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Daylight utilization significantly contributes to energy savings in office buildings. However, daylight integration requires careful design so as to include variations in daylight availability and maintain a balance between factors such as lighting quality and heat gain or loss. Designers with proper planning can not only improve the visual environment and create higher-quality spaces, but simultaneously minimize energy costs for buildings. The utilization of photosensors can exploit the benefits of daylighting by dimming the lighting system, so that no excessive luminous flux is produced, thus leading to energy savings as well as visual contentment. However, the human factor is crucial for the proper function of a lighting control system. Without its acceptance from the users, energy savings can be minimized or even negligible. The objective of this paper is to present a post-occupancy evaluation regarding occupant satisfaction and acceptance in relation to daylighting in offices equipped with automated daylight controls. In addition, the response of the users was compared with lighting measurements that were performed during the post-occupancy evaluation. Three case studies of office buildings with installed daylight-harvesting systems were examined. The age of the occupants was a crucial factor concerning their satisfaction in relation to the lighting levels. Aged users were more comfortable with lighting levels over 500lx, while young users were satisfied with 300lx. The impact of different control algorithms was outlined, with the integral reset algorithm performing poorly. The acceptance of the users for the closed loop systems maintained the expected energy savings of the daylight harvesting technique. Most of the occupants preferred to use daylight as a light source combined with artificial light but having the control to either override or switch it on and off at will. The results shown that a post-occupancy survey along with lighting measurements are significant for making an office environment a humancentric one.

Life Cycle Impact Assessment (LCIA) of lighting products is a methodology that analyses and evaluates environmental impacts throughout their total life cycle, from the extraction and processing of raw materials, design, construction, transportation, distribution, use, recycling and re-use of materials, and last their final disposal. According to the results of a large number of LCIAs, lighting products have a substantial environmental impact in multiple areas, as for example in primary energy, toxicological effects, the effect on global warming, the level of environmental acidification, etc. All of those impacts could result in more efficient products by enhancing the product design process (using Ecodesign). At the initial design stage of lighting products, the manufacturer should also take into consideration circular economy aspects at the End of Life stage (EoL) such as repair, reuse, remanufacturing, retrofitting, recycling, and upcycling and not only the energy savings from the use stage or the selection of raw materials. The scope of this paper is to collect and present an overview of all environmental impacts of LCIA analyses focusing at EoL stage of lighting products. Those impacts could be used as data input into a future model that determines which lighting products are more environmentally friendly.

Climate change is an ongoing fact with evident impacts on earth, humanity and our heritage. The management and protection of heritage from the effects of climate change should be taken into consideration, so as to act dynamically and immediately, since the effects of climate change are rapidly evident in all aspects of life. The objective of this research is to study the vulnerability of the ancient Greek Theatre of Dionysus, as it forms a monument with embedded heritage values exposed to the climate change. This case study is the tangible result of a particular cultural and historic research, bearing historic knowledge, cultural meanings via a recognizable architectural structure and it reflects the conjunction of culture with society and nature. Materiality and its pathology combined with the condition of the natural landscape and the altering pattern of cultural tourism can lead to the study of climate change imprint on this kind of heritage, which should be examined as a wholeness of culture and nature. The uniqueness in the Theatre’s identity and historic path deserves interpretation of the effects of climate change, so as to manage adaptation, proactive planning, mitigation and dissemination of the discovered results.

The scope of this paper is to identify the benefits of lamp recycling from the domestic sector. Data related to the recycled lamps was obtained from two recycling companies and were compared to those related to the waste lamps from the domestic sector. This was achieved by a new methodology which uses two alternative approaches. The first one is dependent on previous research data in relation to the number of active lamps while the second one elaborates on electricity consumption and sales data, in order to define the corresponding number of active lamps., The wasted amount of glass, metal and plastic is calculated along with the energy savings, the annual emissions of CO2-eq, the economic benefit from their sale and the potential reduction of hazardous waste, such as mercury to solid waste landfills under various scenarios. The amount of recovered materials collected by the Hellenic recycling companies contributes to a reduction of CO2-eq by 1298 tonnes, which falls significantly short of the CO2-eq that could have been saved 3108–5463tonnes if all the lamps were recycled. Furthermore, the recycling companies have an annual economic benefit of €32,251 which could be increased by €122,725 if all lamps were recycled together with the proper recycling of 3.4 kg of mercury, which was disposed in the environment. Finally, a future scenario was examined, in which all lamps in the domestic sector were assumed to be LEDs, an issue that can affect the viability of the recycling factories and it was proved that these might be affected.

The scope of the present paper is to promote social, cultural and environmental sustainability in cities by establishing a conceptual framework and the relationship amongst safety in urban public space (UPS), lighting and Information and Communication Technology (ICT)-based surveillance. This framework uses available technologies and tools, as these can be found in urban equipment such as lighting posts, to enhance security and safety in UPS, ensuring protection against attempted criminal activity. Through detailed literary research, publications on security and safety concerning crime and lighting can be divided into two periods, the first one pre-1994, and the second one from 2004&ndash, 2008. Since then, a significant reduction in the number of publications dealing with lighting and crime is observed, while at the same time, the urban nightscape has been reshaped with the immersion of light-emitting diode (LED) technologies. Especially in the last decade, where most municipalities in the EU28 (European Union of all the member states from the accession of Croatia in 2013 to the withdrawal of the United Kingdom in 2020) are refurbishing their road lighting with LED technology and the consideration of smart networks and surveillance is under development, the use of lighting to deter possible attempted felonies in UPS is not addressed. To capitalize on the potential of lighting as a deterrent, this paper proposes a framework that uses existing technology, namely, dimmable LED light sources, presence sensors, security cameras, as well as emerging techniques such as artificial intelligence (AI)-enabled image recognition algorithms and big data analytics and presents a possible system that could be developed as a stand-alone product to alert possible dangerous situations, deter criminal activity and promote the perception of safety thus linking lighting and ICT-based surveillance towards safety and security in UPS.

This research presents evidence of lighting design decisions through a decision support system for the illumination of the facades of neoclassical buildings. The proposed system is based on a novel methodology for lighting neoclassical buildings. The methodology starts with the collection of the most important decorative and architectural elements on facades of neoclassical buildings and filters them to find shared elements. Each element is lit with different types of luminaires in various mounting positions and tested by lighting simulation software to create a database of lighting results. The research is also concentrated on the development of a robust web-platform for modeling Heterogeneous and Semi-Structured lighting design data using a relational database. This database can be used to analyze similarities and differences between identical element types in different buildings, identify architectural “preferences” concerning the elements used in each case, detect common elements in various building uses or the use of different elements in similar types of uses, and in general constitute a valuable tool when researching any aspect of the facades of neoclassical buildings.

This research discusses the feasibility of replacing or supporting artificial lighting with Transgenic Bioluminescent Plants (TBP), as a means of minimizing light pollution, reducing electrical energy consumption and de-carbonizing urban and suburban outdoor environments, creating sustainable conditions and enriching the quality of life. Until now, no information is given about the light output of any TBPs and the question “Are the TBPs capable of producing the necessary lighting levels for exterior lighting?” is unanswered. For this reason, a new methodology is proposed for selecting and analyzing the lighting output potential of transgenic plants ted for specific climatic conditions. This methodology considers growth and reduction factors, as well as a formulae for estimating the plants’ luminous output by performing light measurements. Results show that transgenic plants in medium growth can emit a median luminous flux of up to 57 lm, a value that can definitely support low lighting requirements when used in large numbers of plants. From the lighting measurements and calculations performed in this research, the light output of the TBPs for a typical road with 5m width was found equal to 2lx. The amount of plants required was 40 at each side of the road for every 30m of streets with P6 road class. The results show that the use of bioluminescent plants can actually contribute to the reduction of energy consumption, concerning only the lighting criterium, thus creating an enormous opportunity for a new state-of- the-art market and research that could potentially minimize CO2 emissions and light pollution, improve urban and suburban microclimate, mitigate the effects of climate change, as well as provide an alternative means of lighting affecting both outdoor lighting design and landscape planning in suburban and urban settings. Moreover, further research should be applied considering also other possible ecological impacts before applying TBPs for exterior lighting applications.

We examine sunsets painted by famous artists as proxy information for the aerosol optical depth after major volcanic eruptions. Images derived from precision colour protocols applied to the paintings were compared to online images, and found that the latter, previously analysed, provide accurate information. Aerosol optical depths (AODs) at 550 nm, corresponding to Northern Hemisphere middle latitudes, calculated by introducing red-to-green (R / G) ratios from a large number of paintings to a radiative transfer model, were significantly correlated with independent proxies from stratospheric AOD and optical extinction data, the dust veil index, and ice core volcanic indices. AODs calculated from paintings were grouped into 50-year intervals from 1500 to 2000. The year of each eruption and the 3 following years were defined as "volcanic". The remaining "non-volcanic" years were used to provide additional evidence of a multidecadal increase in the atmospheric optical depths during the industrial "revolution". The increase of AOD at 550 nm calculated from the paintings grows from 0.15 in the middle 19th century to about 0.20 by the end of the 20th century. To corroborate our findings, an experiment was designed in which a master painter/colourist painted successive sunsets during and after the passage of Saharan aerosols over the island of Hydra in Greece. Independent solar radiometric measurements confirmed that the master colourist's R / G ratios which were used to model his AODs, matched the AOD values measured in situ by co-located sun photometers during the declining phase of the Saharan aerosol. An independent experiment was performed to understand the difference between R / G ratios calculated from a typical volcanic aerosol and those measured from the mineral aerosol during the Hydra experiment. It was found that the differences in terms of R / G ratios were small, ranging between −2.6% and +1.6%. Also, when analysing different parts of cloudless skies of paintings following major volcanic eruptions, any structural differences seen in the paintings had not altered the results discussed above. However, a detailed study on all possible sources of uncertainties involved (such as the impact of clouds on R / G ratios) still needs to be studied. Because of the large number of paintings studied, we tentatively propose the conclusion that regardless of the school, red-to-green ratios from great masters can provide independent proxy AODs that correlate with widely accepted proxies and with independent measurements.

Δημοσίευση σε επιστημονικό περιοδικό Summarization: Air temperatures in urban areas continue to increase because of the heat island phenomenon (UHI) and the undeniable warming of the lower atmosphere during the past few decades. The observed high ambient air temperatures intensify the energy demand in cities, deteriorate urban comfort conditions, endanger the vulnerable population and amplify pollution problems especially in regions with hot climatic conditions. The present paper analyses 40 years of hourly data series from nine meteorological stations in Greece in order to understand the impact of air temperature and relative humidity trends on the energy consumption of buildings. Using a typical office building, the analysis showed that for the period in question the heating load in the Greek building sector has decreased by about 1 kWh/m2 per decade, while the cooling load increased by about 5 kWh/m2 per decade. This phenomenon has major environmental, economic and social consequences, which will be amplified in the upcoming decades in view of the expected man-made climatic changes in this geographic area. Παρουσιάστηκε στο: Energy Conversion and Management

This research focuses on projecting the energy demand of the building sector in Greece by calculating energy consumption, using output data from regional climate models up to 2100. More specifically, Greece was subdivided into 13 climatic zones after assessing climate model data taking into account climate change estimates for the period 2010–2100. These zones allow a detailed estimation of the effects of climate change in specific regions of the country, thus creating a database which is used to model the energy demand of the building sector in each zone. Through the use of building data from Eurostat and the European Centre for Environment, a set of three building typologies was created in relation to the building envelope, which corresponds to 85% of the building stock in Greece. These typologies were later appended to each of the 13 climatic zones and a simulation for their energy demand was calculated using climatic data from 3 distinct climatic scenarios. Results show that the energy demand for heating the building sector in Greece could decrease by about 50%, while the respective energy demand for cooling could increase by as much as 248% until 2100. These effects are more evident in the Southern part of the country.

This paper examines the behaviour in energy consumption of buildings that have polygonal and prismatic envelopes and are located in Mediterranean climates. More specifically, it aims at studying the differences in energy consumption of these kinds of buildings compared to orthogonal building envelopes. For this purpose a contemporary building was chosen and modelled in two different versions, one being the original prismatic form and the other a model of the same building with right angles, however retaining all area and volume data of the original prismatic building. Calculations reveal that the prismatic formed building has lower solar gains compared to its orthogonal counterpart and consumes less energy in an annual cycle. The results show a mean annual energy consumption difference of 7.88% in favour of the prismatic building envelope. Also, depending on the orientation, the difference in annual energy needs has a range between 2.51% and 16.01%.

This paper compares the heating and cooling loads between a double skin facade and a single skin facade in different and contrasting climates. The thermal and lighting properties of both types of facades are calculated, based on the hypothesis of a virtual south facing office room. The results of the above calculations show that in climates with high sunshine duration, the difference in heating and cooling loads is less for a double skin facade in comparison to a single skin facade. This difference ranges from about 30% in the Mediterranean to about 40% in the Arabian peninsula in the case that the single skin building is not equipped with automatic shading devices, whereas in the case that both buildings have automatic shading devices the above percentages range from about 5.5% to 7.5%, respectively. The same difference in heating and cooling loads between the two types of facades is significantly reduced in colder Continental climates such as Moscow, as well as temperate climates such as London.

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.

The project BESTFACADE, sponsored by the Energy Intelligent Europe programme of the European Union, and led by MCE-Anlagenbau, Austria, accumulated the state of the art of double skin facades (DSFs) in seven European countries (Austria, Belgium, France, Germany, Greece, Portugal and Sweden). Twenty-eight facades of different buildings in all partner countries of BESTFACADE have been analysed for the aspects, types of facade in different countries, DSFs in different climatic regions of Europe, existing simulations and measurements, thermal behaviour, indoor air quality, comfort, user acceptance, energy demand and consumptions, control strategies, integrated building technology, cost (investment, maintenance and operation), resource conservation, environmental impact, comparison to conventional glass facades (CGFs), integration of renewable energy sources into DSFs, as well as non-energy related issues, such as, acoustics, aesthetics, fire protection, moisture, corrosion, durability, maintenance an...

Light shelves have been discussed in numerous studies as suitable solutions for controlling daylight in side-lit spaces. It is a system that can be easily modified, offering a range of design solutions. It can be easily mounted on the exterior and/or the interior of a vertical opening, it can come in various shapes from static flat forms to curved reflective surfaces, or it can even be actively controlled. A light shelf can offer shading and at the same time can redirect a significant part of the incoming light flux towards the ceiling improving daylight uniformity. Due to the aforesaid functions, light shelves are among the most popular system design solutions when it comes to daylight exploitation. The purpose of this paper is twofold. Firstly, to present the main research findings in relation to light shelves as daylighting systems and secondly to analyze the results, trying to establish a common basis for some efficient and practical design rules. The present paper is a review of the research realized in the last three decades concerning these systems together with their associated implications in a building’s daylight performance as well as in its energy balance in a few cases. In addition, the critical review of their design principles is included, which makes the presented information useful for design teams trying to select the optimal available system for any specific project.

Paintings created by famous artists, representing sunsets throughout the period 1500–1900, provide proxy information on the aerosol optical depth following major volcanic eruptions. This is supported by a statistically significant correlation coefficient (0.8) between the measured red-to-green ratios of 327 paintings and the corresponding values of the dust veil index. A radiative transfer model was used to compile an independent time series of aerosol optical depth at 550 nm corresponding to Northern Hemisphere middle latitudes during the period 1500–1900. The estimated aerosol optical depths range from 0.05 for background aerosol conditions, to about 0.6 following the Tambora and Krakatau eruptions and cover a time period mostly outside of the instrumentation era.

Δημοσίευση σε επιστημονικό περιοδικό Summarization: Heat island which is the most documented phenomenon of climatic change is related to the increase of urban temperatures compared to the suburban. Among the various urban heat island mitigation techniques, green and cool roofs are the most promising since they simultaneously contribute to buildings’ energy efficiency. The aim of the present paper is to study the mitigation potential of green and cool roofs by performing a comparative analysis under diverse boundary conditions defining their climatic, optical, thermal and hydrological conditions. The impact of cool roof’s thermal mass, insulation level and solar reflectance as well as the effect of green roofs’ irrigation rate and vegetation are examined. The parametric study is based on detailed simulation techniques coupled with a comparative presentation of the released integrated sensible heat for both technologies versus a conventional roof under various climatic conditions. Παρουσιάστηκε στο: Solar Energy