Material and technological concept of the construction of a turboshaft engine with the application of isochoric combustion – CFD thermal analysis

Building contributes almost 40% of CO 2 emissions and is a major contributor to the green house gas (GHG) emissions. Different types of construction materials possess a wide variation of embodied energy and emit CO 2 at different magnitudes during its life cycle. Selection of appropriate construction materials can considerably cut down CO 2 emissions and make our buildings more sustainable and energy efficient. The study is an attempt to address the issues of sustainable construction and how its selection of construction materials can reduce CO 2 emissions and play an important role in reducing the impact of climate change directly or indirectly. A case study for a typical house having 90 sq. m. of plan area was analysed to see the variation of CO 2 emission based on altering the types of construction materials to be used. It has been observed from the case study that construction materials like aluminium and steel should be less encouraged due to their higher CO 2 emission rate as compared to glass and timber.

Numerical and experimental studies on a pressurized hybrid tubular and cavity solar air receiver using a Scheffler reflector

The significant part of the constructions’ value consists of construction materials price. With the aim of using financial resources for the construction effectively, it is very important that well considered and reasonable decisions should be made regarding the selection of construction materials. Most of all construction on‐line systems seek to find how to make the most economic construction decisions and essentially these decisions are intended only for economic objectives. Construction alternatives that are under evaluation have to be evaluated not only from the economic position, but also take into consideration qualitative, technical, technological and other characteristics. Additionally, in seeking to facilitate the work of decision‐makers, computer technologies are used that operates according to particular models. These models are based on special mathematical methods in order to facilitate decision‐making and apply to a certain decision area. In this article, the possibilities of applyi...

Purpose Although several models have been developed for handling construction materials, no standard mechanism has been formed to assess the circularity in construction material selection in terms of Circular Economy (CE). Thus, the purpose of this research is to explore the importance of CE for construction material selection and to develop a framework to assess the circularity of construction materials of building construction projects in terms of CE principles. Design/methodology/approach This research was conducted under quantitative phenomenon. A Systematic Reviews and Meta-Analyses (PRISMA) based systematic literature review (SLR) was initially conducted to identify the CE principles applied in the construction industry. Then, a questionnaire survey was conducted to evaluate the level of importance of each CE principle on construction material selection to develop a circularity assessment framework. Expert interviews were conducted to validate the proposed framework. Findings A total of 41 articles, systematically screened and selected through the SLR process, were used to explore the application of CE principles in the construction industry. A total of 10 CE principles were identified through SLR and the level of importance of each principle was first derived through Mean Weighted Average (MWA). Reuse was identified as the most important CE principle while reduce and recycle obtained second and third ranks. Then the MWA of each CE principle was converted to a percentage to develop the circularity assessment framework. Research limitations/implications The research was limited to an objective evaluation of the importance of each CE principle for construction material selection of building construction projects. Originality/value The developed circularity assessment framework provides a new impetus for circular material selection in building construction projects for reducing the embodied impact of building materials on overall lifecycle impact of buildings.

The significant part of the constructions' value consists of construction materials price. Thus proper selection of construction products has significantly impacted on construction effectiveness. With the aim of using financial resources for the construction effectively, it is very important that well considered and reasonable decisions should be made regarding the selection of construction materials. Additionally, in seeking to facilitate the work of decision-makers, computer technologies are used that operates according to particular models. These models are based on special mathematical methods in order to facilitate decision-making and apply to a certain decision area. In this article, the possibilities of applying methods for popular decision-making are analyzed regarding the selection of construction materials.

A typical scheme of a biomass fueled micro-CHP unit with a Stirling engine, including a combustion chamber, a Stirling Engine, a recuperator and water heater, is considered. A brief overview of the main biomass combustion methods used in this installation is made.
 Thermophysical analysis was carried out on the basis of solving a system of equations: the reaction equation for wood biomass combustion, the equations of both the general heat balance and the heat balance of parts of CHP unit, as well as the equation of energy conservation at flows mixing in the combustion chamber, taken into account the heat input and losses. The relationship for calculating the theoretical temperature in the combustion chamber and heat flux in the recuperatoris obtained. The last equation is obtained in dimensionless form. The theoretical temperature in the combustion chamber and the heat flux in the recuperator have been calculated, the influence of the main factors has been analyzed - the efficiency of heat exchange in the recuperator, the share of the total air flow passing through the recuperator, the excess air ratio, dimensionless heat losses and heat flux on the hot heat exchanger of the Stirling engine.
 It is shown that the temperature in the combustion chamber decreases with a decrease in the efficiency of the recuperator and with an increase in the excess air ratio. A significant influence of heat losses in the combustion chamber on the heat flux in therecuperatorwas found. Under certain conditions (high heat losses and high heat exchange on the hot heat exchanger of the Stirling engine), the recuperator is not neededatall.
 It is also shown that the share of the total air flow passing through the recuperator has a significant effect on the heat flux in the recuperator. Thus, when the air flow passing through the recuperator is reduced by 2 times, the heat flow is reduced by 5 times. Therefore, it is necessary to minimize the air flow bypassing the recuperator. As a result of thermophysical analysis, the optimal value of the excess air ratio was obtained, which is 1.7 ... 1.8.

Go Green has become a global slogan today. We desperately need to save the environment which is the resource of life on earth. Unfortunately the development in technology is clubbed with the diminishing of the resources or polluting the environment. The various factories and industries, automobiles, mining processes are causing damage to our environment. It has been a big challenge for technologists, engineers and scientists to save environment and natural resources without compromising with the quality of performance, development rate and comfort level of society. We have come a long way in developing the materials and techniques which may help to save environment and control depleting resources for future generation. Green buildings is a concept on the same theory.In the effective view green construction includes, increasing energy efficiency of a building usinggreen natural or renewable resources instead of non-renewable resources. In this paper we are presenting the factors to be considered to decide the selection of materials for green construction.

A sustainable development concerning economic, environmental, and social aspects is a global need as well as challenge in general and especially regarding the selection of construction materials. However, it is assumed that the importance of sustainability criteria is different in developed and developing countries. This is relevant for the application of Life Cycle Sustainability Assessment, a method that integrates the established methods for economic, ecological, and social evaluation (Life Cycle Costing, Life Cycle Assessment, and Social Life Cycle Assessment) without explicitly including importance weightings. This paper aims to review the reality of sustainable development in construction material selection in Vietnam, a developing country. A list of 18 sustainability criteria was set up by reviewing previous studies and using a questionnaire. These criteria were ranked and used to calculate the importance of weightings based on the Analytic Hierarchy Process method and a Likert scale. The results showed that the “price of material” was ranked as the first among the sustainability criteria. It is also pointed out that 42.06, 29.96, and 27.98 are the weightings of Life Cycle Costing, Life Cycle Assessment, and Social Life Cycle Assessment results, respectively. Besides, 11 obstacles for integrating sustainability criteria into material selection were identified in the questionnaire, and 4 out of them were marked as showing “high” importance.

The United States is faced with the tremendous task of replacing and upgrading bridge structures on the secondary and county highway systems. Properly designed and constructed timber bridges offer one possible solution to this problem. Recognizing the fact that many engineers are unfamiliar with timber design, a comprehensive reference list of design literature on timber highway bridges has been compiled. For each referenced document, a brief abstract is provided to aid the designer in selecting appropriate reference information for a specific timber bridge design problem. With the increasing awareness by the engineering profession of the need to place greater emphasis on both energy and resource conservation in the selection of construction materials, timber has taken on renewed importance as a basic structural material for the design and construction of highway bridges. It requires less energy to process timber to a usable construction material than other conventional structural materials and timber is our only naturally renewable construction material resources.

AimNest microclimate is a critical determinant of the survival and development of embryonic and juvenile birds. While abiotic variables such as temperature, precipitation and elevation will influence the conditions experienced by offspring within the nest, parent birds may also exercise some control through nest design and the selection of construction material. The aim of this study is to determine whether avian nest construction and the composition of nest construction material is influenced by geographical variation in climate. In addition, this study aims to address whether the correlation between nest construction and elevation highlighted by other studies is independent of the association between elevation and climate, or if other unmeasured variables are at play.LocationAustraliaMethodsWe measured the structural and thermal properties of 201 cup‐shaped nests, from 36 Australian passerine species, and related these to temperature, precipitation and elevation.ResultsThe rate of heat loss from avian nests is correlated with temperature, precipitation and elevation. Birds that construct nests in cool climates use well‐insulating materials irrespective of precipitation, while birds in warm climates use poorly insulating materials when exposed to high rainfall but not when exposed to low rainfall.Main conclusionsLocal climate influences the construction of nests, through modification of the materials used, and therefore the rate of heat loss from the nest as a whole. In many climates, birds use well‐insulating materials; however, birds breeding in warm and wet climates construct their nests with materials that have a higher thermal conductivity. Such nests are possibly less absorptive and able to dry out faster following a rain event, to restore the insulating function of the nest. These findings highlight the importance of studies over large geographical scales for understanding nest construction by birds.

Urbanization and living comfort have revolutionized the construction industry. Many techniques and strategies have been used to improve the overall efficiency of construction and to reduce waste during and after the construction activity; some are cost effective and some not. Sustainable construction strategies have addressed these issues by proposing relatively more cost effective and environment-saving solutions. One strategy is to select sustainable construction materials at the building design stage. This article involved a questionnaire survey to collect data about local technical stakeholders’ (architects, designers, engineers, estimators, and managers) awareness of environmental sustainability and current practices for selecting construction materials. A sustainability index (SI) was developed using SPSS (Statistical Package for the Social Sciences) for the complex statistical analysis. These data were used to develop a decision support system (DSS) using the multi-criteria decision making (MCDM) technique, the TOPSIS. The support system was validated by applying it to sustainable roof products in a pilot case study—these materials are frequently used in local markets for residential construction in West Australia. So the main objective was to get insight to local market trends and features involved in construction materials selection. Data analysis was carried out to develop a decision support system to help technical stakeholders in construction materials selection process.

The selection of appropriate materials plays a very important role in satisfying the customer in terms of construction project quality, cost and process. Therefore, accurate construction material information analysis is necessary. Designers with little experience in construction material selection, however, make choices without understanding the characteristics of different construction materials, which lowers the quality of the construction. Material information documents are distributed in personal computer without document management system. This paper suggests document management module that composed tag-manager, server and search interface for systematic using of material information documents. Construction material information document prototype system is developed to support member of material company. The effectiveness and efficiency of the developed prototype system was confirmed through interviews with construction material company staffs. There is a need for further studies, though, that will expand the users of the developed prototype system and that will improve the tag information and the system.

A thermal analysis of a two-storey building was made using a dynamic simulation software (TRNSYS). Thermal performance of a 2000 m2 building was examined by means of several dynamic simulations. The building is located in a region within the BS climate (steppe) according to the Köppen climate classification, where both air cooling and heating are needed to provide comfortable thermal conditions through the entire year. This weather often represents an energy saving challenge, where heat gains and heat losses need to be efficiently managed. A selection of common construction and glazing materials was implemented, and a simple but effective ventilating strategy was tested. Six thermal zones were defined in the building and a comfort temperature range was established as an operating parameter. The results show hourly mean temperatures and energy consumption due to air conditioning throughout a year.

Vacuum weighing of mass artifacts eliminates the necessity of air buoyancy correction and its contribution to the measurement uncertainty. Vacuum weighing is also an important process in the experiments currently underway for the redefinition of the SI mass unit, the kilogram. Creating the optimum vacuum environment for mass metrology requires careful design and selection of construction materials, plumbing components, pumping, and pressure gauging technologies. We review the vacuum technology1 required for mass metrology and suggest procedures and hardware for successful and reproducible operation.

Flame stability and emission characteristics of propane-fueled flat-flame miniature combustor for ultra-micro gas turbines