986 resultados para Energy balances


Relevância:

20.00% 20.00%

Publicador:

Resumo:

The progress of technology has led to the increased adoption of energy monitors among household energy consumers. While the monitors available on the market deliver real-time energy usage feedback to the consumer, the format of this data is usually unengaging and mundane. Moreover, it fails to address consumers with different motivations and needs to save and compare energy. This paper presents a study that seeks to provide initial indications for motivation-specific design of energy-related feedback. We focus on comparative feedback supported by a community of energy consumers. In particular, we examine eco-visualisations, temporal self-comparison, norm comparison, one-on-one comparison and ranking, whereby the last three allow us to explore the potential of socialising energy-related feedback. These feedback types were integrated in EnergyWiz – a mobile application that enables users to compare with their past performance, neighbours, contacts from social networking sites and other EnergyWiz users. The application was evaluated in personal, semi-structured interviews, which provided first insights on how to design motivation-related comparative feedback.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In the face of increasing concern over global warming and climate change, interest in the utilizzation of solar energy for building operations is rapidly growing. In this entry, the importance of using renewable energy in building operations is first introduced. This is followed by a general overview on the energy from the sun and the methods to utilize solar energy. Possible applications of solar energy in building operations are then discussed, which include the use of solar energy in the forms of daylighting, hot water heating, space heating and cooling, and building-integrated photovoltaics.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Air quality and temperatures in classrooms are important factors influencing the student learning process. To improve the thermal comfort of classrooms for Queensland State Schools, Queensland Government initiated the "Cooler Schools Program". One of the key objectives under this program was to develop low energy cooling systems as an alternative to high energy demand conventioanl split system of air conditioning (AC) systems. In order to compare and evaluate the energy performance of different types of air conditioners installed in classrooms, monitoring systems were installed in a state primary school located in the greater outer urban area of Brisbane, Australia. It was found that the installation of monitoring systems could have a significant impact on the accuracy of the data being collected. By comparing the estimated energy efficiency ratio (EER)for four qualified air conditioners included in this study, it was also found that AC6, a hybrid air conditioner newly developed by the Queensland Department of Public Works (DPW), had the best energy performance, although the current data were not able to show the full advantages of the system.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Building insulation is often used to reduce the conduction heat transfer through building envelope. With a higher level of insulation (or a greater R-value), the less the conduction heat would transfer through building envelope. In this paper, using building computer simulation techniques, the effects of building insulation levels on the thermal and energy performance of a sample air-conditioned office building in Australia are studied. It is found that depending on the types of buildings and the climates of buildings located, increasing the level of building insulation will not always bring benefits in energy saving and thermal comfort, particularly for internal-load dominated office buildings located in temperate/tropical climates. The possible implication of building insulation in face of global warming has also been examined. Compared with the influence of insulation on building thermal performance, the influence on building energy use is relatively small.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Appropriate pipe insulation on domestic, pumped storage (split), solar water heating systems forms an integral part of energy conservation measures of well engineered systems. However, its importance over the life of the system is often overlooked. This study outlines the findings of computer modelling to quantify the energy and cost savings by using pipe insulation between the collector and storage tank. System sizes of 270 Litre storage tank, together with either selectively surfaced, flat plate collectors (4m2 area), or 30 evacuated tube collectors, were used. Insulation thicknesses of 13mm and 15mm, pipe runs both ways of 10, 15 and 20 metres and both electric and gas boosting of systems were all considered. The TRNSYS program was used to model the system performance at a representative city in each of the 6 climate zones for Australia and New Zealand, according to AS/NZS4234 – Heat Water Systems – Calculation of energy consumption and the ORER RECs calculation method. The results show:  Energy savings from pipe insulation are very significant, even in mild climates such as Rockhampton. Across all climates zones, savings ranged from 0.16 to 3.5GJ per system per year, or about 2 to 23 percent of the annual load.  There is very little advantage in increasing the insulation thickness from 13 to 15mm. For electricity at 19c/kWh and gas at 2 c/MJ, cost savings of between $27 and $100 per year are achieved across the climate zones. Both energy and cost savings would increase in colder climates with increased system size, solar contribution and water temperatures.  The pipe insulation substantially improves the solar contribution (or fraction) and Renewable Energy Certificates (RECs), as well as giving small savings in circulating pump running costs in milder climates. Solar contribution increased by up to 23 percent points and RECs by over 7 in some cases.  The study highlights the need to install and maintain the integrity of appropriate pipe insulation on solar water heaters over their life time in Australia and New Zealand.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This talk explores a new opportunity renewable energy technology has for society.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Analytical and closed form solutions are presented in this paper for the vibration response of an L-shaped plate under a point force or a moment excitation. Inter-relationships between wave components of the source and the receiving plates are clearly defined. Explicit expressions are given for the quadratic quantities such as input power, energy flow and kinetic energy distributions of the L-shaped plate. Applications of statistical energy analysis (SEA) formulation in the prediction of the vibration response of finite coupled plate structures under a single deterministic forcing are examined and quantified. It is found that the SEA method can be employed to predict the frequency averaged vibration response and energy flow of coupled plate structures under a deterministic force or moment excitation when the structural system satisfies the following conditions: (1) the coupling loss factors of the coupled subsystems are known; (2) the source location is more than a quarter of the plate bending wavelength away from the source plate edges in the point force excitation case, or is more than a quarter wavelength away from the pair of source plate edges perpendicular to the moment axis in the moment excitation case due to the directional characteristic of moment excitations. SEA overestimates the response of the L-shaped plate when the source location is less than a quarter bending wavelength away from the respective plate edges owing to wave coherence effect at the plate boundary

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This paper addresses the tradeoff between energy consumption and localization performance in a mobile sensor network application. The focus is on augmenting GPS location with more energy-efficient location sensors to bound position estimate uncertainty in order to prolong node lifetime. We use empirical GPS and radio contact data from a largescale animal tracking deployment to model node mobility, GPS and radio performance. These models are used to explore duty cycling strategies for maintaining position uncertainty within specified bounds. We then explore the benefits of using short-range radio contact logging alongside GPS as an energy-inexpensive means of lowering uncertainty while the GPS is off, and we propose a versatile contact logging strategy that relies on RSSI ranging and GPS lock back-offs for reducing the node energy consumption relative to GPS duty cycling. Results show that our strategy can cut the node energy consumption by half while meeting application specific positioning criteria.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Background Energy conserving processes reported in undernourished women during pregnancy are a recognised strategy to provide energy required to support fetal development. Women who are obese before conceiving arguably have sufficient fat stores to support the energy demands of pregnancy without the need to provoke energy conserving mechanisms. Objective We tested the hypothesis that obese women would demonstrate behavioural adaptation (i.e. decrease in self-selected walking (SSW) speed) but not metabolic compensation (i.e. decrease in resting metabolic rate (RMR) or metabolic cost of walking) during gestation. Design RMR, SSW speed, metabolic cost of walking, and anthropometry were measured in 23 women (BMI: 33.6 ± 2.5 kg/m2; 31 ± 4 years) at approximately weeks 15 (wk 15) and 30 (wk 30) of gestation. RMR was also measured in two cohorts of non-pregnant controls matched for age, weight and height of the pregnant cohort at wk 15 (N=23) and wk 30 (N=23). Results GWG varied widely (11.3 ± 5.4 kg) and 52% of women gained more weight than is recommended. RMR increased significantly by an average 177 ± 176 kcal/d (11±12%; P<0.0001); however the within-group variability was large. Both the metabolic cost of walking and SSW speed decreased significantly (P<0.01). While RMR increased in >80% of the cohort, the net oxygen cost of walking decreased in the same proportion of women. Conclusions While the increase in RMR was greater than was explained by weight gain, there was evidence of both behavioural and biological compensation in the metabolic cost of walking in obese women during gestation.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Green energy is one of the key factors, driving down electricity bill and zero carbon emission generating electricity to green building. However, the climate change and environmental policies are accelerating people to use renewable energy instead of coal-fired (convention type) energy for green building that energy is not environmental friendly. Therefore, solar energy is one of the clean energy solving environmental impact and paying less in electricity fee. The method of solar energy is collecting sun from solar array and saves in battery from which provides necessary electricity to whole house with zero carbon emission. However, in the market a lot of solar arrays suppliers, the aims of this paper attempted to use superiority and inferiority multi-criteria ranking (SIR) method with 13 constraints establishing I-flows and S-flows matrices to evaluate four alternatives solar energies and determining which alternative is the best, providing power to sustainable building. Furthermore, SIR is well-known structured approach of multi-criteria decision support tools and gradually used in construction and building. The outcome of this paper significantly gives an indication to user selecting solar energy.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The paper presents a demand side response scheme,which assists electricity consumers to proactively control own demands in such a way to deliberately avert congestion periods on the electrical network. The scheme allows shifting loads from peak to low demand periods in an attempt to flattening the national electricity requirement. The scheme can be concurrently used to accommodate the utilization of renewable energy sources,that might be available at user’s premises. In addition the scheme allows a full-capacity utilization of the available electrical infrastructure by organizing a wide-use of electric vehicles. The scheme is applicable in the Eastern and Southern States of Australia managed by the Australian Energy Market Operator. The results indicate the potential of the scheme to achieve energy savings and release capacity to accommodate renewable energy and electrical vehicle technologies.