Search

Abstract: Hotels are a diverse building type with high normalized energy end-use because of its focus to provide best facilities for guests. There is scope, and in many countries legislative requirements, to reduce energy consumption without compromising facilities; case-studies from tourism intensive countries could be useful for demonstrating such possibilities. This paper presents a method of deriving energy benchmarks to enable classification of hotels in Greece based on operational energy use in terms of electricity and oil. The method of classification defines clusters of hotels using the k-means algorithm controlled with the silhouette plot after applying normalization factors for the operational energy data to correct for size, operation (seasonal or annual) and climatic conditions. Ninety hotels are analysed in the sample presented in this paper; and well separated clusters are defined for the whole sample and for the sample split in hotels with annual and seasonal operation. Energy consumption varies considerably between and within clusters indicating that a range of energy consumption targets might be more suitable than single value benchmarks for this type of building. [Copyright &y& Elsevier]

Photovoltaic (PV) power system is a technology for producing electricity from renewable resources that is rapidly expanding thanks to its capability to save conventional fossil fuels and to decrease the emissions of greenhouse gases. However, as more attention is being focused globally on the development of building-integrated PV systems, the technical, the economic as well as the environmental assessment of these systems is crucial to ascertain their viability. The purpose of this paper is to present an economic and environmental analysis of relatively small rooftop PV-grid-interconnected energy systems of 2–10 kW p rated power, located in Athens, Greece. The techno-economic feasibility of the PV systems is conducted employing the computerized renewable energy technologies assessment tool ‘RETScreen’. The energy and environmental assessment of the systems is carried out employing SimaPro 7.1 software, which is a standard Life Cycle Assessment tool. The results of the economic analysis indicate that with the current prices, investment in PV-grid-interconnected systems with power capacity higher than 5 kW p is in general viable. However, an increase in energy sale prices and/or cost reductions in the production of PV systems are crucial for the successful development of small-scale residential size PV systems in the country. The environmental analysis reveals that the PV systems with higher rated power perform worse as far as the environmental impact is concerned. The critical phase of the life cycle of PV systems is the module manufacturing process, which is characterized by high electricity consumption, representing most of the environmental impact. Nevertheless, it is further shown that the application of PV technology presents important environmental benefits compared to conventional energy production systems. [ABSTRACT FROM AUTHOR]

Residential buildings in Greece account for about 79% of the exclusive-use building stock and consume about a quarter of the total final energy consumption, with space heating and domestic hot water being the main energy end-uses. About 58% of the dwellings were constructed before the 80 s and the adoption of the first thermal insulation regulation. This paper presents the results from the Hellenic pilot action within EPISCOPE. The overall approach and analysis are based on the national TABULA residential building typology for single- and multi-family houses in order to estimate heating energy performance and savings. The work exploits Census and statistical data for defining the Hellenic building stock and empirical adaptation factors to make more realistic estimates from normative calculations. The analysis is supported by a detailed data disaggregation in terms of the number of dwellings and floor areas, based on envelope thermal characteristics, heat production units, energy carriers, use of renewables etc. The calculation results are adapted for the building types and then projected to the building stock. Numerous scenarios for different modernization rates are assessed for identifying the most promising refurbishment strategies in space heating and DHW for reaching the 2020 and 2030 national CO 2 emission targets. [ABSTRACT FROM AUTHOR]

Abstract: This paper describes an effort to estimate the impact of a cool roof (characterised by increased solar reflectance compared to the initial roof and high infrared emittance) on the energy performance and thermal behaviour of a non-cooled school building in Athens, Greece. An experimental monitoring campaign has been carried out before and after the application of a white elastomeric coating with a solar reflectance of 0.89 on the roof of the building. The air and surface temperature of the building have been measured and a set of meteorological parameters have been collected. An infrared camera has been used to depict the differences in the surface temperature before and after the cool roof application. The monitoring results are complemented and supported by building simulation. The building has been modelled into TRNSYS software and the model has been calibrated and validated using the experimental data. Simulation results show a decrease in the air temperature in the classes that reaches 2.8°C and a decrease in the annual cooling load by 40%. The corresponding heating penalty (i.e. the increase of heating load) is 10%. Additionally, the impact of the cool roof on thermal comfort, peak power and surface temperature has been assessed. [Copyright &y& Elsevier]

Abstract: Cool roofs are an emerging technique with a recent growing interest worldwide. The aim of the present paper is to present the application of cool roofs’ technology in a laboratory building located in Iraklion, Crete, Greece. The building is monitored towards its energy performance and indoor environment before and after the implementation of the cool roof technology. The specific case study is intended as a shining example of the cool roof capabilities in improving the thermal conditions in non-air conditioned and in reducing the energy consumption in air conditioned buildings. [Copyright &y& Elsevier]

Abstract: The paper presents a methodology that has been developed and implemented for the simulation of electricity use (kWh) as well as electricity pricing (c€/kWh) in buildings. In the simulation, electricity pricing has been treated as dependent on electricity use as energy pricing tariffs usually discriminate between specific electricity consumption zones, time periods, etc. Pricing and electricity use, together, may then provide an estimation of the building electric energy cost (€). The simulation runs on an hourly resolution allowing to highlight some potential wasteful and costly practices in energy use and management and providing insight to user behavior, which has been a key driver for its development. The key aspects of the simulation approach are presented and its use is demonstrated in two different buildings in Greece and Italy. The methodology is now adapted to allow for neural network based, real time training, which will also be briefly introduced. [Copyright &y& Elsevier]