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This paper presents results of a study of the impact of future climate change scenarios as developed by the Intergovernmental Panel on Climate Change and implemented in weather files for specific future time slices (2020, 2050 and 2080) for the three climatic regions of Greece on the design of the external envelope of a hotel building in Greece. The impact of climate change on the hotel is assessed via hourly simulations of a calibrated model developed using the software TRNSYS. Additionally, the paper aims to identify optimal refurbishment strategies, given the constraints of the existing case-study building when transposed to the three different climatic zones in Greece. Two modes of the hotel building were studied: ‘all year’ and ‘seasonally’ operated. It was found that different external envelope energy-efficient strategies can be applied depending on the climatic zone and whether the hotel is all-year or seasonally operated. [ABSTRACT FROM AUTHOR]

The energy performance of buildings directive (EPBD) (91/2002/EU) opened the way for member states of European Union to create and apply a holistic approach on buildings’ energy performance. Taking into consideration the reduced ratio of new buildings, energy refurbishment of existing building stock appears as a nodal point. In particular, buildings in Greece accounts approximately 4 million, while 70% has been constructed before the implementation of the first Thermal Insulation Regulation (TIR), thus they do not have any insulation. So, there is an extremely high potential for energy conservation in Greek building stock. Therefore, an extensive field study was carried out in northern area of Greece in Thessaloniki, through a detailed questionnaire. The purpose of the research is to create an integrated thermal insulation scheme in order to succeed the highest mitigation of energy losses through building envelope. Retrofitting insulation solutions were evaluated and applied through various simulation scenarios with different levels of insulation thickness. [ABSTRACT FROM AUTHOR]

High-spatial resolution multispectral satellite images collected over the metropolitan Athens area in Greece were used to generate (a) a shortwave albedo map depicting the albedo spatial variations across the metropolitan area, (b) a fractional vegetation cover map showing the spatial distribution of urban vegetation and (c) a daytime and night-time land surface temperature (LST) map depicting the spatial variations of the surface temperature across the city. From LST maps, cooling and heating regions were identified and analysed to reveal relationships between surface heat islands and urban surface characteristics. Based on the data acquired with the use of satellite images and in order to better define the heat island problem and the mitigation measures that need to be taken, the most common building and paving materials used in the urban fabric of Athens were examined. Their optical properties were measured using a UV/VIS/NIR spectrophotometer fitted with an integrating sphere, an emissometer and their thermal performance was evaluated. Furthermore, measurements of the spectral reflectance help explore the possibility of increasing the near-infrared reflectance of materials in order to increase their total solar reflectance. The solar reflectance index of the samples was calculated in order to characterise them as 'cool' or 'warm'. Cool materials, with high albedo and thermal emittance values, attain lower surface temperatures when exposed to solar radiation, reducing the transference of heat to the environmental air. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

This paper deals with the state of the art on Passive and Hybrid Cooling of buildings. The existing techniques and components to prevent thermal gains and to dissipate excess energy to environmental heat sinks are reviewed. Topics dealing with the control of internal heat gains and with the occupant activities are discussed. The state of the art on design tools is presented. Thirteen European buildings using passive and hybrid cooling techniques and components are analyzed. Finally, future research needs are discussed. This work summarizes the findings of a Horizontal study on Passive Cooling carried out by the authors (1), as part of the Building 2000 research program of the European Communities. [ABSTRACT FROM PUBLISHER]

Based on a detailed spectral aerosol model (1), the total scattering and absorption broadband aerosol transmission functions are estimated. Using parameterization techniques, analytical expressions for the broadband aerosol transmission functions are obtained. The accuracy of the proposed expressions are verified with various tests. The proposed broadband aerosol transmission functions can be combined directly with the solar radiation models to predict accurately the direct beam, the diffuse and the total solar radiation at a given place. [ABSTRACT FROM PUBLISHER]

A model to estimate the spectral transmittance of the atmospheric aerosol for wavelengths λ = 0 to 20 μm is presented. The model is suitable for use in small and medium size cities with important industrial and other anthropogenic emission sources. Individual size distributions and optical properties for each chemical component are assumed. Humidity effects are discussed. The parameters of the model are compared with the existing measurements and are found in close agreement. The results of the model can be combined directly with solar radiation models to predict the spectral values of the direct, diffuse and total solar radiation. [ABSTRACT FROM PUBLISHER]

The use of passive and hybrid cooling components and techniques for the energy coverage of a holidays complex, is described. The overall architectural design based on the optimization of the summer performance, as well as the performance evaluation of the passive and hybrid cooling components are presented. The coupling problems and the control strategies for the overall system are analysed. [ABSTRACT FROM PUBLISHER]

The present paper investigates the problem of designing control gear for direct gain system applications. First the direct gain systems are briefly reviewed and the controller requirements are established. Next the decision to apply ON/OFF control strategy is made. Then a controller design based on a single chip computer (68701) is described including the choice and necessary interface of the temperature and humidity sensors. [ABSTRACT FROM PUBLISHER]

The article focuses on environmental quality in the built environment, which was discussed during the Second International Conference on Passive and Low Energy Cooling for the Built Environment and the 28th AIVC Conference held in Crete, Greece. The theme of the events was "Building Low Energy Cooling and Advanced Ventilation Technologies in the 21st Century." There were almost 350 papers presented during the events.

This section discusses various articles related to sustainable energy published within the issue.

This paper aims to investigate and present recent progress on the field of passive cooling of buildings achieved mainly through the PASCOOL research program of the European Commission. The PASCOOL group is composed by several national consortia including Belgium, France, Greece, Italy, Portugal, Spain, Switzerland, The Netherlands, UK, Slovenia, Hungary, Bulgaria and the Joint Research Centre of the European Commission at Ispra. The main scientific achievements of the project and especially the developed techniques, tools and design guidelines to promote passive cooling applications in buildings are presented. [ABSTRACT FROM AUTHOR]

The PASCOOL program was the most important European project on passive cooling of buildings. The project addressed topics included solar control, the combined effect of ventilation and thermal mass, thermalcomfort during summer and the potential of natural cooling techniques. PASCOOL put in evidence also the axes towards which future research on passive cooling should be oriented. This research, giving the continuously increasing trend of energy consumption for cooling purposes, is absolutely necessary in order to take advantage of the completepotential that passive cooling can offer to buildings, while maintaining the living standards, health and comfort of the occupants. This paper presents these future issues that comprise (a) research on the microclimatic scale in order to address the impact of outdoor environment on the cooling load of buildings, (b) investigation of comfort requirements under transient conditions during summer, (c) research onnatural ventilation in urban environments and the impact of outdoor pollution on indoor air quality, (d) development of alternative cooling systems and techniques, (e) development of integrating design concepts optimising the use of solar heating, passive cooling and naturallight in buildings. [ABSTRACT FROM AUTHOR]

Ground albedo can influence the estimation of solar radiation incident on tilted surfaces. Depending on the model used to calculate the skv diffuse radiation and the estimated albedo value, it is possible to introduce a significant error in the prediction of global radiationon a tilted surface. In this paper, several methods for calculating ground albedo values used for estimating the global radiation on a tilted surface, are proposed and evaluated. The predicted global solar radiation values are compared with measured data on a south facing vertical surface. from four representative south and north European locations. It appears that there is a significant impact on the accuracyof calculating the global solar radiation incident on a tilted surface using different methods for calculating ground albedo values. [ABSTRACT FROM AUTHOR]