... Energy policy and an action plan for renewable energy sources (RES) for the Hellenic islands ... more ... Energy policy and an action plan for renewable energy sources (RES) for the Hellenic islands of the ... Our case study deals with the Hellenic islands of the North Aegean region. ... be implemented, along with the RES penetration limit in the electric grid, for Mediterranean islands [8 ...
Energy consumption data from 158 Hellenic hotels and estimated energy savings that result from th... more Energy consumption data from 158 Hellenic hotels and estimated energy savings that result from the use of practical retrofitting techniques, materials and new energy efficient systems are presented. The data were collected during an extensive energy audit of buildings that was carried out in Hellas, within the frame of a National Energy Programme sponsored by the CEC VALOREN Programme, for energy conservation in buildings. During this short monitoring campaign and on-site visits of a trained panel of engineers to each building, all information related to the building's construction, heating, cooling and lighting systems, and all other mechanical and electrical systems, was collected. The main results and energy characteristics of cooling, heating and lighting on energy consumption and performance are discussed. The annual average total energy consumption in hotels is 273 kWh/m2, one of the highest among all categories of buildings. Several scenarios for possible interventions to the building's outer envelope, heating, cooling and lighting systems are proposed and evaluated, in order to assess the effectiveness of various energy conservation techniques. Based on the results from several simulations, it is concluded that it is possible to reach an overall 20% energy conservation.
This paper presents the energy, the technical and the environmental characteristics of residentia... more This paper presents the energy, the technical and the environmental characteristics of residential buildings in Greece, as well as their potential for energy conservation, based on their actual energy consumption data. The technical characteristics of residential buildings related to their energy performance (insulation, type of openings, system for space heating and cooling, etc.), the actual energy use (kWh/m2/year) and the environmental factors (kgCO2/m2/year) related to energy consumption, are some of the parameters of this survey. The average annual specific energy consumption of residential buildings in Greece was 112 kWh/m2/year in 2014, the 6th lower consumption among the 28 European member states (EU-28) in which the average residential building energy consumption is of about 158.8 kWh/m/2/year. The potential of space heating energy conservation for Greek residential buildings was estimated, based on (i) the 2011 heating energy consumption data and (ii) the percentages of space heating energy conservation, calculated by analysing 144 different types of residential buildings, having various geometric and technical characteristics, such as the A/V ratio (envelope Area to Volume of building), the heating degree hours (HDHs) and various occupancy profiles. The resulting average actual energy consumption is much lower than that calculated using Heating Degree Hours (HDHs) or the method of Hellenic Building Energy Performance Regulation (REPB). Almost 45% of these buildings were built before 1980, without any thermal insulation or double glazing. The compliance of these buildings to the minimum requirements of the REPB (related to thermal insulation and the efficiency of their electromechanical systems), could result to about 24.4 TWh of savings in space heating energy annually, i.e. to about 32-175 kWh/m2/year, depending on the climate zone that corresponds to 8.5-46.2 kgCO2/m2/year reduction.
The standard efficiency of photovoltaics (PV) often deviates from the one achieved under real out... more The standard efficiency of photovoltaics (PV) often deviates from the one achieved under real outdoor conditions. This paper presents relevant data collected using a small multi-crystalline photovoltaic array at an outdoor experimental facility located north of Athens. Measurements during summer and winter periods were used to quantify the PV performance and operating characteristics. Several correlations are provided in order to facilitate the estimation of the actual PV performance with readily available local parameters (e.g. ambient air temperature, wind speed). The PV efficiency was found to be about 18% lower than that under laboratory standard test conditions, under similar operating conditions. The mean annual PV efficiency was 8.7%.
This paper aims to analyse the changes that the new Hellenic Regulation on the Energy Performance... more This paper aims to analyse the changes that the new Hellenic Regulation on the Energy Performance of Buildings (REPB) has brought to the Hellenic residential buildings, which is in line with the European Directive 2010/31/EC. These changes refer to construction techniques, construction costs and energy performance. Our assessment is based on the numerical analysis of two typical residential buildings, a single and a multi-one. Both buildings were studied according to the requirements set before and after the application of the REPB for all (four in total) climate zones of Greece. The cost for implementing the two regulations was evaluated, as was also the energy consumption cost. Based on these costs we estimated the operating costs for heating, cooling and domestic hot water of the two buildings of this study. The implementation of the REPB significantly reduced the required heating loads for space heating in all climate zones by 37%–48% for both building types; this is mainly attributed to the improvement of the thermal properties of the building envelope and the improved energy performance of the electromechanical systems. The required cooling load was low and the implementation of the REPB did not change it significantly. Significant energy savings, in the range of 51%–58% were also achieved by installing flat plate solar collectors for Domestic Hot Water heating.
Transposition of the European Directive on the energy performance of buildings (EPBD) in Greece w... more Transposition of the European Directive on the energy performance of buildings (EPBD) in Greece was enacted in 2008 by a national law. A follow-up regulation on the energy performance in the building sector—KENAK released in 2010, outlines the overall approach in accordance to European standards and EPBD mandates. All necessary technical specifications and detailed information for the implementation of KENAK are included in four new technical guidelines prepared in 2010, which are supported by an official national software. Issues related to the energy experts are handled by presidential decrees published in 2010; over 5400 temporary energy inspectors are already in place, while permanent accreditation is in progress. Energy performance design study of new buildings for obtaining a building permit is in place since October 2010 and issuing energy performance certificates as of January 2011. This paper presents an overview of the development and current EPBD stage of implementation in Greece, along with a first assessment of the lessons learned and experiences gained.
Comprehensive information and detailed data for the non-residential (NR) building stock (office, ... more Comprehensive information and detailed data for the non-residential (NR) building stock (office, school, hospital, hotel and commercial blds) is rather limited, although it is the fastest growing energy demand sector. This paper elaborates the approach used to determine the potential energy conservation in the Hellenic NR building stock. A major obstacle that had to be overcome was the need to make suitable assumptions for missing detailed primary data. A qualitative and quantitative assessment of scattered national data resulted in a realistic assessment of the existing NR building stock and energy consumption. Different energy conservation scenarios and their impact on the reduction of CO2 emissions were evaluated. Accordingly, the most effective energy conservation measures are: addition of thermal insulation of exposed external walls, primarily in hotels and hospitals; installation of energy efficient lamps; installation of solar collectors for sanitary hot water production, primarily in hotels and health care; installation of building management systems in office/commercial and hotel buildings; replacement of old inefficient boilers; and regular maintenance of central heating boilers.
The existing building stock in European countries accounts for over 40% of final energy consumpti... more The existing building stock in European countries accounts for over 40% of final energy consumption in the European Union (EU) member states, of which residential use represents 63% of total energy consumption in the buildings sector. Consequently, an increase of building energy performance can constitute an important instrument in the efforts to alleviate the EU energy import dependency (currently at about 48%) and comply with the Kyoto Protocol to reduce carbon dioxide emissions. This is also in accordance to the European Directive (EPBD 2002/91/EC) on the energy performance of buildings, which is currently under consideration in all EU member states. This paper presents an overview of the EU residential building stock and focuses on the Hellenic buildings. It elaborates the methodology used to determine the priorities for energy conservation measures (ECMs) in Hellenic residential buildings to reduce the environmental impact from CO 2 emissions, through the implementation of a realistic and effective national action plan. A major obstacle that had to overcome was the need to make suitable assumptions for missing detailed primary data. Accordingly, a qualitative and quantitative assessment of scattered national data resulted to a realistic assessment of the existing residential building stock and energy consumption. This is the first time that this kind of aggregate data is presented on a national level. Different energy conservation scenarios and their impact on the reduction of CO 2 emissions were evaluated. Accordingly, the most effective ECMs are the insulation of external walls (33-60% energy savings), weather proofing of openings (16-21%), the installation of double-glazed windows (14-20%), the regular maintenance of central heating boilers (10-12%), and the installation of solar collectors for sanitary hot water production (50-80%). r
... Hellenic buildings. Elena G. Dascalaki Corresponding Author Contact Information , a , E-mail ... more ... Hellenic buildings. Elena G. Dascalaki Corresponding Author Contact Information , a , E-mail The Corresponding Author , Kaliopi Droutsa a , Athina G. Gaglia a , Simon Kontoyiannidis a and Constantinos A. Balaras a. a Group ...
... The air handling unit (AHU) used to serve the OR can be one (single) or two (double) stage th... more ... The air handling unit (AHU) used to serve the OR can be one (single) or two (double) stage that is without or with a terminal unit (TU). ... The desirable conditions of the supply air are then adjusted at the TU by using the reheat coil. ...
During the last decade the CO2 emissions from the residential and tertiary sectors have been risi... more During the last decade the CO2 emissions from the residential and tertiary sectors have been rising continuously. This is cause for concern but also an area to be targeted for emission reduction measures in national action plans. This paper proposes a methodological framework, using the Greek building sector (characterized by an aging building stock constructed mostly in the period before 1980) as a case study for the examination of the economic attractiveness of possible measures, which incorporates crucial parameters such as local climate, use of buildings, age of building stock, etc. that affect the energy conservation potential and consequently the economic performance of available measures. Utilizing this framework, the approach is able to classify measures into three categories, namely ‘win–win’ cases (i.e. where the implementation of emission reduction measures presents a net economic benefit for end-users), measures that require the implementation of appropriate economic support policies in order to make them economically attractive for end-users, and measures that have excessive cost. The results indicate that the emissions reduction potential of ‘win–win’ cases is significant. They also demonstrate how individual measures can provide significant reductions if carefully targeted economic support policies are applied. Finally, sensitivity analyses performed with respect to the discount rate applied indicate that it has a substantial impact on the economic performance of some measures and consequently on the magnitude of the ‘win–win’ potential associated to emissions reduction.
During the last decade the CO2 emissions from the residential and tertiary sectors have been risi... more During the last decade the CO2 emissions from the residential and tertiary sectors have been rising continuously. This is cause for concern but also an area to be targeted for emission reduction measures in national action plans. This paper proposes a methodological framework, using the Greek building sector (characterized by an aging building stock constructed mostly in the period before 1980) as a case study for the examination of the economic attractiveness of possible measures, which incorporates crucial parameters such as local climate, use of buildings, age of building stock, etc. that affect the energy conservation potential and consequently the economic performance of available measures. Utilizing this framework, the approach is able to classify measures into three categories, namely ‘win–win’ cases (i.e. where the implementation of emission reduction measures presents a net economic benefit for end-users), measures that require the implementation of appropriate economic support policies in order to make them economically attractive for end-users, and measures that have excessive cost. The results indicate that the emissions reduction potential of ‘win–win’ cases is significant. They also demonstrate how individual measures can provide significant reductions if carefully targeted economic support policies are applied. Finally, sensitivity analyses performed with respect to the discount rate applied indicate that it has a substantial impact on the economic performance of some measures and consequently on the magnitude of the ‘win–win’ potential associated to emissions reduction.
... Energy policy and an action plan for renewable energy sources (RES) for the Hellenic islands ... more ... Energy policy and an action plan for renewable energy sources (RES) for the Hellenic islands of the ... Our case study deals with the Hellenic islands of the North Aegean region. ... be implemented, along with the RES penetration limit in the electric grid, for Mediterranean islands [8 ...
Energy consumption data from 158 Hellenic hotels and estimated energy savings that result from th... more Energy consumption data from 158 Hellenic hotels and estimated energy savings that result from the use of practical retrofitting techniques, materials and new energy efficient systems are presented. The data were collected during an extensive energy audit of buildings that was carried out in Hellas, within the frame of a National Energy Programme sponsored by the CEC VALOREN Programme, for energy conservation in buildings. During this short monitoring campaign and on-site visits of a trained panel of engineers to each building, all information related to the building's construction, heating, cooling and lighting systems, and all other mechanical and electrical systems, was collected. The main results and energy characteristics of cooling, heating and lighting on energy consumption and performance are discussed. The annual average total energy consumption in hotels is 273 kWh/m2, one of the highest among all categories of buildings. Several scenarios for possible interventions to the building's outer envelope, heating, cooling and lighting systems are proposed and evaluated, in order to assess the effectiveness of various energy conservation techniques. Based on the results from several simulations, it is concluded that it is possible to reach an overall 20% energy conservation.
This paper presents the energy, the technical and the environmental characteristics of residentia... more This paper presents the energy, the technical and the environmental characteristics of residential buildings in Greece, as well as their potential for energy conservation, based on their actual energy consumption data. The technical characteristics of residential buildings related to their energy performance (insulation, type of openings, system for space heating and cooling, etc.), the actual energy use (kWh/m2/year) and the environmental factors (kgCO2/m2/year) related to energy consumption, are some of the parameters of this survey. The average annual specific energy consumption of residential buildings in Greece was 112 kWh/m2/year in 2014, the 6th lower consumption among the 28 European member states (EU-28) in which the average residential building energy consumption is of about 158.8 kWh/m/2/year. The potential of space heating energy conservation for Greek residential buildings was estimated, based on (i) the 2011 heating energy consumption data and (ii) the percentages of space heating energy conservation, calculated by analysing 144 different types of residential buildings, having various geometric and technical characteristics, such as the A/V ratio (envelope Area to Volume of building), the heating degree hours (HDHs) and various occupancy profiles. The resulting average actual energy consumption is much lower than that calculated using Heating Degree Hours (HDHs) or the method of Hellenic Building Energy Performance Regulation (REPB). Almost 45% of these buildings were built before 1980, without any thermal insulation or double glazing. The compliance of these buildings to the minimum requirements of the REPB (related to thermal insulation and the efficiency of their electromechanical systems), could result to about 24.4 TWh of savings in space heating energy annually, i.e. to about 32-175 kWh/m2/year, depending on the climate zone that corresponds to 8.5-46.2 kgCO2/m2/year reduction.
The standard efficiency of photovoltaics (PV) often deviates from the one achieved under real out... more The standard efficiency of photovoltaics (PV) often deviates from the one achieved under real outdoor conditions. This paper presents relevant data collected using a small multi-crystalline photovoltaic array at an outdoor experimental facility located north of Athens. Measurements during summer and winter periods were used to quantify the PV performance and operating characteristics. Several correlations are provided in order to facilitate the estimation of the actual PV performance with readily available local parameters (e.g. ambient air temperature, wind speed). The PV efficiency was found to be about 18% lower than that under laboratory standard test conditions, under similar operating conditions. The mean annual PV efficiency was 8.7%.
This paper aims to analyse the changes that the new Hellenic Regulation on the Energy Performance... more This paper aims to analyse the changes that the new Hellenic Regulation on the Energy Performance of Buildings (REPB) has brought to the Hellenic residential buildings, which is in line with the European Directive 2010/31/EC. These changes refer to construction techniques, construction costs and energy performance. Our assessment is based on the numerical analysis of two typical residential buildings, a single and a multi-one. Both buildings were studied according to the requirements set before and after the application of the REPB for all (four in total) climate zones of Greece. The cost for implementing the two regulations was evaluated, as was also the energy consumption cost. Based on these costs we estimated the operating costs for heating, cooling and domestic hot water of the two buildings of this study. The implementation of the REPB significantly reduced the required heating loads for space heating in all climate zones by 37%–48% for both building types; this is mainly attributed to the improvement of the thermal properties of the building envelope and the improved energy performance of the electromechanical systems. The required cooling load was low and the implementation of the REPB did not change it significantly. Significant energy savings, in the range of 51%–58% were also achieved by installing flat plate solar collectors for Domestic Hot Water heating.
Transposition of the European Directive on the energy performance of buildings (EPBD) in Greece w... more Transposition of the European Directive on the energy performance of buildings (EPBD) in Greece was enacted in 2008 by a national law. A follow-up regulation on the energy performance in the building sector—KENAK released in 2010, outlines the overall approach in accordance to European standards and EPBD mandates. All necessary technical specifications and detailed information for the implementation of KENAK are included in four new technical guidelines prepared in 2010, which are supported by an official national software. Issues related to the energy experts are handled by presidential decrees published in 2010; over 5400 temporary energy inspectors are already in place, while permanent accreditation is in progress. Energy performance design study of new buildings for obtaining a building permit is in place since October 2010 and issuing energy performance certificates as of January 2011. This paper presents an overview of the development and current EPBD stage of implementation in Greece, along with a first assessment of the lessons learned and experiences gained.
Comprehensive information and detailed data for the non-residential (NR) building stock (office, ... more Comprehensive information and detailed data for the non-residential (NR) building stock (office, school, hospital, hotel and commercial blds) is rather limited, although it is the fastest growing energy demand sector. This paper elaborates the approach used to determine the potential energy conservation in the Hellenic NR building stock. A major obstacle that had to be overcome was the need to make suitable assumptions for missing detailed primary data. A qualitative and quantitative assessment of scattered national data resulted in a realistic assessment of the existing NR building stock and energy consumption. Different energy conservation scenarios and their impact on the reduction of CO2 emissions were evaluated. Accordingly, the most effective energy conservation measures are: addition of thermal insulation of exposed external walls, primarily in hotels and hospitals; installation of energy efficient lamps; installation of solar collectors for sanitary hot water production, primarily in hotels and health care; installation of building management systems in office/commercial and hotel buildings; replacement of old inefficient boilers; and regular maintenance of central heating boilers.
The existing building stock in European countries accounts for over 40% of final energy consumpti... more The existing building stock in European countries accounts for over 40% of final energy consumption in the European Union (EU) member states, of which residential use represents 63% of total energy consumption in the buildings sector. Consequently, an increase of building energy performance can constitute an important instrument in the efforts to alleviate the EU energy import dependency (currently at about 48%) and comply with the Kyoto Protocol to reduce carbon dioxide emissions. This is also in accordance to the European Directive (EPBD 2002/91/EC) on the energy performance of buildings, which is currently under consideration in all EU member states. This paper presents an overview of the EU residential building stock and focuses on the Hellenic buildings. It elaborates the methodology used to determine the priorities for energy conservation measures (ECMs) in Hellenic residential buildings to reduce the environmental impact from CO 2 emissions, through the implementation of a realistic and effective national action plan. A major obstacle that had to overcome was the need to make suitable assumptions for missing detailed primary data. Accordingly, a qualitative and quantitative assessment of scattered national data resulted to a realistic assessment of the existing residential building stock and energy consumption. This is the first time that this kind of aggregate data is presented on a national level. Different energy conservation scenarios and their impact on the reduction of CO 2 emissions were evaluated. Accordingly, the most effective ECMs are the insulation of external walls (33-60% energy savings), weather proofing of openings (16-21%), the installation of double-glazed windows (14-20%), the regular maintenance of central heating boilers (10-12%), and the installation of solar collectors for sanitary hot water production (50-80%). r
... Hellenic buildings. Elena G. Dascalaki Corresponding Author Contact Information , a , E-mail ... more ... Hellenic buildings. Elena G. Dascalaki Corresponding Author Contact Information , a , E-mail The Corresponding Author , Kaliopi Droutsa a , Athina G. Gaglia a , Simon Kontoyiannidis a and Constantinos A. Balaras a. a Group ...
... The air handling unit (AHU) used to serve the OR can be one (single) or two (double) stage th... more ... The air handling unit (AHU) used to serve the OR can be one (single) or two (double) stage that is without or with a terminal unit (TU). ... The desirable conditions of the supply air are then adjusted at the TU by using the reheat coil. ...
During the last decade the CO2 emissions from the residential and tertiary sectors have been risi... more During the last decade the CO2 emissions from the residential and tertiary sectors have been rising continuously. This is cause for concern but also an area to be targeted for emission reduction measures in national action plans. This paper proposes a methodological framework, using the Greek building sector (characterized by an aging building stock constructed mostly in the period before 1980) as a case study for the examination of the economic attractiveness of possible measures, which incorporates crucial parameters such as local climate, use of buildings, age of building stock, etc. that affect the energy conservation potential and consequently the economic performance of available measures. Utilizing this framework, the approach is able to classify measures into three categories, namely ‘win–win’ cases (i.e. where the implementation of emission reduction measures presents a net economic benefit for end-users), measures that require the implementation of appropriate economic support policies in order to make them economically attractive for end-users, and measures that have excessive cost. The results indicate that the emissions reduction potential of ‘win–win’ cases is significant. They also demonstrate how individual measures can provide significant reductions if carefully targeted economic support policies are applied. Finally, sensitivity analyses performed with respect to the discount rate applied indicate that it has a substantial impact on the economic performance of some measures and consequently on the magnitude of the ‘win–win’ potential associated to emissions reduction.
During the last decade the CO2 emissions from the residential and tertiary sectors have been risi... more During the last decade the CO2 emissions from the residential and tertiary sectors have been rising continuously. This is cause for concern but also an area to be targeted for emission reduction measures in national action plans. This paper proposes a methodological framework, using the Greek building sector (characterized by an aging building stock constructed mostly in the period before 1980) as a case study for the examination of the economic attractiveness of possible measures, which incorporates crucial parameters such as local climate, use of buildings, age of building stock, etc. that affect the energy conservation potential and consequently the economic performance of available measures. Utilizing this framework, the approach is able to classify measures into three categories, namely ‘win–win’ cases (i.e. where the implementation of emission reduction measures presents a net economic benefit for end-users), measures that require the implementation of appropriate economic support policies in order to make them economically attractive for end-users, and measures that have excessive cost. The results indicate that the emissions reduction potential of ‘win–win’ cases is significant. They also demonstrate how individual measures can provide significant reductions if carefully targeted economic support policies are applied. Finally, sensitivity analyses performed with respect to the discount rate applied indicate that it has a substantial impact on the economic performance of some measures and consequently on the magnitude of the ‘win–win’ potential associated to emissions reduction.
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single and a multi-one. Both buildings were studied according to the requirements set before and after the application of the REPB for all (four in total) climate zones of Greece. The cost for implementing the two regulations was evaluated, as was also the energy consumption cost. Based on these costs we estimated the operating costs for heating, cooling and domestic hot water of the two buildings of this
study.
The implementation of the REPB significantly reduced the required heating loads for space heating in all climate zones by 37%–48% for both building types; this is mainly attributed to the improvement of the thermal properties of the building envelope and the improved energy performance of the electromechanical systems. The required cooling load was low and the implementation of the REPB did not change it significantly. Significant energy savings, in the range of 51%–58% were also achieved by installing flat plate solar collectors for Domestic Hot Water heating.
stock and energy consumption. Different energy conservation scenarios and their impact on the reduction of CO2 emissions were evaluated.
Accordingly, the most effective energy conservation measures are: addition of thermal insulation of exposed external walls, primarily
in hotels and hospitals; installation of energy efficient lamps; installation of solar collectors for sanitary hot water production,
primarily in hotels and health care; installation of building management systems in office/commercial and hotel buildings; replacement
of old inefficient boilers; and regular maintenance of central heating boilers.
single and a multi-one. Both buildings were studied according to the requirements set before and after the application of the REPB for all (four in total) climate zones of Greece. The cost for implementing the two regulations was evaluated, as was also the energy consumption cost. Based on these costs we estimated the operating costs for heating, cooling and domestic hot water of the two buildings of this
study.
The implementation of the REPB significantly reduced the required heating loads for space heating in all climate zones by 37%–48% for both building types; this is mainly attributed to the improvement of the thermal properties of the building envelope and the improved energy performance of the electromechanical systems. The required cooling load was low and the implementation of the REPB did not change it significantly. Significant energy savings, in the range of 51%–58% were also achieved by installing flat plate solar collectors for Domestic Hot Water heating.
stock and energy consumption. Different energy conservation scenarios and their impact on the reduction of CO2 emissions were evaluated.
Accordingly, the most effective energy conservation measures are: addition of thermal insulation of exposed external walls, primarily
in hotels and hospitals; installation of energy efficient lamps; installation of solar collectors for sanitary hot water production,
primarily in hotels and health care; installation of building management systems in office/commercial and hotel buildings; replacement
of old inefficient boilers; and regular maintenance of central heating boilers.