimental campaign regarding indoor air quality revealed, there is a need to find a balance between energy consumption and the quality of the indoor air. To achieve superior indoor air quality, the proposed mitigation systems (decentralized mechanical ventilation with heat recovery combined with a minimally invasive active sub-slab depressurization) have been installed to reduce the high radon level in the dwelling, achieving an energy reduction loss of up to 86%, compared to the traditional natural ventilation of the house. The sub-slab depressurization system was inst...

The study presented in this paper has as main objective to assess the importance of the solar-shading systems on the building cooling load, particularly for the buildings with high ratios between glazed and opaque parts of their facades. According to this objective, a selected reference building was analyzed by means of annual numerical simulation, applying four sun shading scenarios. The simulation results show how these systems have a positive impact on the reduction of the building cooling load. Moreover, a cost-effective analysis is performed, in order to determine the magnitude of energy savings for the scenarios proposed.

Indoor air quality in schools is one of the main concerns for the health of children. Inside a classroom there are high levels of different pollutants concentrations along with high levels of particulate matter (PM). Many studies showed that PM can severely affect the health of children, especially those with asthma problems. In this article an experimental campaign was conducted in two identical classrooms as size, orientation and number of persons with the purpose to evaluate the PM concentration. The only difference is one classroom is ventilated with fresh air while the other one is not. With two GRIMM measurement equipment we have measured for two days the indoor levels. In fact, the ventilation system was found efficient especially for larger particles (PM10) of dust while for smaller ones (PM1) the results were similar. We have calculated a reduction of PM concentration of 10%,...,12% on the mean values. It is concluded that ventilation of schools has multiple benefits on the...

This article presents the results from a simulation work regarding the analysis of energy balance of an positive energy building. To meet the criteria for an energy-positive house, a high priority was given to the performance of the thermal envelope, such as high insulation of walls, roofs, floors and windows, thermal bridge-free construction and air tightness. Due to the required air tightness, special attention was also paid to indoor air quality through proper ventilation. We have simulated the building and the heating/cooling system which in our case is a water source heat pump connected with U-pipes vertical boreholes. With the geothermal system, along with solar thermal system used to produce the domestic hot water demand and along with the photovoltaic-PV system we managed to obtain a positive energy construction. The multisource system is simulated with multiple specialized software. The installed PV system produces 5379 kWh/year while the energy consumption of the house is ...

The air quality inside buildings is a major problem in EU countries because of lack of any source of fresh air. The situation is even more dramatic in schools were many individuals breathe the same air for multiple hours a day increasing the risk of illness and reduced mental performances. Finding a solution for existing buildings is a challenging task as numerous factors must be considered: noise, weight of the system, required air flow, energy efficiency, costs, maintenance, etc. The present study reports on the analysis of a novel heat recovery ventilation unit inside a high school classroom. The analysis consists of measurement of the indoor environment quality especially on the radon concentrations and CO2 level for one week. The polluted air is evacuated while a heat recovery ventilator introduces the fresh nonpolluted air. This decentralized system is for the first time studied in the literature as most of the studies were focused on centralized systems for new buildings. If ...

The basic goal of this paper is that the two phenomena, air transfer and sound wave transfer, are correlated. The correlation of Air infiltration flow (Q) using different Window Types (WT) for different Reverberation Time (RT) corresponding to 1 KHz Frequency and Global Weighted Noise Level Difference (ΔLA) has been analyzed in this study. This correlation has been studied for the specific application (building air infiltration) and the relationship between the physical parameters corresponding to the two phenomena.

In the current implementation of EPC-s, the assessment focus is purely on the energy consumption data. For the next generation of EPC-s, new performance indicators are proposed to address relevant building performance aspects, such as sustainability, productivity and market value. These indicators would enable evidence-based decision-making processes and facilitate the delivery of renovation triggers. Within the EPC framework, the problem is not the availability of such performance indicators, but the assessment effort required. Only easily available data can justifiably be introduced to bulk EPC-s, either as direct complementary input or as a performance indicator. Availability of such data was analysed from case studies that included EPC-s from 11 EU member states, mainly non-residential buildings. Analysed data included relevant HVAC information such as ventilation air flows, heating and cooling set-points and installed power, but also output data, such as EPC classes, net and pr...

There are several physical parameters that are taken into consideration when determining the level of agreeability of an enclosed space. For instance, when choosing the louvers for a room there are a multitude of criteria that might be considered such as colour, material or the degree of opacity. However, these apparently small fixtures may have a significant impact also on other apparently unimportant factors like the sound pressure level and the reverberation time. This paper aims to present different types of devices used to control the way daylight enters a room, from both the illuminance level and the acoustical point of view. During the experimental campaign, five of the most common types of louvers were examined regarding their main role of blocking the light and moreover their influence on the reverberation time and sound pressure level in the analysed chamber.

Through this research we have studied the influence of the closure of the balconies on the temperature and humidity. Three residential apartments with enclosed balconies are monitored simultaneously over two periods: a colder one in March and a warmer one in May providing an overview of the thermal performance of a balcony relative to the interior. The results of the balcony#1 simulations made with the Trnsys 17 software show a good energy saving in the cold period, but higher cooling consumption in warm weather.The total energy demand difference between closed and open balconies is about 840 kWh. The simulation also showed us the close connection between the temperature in the balcony and the solar radiation that both grow and decrease simultaneously. At the end of the two campaigns, we came to the conclusion that a closed and thermally rehabilitated balcony is the best solution, being proven to have a winter advantage, the difference between the outdoor temperature and the balcony...

Climate change has become a fundamental concern for scientific researchers, architects and engineers, and requires improving the performance of the sectors responsible for city and building infrastructure. Burning fossil fuels to produce electricity and heat are the biggest cause of climate change and emissions and represent one third of total greenhouse gas emissions. Thus, buildings become responsible for improving the external environment, either by construction phases, rehabilitating process or by maintaining process. In Romania the building sector is the main contributor to gas emission and most of the residential multi-storeys constructions are buildings from the communist period built using standardized projects. In Romania one the main goals are the thermal rehabilitation of buildings and construction of apartments especially in the inner circle of the capital. However, the renovation measures are very basic and do not target actual/future EU legislation that imposes the Nea...

Indoor air quality (IAQ) inside educational institutions is an important topic in the field of building and health research. School absenteeism and educational performance have been linked to poor air quality inside classrooms. A numerical simulation software has been used to test 5 different scenarios of natural ventilation during summer and winter. CO2 levels, air relative humidity, operative temperature and PMV were used as indoor air quality and thermal comfort indicators. Results have shown high CO2 and humidity levels when all windows are closed, and a variable improvement when different natural ventilations strategies are employed. A detailed procedure for the numerical simulation has been presented.

Achieving high acoustic quality in meeting rooms is important for intelligibility therefore several measures are needed especially in reflective high volume rooms. This article tackles the method and the solution to renovate a complex enclosure. The study is divided in multiple stages: development of the 3D room model exported in ODEON acoustic software, validation of the actual condition of the room with measurements, proposing and analysing different acoustic ceiling tiles and finally selecting the optimum solution based on the cost and efficacy in reducing the reverberation time (RT). The measured RT was four times higher (3.45 sec at f=1kHz) than the recommended value (0.9 sec at f=1kHz). The numerical simulation results were in accordance with the experimental measurements with errors of less than 0.2 sec. Using the difference between the RT obtained with the acoustic measures and the optimum RT we were able to calculate an efficiency that was later on compared with the cost of...

Having in sight the need for a strong reduction in CO2 emissions and the fluctuation of the price of fossil fuels, the ground source resources alongside with the ground source heat pumps are becoming more and more widespread for meeting the heating/cooling demand of several types of buildings. This article targets to develop the thermal modelling of borehole heat storage systems. Trying to emphasize some certain advantages of a GSHP (ground source heat pump) with vertical boreholes, a case study analysing a residential solar passive house is presented. The numerical results are produced using different modelling software like DesignBuilder, EED (Earth Energy Designer) and a sizing method for the length of the boreholes (ASHRAE method). The idea of sizing the length of boreholes (main design parameter and good index in estimating the system’s cost) using two different methods shows the reliability of this modelling tool. The study shows that borehole’s length of a GSHP system can tri...

Acoustic comfort is a requirement of major importance during the design of houses. This study focused on the acoustic comfort parameter called sound pressure level. The value of this parameter is variable during operation of a particular building , depending on the type of absorbent material and them surface. The aim of this study is to determine the influence of the equipment of the technical space for a passive house . In this study was experimentally determined the value of noise for a Passive House in Romania using specialized equipment and software from Bruel & Kjaer . With these equipment and software were simulated different functional parameters of heat recovery and circulation pump, and different ways of placing the house on various types of roads leading sound pressure level simultaneously for five rooms , result compared with rules imposed values for each type of room.

Underground energy sources are becoming increasingly popular and now geothermal heat pumps are frequently used to heat/cool different types of buildings, including for solar passive houses. This article aims at giving a contribution in the development of the thermal modelling of borehole heat storage systems, investigating the possibility of a GSHP (ground source heat pump) implementation with vertical boreholes in a solar passive house. A case study analysing a residential solar passive house is presented as a suitable modelling tool for the estimation of the thermal behaviour of GSHP systems by combining the outcome from different modelling programs. The software DesignBuilder, Earth Energy Designer and a sizing method for borehole’s length are used for producing the numerical results. The results highlight that the length of the borehole, a major index in estimating the system’s cost, is directly influenced by fundamental variables like thermal conductivity of grout or soil. Addi...

In order to achieve the numerical model of a transpired solar collector (TSC) with integrated phase changing materials (PCM) it is mandatory to study the impact of the orifice geometry on the entire system. The numerical simulation of the entire solar collector absorber metal plate (1000x2000mm and 5000 orifices) is not feasible thus resulting a huge number of cells for the numerical grid for which we will need very high computational resources and a very large amount of time to be solved. By taking these aspects into account we decided to simulate only four equivalent orifices and then to transpose the results to the actual case for further studies. The present paper aims to analyse the mesh independency study for an elementary perforated panel with four equivalent lobed orifices which is part of a real case TSC. This analysis represents one of the most important stages within the construction of the TSC numerical model and doesn't need an experimental validation. The study was...

In this article the main objective is to analyze the thermal comfort in a rural educational facility by means of an experimental campaign coupled with a simulation study. The experimental measurements were conducted in February and June 2014 and consisted of assessing air temperature, mean radiant temperature, humidity and air velocity. The case study building was comprised of a renovated new wing which was thermally insulated and an old one to which no insulation was added. The reference case is the building with 5 cm of insulation on the walls while the improved case consisted of a higher level of insulation. The environmental measurements facilitated the assessment of thermal comfort during a period of a few days and allowed the numerical model to be calibrated and tested, while the whole year dynamic simulation focused on illustrating the positive impact of higher insulation on the thermal comfort of the occupants. With an overall 10 cm insulation layer, the indoor air temperature during winter was higher while the summer values were closer to comfortable limits. Knowing that the lifetime of any school is spread across multiple decades, investing an extra amount in the exterior envelope insulation is more than recommended.

Avec un plafond refroidi, les temperatures des surfaces d'une piece sont inferieurs a ceux des solutions de climatisation et la meme chose est vraie quand d'autres surfaces de separation sont refroidis. Il est possible d'obtenir les memes conditions de confort, avec des temperatures de l'air plus elevees. La sensation de confort produite par un plafond froid peut etre comparee a celle ressentie lors d'une nuit d'ete ou l'on sent la fraicheur du ciel, meme si la temperature de l'air ambiant peut etre superieure a 25 ° C. En principe, un plafond de refroidissement n'est pas tres different d'un radiateur avec des tubes ou des plaques de cuisson. L'eau froide circule dans les elements du matelas capillaire, le refroidissement de la surface visible du plafond. Condensation represente le point sensible des plafonds froids, mais cette situation peut etre facilement evite avec soit l'utilisation d'une sonde pour mesurer le point de rosee ou avec une ventilation appropriee. Cette communication presente la modelisation et la simulation d'un plafond de refroidissement utilisant nattes capillaires comme le moyen de transport de l'energie. Le plafond rayonnant a ete simule dans une salle virtuelle creee avec l'aide d'un outil d'energie appelee TRNSYS [1]. Cela a ete utilise pour etudier le confort thermique, la temperature de l'air interieur et d'autres parametres specifiques du plafond. Nous avons effectue des simulations pour plusieurs villes de France afin de voir l'influence du climat, et en particulier celle de l'humidite a l'exterieur, sur la piece et sur la surface du plafond.

The present research work concerns development of regression models to predict the monthly heating demand for single-family residential sector in temperate climates, with the aim to be used by architects or design engineers as support tools in the very first stage of their projects in ...

... Heating, ventilating and air conditioning (HVAC) systems, which consume large quantities of energy, have become a necessity for almost all the buildings [1] to provide a comfortable indoor environment. ... The surface buffer is additionally connected with the air zone node. ...

Nowadays, the building sector has a great impact on the CO2 emissions worldwide being responsible for more than a third of energy consumptions. In order to reduce their impact on the environment it is mandatory to implement renewable energy sources (RES) to produce the so called “green energy”. One of the main disadvantages of the systems using RES is the discontinuity in operation and one of the most used RES is the solar radiation which is implemented worldwide and has a great potential to be successfully used. Among the solar systems, solar air collectors (SAC) are systems easy to implement and with low operating costs. For enhancing the overall efficiency of a SAC and to increase the number of hours of operation it is imperative to use thermal energy storage materials (TES). The aim of this paper is to experimentally analyse the implementation of latent heat storage materials (phase changing materials – PCM) in glazed solar air collectors and for this purpose two similar collect...

This paper describes a decision-support tool, SERAD, which was created with the aim to be used as an instrument to predict the heating/electrical demand of residential houses and to optimize the design parameters to improve the energy performance. Another aim of this tool is to analyze different renewable energy systems (photovoltaic/thermal solar systems, geothermal heat pumps or wood boiler heating system) and to design them in order to match the energy demands. Different aspects, like economic analysis, environmental impact and energy reduction potential are studied and used as criterions in the last stage of the tool which concerns the selection of the technology. At this point, it is possible to have multiple solutions formed by an arrangement of different systems on the same construction site, their advantages being added. Using a complex multi-criteria decision-support method, SERAD will automatically outrank the alternatives for the specific project by taking into account th...

A recent challenge in research dedicated to residential exposure to radon comes from the growing number of houses retrofitted to reduce energy consumption. Efficiently insulated buildings and modern architectural solutions can lead to the accumulation of high levels of indoor pollutants. A systematic analysis was conducted in a residential complex (consisting of six houses) in order to assess the annual radon concentration and to evaluate the intensity of the relationships with various factors, such as the indoor-outdoor temperature differences, wind speed and wind direction. Three types of occupational behaviour, influencing the ventilation rate of the dwellings and, implicitly, the indoor radon activity concentration were observed. By calculating the partial correlation coefficient between the radon concentration and the wind direction, with the wind speed as the control variable, for all six houses the correlation coefficient presents negative values.

In the current energy and environmental context it is imperative to implement systems based on renewable energy sources in order to reduce energy consumptions worldwide. Solar collectors are studied by many years and many researchers are focusing their attention in order to increase their efficiency and cost-effectiveness. Water solar collectors are often implemented for domestic hot water, heating or industrial processes and already have a place on the market. A promising system which is not yet widely known is represented by air solar collectors that could represent an efficient way to use the solar energy with a lower investment cost, a system that can be used in order to preheat the fresh air required for heating, drying, or to maintain a minimum temperature during winter. This paper presents a comprehensive literature review on air solar collectors used mainly in buildings, acting as a solar wall. Air solar collectors are roughly classified into two types: glazed and opaque. Th...

Buildings sector has one of the highest potential regarding the reduction of greenhouse gases emissions, as being responsible for more than 40% of energy consumption worldwide. This is why, in order to achieve indoor thermal comfort, it is mandatory to use energy-efficient systems. Materials acting as thermal energy storage (TES) represents one of the most effective strategy that can be implemented and nowadays, many studies are focusing their attention on latent heat storage, respectively on phase changing materials (PCM) which can embed a large embed a high quantity of energy, unlike classic materials acting as thermal mass. This purpose of this paper is to experimentally investigate the charge and discharge processes for an organic PCM (RT35 paraffin) macroencapsulated in an aluminium rectangular cavity which was placed first in a horizontal position and after in a vertical position. After several experimental campaigns conducted we determined that the vertical position enhance t...

This paper investigates the air pollutions in space ventilated in two High School classrooms. The analysis consists of comparison of one classroom with hybrid ventilation system and another one stander-by classroom with natural ventilation. Several studies regarding indoor air quality during the experimental campaign have been done for VOC, CO2, CO, other pollutants, keeping monitored for humidity and temperature. The experimental demonstrated that the highest value for CO2 in stander-by classroom is 2691 ppm and in classroom with hybrid ventilation is 1897 ppm, while values for CO are 1.1 / 1.1 ppm and VOC 0.14 / 0.06 ppm, better use hybrid ventilation.

Thermal and acoustic comfort, inside a vehicle’s cabin, are highly interconnected and can greatly influence the health of the passengers. On one hand, the H.V.A.C. system brings the interior air parameters to a comfortable value while on the other hand, it is the main source of noise. It is an intriguing task to find a balance between the two. In this paper, several types of air diffusers were used in order to optimize the ratio between thermal and acoustic interior comfort. Using complex measurements of noise and thermal comfort parameters we have determined for each type of air diffuser the sound pressure level and its impact on air temperature and air velocity.

In view of the recent preoccupation at worldwide level, for the integration of the solar systems components within the building skin, we made a numerical investigation in order to assess the opportunity to implement a long string of solar panels along a horizontal or vertical building surface.The study analyses deals with the phenomenon of self-shading, which appears in the case of medium and large solar systems that use solar panels placed one behind the other, along the same row (individual string), but also under the shape of parallel rows (parallel strings). The study creates a mathematical instrument for the evaluation of the shaded surface depending on the location of the panels and the relative position of the Sun. The shading-caused energy loss is analysed along the one-year period, for each of the 12 months, while the panels are considered either placed on a horizontal surface such as a building terrace, or on a vertical surface, such as a building facade. The simulations a...

The advantages of green roofs are well documented, ranging from heat island reduction, thermal comfort, air quality, stormwater management and energy savings for buildings. However, it has been shown that green roof retrofits are more effective in old, low efficiency buildings. This paper studies the possibility of retrofitting a high efficiency solar house with a green roof system being partially shaded, optimising its characteristics by means of parametric simulation. The input variables of the green roof system are: growth medium thickness, LAI (leaf area index) and height of plants. The output variables by which the different green roof systems are compared are: annual energy demand for heating and for cooling. The study concluded that the average reductions of energy consumption when retrofitting an efficient building with an extensive green roof are of 1.01% for heating and 4.61% for cooling, but optimising parameters (low LAI in winter, high LAI and height of plants in summer...

Nowadays, there is an increasing emphasis on indoor air quality due to technological evolution and the fact that people spend most of the time in enclosed spaces. Also, energy efficiency is another related factor that gains more and more attention. Improving air distribution in an enclosure can lead to achieve these goals. This improvement can be done by adjustingthe air terminals position, theredimensions or the air diffuser perforations. The paper presents the study of 8 types of panels with different perforations shapes. The systems were characterized by flow, pressure loss and noise. Usualand special geometries were chosen, all having the same flowsurface. The perforated panels were mounted in a unidirectional air flow (UAF)diffuser, also called a laminar air flow (LAF)diffuser, that is placed in a real scale operating room (OR) in our laboratory.The purpose of this study is to determine whether changing the shape in the perforated panels can improve the technical parameters of ...

The analysis presented in this paper is dealing with the correct and energy efficient measures of cooling buildings through nocturnal natural ventilation. Using this solution is proved in this article to be efficient and can reduce substantially the cooling demand. In order to establish the factors influencing the process of passively cooling a building (the ventilation volume, exterior temperature, thermal capacity of the building, possible duration of the ventilation), we have chosen different buildings, which we have placed them in different temperature zones of Romania. The study is based on multiple simulations realized with a time step of one hour, with the following variations: the climatic parameters, the thermal characteristics of the building, the air flow during night time, the proposed interior temperature. Since the study consisted of numerous simulations, in order to treat the results we have used statistical methods that cover the practical and possible situations, an...

ABSTRACT L’Union européenne (UE) a établi la prospective politique pour atteindre ses objectifs énergétiques fondamentaux pour le développent durable, la compétitivité et la sécurité énergétique, en réduisant les émissions de gaz à effet de serre par le biais d'une augmentation de la part des énergies renouvelables dans la consommation d'énergie et par l'amélioration de l'efficacité énergétique. Les principales questions sur l'utilisation à grande échelle des EnR sont liées au dimensionnement des systèmes, le choix parmi une grande variété de solutions vis-à-vis de plusieurs critères, et enfin le contrôle de ces sources. Dans un proche avenir, de plus en plus les EnR vont cohabiter avec les sources d'énergie fossiles et la recherche doit être orientée vers des solutions qui sont efficaces du point de vue énergétique, économiquement viable et respectueuses de l'environnement. Dans cette thèse, les travaux de recherche établissent une démarche en vue de proposer des solutions qui pourraient être les réponses aux deux premières problématiques que sont le dimensionnement mais surtout la seconde, qui est le choix des systèmes énergétiques les mieux adaptés par rapport a un nombre donné de critères. La première partie de la thèse traite des questions liées à l’estimation des besoins pour le chauffage, l’eau chaude sanitaire et l’énergie électrique. Cette estimation a été abordée par le développement de modèles polynomiaux de régression. La deuxième partie de la thèse examine les techniques de modélisation des systèmes afin d'obtenir les profils de l'approvisionnement en énergie renouvelable : ces quantités d’énergie de l’offre sont nécessaires dans d'analyse décisionnelle. Dans la troisième partie, une méthode d'aide à la décision multicritères (ELECTRE III) est décrite, puis appliquée à un exemple. La technique consiste à utiliser les règles obtenues à partir des modèles précédents et à réaliser un classement de solutions possibles envisagées. L'analyse multicritères fournit ainsi une technique intéressante d’aide dans le processus de décision et est capable de justifier les choix et de surclasser les alternatives dans le secteur des énergies renouvelables. Enfin, les théories, les algorithmes et les modèles qui ont été décrits dans ce travail ont été intégrées dans un outil d'aide à la décision que nous avons développé visant spécifiquement l'intégration des technologies à énergie renouvelable par une analyse multicritères et de faire rapidement des études paramétriques sur les consommations d'énergie des bâtiments. Dans la dernière partie de la thèse une analyse complète d'une étude de cas (maison Mozart) est réalisée avec la mise en application des méthodes proposées.