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Metal–organic frameworks (MOFs) could be utilized for a wide range of applications such as sorption, catalysis, chromatography, energy storage, sensors, drug delivery, and nonlinear optics. However, to date, there are very few examples of MOFs exploited on a commercial scale. Nevertheless, progress in MOF-related research is currently paving the way to new industrial opportunities, fostering applications and processes interconnecting fundamental chemistry with engineering and relevant sectors. Yet, the fabrication of porous MOF materials within resistant structures is a key challenge impeding their wide commercial use for processes such as adsorptive separation. In fact, the integration of nano-scale MOF crystallic structures into bulk components that can maintain the desired characteristics, i.e., size, shape, and mechanical stability, is a prerequisite for their wide practical use in many applications. At the same time, it requires sophisticated shaping techniques that can structure nano/micro-crystalline fine powders of MOFs into diverse types of macroscopic bodies such as monoliths. Under this framework, this review aims to bridge the gap between research advances and industrial necessities for fostering MOF applications into real life. Therefore, it critically explores recent advances in the shaping and production of MOF macro structures with regard to the binding materials that have received little attention to date, but have the potential to give new perspectives in the industrial applicability of MOFs. Moreover, it proposes future paths that can be adopted from both academy and industry and can further boost MOF exploitation. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.

Building materials, due to their mass and energy-consuming production processes, dras-tically increase the embodied energy of construction. This study assesses circularity processes for the construction industry with a life cycle assessment (LCA) of a case study located in a large cos-mopolitan city. The research concludes that a significant decrease in environmental impacts results from a shift to recycled materials in the construction phase, as well as from changing the landfill disposal method to recycling. In particular, it was found that the use of recycled building materials (such as recycled cement, metal, concrete, or glass) during the construction phase and recycling disposal methods lead to an overall decrease of impact up to 65%. This work also underlines the importance of circularity in renewable energy production systems. In both wind and solar systems, most of the environmental impact caused during the production phase are paid back during the second year of their life due to the energy gains of the renewable energy system. However, the recovery of metal depletion requires 667 years. This result provides evidence of the emerging need for integrating circular processes regarding recycling and reusing materials in construction and also in the energy-generating sector. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.

Background: Diesel exhaust fumes represent one of the most common toxic pollutants. The prolonged effects of acute exposure to this pollutant on inflammatory status and vascular properties are unknown. Methods: During a 2-h session, 40 healthy subjects were exposed to diesel exhaust fumes and/or filtered air. Endothelial function was assessed with flow mediated dilation, arterial stiffness with pulse wave velocity and reflected waves with augmentation index. C-reactive protein, fibrinogen, protein C levels and protein S activity were also measured. Standard deviation of normal to normal R-R intervals (SDNN) was used to assess heart rate variability. Measurements were assessed before exposure and 2 and 24 h after diesel exposure. Results: Compared with filtered air, exposure to diesel exhaust fumes decreased flow mediated dilation and increased pulse wave velocity and augmentation index up to 24 h after the exposure (p < 0.001 for all). Similarly, compared with filtered air, diesel exhaust exposure impaired SDNN during the 24-h study period (p = 0.007). C-reactive protein and fibrinogen levels were significantly increased after diesel exhaust exposure while protein C levels and protein S activity decreased (p < 0.01 for all). Exposure to diesel exhaust fumes resulted in higher C-reactive protein concentration in smokers compared with non-smokers (p < 0.001). Conclusion: Short-Term exposure to diesel exhaust fumes has a prolonged adverse impact on endothelial function and vascular wall properties, along with impaired heart rate variability, abnormal fibrinolytic activity and increased markers of inflammation. These findings give insights into the mechanisms underlining the increased cardiovascular risk of subjects regularly exposed to diesel exhaust fumes. © 2020 Published on behalf of the European Society of Cardiology. All rights reserved.

The assessment of indoor environmental quality in historic buildings converted to museums is a significant tool in deep energy renovation processes, as it provides insights for the microclimatic conditions in the interiors of the building where vast numbers of visitors walk every year and where artifacts that are vulnerable to pollution are exhibited. In this work, aiming to contribute to the development of an energy retrofitting protocol applied in the Mediterranean region (HAPPEN MedZeb protocol) for museums hosted in historic buildings by providing useful data, an experimental campaign to evaluate the indoor environmental quality of a museum housed in a historic building located in Athens took place from February 2019 to April 2021 and was divided into two periods. The findings revealed high concentrations of volatile organic compounds as well as poor thermal comfort levels since the sensors recorded low acceptable percentages of T values within the limits from 7 to 33% for the entire experimental period. Based on the findings, recommendations for retrofitting interventions are made. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

Research on air quality issues in recently refurbished educational buildings is relatively limited. However, it is an important topic as students are often exposed to high concentrations of air pollutants, especially in urban environments. This study presents the results of a 25-day experimental campaign that took place in a primary school located in a densely built-up area, which retains a green roof system (GRS). All measurements refer to mass concentrations and chemical analysis of PM10 (particulate matter less than 10 micrometers), and they were implemented simultaneously on the GRS and within the classroom (C3) below during different periods of the year. The results demonstrated relatively low levels of PM10 in both experimental points, with the highest mean value of 72.02 µg m−3 observed outdoors during the cold period. Elemental carbon (EC) was also found be higher in the ambient environment (with a mean value of 2.78 µg m−3), while organic carbon (OC) was relatively balanced between the two monitoring sites. Moreover, sulfate was found to be the most abundant water soluble anion (2.57 µg m−3), mainly originating from ambient primary SO2 and penetrating into the classroom from windows. Additionally, the crustal origin of particles was shown in trace metals, where Al and Fe prevailed (9.55% and 8.68%, respectively, of the total PM10). Nevertheless, infiltration of outdoor particles within the classroom was found to affect indoor sources of metals. Finally, source apportionment using a positive matrix factorization (PMF) receptor model demonstrated six main factors of emissions, the most important of which were vehicles and biomass burning (30.30% contribution), along with resuspension of PM10 within the classroom from human activities (29.89% contribution). Seasonal variations seem to play a key role in the results. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.

A primary school was investigated for airborne fungi by a culture-based method, in classrooms underneath a green roof in comparison to conventional concrete roofs. A portable Burkard sampler was used for the collection of air samples onto petri dishes with 2% Malt Extract Agar. The fungal aerosol mean concentration was 71 CFU m−3 (range 17–176 CFU m−3, median 51) in the classroom directly under the green roof, significantly lower than 192–228 CFU m−3 (range 0–1090 CFU m−3, median 69) under the concrete roofs and 188–412 CFU m−3 (range 0–2183 CFU m−3, median 771) in ground floor classrooms. The Indoor/Outdoor ratio was 0.4 for total fungi and 0.2–1.1 for predominant genera underneath the green roof, whereas 1–2.1 and 0.3–3.2 respectively for the rest of classrooms. The Potential Exposure Dose (PED) for fungal particles was calculated to 4.6 CFU kg−1 and 9.3–35.3 CFU kg−1 respectively. The genera Penicillium, Cladosporium and Aspergillus prevailed indoors and in ambient air. Aspergillus concentrations indoors correlated significantly with the concentration of the coarse fraction (PM10) of particulate matter. The genus Penicillium increased indoors during late spring and summer, in temperature 20–23 °C and relative humidity 42–53% and also predominated in ambient air, both indicative of multiple anthropogenic sources of amplification. The evidence about the green roof positive effect on microbial indoor air quality (mIAQ) is a matter of concern for further investigation. © 2020 Elsevier B.V.

Substantial knowledge is available on the association of the indoor school environment and its effect among schoolchildren. In the same context, the SINPHONIE (School indoor pollution and health: Observatory network in Europe) conducted a study to collect data and determine the distribution of several indoor air pollutants (IAPs), physical and thermal parameters and their association with eye, skin, upper-, lower respiratory and systemic disorder symptoms during the previous three months. Finally, data from 115 schools in 54 European cities from 23 countries was collected and included 5175 schoolchildren using a harmonized and standardized protocol. The association between exposures and the health outcomes were examined using logistic regression models on individual indoor air pollutants (IAPs); a VOC (volatile organic compound) score defined as the sum of the number of pollutants to which the children were highly exposed (concentration > median of the distribution) in classroom was also introduced to evaluate the multiexposure – outcome association, while adjusting for several confounding factors. Schoolchildren exposed to above or equal median concentration of PM2.5, benzene, limonene, ozone and radon were at significantly higher odds of suffering from upper, lower airways, eye and systemic disorders. Increased odds were also observed for any symptom (sick school syndrome) among schoolchildren exposed to concentrations of limonene and ozone above median values. Furthermore, the risks for upper and lower airways and systemic disorders significantly increased with the VOCs score. Results also showed that increased ventilation rate was significantly associated with decreased odds of suffering from eye, skin disorders whereas similar association was observed between temperature and upper airways symptoms. The present study provides evidence that exposure to IAPs in schools is associated with allergic and respiratory symptoms in children. Further investigations are needed to confirm our findings. © 2020 Elsevier B.V.

In the following years all European Union member states should bring into force national laws on the energy performance of buildings. Moreover, university campus dormitories are buildings of great importance, due to their architectural characteristics and their social impact. In this study, the energy performance along with the indoor environmental conditions of a dormitory of a university has been analysed. The in situ measurements included temperature, relative humidity, concentrations of carbon dioxide, total volatile organic compounds, and electrical consumption; lastly, the energy signature of the whole building was investigated. The study focused on the summer months, during which significantly increased thermal needs of the building were identified. The ground floor was found to be the floor with the highest percentage of thermal conditions within the comfort range, and the third floor the lowest. Lastly, a significant correlation between electrical consumption and the outdoor temperature was presented, highlighting the lack of thermal insulation. Overall, it was clear that a redesign of the cooling and heating system, the installation of a ventilation system, and thermal insulation are essential for improving the energy efficiency of this building. © 2019 by the authors.

The building stock in southern Europe grossly lacks sufficient thermal envelope insulation, leading to high energy inputs and corresponding CO2 emissions. Phase change materials (PCMs) and vacuum insulations panels (VIPs) could be an innovative way to curtail the high heating and cooling energy inputs to maintain comfort; however, their efficiency and environmental performance in the southern Mediterranean climate is largely unknown. To this end, two demo houses, 27 m3 each, were constructed in the island of Crete, southern Greece. The first was constructed using conventional building materials, while in the second PCMs and VIPs were used, as a research test-bed. Actual life cycle inventory (LCI) data were collected and the life cycle assessment (LCA) methodology was employed to estimate the environmental impacts attributed both to their construction and operational phase. Compared to the conventional demo house the one covered with PCMs and VIPs appear to have a 34% higher total environmental footprint, which is attributed to the production process of PCMs and VIPs. Nonetheless, the energy savings observed during the operational phase, attributed to their higher thermal insulation, can compensate the higher environmental footprint of the construction phase within a year, depending on PCM's enthalpy. Specifically, it was identified that PCMs and VIPs largely reduced daily indoor temperature fluctuations, improving indoor thermal comfort and leading to energy savings. As such, even though their installation is associated with an initial higher environmental footprint, large energy savings, compared to conventional demo house, are achieved during its operational phase. This suggests that the introduction of PCMs and VIPs could be an efficient and environmentally friendly route to enhance energy savings and reduce the environmental footprint of building stock. © 2019 AIMS Press.

Several parameters, including specific surface area, morphology, crystal size, and dopant concentration, play a significant role in improving the photocatalytic performance of ZnO. However, it is still unclear which of these parameters play a significant role in enhancing the photocatalytic activity. Herein, undoped and Mn-, Co-, and Cu-doped platelet-like zinc oxide (ZnO) nanostructures were synthesized via a facile microwave synthetic route, and their ultraviolet (UV) and visible-light-induced photocatalytic activities, by monitoring the gaseous acetaldehyde (CH3CHO) degradation, were systematically investigated. Both the pure and doped ZnO nanostructures were found to be UV-active, as the CH3CHO oxidation photocatalysts with the Cu-doped ZnO one being the most UV-efficient photocatalyst. However, upon visible light exposure, all ZnO-nanostructured samples displayed no photocatalytic activity except the Co-doped ZnO, which showed a measurable photocatalytic activity. The latter suggests that Co-doped ZnO nanostructures are potent candidates for several indoor photocatalytic applications. Various complementary techniques were utilized to improve the understanding of the influence of Mn-/Co-/Cu-doping on the photocatalytic performance of the ZnO nanostructures. Results showed that the synergetic effects of variation in morphology, surface defects, that is, VO, high specific surface areas, and porosity played a significant role in modulating the photocatalytic activity of ZnO nanostructures. © 2019 American Chemical Society.

HVAC systems are responsible for a significant part of the total building energy consumption and in many cases a large portion of that energy is actually used inefficiently. The ability of these systems to adapt to changing numbers of occupants will play a major role in reducing their energy load. Demand Controlled Ventilation systems are helping towards that goal and many of them use CO2 sensors as their core information source, whereby the system tries to maintain CO2 near or under a specified set point. Besides providing a simple feedback mechanism, CO2 can also be utilised in predictive models for indoor air quality and in the estimation of occupancy. The choice of location for the CO2 sensors however can have an impact in the estimations. The objective of this study is two-pronged: Firstly to identify a relationship between occupancy, CO2 setpoint, ventilation rate and cooling load for a university lecture theatre, in a way that it can be used as a decision tool by the facility manager to balance indoor air quality and energy consumption. Secondly, to investigate and quantify how representative the CO2 values detected by different sensors within the lecture theatre are and whether any differences can have a significant effect in estimating the number of occupants within. Results show that both CO2 and occupancy can be estimated with good accuracy with little effect from sensor placement and that it is feasible to easily visualise the balance between CO2 threshold and cooling load for a given level of occupancy. © 2018 Elsevier B.V.

The authors would like to correct the published article [1] concerning acknowledgments as follows: The authors would like to thank the Ministry of Education, Research and Religious Affairs of Greece for licensing the experiment and moreover the direction of the 2nd primary school of Nea Smyrni for their cooperation and contribution to the measurements. This project has received funding from the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No 645677. © 2018 by the authors.

An integrated indoor-outdoor 15-day PM sampling campaign in a general area close to the centre of Athens, targeted to examine personal exposure. All microenvironments (MEs) (second and fourth floor flats, cafes, cars, restaurants, underground metro, outdoor etc.) frequented by the residents were included in the study. The instrumentation used was both stationary (low volume samplers) and portable/wearable to be able to measure continuously PM10, PM2.5, PM1 and analyze chemically PM2.5 and PM1 samples. The study showed that the residences' air quality was determined by the type and intensity of outdoor sources and their vertical distance from the street. Indoor activities such as cooking, cleaning further increased PM levels and formulated the air quality, while particulate accumulation was evident. In general, PM2.5 concentrations were higher outdoors, 11–43 μg/m3, than in the second floor flat as well as on days within different MEs, 13–33 μg/m3 and 8–35 μg/m3, respectively and finally in the fourth floor 10–18 μg/m3. PM2.5 chemical composition was typical of a Mediterranean urban area predominantly composed on average of OC/EC (33%), sulfate (13%), ammonium (9%), nitrate (5%) and crustal material (Cl−, Na+, K+, Mg2+ and Ca2+) (5%). On days when other MEs were visited crustal material increased on average to 16%. The PM levels measured with the portable instrumentation at all mEs showed that the persons were exposed to higher PM10 concentrations in the subway (avg. 218 μg/m3) due to the resuspension of crustal material, while maximum PM2.5 and PM1 were experienced in cafes where smoking was allowed (avg. 126 and 108 μg/m3, respectively). Using the car resulted to the lowest PM10, PM2.5 and PM1 exposure (58, 10 and 6 μg/m3, respectively). Total exposure to particulates depended both on the time spent in each ME and on the mixture of MEs visited in 24 h. © 2018 Elsevier B.V.

The aim of this study is to investigate the energy performance of a medium scale green roof system installed on a two-story commercial building in Athens, Greece and its possible contribution to the mitigation of the urban heat island phenomenon. For the purpose of this research, in-situ measurements of temperature and humidity took place during the cold period of the year. The surface temperature of the conventional concrete floor of the roof was found to be up to 21.9 K higher than the one of the planted area during the day, while at the first hours of the day, the surface temperature of the green roof appeared to be up to 1.6 K higher than the one of the cement floor of the roof. Differences of the surface temperatures of the varying plants of the green roof were measured and led to a proposal of an optimum selection among them for the best performance of such a green roof system. Furthermore, simulations for this building were performed by using the EnergyPlus program. It was calculated that, the indoor air temperature, for a non air conditioned status of the building, was decreased up to 1.1 K during a typical summer day and was increased up to 0.7 K during a typical winter day. Lastly, an overall saving of 15.1% for a whole year on the energy consumption of the building was calculated. © 2016 Elsevier B.V.

Although the indoor thermal comfort concept has received increasing research attention, the vast majority of published work has been focused on the building environment, such as offices, residential and non-residential buildings. The present study aims to investigate the thermal comfort conditions in the unique and complex underground railway environment. Field measurements of air temperature, air humidity, air velocity, globe temperature and the number of passengers were conducted in the modern underground railway of Athens, Greece. Environmental monitoring was performed in the interior of two types of trains (air-conditioned and forced air ventilation cabins) and on selected platforms during the summer period. The thermal comfort was estimated using the PMV (predicted mean vote) and the PPD (predicted percentage dissatisfied) scales. The results reveal that the recommended thermal comfort requirements, although at relatively low percentages are met only in air-conditioned cabins. It is found that only 33% of the PPD values in air-conditioned cabins can be classified in the less restrictive comfort class C, as proposed by ISO-7730. The thermal environment is "slightly warm" in air-conditioned cabins and "warm" in forced air ventilation cabins. In addition, differences of the thermal comfort conditions on the platforms are shown to be associated with the depth and the design characteristics of the stations. The average PMV at the station with small depth is 0.9 scale points higher than that of the station with great depth. The number of passengers who are waiting at the platforms during daytime reveals a U-shaped pattern for a deep level station and an inverted course of PMV for a small depth station. Further, preliminary observations are made on the distribution of air velocity on the platforms and on the impact of air velocity on the thermal comfort conditions. © 2016 Elsevier B.V.

The development of an effective maximum power point tracking (MPPT) algorithm is important in order to achieve maximum power operation in a photovoltaic system (PV). In this study, a direct neural control (DNC) scheme is developed. The intelligent MPPT controller consists of a hybrid learning mechanism; an on-line learning rule based on gradient decent method and an off-line learning rule based on Big Bang-Big Crunch (BB-BC) algorithm. The effectiveness of the proposed system is tested under partial shading conditions by applying the cascaded converter topology. The feasibility of the DNC is evaluated by the simulation results and compared to the conventional perturbation and observation (P&O) method. © 2015 Elsevier B.V. All rights reserved.

According to past experience, the concentration of air pollutants indoor varies significantly in different environmental conditions. The present study focuses on the investigation of the indoor air quality (IAQ) of the underground trains in Athens, Greece. The investigation was performed in both major lines of the ATTIKO METRO. Monitoring was performed in order to determine the concentration of pollutants and particulate matter, specifically TVOCs, PM10, ΡΜ2.5, ΡΜ1 as well as temperature and relative humidity in the coaches of the trains. In the present study, a methodology based on fuzzy inference systems to assess air quality is proposed. A fuzzy logic assessment system (FLAS) is developed incorporating rules stem collected from real data, human experience and intuition. The results demonstrate the applicability and effectiveness of the FLAS. © 2012.

The concentration levels of particulate matter (PM), airborne fungi, carbon dioxide as well as temperature and relative humidity were investigated in the indoor and outdoor environment of two schools in Athens, Greece during the period January to May 2011. The overall concentration ranges of the indoor measured pollutants were: PM10: 14.92-166.18 μg/m3, PM2.5: 3.16-31.27 μg/m3, PM1: 0.72-9.01 μg/m3, UFP: 4188- 63093 pt/cm3, total airborne fungi: 28-2098 CFU/m3 and CO2: 389-1717 ppm. The relationships between PM and airborne fungi were mainly examined, and bivariate correlations of all the measured environmental parameters are also reported. The results indicate that PM of certain aerodynamic diameters significantly correlate to the total airborne fungi and their prevalent genera, Penicillium, Cladosporium and Aspergillus. Principal Component Analysis (PCA) was conducted so as to cluster variables of common characteristics. Furthermore, simple and multiple linear regression models were developed to investigate several cases of dependent variables to be used for prediction purposes in health risk assessments.

Aluminium modified clays were prepared, characterised and tested for their potential application as solar coolers of roof surfaces. The water adsorption isotherm of the samples with restored cation exchange capacity was of hydrophilic type II, indicating multilayer adsorption with large heat of adsorption and pore condensation of water vapour at the pressures of the proposed application. In addition, high moisture adsorption capacity (more than 0.1 g of moisture per g of material at 6070% of relative humidity) and fast kinetics for night sorption (comparable to silica gel) were determined for the freeze-dried pillared sample. In cyclic experiments with low irradiation during the day and night relative humidity of 55%, the maximum temperature inside the pillared montmorillonite was 6.5 °C lower than the corresponding temperature inside a typical soil sample. The primary mechanism for the reduced temperature elevation at aluminium modified clays was evaporative cooling and desorption with minor influence of solar reflection. These results indicate the suitability of aluminium pillared clays for lowering the roof surface temperatures. © 2011 Elsevier B.V.

The impact of ventilation on indoor particulate pollution is highlighted by numerous studies. The aim of the present study is to examine the influence of ventilation on the levels of particulate concentrations found in dining halls where a large number of students are accommodated. Indoor particulate sources were also quantified and their influence on the particulate concentrations was examined. Measurements were conducted in four University dining halls, which are located in different parts of the city of Athens. Indoor and outdoor CO 2, PM1, PM2.5 and PM10 concentrations along with the number of occupants and smokers were measured in each dining hall during the accommodation of the students. Measurements were repeated for five working days in each dining hall. Ventilation rates were estimated by applying a methodology that involves the solution of the mass balance equation for the CO2 concentrations. The indoor particulate production rates were estimated by performing consecutive numerical experiments with the Multi Chamber Indoor Air Quality Model (MIAQ). Median CO2 concentrations ranged between 1043 μg m-3 and 1590 μg m -3 and ventilation rates ranged between 0.58 h-1 and 5.15 h-1. The respective values for PM1 ranged between 8.6 μg m-3 and 22 μg m-3, for PM2.5 between 17 μg m-3 and 60 μg m-3 and for PM10 between 24 μg m-3 and 78 μg m-3. The Pearson correlation coefficient between the log transformed ventilation rates and the PM10 concentrations were found to be -0.6. Median values of the total production rates were found to range between 100 μg min-1 and 5500 μg min-1 and are highly correlated with the number of occupants (Pearson correlation coefficient 0.86). Examination of the origin of the particulate sources indicated that, in the majority of cases, re-suspension is more significant than combustion sources. Significant short-term variation (one hour time interval) of the various sources was also observed. Even though the production rates were significantly elevated, the measured particulate concentrations were moderate due to the high air change rates obtained. These findings support the results of other studies that highlight the significance of ventilation in environments where indoor sources are prominent.

Measurements of the thermal behaviour of two residential buildings equipped with a green roof system have been performed in Athens, Greece. Experimental data have been used to calibrate detailed simulation tools and the specific energy and environmental performance of the planted roofs system has been estimated in detail. Simulations have been performed for free-floating and thermostatically controlled conditions. The expected energy benefits as well as the possible improvements of the indoor thermal comfort have been assessed. It is found that green roofs have a limited contribution to the heating demand of insulated buildings operating under the Mediterranean climate. On the contrary, the green roof system is found to contribute highly to reduce the cooling load of thermostatically controlled buildings. For the considered residential buildings, a cooling load decrease of about 11% has been calculated. In parallel, it is found that green roofs contribute to improve thermal comfort in free-floating buildings during the summer period. The expected maximum decrease of the indoor air and roof surface temperatures is close to 0.6°C. Such a decrease contributes to reduce by 0.1 the summer absolute Predicted Mean Vote Comfort Index levels in the building. Copyright © 2009 John Wiley & Sons, Ltd.

For a long time, scientists have been concerned about the effects of air pollution on materials and especially on the monuments of the cultural heritage. The EU funded a project, entitled MULTI-ASSESS, to determine these effects and to develop dose-response functions appropriate for the new multi-pollutant environment. The University of Athens participated in this effort as a targeted field exposure test site. In the present paper, the measurements of the passive samplers, which were exposed during the same period with the samples for corrosion studies, at the Athens station, are presented. The results have shown that only 16.5% of the deposited mass was water soluble. The vertical distribution of passive particle collectors has led to the conclusion that the height of maximum deposition of each ion is different. In addition, a variation of the water-soluble mass to total deposited mass between 8% and 31% was observed.

(1) The main objectives of this study are the spatial and temporal analysis of annual 24-hour extreme precipitation amounts for different return periods, and (2) the interannual variability of the frequency of month-to-month maximum rainfall using harmonic analysis. Long time series data from 110 well-scattered rain gauges are analysed using extreme values theory and harmonic analysis techniques. The results indicate that the Jenkinson solution is more appropriate than the linear Gumbel solution for the extreme value law. The maximum expected values of 180-200 mm are observed along the southern coasts of the Greek peninsula and in the islands close to the Turkish coast, as well as in the north-west parts of the country. The harmonic analysis showed that the highest percentage of variance for rainfall extremes explained by the first harmonic (PVR(1)) appears over the southern and south-eastern parts of Greece in association with the greatest values of the amplitude of this harmonic, therefore explaining more than 90% of the variation of the frequency of maximum annual 24-hour rainfall amounts. In contrast, for regions north of 38°N and especially mountainous regions, more harmonics (3-5) are necessary to describe the parameter under investigation. © Springer-Verlag 2008.

A detailed and integrated presentation of the green roof systems is provided in the present paper. Aiming to analyse a specific urban case study, we describe the basic architectural and scientific principles that characterize its performance and efficiency. Furthermore, a state of the art presentation of the system is provided, including the presentation of several case studies as well as a selection and description of plants that usually are extensively used in the green roof system all over the world. Energy and environmental investigation data of the green roof system performance in an office building located in the greater Athens area are provided. The energy efficiency was examined by calculating the energy savings through an accurate dynamic mathematical model. The thermal performance investigation showed a significant reduction of the building's cooling load during the summer period arriving at approximately 40%. Moreover, the influence of the green roof system in the building's heating load was fount insignificant, and this can be regarded as a great advantage of the system as any interference in the building shell for the reduction of cooling load leads usually to an increase of its heating load. © 2007 Elsevier Ltd. All rights reserved.

Weibull parameters estimated by three different methods at four weather stations in the area of central Western Greece were used to estimate wind power potential in this area. A linear correlation was observed between the above mentioned parameters and the measured mean wind speed values. Additionally, analysis of the "unit energy cost", being the specific cost per kilowatt hour, obtained for several wind turbines at different hub heights has been conducted for every station. Our analysis demonstrated that it is possible to profit from electricity generation in Missolonghi and Aktio, especially if larger wind turbines are to be used. The specific cost per kW h decreases as wind turbine size increases for comparable systems made by the same manufacturer with similar performance but with different rated power (size). The observed correlation between these parameters is hyperbolic with the greater decreasing rate in the less windy sites. Moreover, the cost per kilowatt hour increases with hub height due to the increasing tower cost. © 2006 Elsevier Ltd. All rights reserved.

In this study an attempt is made to investigate the impact of the urban heat island (UHI) effect on the energy consumption of a building using both, an accurate, extensively validated, transient simulation model and a neural network one. The energy consumption is calculated for a typical building during the summer period at 20 different sites of the Greater Athens area with the aid of the TRNSYS model. It was found that the UHI affects significantly the thermal behaviour of the building, implying much lower cooling load cost and energy cost in the suburban areas. A neural network model was then appropriately designed and tested for the estimation of the energy consumption, employing as an input, the UHI intensity. The results of both methods were tested and compared and it was found that there is a good agreement between the cooling rate values calculated by the TRNSYS programme and those derived by the neural model. Moreover, the employment of the neural model helped in quantifying the contribution of each input parameter in the calculation of the cooling rate, and it was demonstrated that the UHI effect is a predominant parameter, affecting considerably the energy consumption of a building in the Mediterranean region. © 2006 Elsevier Ltd. All rights reserved.

Electrochromic glazing can involve substantial energy consumption in the building sector with their optical properties driven either by various occupant needs or environmental conditions. This paper presents comparison of ten different control strategies developed for such a glazing system in terms of specific energy consumption of a PASSYS test cell where the glazing was installed. The control strategies include scheduled ON-OFF controllers, a PID and advanced fuzzy controllers which were developed using experimental data. We used energy simulation to analyse the annual heating, cooling and lighting demands investigating the influence of each control strategy to the thermal behaviour of the building. © 2006.

The present paper deals with the energy performance, energy classification and rating and the global environmental quality of school buildings. A new energy classification technique based on intelligent clustering methodologies is proposed. Energy rating of school buildings provides specific information on their energy consumption and efficiency relative to the other buildings of similar nature and permits a better planning of interventions to improve its energy performance. The overall work reported in the present paper, is carried out in three phases. During the first phase energy consumption data have been collected through energy surveys performed in 320 schools in Greece. In the second phase an innovative energy rating scheme based on fuzzy clustering techniques has been developed, while in the third phase, 10 schools have been selected and detailed measurements of their energy efficiency and performance as well as of the global environmental quality have been performed using a specific experimental protocol. The proposed energy rating method has been applied while the main environmental and energy problems have been identified. The potential for energy and environmental improvements has been assessed. © 2006 Elsevier B.V. All rights reserved.

Measurements of indoor air pollutants covering the concentrations of CO2, CO, TVOC's, PM2.5, and PM10 were performed in 50 residences in Athens. In addition the ventilation rate in each dwelling was continuously measured by monitoring CO2 concentration. Apart from carbon monoxide, almost all the remaining pollutants showed high concentrations that exceeded the maximum threshold levels of the relevant standards. The rate of ventilation was found to have a very important impact on the concentration of indoor pollutants. Finally, the impact of tobacco smoking was found to be very important and the concentration of almost all pollutants increased significantly when the rate of smoking increased.

The increase of living standards in buildings and the high, summer maximum air-temperature values during the last years have important economic, technical, social, and environmental consequences. Analysis of the summer ambient temperatures is thus necessary to investigate, among others, the important impact on energy consumption. Ambient temperature data from the National Observatory of Athens station for the period 1950-2004 are presented. The number of hours with air temperature above 30°C, as well as the degree hour values (DH) in base of 30°C are estimated and statistically analyzed in order to evaluate passive, hybrid, and conventional cooling systems and techniques. The general conclusion of this study is that during the last 15 years there is a dramatic increase of the number of hours with high air temperatures that leads to an increasing persistence of hot weather conditions. This corresponds, however, to the rising part of the air temperature cyclic change which does not verify yet the estimated significant increasing tendency. Copyright 2007 by the American Geophysical Union.

Social, financial, energy and technical data from about 1110 households have been collected during 2004 in the major Athens area. The sample has been divided in seven income groups and a detailed analysis has been performed. Important conclusions have been drawn regarding the quality of households, the operational conditions and the energy spent per income group. Low income people are more likely to be living in old buildings with poor envelope conditions. The cost per person and unit area is much higher for the low income group for both heating and electricity. Fuel poverty is quite high, especially when the actual oil prices are considered. © 2006 Elsevier B.V. All rights reserved.

This article deals with the energy performance of eight new and existing museum buildings located around Europe. Various energy efficiency and microclimate improvement measures have been adopted to reduce the energy consumption of the buildings and improve the comfort conditions. The investigation was implemented in two principal phases. During the first phase, energy simulation studies were performed in all buildings to evaluate the efficiency of the proposed measures and the various design possibilities. The energy consumption for heating, cooling, lighting and other electrical devices was calculated with and without the application of the proposed techniques and the corresponding energy conservation was estimated. Therefore, the proper measures from the energy point of view were adopted. During the second phase, measurements of the energy consumption were performed in the buildings after the finalization of the construction and the implementation of the proposed measures. The energy conservation was again calculated to evaluate the energy efficiency of the final construction. In addition to the energy aspect, the environmental impact of the final construction of the museums was investigated by calculating the reduction of the CO2 emissions due to the applied energy conservation techniques. Finally, the economic efficiency was examined by assessing the payback period of the adopted measures. The results of the present work show that the adaptation of energy conservation techniques in museums buildings can reduce significantly the energy consumption by respecting at the same time the requirements of the exhibition spaces and the comfort conditions of the visitors.

The archaeological museum of Delphi is one of the most visited museums in Greece with visitors ranging from about 150,000 to 300,000 per year. The building was retrofitted as a result of the Greek case study in the demonstration project 'MUSEUMS - Energy Efficiency and Sustainability in Retrofitted and New Museum Buildings' which was executed within the fifth Framework Programme of the European Commission DG TREN (Energie Programme). The retrofitting works aimed to integrate bioclimatic and sustainable measures in the existing exhibition halls, to minimize energy consumption and to improve comfort and exhibition quality.

The potential of controlling techniques for an electrochromic device is investigated in a systematic way, using both experimental and theoretical tools. Concerning the theoretical part a model was developed in the TRNSYS environment and validated against experimental data. These data were collected from experiments, which were carried out in a PASSYS test cell with a movable wall. Having established a good model performance several cases of window types (such as a 4mm clear window and a low-e double glazing) and controlling strategies for the electrochromic device are simulated. Obtained results from the series of simulations were compared in terms of the heating and cooling loads of the test cell for each case. It was found that the development of a scheduled control strategy for the electrochromic glazing is better in terms of cooling loads. Finally, a more sophisticated control strategy was examined based on the adaptive fuzzy approach. © 2004 Published by Elsevier B.V.

The present paper aims in investigating, in a systematic way, using both experimental and theoretical tools, the potential of natural ventilation control techniques when applied to full scale buildings. Experiments have been carried out in outdoor test cell and different configurations have been tested for two window types (bottom hung and sliding) under various meteorological conditions. Based on the experimental results, specific modeling activities have been undertaken and theoretical methods for calculating airflow rates through the above-mentioned windows have been developed. The theoretical predictions are compared with the corresponding experimental data and a very satisfactory agreement has been observed. Following the data analysis an algorithm was developed for the control of the natural ventilation. © 2002 Elsevier Science B.V. All rights reserved.