The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Masanori Shukuya - One of the best experts on this subject based on the ideXlab platform.
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unsteady state human body Exergy Consumption rate and its relation to subjective assessment of dynamic thermal environments
Energy and Buildings, 2016Co-Authors: Marcel Schweiker, Jakub Kolarik, Mateja Dovjak, Masanori ShukuyaAbstract:Abstract Few examples studied applicability of Exergy analysis on human thermal comfort. These examples relate the human-body Exergy Consumption rate with subjectively obtained thermal sensation votes and had been based on steady-state calculation methods. However, humans are rarely exposed to steady-state thermal environments. Therefore, the first objective of the current paper was to compare a recently introduced unsteady-state model with previously used steady-state model using data obtained under both constant and transient temperature conditions. The second objective was to explore a relationship between the human-body Exergy Consumption rate and subjective assessment of thermal environment represented by thermal sensation as well as to extend the investigation towards thermal acceptability votes. Comparison of steady-state and unsteady-state model showed that results from both models were comparable when applied to data from environments with constant operative temperature. In contrast, when applied to data with temperature transients the prediction of particular models differed significantly and the unsteady-state model resulted in better prediction of mean skin temperature. The results of the present study confirmed previously indicated trends that lowest human body Exergy Consumption rate is associated with thermal sensation close to neutrality. Moreover, higher acceptability was in general associated with lower human body Exergy Consumption rate.
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human body Exergy Consumption and thermal comfort of an office worker in typical and extreme weather conditions in finland
Energy and Buildings, 2014Co-Authors: Mia Alajuusela, Masanori ShukuyaAbstract:Abstract Finding the way to predict optimal thermal conditions for an office worker would contribute to sustainable building design: the environmental effects would be reduced, the economics of the organization and whole society would improve and there would be indisputable social benefits for the individual and the global community. These benefits stem from the improved productivity of the office worker in most favorable thermal environment and the possibilities to achieve this with lower energy demand. This study uses a new approach, Exergy analysis, to recognise the optimal conditions by looking for the combination of mean radiant temperature and room air temperature giving the lowest human body Exergy Consumption rate. All of the commonly used thermal comfort prediction methods use energy analysis, and it seems that Exergy analysis could give more accurate prediction of the conditions giving optimal thermal comfort. The new method is applied to the case of office worker in typical and extreme weather conditions in Finland. The results agree well with the previous analyses, and moreover, the points giving minimum human body Exergy Consumption rate coincide with the points usually regarded as most comfortable in summer conditions. According to recent studies, people are also most productive at these conditions.
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theoretical analysis on ground source heat pump and air source heat pump systems by the concepts of cool and warm Exergy
Energy and Buildings, 2014Co-Authors: Rongling Li, Ryozo Ooka, Masanori ShukuyaAbstract:Abstract This study presents exergetic characteristics of both ground source heat pump systems (GSHPs) and air source heat pump systems (ASHPs) based on the concepts of “cool Exergy” and “warm Exergy”. Quantitative example followed by theoretical analysis shows that GSHPs consume less Exergy than ASHPs do. This is because firstly “cool Exergy” is obtained from the ground in GSHPs, whereas no “cool Exergy” is extracted from the environment by the ASHPs. Secondly, temperature difference between refrigerant via cooling water and ground in GSHPs is smaller than that between refrigerant and air in ASHPs. In the GSHP, cool Exergy flows into the cooling water from the ground and then enters the indoor air through the refrigerant cycle. In the ASHP, the refrigerant cycle separates the electricity input of the compressor into “cool Exergy” and “warm Exergy.” The “cool Exergy” enters the indoor air and the “warm Exergy” is exhausted to the ambient environment. The analysis also shows that compressor requires largest Exergy input among the total Exergy inputs, and the Exergy Consumption in the refrigerant cycle is the highest. Thus, the improvement of the compressor performance to reduce its electricity Consumption was confirmed to be of vital in minimizing unnecessary Exergy Consumption.
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study on the effect of preference of air conditioning usage on the Exergy Consumption pattern within a built environment
International Journal of Exergy, 2012Co-Authors: Marcel Schweiker, Masanori ShukuyaAbstract:According to previous work, preference is one major factor influencing occupants' behaviour. This paper aims at identifying the magnitude preference on the Exergy Consumption pattern within a built environment. The comparison is made between one group claiming to like sleeping in air–conditioned spaces and the other claiming to dislike it. In conclusion, the Exergy analysis showed that at the individual level, preference accounts for an Exergy Consumption rate up to 15% higher and that, at the community level, the Exergy Consumption rate of those preferring the AC–unit use is up to four times higher than that of the others'.
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visual and thermal comfort and its relations to Exergy Consumption in a classroom with daylighting
International Journal of Exergy, 2012Co-Authors: Yoko Maki, Masanori ShukuyaAbstract:This paper discusses the exergetic aspect of daylighting together with luminous and thermal comfort aspect. We calculated the Exergy Consumption for lighting and cooling in a classroom for the cases with and without electric lighting. The full use of daylighting decreases chemical Exergy input to the power plant by 89%. According to a questionnaire survey asking the students' perception of sensations and comfort in the classroom, while daylighting was being used, the cut–off of fluorescent tubes did not cause any luminous discomfort and it made their thermal comfort even better.
Zhaoliang Wang - One of the best experts on this subject based on the ideXlab platform.
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specific Exergy Consumption as an index for steam extraction scheme selection for co 2 capture systems in coal fired power plants
Greenhouse Gases-Science and Technology, 2016Co-Authors: Kefang Zhang, Zhongliang Liu, Zhaoliang WangAbstract:In coal‐fired power plants, steam is extracted from steam turbine to supply the regeneration heat for chemical absorption carbon capture. This research analyses the steam and heat Consumption of a CO 2 capture system for different extracted steam, as well as the influences of different extracted steam on electricity production and power plant electric efficiency. Results show that specific steam Consumption and specific heat Consumption, which only reveal the quantity of the steam Consumption, could not be used for evaluating the true energy savings of different steam extraction methods. Specific Exergy Consumption of the extracted steam (SEXCS), which focuses on both the quantity and quality of energy, is proposed and used as a main comprehensive evaluation index in the CO 2 capture system. Compared with specific steam Consumption and specific heat Consumption, SEXCS can better evaluate the true energy saving of the different extracted steam. Compared with plant electric efficiency and specific primary energy Consumption for carbon avoided (SPECCA), SEXCS is both simple in calculation and easy in acquiring the required data. SEXCS is thus recommended to be used as an important index for selection of steam extraction schemes for CO 2 capture systems. © 2016 Society of Chemical Industry and John Wiley & Sons, Ltd
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specific Exergy Consumption as an index for steam extraction scheme selection for co2 capture systems in coal fired power plants
Greenhouse Gases-Science and Technology, 2016Co-Authors: Kefang Zhang, Zhongliang Liu, Zhaoliang WangAbstract:In coal-fired power plants, steam is extracted from steam turbine to supply the regeneration heat for chemical absorption carbon capture. This research analyses the steam and heat Consumption of a CO2 capture system for different extracted steam, as well as the influences of different extracted steam on electricity production and power plant electric efficiency. Results show that specific steam Consumption and specific heat Consumption, which only reveal the quantity of the steam Consumption, could not be used for evaluating the true energy savings of different steam extraction methods. Specific Exergy Consumption of the extracted steam (SEXCS), which focuses on both the quantity and quality of energy, is proposed and used as a main comprehensive evaluation index in the CO2 capture system. Compared with specific steam Consumption and specific heat Consumption, SEXCS can better evaluate the true energy saving of the different extracted steam. Compared with plant electric efficiency and specific primary energy Consumption for carbon avoided (SPECCA), SEXCS is both simple in calculation and easy in acquiring the required data. SEXCS is thus recommended to be used as an important index for selection of steam extraction schemes for CO2 capture systems. © 2016 Society of Chemical Industry and John Wiley & Sons, Ltd
Bjarne W. Olesen - One of the best experts on this subject based on the ideXlab platform.
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a novel human body Exergy Consumption formula to determine indoor thermal conditions for optimal human performance in office buildings
Energy and Buildings, 2013Co-Authors: Jianing Zhao, Bjarne W. Olesen, Lei FangAbstract:Abstract In this paper, a novel human body Exergy Consumption formula was derived strictly according to Gagge's two-node thermal transfer model. The human body Exergy Consumption calculated by the formula was compared with values calculated using Shukuya's formula for a typical office environment. The results show that human body Exergy Consumption calculated by either of these formulas reaches a minimum under the same thermal condition. It is shown that this is in accordance with expectation. The relation between human performance and human body Exergy Consumption was studied by analyzing the data obtained in simulated office environments in winter. The results show that human body Exergy Consumption and human performance are inversely as operative temperature changes from 17 to 28 °C or human thermal sensation changes from −1.0 to +1.4, and that optimum thermal comfort cannot be expected to lead to optimal human performance, as has so often been assumed. According to the second law of thermodynamics, it makes sense that optimal human performance coincides with minimum human body Exergy Consumption and that this should occur under thermal conditions in which human thermal sensation is close to “slightly cool”.
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a relation between calculated human body Exergy Consumption rate and subjectively assessed thermal sensation
Energy and Buildings, 2011Co-Authors: Angela Simone, Jakub Kolarik, Mateja Dovjak, Masanori Shukuya, Toshiya Iwamatsu, Hideo Asada, L Lisje Schellen, Bjarne W. OlesenAbstract:Abstract Application of the Exergy concept to research on the built environment is a relatively new approach. It helps to optimize climate conditioning systems so that they meet the requirements of sustainable building design. As the building should provide a healthy and comfortable environment for its occupants, it is reasonable to consider both the Exergy flows in building and those within the human body. Until now, no data have been available on the relation between human-body Exergy Consumption rates and subjectively assessed thermal sensation. The objective of the present work was to relate thermal sensation data, from earlier thermal comfort studies, to calculated human-body Exergy Consumption rates. The results show that the minimum human body Exergy Consumption rate is associated with thermal sensation votes close to thermal neutrality, tending to the slightly cool side of thermal sensation. Generally, the relationship between air temperature and the Exergy Consumption rate, as a first approximation, shows an increasing trend. Taking account of both convective and radiative heat exchange between the human body and the surrounding environment by using the calculated operative temperature, Exergy Consumption rates increase as the operative temperature increases above 24 °C or decreases below 22 °C. With the data available so far, a second-order polynomial relationship between thermal sensation and the Exergy Consumption rate was established.
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subjective thermal sensation and human body Exergy Consumption rate analysis and correlation
2011Co-Authors: Angela Simone, Jakub Kolarik, Mateja Dovjak, Masanori Shukuya, Toshiya Iwamatsu, Hideo Asada, L Lisje Schellen, Bjarne W. OlesenAbstract:BOOK – SYMPOSIUM PROGRAMME ELCAS 2011 39 quality is solar radiation, and as such its about time and space occupied to establish quality that should provide the real evaluations of Exergy. This implies also that its not only about energy but also about food and mass derived from solar radiation which determines the exergetic performance of any function/action in the system. And it turns out that mass and materials are far more decisive for maintaining quality, or avoid system quality decrease, as is energy in its current forms. IV.4. Exergy Analysis of Extractive Vacuum MetallurgySustainability prospects E. BALOMENOS*, D. PANIAS, I. PASPALIARIS National Technical University of Athens, Laboratory of Metallurgy 9, Heroon Polytechneiou str., 157 73, Zographou Campus, Greece, Email: thymis@metal.ntua.gr Based on the fundamental Le Chatellier principle, gas producing reactions can be pushed at lower temperatures if an appropriate vacuum is applied. A basic thermodynamic analysis is used to predict the effect of pressure decrease on the temperature and Exergy cost of a reaction with gaseous products. The energy analysis of 11 different metal producing carbothermic reductions revealed that the pumping work substitutes relatively the same amount of heat in all 11 reactions, despite the fact that the volume of gases evolved in each case differs significantly. The Exergy analysis for conducting these reactions with non-renewable resources showed that due to the high Exergy cost of fossil fuel generated electricity the application of vacuum would increase the overall Exergy cost of these reductions. If the heat needed for the reactions could be produced through renewable resources, such as concentrated solar radiation, then the use of vacuum would have a positive effect in the cases of high temperature reductions of Al2O3, MgO and CaO, where a significant decrease in reaction temperature is observed as more Exergy is spent in pumping work. IV.5. Subjective Thermal Sensation and Human Body Exergy Consumption Rate: Analysis and Correlation. A. SIMONE, M. DOVJAK, J. KOLARIK, H. ASADA, T. IWAMATSU, L. SCHELLEN, M. SHUKUYA, B. W. OLESEN a International Centre for Indoor Environment and Energy, Department of Civil Engineering, Technical University of Denmark, Nils Koppels Alle Building 402, 2800 Lyngby, Denmark, Email: asi@byg.dtu.dk; jakol@byg.dtu.dk; bwo@byg.dtu.dk b Faculty of Civil and Geodetic Engineering Ljubljana, University of Ljubljana, Chair for Buildings and Constructional Complexes, Jamova cesta 2, 1000 Ljubljana, Slovenia, Email: mdovjak@fgg.uni-lj.si c Architech Consulting Co., 1-22-4 Taito, Taito-ku, Tokyo 110-0016, Japan, Email: h_asada@architec.jp d Central Research Institute of Electric Power Industry, Japan, Email: iwamatsu@tmu.ac.jp e Eindhoven University of Technology, Faculty of Architecture, Building and Planning, Den Dolech 2, 5612 AZ Eindhoven, Netherlands, Email: L.Schellen@tue.nl f Laboratory of Building environment, Tokyo City University, 3-3-1 Ushikubo-Nishi, Tsuzuki-ku, Yokohama 224-8551, Japan, Email: shukuya@tcu.ac.jp The Exergy approach to design and operation of climate conditioning systems is relatively well established, while its exploitation in connection to human perception of the indoor environment is relatively rare. As the building should provide healthy and comfortable environment for its occupants, it is reasonable to consider both the Exergy flows in building and those within the human body. There is a need to verify the human-body Exergy model with the Thermal-Sensation (TS) response of subjects exposed to different combinations of indoor climate parameters (temperature, humidity, etc.). ABSTRACT BOOK – SYMPOSIUM PROGRAMME ELCAS 2011BOOK – SYMPOSIUM PROGRAMME ELCAS 2011 40 First results available on the relation between human-body Exergy Consumption rates and subjectively assessed thermal sensation showed that the minimum human body Exergy Consumption rate is associated with thermal sensation votes close to thermal neutrality, tending to slightly cool side of thermal sensation. By applying the Exergy concept to the built indoor environment, additional results are going to be explored. By using the data available so far of operative temperature (to), the human body Exergy Consumption rates increase as to increases above 24°C or decreases below 22°C at relative humidity (RH) lower than 50%. While, at 85% of RH, the human-body Exergy Consumption rates decrease when to is increasing above 24 °C. IV.6. Exergy Analysis: The Effect of Relative Humidity, Air Temperature and Effective Clothing Insulation on Thermal Comfort M. DOVJAK, A. SIMONE, J. KOLARIK, H. ASADA, T. IWAMATSU, L. SCHELLEN, M. SHUKUYA, B. W. OLESEN, A. KRAINER a Faculty of Civil and Geodetic Engineering Ljubljana, University of Ljubljana, Chair for Buildings and Constructional Complexes, Jamova cesta 2, 1000 Ljubljana, Slovenia, Email: mdovjak@fgg.uni-lj.si b International Centre for Indoor Environment and Energy, Department of Civil Engineering, Technical University of Denmark, Nils Koppels Alle Building 402, 2800 Lyngby, Denmark, Email: asi@byg.dtu.dk; jakol@byg.dtu.dk; bwo@byg.dtu.dk Architech Consulting Co., 1-22-4 Taito, Taito-ku, Tokyo 110-0016, Japan, Email: h_asada@archi-tec.jp Central Research Institute of Electric Power Industry, Japan, Email: iwamatsu@tmu.ac.jp e Eindhoven University of Technology, Faculty of Architecture, Building and Planning, Den Dolech 2, 5612 AZ Eindhoven, Netherlands, Email: L.Schellen@tue.nl Laboratory of Building environment, Tokyo City University, 3-3-1 Ushikubo-Nishi, Tsuzuki-ku, Yokohama 224-8551, Japan, Email: shukuya@tcu.ac.jp Exergy analysis enables us to make connections among processes inside the human body and processes in a building. So far, only the effect of different combinations of air temperatures and mean radiant temperatures have been studied, with constant relative humidity in experimental conditions. The objective of this study is to determine the effects of different levels of relative humidity (RH), air temperature (Ta) and effective clothing insulation on thermal comfort conditions from the exergetic point of view. The analyses take into consideration the available data from the study by Toftum et al. (1998). The effect of different levels of RH, Ta and effective clothing insulation on human body Exergy balance chain, changes in human body Exergy Consumption rate (hbExCr) and predicted mean vote (PMV) index were analyzed. The results show that thermal comfort conditions do not always result in lower hbExCr as it was proven in previous studies.Variations in effective clothing insulation, Ta and RH affect individual parts of human body Exergy balance chain with an important effect on hbExCr. At hot and dry conditions the hbExCr is the largest while at hot and humid conditions it is the minimal. Hot and dry and cold and dry conditions have similar hbExCr. The difference appears if the whole human body Exergy balance chain is taken into consideration. To maintain comfortable conditions it is important that Exergy Consumption and stored Exergy are at optimal values with a rational combination of Exergy input and output.
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analysis on Exergy Consumption patterns for space heating in slovenian buildings
Energy Policy, 2010Co-Authors: Mateja Dovjak, Masanori Shukuya, Bjarne W. Olesen, Ales KrainerAbstract:Problem of high energy use for heating in Slovenian buildings is analyzed with Exergy and energy analysis. Results of both are compared and discussed. Three cases of exterior building walls are located in three climatic zones in winter conditions. Results of energy analyses show that the highest heating energy demand appears in the case with less thermal insulation, especially in colder climate. If the comparison is made only on the energy supply and Exergy supply, the results of Exergy analysis are the same as those of energy analysis. The main difference appears, if the whole chain of supply and demand is taken into consideration. Exergy calculations enable us to analyze how much Exergy is consumed in which part, from boiler to building envelope. They also reveal how much energy is supplied for the purpose of heating. Results show that insulation has much bigger effect than effect of boiler efficiency. However, the most effective solution is to improve building envelope together with boiler efficiency. Better thermal insulation also makes an important contribution to the improvement of thermal comfort conditions. It causes higher surface temperatures resulting in a larger warm radiant Exergy emission rate and consequently better thermal comfort.
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An investigation on the assessed thermal sensation an human body Exergy Consumption rate
2010Co-Authors: Angela Simone, Jakub Kolarik, Mateja Dovjak, Masanori Shukuya, Toshiya Iwamatsu, Hideo Asada, L Lisje Schellen, Bjarne W. OlesenAbstract:The Exergy concept helps to optimize indoor climate conditioning systems to meet the requirements of sustainable building design. While the Exergy approach to design and operation of indoor climate conditioning systems is relatively well established, its exploitation in connection to human perception of the indoor environment is rare. As the building should provide healthy and comfortable environment for its occupants, it is reasonable to consider both the Exergy flows in the building and within the human body. A relatively new approach of the relation between the Exergy concept and the built-environment research has been explored in the present work. The relationship of subjectively assessed thermal sensation data, from earlier thermal comfort studies, to the calculated human-body Exergy Consumption has been analysed. The results show that the minimum human body Exergy Consumption rate was related to the thermal sensation votes close to thermal neutrality, tending to the slightly cool side.
Mateja Dovjak - One of the best experts on this subject based on the ideXlab platform.
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unsteady state human body Exergy Consumption rate and its relation to subjective assessment of dynamic thermal environments
Energy and Buildings, 2016Co-Authors: Marcel Schweiker, Jakub Kolarik, Mateja Dovjak, Masanori ShukuyaAbstract:Abstract Few examples studied applicability of Exergy analysis on human thermal comfort. These examples relate the human-body Exergy Consumption rate with subjectively obtained thermal sensation votes and had been based on steady-state calculation methods. However, humans are rarely exposed to steady-state thermal environments. Therefore, the first objective of the current paper was to compare a recently introduced unsteady-state model with previously used steady-state model using data obtained under both constant and transient temperature conditions. The second objective was to explore a relationship between the human-body Exergy Consumption rate and subjective assessment of thermal environment represented by thermal sensation as well as to extend the investigation towards thermal acceptability votes. Comparison of steady-state and unsteady-state model showed that results from both models were comparable when applied to data from environments with constant operative temperature. In contrast, when applied to data with temperature transients the prediction of particular models differed significantly and the unsteady-state model resulted in better prediction of mean skin temperature. The results of the present study confirmed previously indicated trends that lowest human body Exergy Consumption rate is associated with thermal sensation close to neutrality. Moreover, higher acceptability was in general associated with lower human body Exergy Consumption rate.
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a relation between calculated human body Exergy Consumption rate and subjectively assessed thermal sensation
Energy and Buildings, 2011Co-Authors: Angela Simone, Jakub Kolarik, Mateja Dovjak, Masanori Shukuya, Toshiya Iwamatsu, Hideo Asada, L Lisje Schellen, Bjarne W. OlesenAbstract:Abstract Application of the Exergy concept to research on the built environment is a relatively new approach. It helps to optimize climate conditioning systems so that they meet the requirements of sustainable building design. As the building should provide a healthy and comfortable environment for its occupants, it is reasonable to consider both the Exergy flows in building and those within the human body. Until now, no data have been available on the relation between human-body Exergy Consumption rates and subjectively assessed thermal sensation. The objective of the present work was to relate thermal sensation data, from earlier thermal comfort studies, to calculated human-body Exergy Consumption rates. The results show that the minimum human body Exergy Consumption rate is associated with thermal sensation votes close to thermal neutrality, tending to the slightly cool side of thermal sensation. Generally, the relationship between air temperature and the Exergy Consumption rate, as a first approximation, shows an increasing trend. Taking account of both convective and radiative heat exchange between the human body and the surrounding environment by using the calculated operative temperature, Exergy Consumption rates increase as the operative temperature increases above 24 °C or decreases below 22 °C. With the data available so far, a second-order polynomial relationship between thermal sensation and the Exergy Consumption rate was established.
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subjective thermal sensation and human body Exergy Consumption rate analysis and correlation
2011Co-Authors: Angela Simone, Jakub Kolarik, Mateja Dovjak, Masanori Shukuya, Toshiya Iwamatsu, Hideo Asada, L Lisje Schellen, Bjarne W. OlesenAbstract:BOOK – SYMPOSIUM PROGRAMME ELCAS 2011 39 quality is solar radiation, and as such its about time and space occupied to establish quality that should provide the real evaluations of Exergy. This implies also that its not only about energy but also about food and mass derived from solar radiation which determines the exergetic performance of any function/action in the system. And it turns out that mass and materials are far more decisive for maintaining quality, or avoid system quality decrease, as is energy in its current forms. IV.4. Exergy Analysis of Extractive Vacuum MetallurgySustainability prospects E. BALOMENOS*, D. PANIAS, I. PASPALIARIS National Technical University of Athens, Laboratory of Metallurgy 9, Heroon Polytechneiou str., 157 73, Zographou Campus, Greece, Email: thymis@metal.ntua.gr Based on the fundamental Le Chatellier principle, gas producing reactions can be pushed at lower temperatures if an appropriate vacuum is applied. A basic thermodynamic analysis is used to predict the effect of pressure decrease on the temperature and Exergy cost of a reaction with gaseous products. The energy analysis of 11 different metal producing carbothermic reductions revealed that the pumping work substitutes relatively the same amount of heat in all 11 reactions, despite the fact that the volume of gases evolved in each case differs significantly. The Exergy analysis for conducting these reactions with non-renewable resources showed that due to the high Exergy cost of fossil fuel generated electricity the application of vacuum would increase the overall Exergy cost of these reductions. If the heat needed for the reactions could be produced through renewable resources, such as concentrated solar radiation, then the use of vacuum would have a positive effect in the cases of high temperature reductions of Al2O3, MgO and CaO, where a significant decrease in reaction temperature is observed as more Exergy is spent in pumping work. IV.5. Subjective Thermal Sensation and Human Body Exergy Consumption Rate: Analysis and Correlation. A. SIMONE, M. DOVJAK, J. KOLARIK, H. ASADA, T. IWAMATSU, L. SCHELLEN, M. SHUKUYA, B. W. OLESEN a International Centre for Indoor Environment and Energy, Department of Civil Engineering, Technical University of Denmark, Nils Koppels Alle Building 402, 2800 Lyngby, Denmark, Email: asi@byg.dtu.dk; jakol@byg.dtu.dk; bwo@byg.dtu.dk b Faculty of Civil and Geodetic Engineering Ljubljana, University of Ljubljana, Chair for Buildings and Constructional Complexes, Jamova cesta 2, 1000 Ljubljana, Slovenia, Email: mdovjak@fgg.uni-lj.si c Architech Consulting Co., 1-22-4 Taito, Taito-ku, Tokyo 110-0016, Japan, Email: h_asada@architec.jp d Central Research Institute of Electric Power Industry, Japan, Email: iwamatsu@tmu.ac.jp e Eindhoven University of Technology, Faculty of Architecture, Building and Planning, Den Dolech 2, 5612 AZ Eindhoven, Netherlands, Email: L.Schellen@tue.nl f Laboratory of Building environment, Tokyo City University, 3-3-1 Ushikubo-Nishi, Tsuzuki-ku, Yokohama 224-8551, Japan, Email: shukuya@tcu.ac.jp The Exergy approach to design and operation of climate conditioning systems is relatively well established, while its exploitation in connection to human perception of the indoor environment is relatively rare. As the building should provide healthy and comfortable environment for its occupants, it is reasonable to consider both the Exergy flows in building and those within the human body. There is a need to verify the human-body Exergy model with the Thermal-Sensation (TS) response of subjects exposed to different combinations of indoor climate parameters (temperature, humidity, etc.). ABSTRACT BOOK – SYMPOSIUM PROGRAMME ELCAS 2011BOOK – SYMPOSIUM PROGRAMME ELCAS 2011 40 First results available on the relation between human-body Exergy Consumption rates and subjectively assessed thermal sensation showed that the minimum human body Exergy Consumption rate is associated with thermal sensation votes close to thermal neutrality, tending to slightly cool side of thermal sensation. By applying the Exergy concept to the built indoor environment, additional results are going to be explored. By using the data available so far of operative temperature (to), the human body Exergy Consumption rates increase as to increases above 24°C or decreases below 22°C at relative humidity (RH) lower than 50%. While, at 85% of RH, the human-body Exergy Consumption rates decrease when to is increasing above 24 °C. IV.6. Exergy Analysis: The Effect of Relative Humidity, Air Temperature and Effective Clothing Insulation on Thermal Comfort M. DOVJAK, A. SIMONE, J. KOLARIK, H. ASADA, T. IWAMATSU, L. SCHELLEN, M. SHUKUYA, B. W. OLESEN, A. KRAINER a Faculty of Civil and Geodetic Engineering Ljubljana, University of Ljubljana, Chair for Buildings and Constructional Complexes, Jamova cesta 2, 1000 Ljubljana, Slovenia, Email: mdovjak@fgg.uni-lj.si b International Centre for Indoor Environment and Energy, Department of Civil Engineering, Technical University of Denmark, Nils Koppels Alle Building 402, 2800 Lyngby, Denmark, Email: asi@byg.dtu.dk; jakol@byg.dtu.dk; bwo@byg.dtu.dk Architech Consulting Co., 1-22-4 Taito, Taito-ku, Tokyo 110-0016, Japan, Email: h_asada@archi-tec.jp Central Research Institute of Electric Power Industry, Japan, Email: iwamatsu@tmu.ac.jp e Eindhoven University of Technology, Faculty of Architecture, Building and Planning, Den Dolech 2, 5612 AZ Eindhoven, Netherlands, Email: L.Schellen@tue.nl Laboratory of Building environment, Tokyo City University, 3-3-1 Ushikubo-Nishi, Tsuzuki-ku, Yokohama 224-8551, Japan, Email: shukuya@tcu.ac.jp Exergy analysis enables us to make connections among processes inside the human body and processes in a building. So far, only the effect of different combinations of air temperatures and mean radiant temperatures have been studied, with constant relative humidity in experimental conditions. The objective of this study is to determine the effects of different levels of relative humidity (RH), air temperature (Ta) and effective clothing insulation on thermal comfort conditions from the exergetic point of view. The analyses take into consideration the available data from the study by Toftum et al. (1998). The effect of different levels of RH, Ta and effective clothing insulation on human body Exergy balance chain, changes in human body Exergy Consumption rate (hbExCr) and predicted mean vote (PMV) index were analyzed. The results show that thermal comfort conditions do not always result in lower hbExCr as it was proven in previous studies.Variations in effective clothing insulation, Ta and RH affect individual parts of human body Exergy balance chain with an important effect on hbExCr. At hot and dry conditions the hbExCr is the largest while at hot and humid conditions it is the minimal. Hot and dry and cold and dry conditions have similar hbExCr. The difference appears if the whole human body Exergy balance chain is taken into consideration. To maintain comfortable conditions it is important that Exergy Consumption and stored Exergy are at optimal values with a rational combination of Exergy input and output.
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analysis on Exergy Consumption patterns for space heating in slovenian buildings
Energy Policy, 2010Co-Authors: Mateja Dovjak, Masanori Shukuya, Bjarne W. Olesen, Ales KrainerAbstract:Problem of high energy use for heating in Slovenian buildings is analyzed with Exergy and energy analysis. Results of both are compared and discussed. Three cases of exterior building walls are located in three climatic zones in winter conditions. Results of energy analyses show that the highest heating energy demand appears in the case with less thermal insulation, especially in colder climate. If the comparison is made only on the energy supply and Exergy supply, the results of Exergy analysis are the same as those of energy analysis. The main difference appears, if the whole chain of supply and demand is taken into consideration. Exergy calculations enable us to analyze how much Exergy is consumed in which part, from boiler to building envelope. They also reveal how much energy is supplied for the purpose of heating. Results show that insulation has much bigger effect than effect of boiler efficiency. However, the most effective solution is to improve building envelope together with boiler efficiency. Better thermal insulation also makes an important contribution to the improvement of thermal comfort conditions. It causes higher surface temperatures resulting in a larger warm radiant Exergy emission rate and consequently better thermal comfort.
-
An investigation on the assessed thermal sensation an human body Exergy Consumption rate
2010Co-Authors: Angela Simone, Jakub Kolarik, Mateja Dovjak, Masanori Shukuya, Toshiya Iwamatsu, Hideo Asada, L Lisje Schellen, Bjarne W. OlesenAbstract:The Exergy concept helps to optimize indoor climate conditioning systems to meet the requirements of sustainable building design. While the Exergy approach to design and operation of indoor climate conditioning systems is relatively well established, its exploitation in connection to human perception of the indoor environment is rare. As the building should provide healthy and comfortable environment for its occupants, it is reasonable to consider both the Exergy flows in the building and within the human body. A relatively new approach of the relation between the Exergy concept and the built-environment research has been explored in the present work. The relationship of subjectively assessed thermal sensation data, from earlier thermal comfort studies, to the calculated human-body Exergy Consumption has been analysed. The results show that the minimum human body Exergy Consumption rate was related to the thermal sensation votes close to thermal neutrality, tending to the slightly cool side.
Marcel Schweiker - One of the best experts on this subject based on the ideXlab platform.
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unsteady state human body Exergy Consumption rate and its relation to subjective assessment of dynamic thermal environments
Energy and Buildings, 2016Co-Authors: Marcel Schweiker, Jakub Kolarik, Mateja Dovjak, Masanori ShukuyaAbstract:Abstract Few examples studied applicability of Exergy analysis on human thermal comfort. These examples relate the human-body Exergy Consumption rate with subjectively obtained thermal sensation votes and had been based on steady-state calculation methods. However, humans are rarely exposed to steady-state thermal environments. Therefore, the first objective of the current paper was to compare a recently introduced unsteady-state model with previously used steady-state model using data obtained under both constant and transient temperature conditions. The second objective was to explore a relationship between the human-body Exergy Consumption rate and subjective assessment of thermal environment represented by thermal sensation as well as to extend the investigation towards thermal acceptability votes. Comparison of steady-state and unsteady-state model showed that results from both models were comparable when applied to data from environments with constant operative temperature. In contrast, when applied to data with temperature transients the prediction of particular models differed significantly and the unsteady-state model resulted in better prediction of mean skin temperature. The results of the present study confirmed previously indicated trends that lowest human body Exergy Consumption rate is associated with thermal sensation close to neutrality. Moreover, higher acceptability was in general associated with lower human body Exergy Consumption rate.
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study on the effect of preference of air conditioning usage on the Exergy Consumption pattern within a built environment
International Journal of Exergy, 2012Co-Authors: Marcel Schweiker, Masanori ShukuyaAbstract:According to previous work, preference is one major factor influencing occupants' behaviour. This paper aims at identifying the magnitude preference on the Exergy Consumption pattern within a built environment. The comparison is made between one group claiming to like sleeping in air–conditioned spaces and the other claiming to dislike it. In conclusion, the Exergy analysis showed that at the individual level, preference accounts for an Exergy Consumption rate up to 15% higher and that, at the community level, the Exergy Consumption rate of those preferring the AC–unit use is up to four times higher than that of the others'.
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adaptive comfort from the viewpoint of human body Exergy Consumption
Building and Environment, 2012Co-Authors: Marcel Schweiker, Masanori ShukuyaAbstract:Thermally comfortable indoor conditions can be found using the predicted mean vote (PMV)-approach, the adaptive comfort model, or the calculation of the human body Exergy Consumption (HBx-) rate. Thus, it would be practical either to find a combined model applicable to all conditions or the underlying effects for the observed differences. This paper compares all three approaches by three distinctive procedures: first, conditions leading to temperatures within the adaptive comfort range and those leading to the minimum HBx-rate are compared first based on hourly weather data and second on general assumptions; Third, for the datasets contained in the ASHRAE comfort database, the PMV-value, adaptive comfort temperature, and HBx-rate are calculated and the results compared. According to the first procedure, a linear relationship between adaptive comfort temperature and minimum HBx-rate is found. The exploration of results gained by using the ASHRAE comfort database showed that the minimum HBx-rate corresponds well to the neutral temperature given by the adaptive comfort model. These results can be used as a starting point for a further exploration of differences and similarities between the three approaches, which may lead to a combined model of thermal comfort. Nevertheless, more detailed analyses are necessary to obtain statistically and theoretically assured conclusions.
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investigation on the effectiveness of various methods of information dissemination aiming at a change of occupant behaviour related to thermal comfort and Exergy Consumption
Energy Policy, 2011Co-Authors: Marcel Schweiker, Masanori ShukuyaAbstract:These days the number of projects trying to urge a change in the occupant's behaviour towards a sustainable one is increasing. However, still less is known about the effect of such measures. This paper describes the findings of two investigations, a field measurement and an Internet-based survey, both including the dissemination of information about strategies for a high level of comfort without much energy usage. The focus was on the ability to quantify the effect of such measures on the heating and cooling behaviour. As a result, those who participated in a workshop were more likely to change their behaviour than those who received an information brochure only; whether this was due to the method employed or the type of participants could not be ascertained. However, the workshop participants reduced their cooling device usage by up to 16%. The concept of Exergy was used to show how this reduction affects the Exergy Consumption of the cooling device, because it enables us to consider the qualitative aspect of energy as a quantity to be calculated. This showed that the Exergy consumed by the workshop group was reduced by up to 20% comparing their behaviour before and after the information dissemination.
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comparative effects of building envelope improvements and occupant behavioural changes on the Exergy Consumption for heating and cooling
Energy Policy, 2010Co-Authors: Marcel Schweiker, Masanori ShukuyaAbstract:Much focus is put on measures to improve the building envelope system performance to reduce the impact of the building sector on the global environmental degradation. This paper compares the potential of building envelope improvements to those of a change in the occupant's behavioural pattern. Three cases of improvements together with a base case were analysed using Exergy analysis, because the Exergy concept is useful to understand the underlying processes and the necessary adjustments to the calculation of the heat-pump system. The assumptions for the occupant behaviour were set up based on our field measurements conducted in a dormitory building and the calculation was for steady-state conditions. It was found that the potential of occupant behavioural changes for the reduction in Exergy Consumption is more affected by the outdoor temperature compared to building envelope improvements. The influence of occupant behaviour was highly significant (more than 90% decrease of Exergy Consumption) when the temperature difference between indoors and outdoors is small, which is the case for long periods in regions with moderate temperatures during summer and/or winter. Nevertheless, both measures combined lead to a reduction from 76% up to 95% depending on the outside conditions and should be the final goal.