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An optimization approach is presented in this paper to minimize life-cycle environmental impacts and evaluated in terms of expanded cumulative exergy consumption during a building service life, resulting to negative impacts due to waste emission. The optimal solution is found using the strong-searched and structured genetic algorithms. A case study...
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The utilisation of exergy and anergy concepts for low exergy system design extends the potential of performance optimisation of buildings. We propose a new perspective for buildings and their external environment. It recognises exergy as the utilisable potential that maintains comfort inside relative to outside ambient conditions. It considers envi...
![Figure 1. System diagram of case 1 [5].](publication/364555607/figure/fig1/AS:11431281092523244@1666880223928/System-diagram-of-case-1-5_Q320.jpg)
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Citations
... It is also the maximum work potential of an energy or mass flow in a system to its environment. Exergy can be defined as the product of energy quality and energy quantity [2]. In thermodynamics, the exergy of a system is the maximum work possible during a process that brings the system into equilibrium with heat reservoir [3]. ...
... TheFig.1 A building envelope system under thermally steady state condition. Energy,entropy and exergy flow into the wall and out to the ambient environment are shown [2, 7] Fig. ...
... World Academy of Science, Engineering The Solar intensity/lighting power is obtained from Shekoni [10], The walls of the building are sandcrete blocks. The thermal transmittance used was 1.73W/m 2 K for the 225mm sandcrete blocks [2]. The results are shown in numerical examples of exergy/energy consumption for the whole process of space heating. ...
This paper showed the use of the exergy and energy analyses during the service live of a residential building. In order to understand the exergy flow and find possibilities for further improvement in energy utilization in the building, a pre-design analysis tool has been used in this paper. The tool was divided into sub-systems which are primary energy transformation, generation, storage, distribution, emission and control, room air and envelope. The concepts of first and second laws of thermodynamics were used. From the analysis, the heat energy demand for the specimen building, in its service life, was obtained. It was noted that the greatest losses of exergy in this building occur in the primary energy transformation and heat generation. Design results showed that, whereas the flow of the exergy began to drop at the emission and control component to the envelope, the flow of energy remained constant. The spreadsheet application simplifies the design.
... The more comprehensive is analysis, the more indicators will be used. Various decision-making tools are used to solve the problem of coping with a number of indictors obtained during analysis -multi-criteria analysis, artificial neural network, genetic algorithm (Adedeji 2008;Kaklauskas et al. 2005;Rogoža et al. 2006;Yalcintas 2008;Zavadskas et al. 2009). In this paper multi-criteria analysis will be used to get an answer to the question which alternative is the most optimal. ...
Climate change became a priority issue on the agenda of the energy and environmental policy of the European Union. Energy efficiency and renewable energy are the main pillars to cope with climate change. Buildings consuming 40% of final energy in the European Union play a vital role here. This is the reason for changing attitude towards evaluation of the benefits of the renovation of existing buildings. Previously before making a decision on building renovation solutions the main factor was cost‐efficiency. Today life‐cycle approach taking into account energy consumption and abatement of greenhouse gases is more relevant.
The goal of the paper is to compare different alternatives for the renovation of buildings taking into account energy, economic and environmental criteria while evaluating impact of renovation measures during their life cycle. The first alternative is renovation of a building up to the requirements of existing building codes. The second alternative is renovation of a building making its thermal characteristics of the envelopes by 25% better. The third alternative is renovation of a building making its thermal characteristics of the envelopes by 50% better. Possibility to use renewable energy in all the three alternatives is also investigated.
The results of analysis show that in the case under consideration replacement of district heating, mostly based on fossil fuel, with a biomass boiler has an advantage in terms of environment and energy. However, economic attractiveness of these alternatives is rather moderate. Final choice of the alternatives depends on the priorities of a decision‐maker.
Santrauka
Klimato kaita tapo prioritetiniu punktu Europos Sajungos energetikos ir aplinkosaugos politikos darbotvarkeje. Energijos vartojimo efektyvumas ir atsinaujinantys energijos ištekliai ‐ pagrindines nuostatos siekiant iveikti klimato kaitos keliamas problemas. Pastatams, kuriuose suvartojama 40 % Europos Sajungos galutines energijos, čia tenka pagrindinis vaidmuo. Tai yra priežastis keisti požiūri, vertinant esamu pastatu renovavimo nauda. Anksčiau prieš priimant sprendima del pastatu renovacijos pagrindinis faktorius buvo ekonominis efektyvumas. Šiandien tikslingiau yra atsižvelgti i gyvavimo cikla, ivertinant energijos suvartojimo mastus ir šiltnamio duju išmetius. Šio darbo tikslas ‐ palyginti skirtingas pastatu renovavimo alternatyvas, atsižvelgiant i energetinius, ekonominius ir aplinkos apsaugos kriterijus, vertinant renovacijos priemoniu itaka per ju gyvavimo laika. Pirmoji renovacijos alternatyva ‐ pastatas renovuojamas, kad atitiktu reikalavimus, keliamus pastatu atitvaru šiluminems charakteristikoms. Antroji renovacijos alternatyva ‐ pastato atitvaru šilumines charakteristikos, palyginti su galiojančiais reikalavimais, gerinamos 25 %. Trečioji alternatyva ‐ pastato atitvaru šilumines charakteristikos, palyginti su galiojančiais reikalavimais, gerinamos 50 %. Papildomai ivertinama galimybe visais trim atvejais naudoti atsinaujinančius energijos išteklius. Analizes rezultatai parode, kad nagrinejamu atveju gaunama energetine ir aplinkosaugine nauda, kai vietoje esamos centralizuotai tiekiamos šilumos sistemos, kurioje šilumai gaminti pagrindinai naudojamas iškastinis kuras, irengiamas biomases katilas. Ekonomiškai šios alternatyvos yra mažiau patrauklios. Galutinis alternatyvu pasirinkimas priklauso nuo sprendimu priemejo prioritetu.
Резюме
Изменение климата стало приоритетным вопросом на повестке дня энергетической и экологической политики Европейского Cоюза. Энергетическая эффективность и возобновляемые источники энергии являются основными мерами для уменьшения изменений климата. С этой точки зрения большое значение имеют здания, так как они в Европейском Союзе потребляют 40% энергии. Это является причиной изменения отношения к оценке выгод от реновации существующих зданий. Ранее для принятия решения о реновации здания основным фактором являлась экономическая эффективность. Сегодня более актуальным является учет потребления энергии и сокращения выбросов парниковых газов. Целью настоящей работы было сравнить различные варианты реконструкции здания с учетом энергетических, экономических и экологических критериев при оценке воздействия мер по реконструкции во время их жизненного цикла. Первый вариант – это реновация здания с целью улучшения его тепловых характеристик, доводя их до требований существующих строительных норм. Второй вариант – реновация здания с целью улучшения его тепловых характеристик на 25% по сравнению с требованиями существующих строительных норм. Третий вариант – реновация здания с целью улучшения его тепловых характеристик на 50% по сравнению с требованиями существующих строительных норм. Кроме этого, во всех трех вариантах исследована возможность использования возобновляемых источников энергии. Результаты анализа показали, что замена централизованного теплоснабжения, основaнного главным образом на использовании ископаемых видов топлива, на котел с биомассой имеет преимущество с точки зрения окружающей среды и энергетики, однако экономическая привлекательность такой альтернативы довольно умеренна. Окончательный выбор вариантов зависит от приоритетов субъекта, принимающего решение.
First Publish Online: 27 Jun 2011
Reikšminiai žodžiai: visuomeninis pastatas, renovacija, energijos vartojimo efektyvumas, įkūnytoji energija, gyvavimo ciklo analizė, gyvavimo ciklo kaštai, CO2 emisijos.
Ключевые слова: общественное здание, реновация, эффективность применения энергии, воплощенная энергия, анализ жизненного цикла, стоимость жизненного цикла, эмиссия CO2.
... The more comprehensive is analysis, the more indicators will be used. Various decision-making tools are used to solve the problem of coping with a number of indictors obtained during analysis -multi-criteria analysis, artificial neural network, genetic algorithm (Adedeji 2008;Kaklauskas et al. 2005;Rogoža et al. 2006;Yalcintas 2008;Zavadskas et al. 2009). In this paper multi-criteria analysis will be used to get an answer to the question which alternative is the most optimal. ...
In recent years, energy policy increasingly focuses on reducing energy consumption in buildings. The European Union has the objective that from 2020 all newly constructed buildings should be close to nearly zero-energy. However, these buildings will have an effect only in the long-term perspective. Meanwhile, the problem of the existing energy-inefficient buildings remains critical. One of the main obstacles in buidlings renovation is the lack of financial resources and of effective financial mechanisms. Therefore, the energy and hence the environmental benefits of building renovation are often neglected. Currently, building renovation frequency is measured primarily by the criteria of economic and sometimes of physical deterioration of a building. The goal of the research presented in this article is to assess the impact of building renovation frequency on its life-cycle energy consumption.
This paper showed the use of the exergy and energy analyses during the service live of a residential building. In order to understand the exergy flow and find possibilities for further improvement in energy utilization in the building, a pre-design analysis tool has been used in this paper. The tool was divided into sub-systems which are- primary energy transformation, generation, storage, distribution, emission and control, room air and envelope. The concept of first and second laws of thermodynamics were used. From the analysis, the heat energy demand for the specimen building, in its service life, was obtained. It was noted that the greatest losses of exergy in this building occur in the primary energy transformation and heat generation. Design results have shown that whereas the flow of the exergy began to drop at the emission and control component to the envelope, the flow of energy remained constant.
