Construction Of Energy Efficient Buildings Research Articles

In situ preparation and characterization of encapsulated high-chain fatty acid ester-based phase change material (PCM) in poly(urethane-urea) by using amino alcohol

A fatty acid ester-based phase change material (PCM) has been encapsulated with a proper poly-functional amino alcohol and toluene diisocyanate under in situ polymerization conditions for further use in thermal applications. N-(2-hydroxyethyl)ethylenediamine has been utilized for the first time for encapsulation of PCMs to form poly(urethane-urea) shell material. The research reports the influence of utilized anionic and non-ionic surfactants on properties of the encapsulated end products at different surfactant/PCM stoichiometric ratios. The thermal properties are reported in terms of phase change temperature, enthalpy and PCM encapsulation efficiency with necessary statistical calculations by differential scanning calorimeter (DSC) analyses after the conducted effective scrubbing procedure for excess PCM in the boundary layer and on walls of the shell material. Particle size distribution analysis and high-resolution transmission electron microscope (HRTEM) imaging have been utilized for further discussions on relations between surfactant types, stoichiometric ratios and structural properties. The prepared PCM composites with micro- and nano-structures are suitable candidates for use in desirable exterior building materials and solar units as outdoor thermal energy storage agents for construction of energy efficient buildings.

A scenario analysis of the life cycle greenhouse gas emissions of a new residential area

While buildings are often credited as accounting for some 40% of the global greenhouse gas (GHG) emissions, the construction phase is typically assumed to account for only around one tenth of the overall emissions. However, the relative importance of construction phase emissions is quickly increasing as the energy efficiency of buildings increases. In addition, the significance of construction may actually be much higher when the temporal perspective of the emissions is taken into account. The construction phase carbon spike, i.e. high GHG emissions in a short time associated with the beginning of the building’s life cycle, may be high enough to question whether new construction, no matter how energy efficient the buildings are, can contribute to reaching the greenhouse gas mitigation goals of the near future. Furthermore, the construction of energy efficient buildings causes more GHG emissions than the construction of conventional buildings. On the other hand, renovating the current building stock together with making energy efficiency improvements might lead to a smaller construction phase carbon spike and still to the same reduced energy consumption in the use phase as the new energy efficient buildings. The study uses a new residential development project in Northern Europe to assess the overall life cycle GHG emissions of a new residential area and to evaluate the influence of including the temporal allocation of the life cycle GHG emissions in the assessment. In the study, buildings with different energy efficiency levels are compared with a similar hypothetical area of buildings of the average existing building stock, as well as with a renovation of an area with average buildings from the 1960s. The GHG emissions are modeled with a hybrid life cycle assessment. The study suggests that the carbon payback time of constructing new residential areas is several decades long even when using very energy efficient buildings compared to utilizing the current building stock. Thus, while increasing the overall energy efficiency is important in the long term, the construction of new energy efficient buildings cannot be used as a means to achieve the short term and medium term climate change mitigation goals as cities and governments often suggest. Furthermore, given the magnitude of the carbon spike from construction and its implications, the climate change mitigation strategies should set reduction targets for the construction phase emissions alongside the ones for the use phase, which currently receives almost all of the attention from policy-makers.

Energy efficiency of buildings with phase-change materials

The construction of energy efficient buildings using innovative building materials such as phase change materials, in addition to improving indoor comfort, energy savings and costs, can be achieved by increasing their market value. Because of its ability to absorb and release energy at predictable temperatures, phase change materials are effective in controlling and maintaining the thermal environment in the building. The use of phase changing materials, materials stored latent energy storage is an effective form of heat.

Assessing embodied energy of building structural elements

Although operational energy is currently the focal point of sustainability in building regulations, embodied energy and carbon dioxide emissions will become more significant as operational energy consumption is reduced. In the near future, embodied energy could account for a significant proportion of a building's carbon footprint over its lifetime, bearing in mind that the construction of energy-efficient buildings is carbon and energy intensive. Unlike operational energy, embodied energy savings have an immediate significant effect on carbon footprint and are independent of human behaviour. However, there is a lack of consensus within the construction industry on how to assess embodied energy and carbon dioxide and where to draw system boundaries, which has impeded advancement on the issue. This paper analyses the life-cycle embodied energy and carbon dioxide emissions of a building's structural elements, and examines which stages within a building's life are the most significant and offer the most opportunities for a reduction of embodied energy and carbon dioxide. The embodied energy and associated carbon dioxide at the product and construction, maintenance and end-of-life stages of a structure are examined, as well as the potential for energy recovery and carbon dioxide offsetting. A simple single-storey structure is used as a case study to perform comparative analyses between two structural design alternatives: glue-laminated timber panels and steel frame with infill concrete blockwork.

High-Recycled-Content Concrete for Energy-Efficient Building Construction

High-Recycled-Content Concrete for Energy-Efficient Building Construction

Metabolism of Neighborhoods

Analysis of urban metabolism has been established as an appropriate approach for assessing the sustainability of cities. A desirable next step is to use the metabolism as a guide to designing more sustainable cities. This study provides an analysis of the metabolism of four representative Toronto neighborhoods. The annual energy consumption for buildings and transport is determined to be from 57to107GJ/capita and from 0.5to9.2GJ/capita, respectively. The annual consumption of food and water is found to be 1,100 and 92,300kg/capita. The findings of the study have implications for the design of sustainable neighborhoods. This includes the construction of energy-efficient buildings, development of public transit, and encouragement of residents to replace inefficient water fixtures. More advanced methods might consist of growing the urban forest using nutrients from wastewater, and converting solar energy to building operational energy

Whatman plc, UK

Developing a strong, flame resistant, and thermally insulating structural material is essential for reducing energy consumption and improving safety in buildings. Wood is a pervasive structural material with natural thermally insulating properties. However, its flammability and insufficient mechanical strength compromises its safety, particularly in mid-rise and high-rise buildings that have higher safety and structural requirements. Herein, we demonstrate a strong, flame-retardant, and thermally insulating wood laminate featuring a compact structure that we synthesized by infiltrating delignified basswood with bentonite nanosheets, followed by hot-pressing to densify the material. Bentonite nanosheets can be infiltrated into the microchannel of the delignified wood to achieve a good compatible and 3D flame resistant protective surface. Flame retardant tests show that the peak heat release rate of this wood laminate is reduced by more than 50% compared to natural basswood. Additionally, the wood laminate does not start to burn until after 7 min of direct exposure to an open flame, and then self-extinguishing when removed from the igniting flame, suggesting the excellent flame resistance of the composite. The wood laminate also exhibits a high tensile strength of 330 MPa that is more than 8-times higher than the starting material. In addition, the wood laminate exhibits lower thermal conductivities of 0.2 and 0.18 W m−1 K−1 in the axial and radial direction, respectively. The demonstrated wood laminate shows great promise as a high-performance structural material with strong flame-retardant, thermally insulating, and mechanical robust properties that are needed for the construction of energy efficient buildings.

Energy performance and energy conservation in health care buildings in hellas

Energy performance data for 30 health care buildings have been collected during an extensive energy audit of buildings in Hellas, within the frame of a National Energy Programme sponsored by the CEC VALOREN Programme for energy conservation in buildings. This short monitoring campaign was performed with on-site visits of a trained panel of engineers to each building, in order to register all information relevant to the buildings' construction, heating, cooling, lighting, systems and all other mechanical and electrical systems. The technical results of these audits, the role of the cooling and heating systems on the energy consumed in health care buildings, are discussed. The annual average total energy consumption in hospitals is 407 kWh/m 2 and in clinics is 275 kWh/m 2, the majority of which is consumed for space heating (73.4% in hospitals and 65.3% in clinics). Several scenarios for possible interventions to the outer envelope of the buildings and to the 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. The energy consumption for heating can be reduced by 15% in hospitals and 11% in clinics by using more efficient heat production and distribution systems. Proper insulation of the buildings can conserve 173 kWh/m 2 in hospitals and 103 kWh/m 2 in clinics. Cooling can be reduced by 68% (in hospitals) and 56% (in clinics) by using night ventilation and by 80 and 97%, respectively, by using ceiling fans. Natural cooling techniques, under certain conditions, can also provide an important reduction of the cooling load. The use of high efficacy lamps can reduce the electric energy consumed for lighting by up to 50%. This information provides a representative picture of the existing conditions on energy consumption in health care buildings and can be used as guidelines for future energy efficient building construction.

Energy Conservation in New Buildings: Opportunities, Experience, and Options

It is in the public interest to see to the construction of energy-efficient buildings for three reasons: possible interruption in the oil supply; the true cost of fuels not reflected in their prices; and that private builders do not build energy-efficient buildings. As a result, Congress enacted the Energy Conservation and Production Act of 1976. Three events that occurred in response to the act's mandate are reviewed: regulatory analysis, promulgation of proposed regulations, and issues raised at the public hearings. This is followed by a discussion of alternatives available within the constraints of existing law, and preliminary analysis of alternatives to the act's approach, including nonregulatory policy initiatives. 39 refs.