A simplified method for referring the energy and overheating performance of window design

This paper describes a simplified dynamic thermal model which simulates the energy and overheating performance of windows. To calculate artificial energy use within a room, the model employs the average illuminance method, which takes into account the daylight energy impacting upon the room by the use of hourly climate data. This tool describes the main thermal performance ( heating, cooling and overheating risk) resulting proposed a design of window. The inputs are fewer and simpler than that are required by complicated simulation programmes. The method is suited for the use of architects and engineers at the strategic phase of design, when little is available.

The impact of energy performance certificates on the rental and capital values of commercial property assets: some preliminary evidence from the UK

This paper focuses on the effect of energy performance ratings on the capital values, rental values and equivalent yields of UK commercial property assets. Of which a small number are also BREEAM rated, the study is based upon 708 commercial property assets held in the IPD UK Universe drawn from across all PAS segments. Incorporating a range of controls such as unexpired lease term, vacancy rate and tenant credit risk, hedonic regression procedures are used to estimate the effect of EPC rating. The study finds no evidence of a strong relationship between environmental and/or energy performance and rental and capital value. Bearing in mind the small number of BREEAM rated assets, there was a small but statistically significant effect on equivalent yield only. Similarly, there was no evidence that the EPC rating had any effect on Market Rent or Market Value with only minor effects of EPC ratings on equivalent yields. The preliminary conclusion is that energy labelling is not yet having the effects on Market Values and Market Rents that provide incentives for market participants to improve the energy efficiency of their commercial real estate assets.

Assessing the impact of occupant behaviour on the electricity consumption for lighting and small power in office buildings

Lighting and small power will typically account for more than half of the total electricity consumption in an office building. Significant variations in electricity used by different tenants suggest that occupants can have a significant impact on the electricity demand for these end-uses. Yet current modelling techniques fail to represent the interaction between occupant and the building environment in a realistic manner. Understanding the impact of such behaviours is crucial to improve the methodology behind current energy modelling techniques, aiming to minimise the significant gap between predicted and in-use performance of buildings. A better understanding of the impact of occupant behaviour on electricity consumption can also inform appropriate energy saving strategies focused on behavioural change. This paper reports on a study aiming to assess the intent of occupants to switch off lighting and appliances when not in use in office buildings. Based on the Theory of Planned Behaviour, the assessment takes the form of a questionnaire and investigates three predictors to behaviour individually: 1) behavioural attitude; 2) subjective norms; 3) perceived behavioural control. The paper details the development of the assessment procedure and discusses preliminary findings from the study. The questionnaire results are compared against electricity consumption data for individual zones within a multi-tenanted office building. Initial results demonstrate a statistically significant correlation between perceived behavioural control and energy consumption for lighting and small power

Post-occupancy evaluation studies in recently refurbished office building: energy performance and employees' satisfaction

Existing buildings contribute greatly to global energy use and greenhouse gas emissions. In the UK, about 18% of carbon emissions are generated by non-domestic buildings; sustainable building refurbishment can play an important role in reducing carbon emissions. This paper looks at the performance of a recently refurbished 5-storey office building in London, in terms of energy consumption as well as occupants’ satisfaction. Pre- and post-occupancy evaluation studies were conducted using online questionnaire surveys and energy consumption evaluation. Results from pre-occupancy and post-occupancy evaluation studies showed that employees, in general, were more satisfied with their work environment at the refurbished building than with that of their previous office. Employees’ self-reported productivity improved after the move to Elms House. These surveys showed a positive relationship between employees’ satisfaction with their work environment and their self-reported productivity, well-being and enjoyment at work. The factor that contributed to increasing employee satisfaction the most was: better use of interior space. Although the refurbishment was a success in terms of reducing energy consumption per m2, the performance gap was almost 3 times greater than that estimated. Unregulated loads, problems with building control, ineffective use of space and occupants’ behaviour are argued to be reasons for this gap.

A review of the performance of different ventilation and airflow distribution systems in buildings

The objective of this article is to review the scientific literature on airflow distribution systems and ventilation effectiveness to identify and assess the most suitable room air distribution methods for various spaces. In this study, different ventilation systems are classified according to specific requirements and assessment procedures. This study shows that eight ventilation methods have been employed in the built environment for different purposes and tasks. The investigation shows that numerous studies have been carried out on ventilation effectiveness but few studies have been done regarding other aspects of air distribution. Amongst existing types of ventilation systems, the performance of each ventilation methods varies from one case to another due to different usages of the ventilation system in a room and the different assessment indices used. This review shows that the assessment of ventilation effectiveness or efficiency should be determined according to each task of the ventilation system, such as removal of heat, removal of pollutant, supply fresh air to the breathing zone or protecting the occupant from cross infection. The analysis results form a basic framework regarding the application of airflow distribution for the benefit of designers, architects, engineers, installers and building owners.

The impact of location and type on the performance of Low-Voltage network connected Battery Energy Storage Systems

This paper assesses the impact of the location and configuration of Battery Energy Storage Systems (BESS) on Low-Voltage (LV) feeders. BESS are now being deployed on LV networks by Distribution Network Operators (DNOs) as an alternative to conventional reinforcement (e.g. upgrading cables and transformers) in response to increased electricity demand from new technologies such as electric vehicles. By storing energy during periods of low demand and then releasing that energy at times of high demand, the peak demand of a given LV substation on the grid can be reduced therefore mitigating or at least delaying the need for replacement and upgrade. However, existing research into this application of BESS tends to evaluate the aggregated impact of such systems at the substation level and does not systematically consider the impact of the location and configuration of BESS on the voltage profiles, losses and utilisation within a given feeder. In this paper, four configurations of BESS are considered: single-phase, unlinked three-phase, linked three-phase without storage for phase-balancing only, and linked three-phase with storage. These four configurations are then assessed based on models of two real LV networks. In each case, the impact of the BESS is systematically evaluated at every node in the LV network using Matlab linked with OpenDSS. The location and configuration of a BESS is shown to be critical when seeking the best overall network impact or when considering specific impacts on voltage, losses, or utilisation separately. Furthermore, the paper also demonstrates that phase-balancing without energy storage can provide much of the gains on unbalanced networks compared to systems with energy storage.

Heat losses and thermal performance of commercial combined solar and pellet heating systems

Various pellet heating systems are marketed in Sweden, some of them in combination with a solar heating system. Several types of pellet heating units are available and can be used for a combined system. This article compares four typical combined solar and pellet heating systems: System 1 and 2 two with a pellet stove, system 3 with a store integrated pellet burner and system 4 with a pellet boiler. The lower efficiency of pellet heaters compared to oil or gas heaters increases the primary energy demand. Consequently heat losses of the various systems have been studied. The systems have been modeled in TRNSYS and simulated with parameters identified from measurements. For almost all systems the flue gas losses are the main heat losses except for system 3 where store heat losses prevail. Relevant are also the heat losses of the burner and the boiler to the ambient. Significant leakage losses are noticed for system 3 and 4. For buildings with an open internal design system 1 is the most efficient solution. Other buildings should preferably apply system 3. The right choice of the system depends also on whether the heater is placed inside or outside of the heated are. A large potential for system optimization exist for all studied systems, which when applied could alter the relative merits of the different system types.

Policy instruments to improve energy efficiency in buildings

The newly adopted energy efficiency directive (2012/27/EU) highlights the importance of energy efficiency in reaching the Union’s 2020 targets. The directive commits member states to defining national energy efficiency targets (art. 3), achieving yearly energy savings of 1.5% of the annual energy sales through the energy efficiency obligation scheme (art. 7), and providing a long-term strategy for the building sector that aims at a 3% refurbishment rate for public buildings (art. 4+5). Buildings currently account for 40% of energy use in most countries, putting them among the largest end-use sectors. This report takes a closer look at the best practices for implementing increasing energy efficiency in different regions and countries in Europe. The final aim is to identify some policy tools to be suggested to the region of Dalarna (Dalarna having been chosen as the pilot county in Sweden) as a means of implementing energy efficiency in the building sector. The final objective is to give analysts and decision-makers a better analytical foundation to explore future policy development in the area of buildings to be proposed and tested at the regional level in Dalarna and later at the national level in Sweden.

High performance green buildings

This work aims to study and analyze strategies and measures to improve energy performance in residential and service buildings, in order to minimize energy losses and energy consumption. Due to the high energy dependence of European Union (EU), including Portugal and Slovenia, and high percentage of energy consumption in the building sector, there was a need to adopt strategies at European level with ambitious goals. This came to force EU - Member States to take measures to achieve the proposed targets for energy consumption reduction. To this end, EU - Member States have adapted the laws to their needs and formed specialized agencies and qualified experts on energy certification, which somehow evaluate buildings according to their performance. In this study, the external characteristics of the building in order to meet its thermal needs and from there to survey the existing and possible constructive solutions to be used at the envelope will be examined, in order to increase comfort and reduce the need of use technical means of air conditioning. The possibility of passive heating and ventilation systems also will be discussed. These techniques are developed in parallel with the deployment and design of the building. In this manner, to reduce the energy consumption, various techniques and technologies exploit natural resources. Thus, appear the more sustainable and efficient buildings, so-called Green Buildings have been appeared. The study ends with the identification of measures used in several buildings, proving the economic return in the medium to long term, as well as the satisfaction of their users.

Effects of energy and protein levels on egg quality and performance of laying hens at early second production cycle

One hundred sixty-two commercial 70-wk-old ISA Brown laying hens, previously subjected to induced molting by feed restriction, were distributed in a completely randomized design with 3 x 3 factorial arrangement (i.e., 3 metabolizable energy levels: 2,850; 2,950, and 3,050 kcal of ME/kg) and 3 protein levels (16, 18, and 20% CP), which totaled 9 treatments with 3 replicates of 6 birds each. Experimental diets were offered to birds after the feed restriction period. Performance and egg quality parameters were evaluated in 14-d intervals from the 4th to 12th weeks after forced molting for a total of 4 evaluation periods. Increases in dietary energy and protein levels did not improve performance or egg quality. The levels of 2,850 kcal of ME and 16% protein were sufficient for laying hens starting the second production cycle without decreasing their performance or egg quality.

On the performance of a dual-mode non-linear vibration energy harvesting device

The research trend for harvesting energy from the ambient vibration sources has moved from using a linear resonant generator to a non-linear generator in order to improve on the performance of a linear generator; for example, the relatively small bandwidth, intolerance to mistune and the suitability of the device for low-frequency applications. This article presents experimental results to illustrate the dynamic behaviour of a dual-mode non-linear energy-harvesting device operating in hardening and bi-stable modes under harmonic excitation. The device is able to change from one mode to another by altering the negative magnetic stiffness by adjusting the separation gap between the magnets and the iron core. Results for the device operating in both modes are presented. They show that there is a larger bandwidth for the device operating in the hardening mode compared to the equivalent linear device. However, the maximum power transfer theory is less applicable for the hardening mode due to occurrence of the maximum power at different frequencies, which depends on the non-linearity and the damping in the system. The results for the bi-stable mode show that the device is insensitive to a range of excitation frequencies depending upon the input level, damping and non-linearity.

Performance of an operating high energy physics data grid: DOSAR-Grid

The DO experiment at Fermilab's Tevatron will record several petabytes of data over the next five years in pursuing the goals of understanding nature and searching for the origin of mass. Computing resources required to analyze these data far exceed capabilities of any one institution. Moreover, the widely scattered geographical distribution of DO collaborators poses further serious difficulties for optimal use of human and computing resources. These difficulties will exacerbate in future high energy physics experiments, like the LHC. The computing grid has long been recognized as a solution to these problems. This technology is being made a more immediate reality to end users in DO by developing a grid in the DO Southern Analysis Region (DOSAR), DOSAR-Grid, using a available resources within it and a home-grown local task manager, McFarm. We will present the architecture in which the DOSAR-Grid is implemented, the use of technology and the functionality of the grid, and the experience from operating the grid in simulation, reprocessing and data analyses for a currently running HEP experiment.

Performance of electronic devices submitted to X-rays and high energy proton beams

In this work we have studied the radiation effects on MOSFET electronic devices. The integrated circuits were exposed to 10 key X-ray radiation and 2.6 MeV energy proton beam. We have irradiated MOSFET devices with two different geometries: rectangular-gate transistor and circular-gate transistor. We have observed the cumulative dose provokes shifts on the threshold voltage and increases or decreases the transistor's off-state and leakage current. The position of the trapped charges in modern CMOS technology devices depends on radiation type, dose rate, total dose, applied bias and is a function of device geometry. We concluded the circular-gate transistor is more tolerant to radiation than the rectangular-gate transistor. (C) 2011 Elsevier B.V. All rights reserved.