Página 3 dos resultados de 476117 itens digitais encontrados em 0.100 segundos

‣ Energy Production System Management – Renewable Energy Power Supply Integration with Building Automation System

Figueiredo, Joao; Martins, Joao
Fonte: Energy Conversion and Management, Elsevier Publicador: Energy Conversion and Management, Elsevier
Tipo: Artigo de Revista Científica
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Intelligent buildings, historically and technologically, refers to the integration of four distinctive systems: Building Automation Systems (BAS), Telecommunication Systems, Office Automation Systems and Computer Building Management Systems. The increasing sophisticated BAS has become the “heart and soul” of modern intelligent buildings. Integrating energy supply and demand elements – often known as Demand-Side Management (DSM) – has became an important energy efficiency policy concept. Nowadays, European countries have diversified their power supplies, reducing the dependence on OPEC, and developing a broader mix of energy sources maximizing the use of renewable energy domestic sources. In this way it makes sense to include a fifth system into the intelligent building group: Energy Production System Management (EPSM). This paper presents a Building Automation System where the Demand-Side Management is fully integrated with the building’s Energy Production System, which incorporates a complete set of renewable energy production and storage systems.

‣ Heat loss by the Earth, geothermal energy and geothermal Heat pumps

Duque, Maria Rosa
Fonte: 4th International Congress on Energy and Environment Engineering and Management Publicador: 4th International Congress on Energy and Environment Engineering and Management
Tipo: Artigo de Revista Científica
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Geothermal energy is often labeled as renewable and sustainable. It is listed together with solar, wind and biomass as alternative energy options in governmental R& D programs. The temperature in the Earth’s interior increases with depth. This fact is responsible for the heat flow, from the interior to the surface. Heat loss through the Earth was calculated using heat flow density values obtained in continents and oceans. The result obtained [1] for the total heat loss is 46± 2 TW. Heat loss through continents is 14 TW. The direct use of geothermal energy dates back thousands of years when people began using hot springs for bathing and cooking. Today, geothermal energy can be used to generate electricity or directly in many applications. Worldwide direct utilizations of geothermal energy in 2005 was [2] 273372TJ/year, of which 32% were obtained through geothermal heat pumps. At this time, the equivalent annual savings in fuel oil amounts to 170 million barrels and 24 million tons in carbon emissions to the atmosphere. Since 2005, the use of geothermal heat pumps has been wide in both residential and commercial buildings, due to the attractive advantages of high efficiency and environmental friendliness. Geothermal heat pumps are similar to ordinary heat pumps...

‣ Energy conservation: a case study for a large manufacturing plant

Felton, Lewis Allen; Glicksman, Leon R.
Fonte: MIT Energy Lab Publicador: MIT Energy Lab
Tipo: Relatório Formato: 4079287 bytes; application/pdf
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The methods of formulating, implementing, and evaluating a conservation program in a commercial building or light industrial plant are examined in this paper. The results of one case study are also presented. In commercial and light industrial applications, most energy is consumed to maintain proper environmental conditions; light levels, heat levels, and fresh air levels. Most buildings today expend too much energy on these services. A co-ordinated program to maintain environmental conditions at levels pointed out in this report could save as mu h as 20% each year in energy consumption. This report presents a method that can be used by many commercial and light industrial concerns to establish a conservation program. Guidelines are presented that can be used to examine environmental conditions and determine how they must be changed. A system of program analysis is also presented. Results of this study show that saving 20% is possible, but motivation of the company and workforce will be a problem. The report also concludes that new buildings can be made more energy efficient if energy conservation is kept in mind during building design.

‣ Application of sector and location specific models of the "worth" of renewable energy technologies

Tabors, Richard D
Fonte: Massachusetts Institute of Technology. Energy Laboratory Publicador: Massachusetts Institute of Technology. Energy Laboratory
Tipo: Trabalho em Andamento Formato: 1194499 bytes; application/pdf
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Renewable energy sources such as solar and wind hold the potential for providing a significant portion of the U.S. energy requirements in the decades ahead. Unlike other energy sources their availability is determined by nonrandom events beyond the control of the consumer. In addition, macro-, meso-, and microclimatic conditions play a major role in determining the worth of such renewable energy sources to their owners. The worth of these new technologies will be a function of owner, location, and application as well as the traditional capital and operating cost, i.e., their worth to an owner in the southwest will be different form that to an owner in the northeast or the southeast. Dealing with energy sources, with geographic and sectorally specific energy values and with energy technologies with which we have little or no experience in the marketplace has created a set of challenges in analysis and modeling of these new technologies in competition with traditional energy technologies and with other emerging technologies. This paper will look at one simulation methodology for estimating the worth of renewable energy systems providing electricity, such as wind or solar photovoltaic power systems, and will discuss the interaction between such systems and traditional electric utilities with which they may or may not be integrated...

‣ Energy prices and the adoption of energy-saving technology

Linn, Joshua
Fonte: MIT Center for Energy and Environmental Policy Research Publicador: MIT Center for Energy and Environmental Policy Research
Tipo: Trabalho em Andamento Formato: 30, [11]
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This paper investigates the link between factor prices, technology and factor demands. I estimate the effect of price-induced technology adoption on energy demand in the U.S. manufacturing sector, using plant data from the Census of Manufactures, 1963-1997. I compare the energy efficiency of entrants and incumbents to measure the effect of technology adoption on the demand for energy. A 10 percent increase in the price of energy causes technology adoption that reduces the energy demand of entrants by 1 percent. This elasticity has two implications: first, technology adoption explains a statistically significant but relatively small fraction of changes in energy demand in the 1970s and 1980s; and second, technology adoption can reduce the long run effect of energy prices on growth, but by less than previous research has found.

‣ Planning Energy Efficient and Livable Cities

Energy Sector Management Assistance Program
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Tipo: Publications & Research; Publications & Research :: ESMAP Paper
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The world's urban population is expected to increase by about 2.7 billion by 2050.Virtually all of the increased population will be in developing countries, leading to massive needs for new and improved housing and urban infrastructures (UNDESA 2012). The planning and design of these new developments will reshape or create new urban landscapes with significant implications for energy consumption, infrastructure costs, as well as the livability and social and economic resilience of cities. Studies of cities around the world indicate that a city's livability and its level of energy use are closely linked to its physical form, namely the spatial distribution and dimensions of buildings, streets, and parks, as well as the spatial coordination of residences, jobs, social services, and environmental amenities.

‣ Final report on energy, supply, demand/need and the gaps between : to the M.W. Kellogg Co., Houston, Texas and the Environmental Protection Agency under Task 27 of EPA Contract 8-01-1308

Meyer, James Wagner; Jones, William J.; Kessler, Myer M.
Fonte: MIT Energy Lab Publicador: MIT Energy Lab
Tipo: Relatório Formato: 14502067 bytes; 4493381 bytes; application/pdf; application/pdf
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This paper is a summary, based on a critical review of selected literature pertaining to energy supply, demand, supply/ demand imbalances and the operational/technological developments needed to redress imbalances. Crises have been a recurrent feature of man's history. There was a crisis based on a shortage of wood fuel in the early 17th century. Whale oil was so short during the Civil War that the price doubled, yet it then dropped by a factor of six before the end of the century as kerosene became an alternate option. Energy demand growth soared in the U.S. over the last two decades not because of need but because real energy prices dropped. Energy was substituted for labor and material which were costing more. Now we have materials as well as energy shortages and massive unemployment. There is little agreement regarding our future supply of fossil fuels and no consensus on the best way to reduce demand. History tells us that the imbalance will be resolved. It is our task to make sure that the resolution occurs with the lowest possible social and environmental cost. Price can resolve the imbalance, but because price dbes not often reflect all costs this resolution can be very disruptive. Alternatives must be developed and options broadened. Opportunities for conservation should not be overlooked for the marginal barrel of oil saved is of greater value than the marginal barrel of new production. A series of working papers and monographs which discuss certain aspects of this review more broadly are included in Volume II of this report.; Environmental Protection Agency of United States and M.W. Kellogg Company

‣ Large Synoptic Survey Telescope: Dark Energy Science Collaboration

LSST Dark Energy Science Collaboration
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 01/11/2012 Português
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This white paper describes the LSST Dark Energy Science Collaboration (DESC), whose goal is the study of dark energy and related topics in fundamental physics with data from the Large Synoptic Survey Telescope (LSST). It provides an overview of dark energy science and describes the current and anticipated state of the field. It makes the case for the DESC by laying out a robust analytical framework for dark energy science that has been defined by its members and the comprehensive three-year work plan they have developed for implementing that framework. The analysis working groups cover five key probes of dark energy: weak lensing, large scale structure, galaxy clusters, Type Ia supernovae, and strong lensing. The computing working groups span cosmological simulations, galaxy catalogs, photon simulations and a systematic software and computational framework for LSST dark energy data analysis. The technical working groups make the connection between dark energy science and the LSST system. The working groups have close linkages, especially through the use of the photon simulations to study the impact of instrument design and survey strategy on analysis methodology and cosmological parameter estimation. The white paper describes several high priority tasks identified by each of the 16 working groups. Over the next three years these tasks will help prepare for LSST analysis...

‣ Evaluation of the LEP Centre-of-Mass Energy Above the W-Pair Production Threshold

Hildreth, Michael D.; Group, for the LEP Energy Working
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 01/10/1998 Português
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Knowledge of the beam energy at LEP2 is of primary importance to set the absolute energy scale for the measurement of the W-boson mass. The beam energy above 80 GeV is derived from continuous measurements of the magnetic bending field by 16 NMR probes situated in a number of the LEP dipoles. The relationship between the fields measured by the probes and the beam energy is calibrated against precise measurements of the average beam energy between 41 and 55 GeV made using the resonant depolarisation technique. The linearity of the relationship is tested by comparing the fields measured by the probes with the total bending field measured by a flux loop. Several further corrections are applied to derive the the centre-of-mass energies at each interaction point. The beam energy has been determined with a precision of 25 MeV for the data taken in 1997, corresponding to a relative precision of 2.7x 10^{-4}. Prospects for improvements are outlined.; Comment: 5 pages, 3 figures, Latex, epsfig; to be published in proceedings of the "International Conference on High Energy Physics (ICHEP98)", Vancouver, BC, 23-29 July 1998

‣ Evaluation of the LEP Centre-of-Mass Energy Above the W-Pair Production Threshold

The LEP Energy Working Group
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
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Knowledge of the centre-of-mass energy at LEP2 is of primary importance to set the absolute energy scale for the measurement of the W-boson mass. The beam energy above 80 GeV is derived from continuous measurements of the magnetic bending field by 16 NMR probes situated in a number of the LEP dipoles. The relationship between the fields measured by the probes and the beam energy is calibrated against precise measurements of the average beam energy between 41 and 55 GeV made using the resonant depolarisation technique. The linearity of the relationship is tested by comparing the fields measured by the probes with the total bending field measured by a flux loop. This test results in the largest contribution to the systematic uncertainty. Several further corrections are applied to derive the the centre-of-mass energies at each interaction point. In addition the centre-of-mass energy spread is evaluated. The beam energy has been determined with a precision of 25 MeV for the data taken in 1997, corresponding to a relative precision of 2.7x10^{-4}. This is small in comparison to the present uncertainty on the W mass measurement at LEP. However, the ultimate statistical precision on the W mass with the full LEP2 data sample should be around 25 MeV...

‣ Comparing performance of MLP and RBF neural network models for predicting South Africa's energy consumption

Oludolapo,Olanrewaju A; Jimoh,Adisa A; Kholopane,Pule A
Fonte: Journal of Energy in Southern Africa Publicador: Journal of Energy in Southern Africa
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2012 Português
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In view of the close association between energy and economic growth, South Africa's aspirations for higher growth, more energy is required; formulating a long-term economic development plan and implementing an energy strategy for a country /industry necessitates establishing the correct relationship between energy and the economy. As insufficient energy or a lack thereof is reported to be a major cause of social and economic poverty, it is very important to select a model to forecast the consumption of energy reasonably accurately. This study presents techniques based on the development of multilayer perceptron (MLP) and radial basis function (RBF) of artificial neural network (ANN) models, for calculating the energy consumption of South Africa's industrial sector between 1993 and 2000. The approach examines the energy consumption in relation to the gross domestic product. The results indicate a strong agreement between model predictions and observed values, since the mean absolute percentage error is below 5%. When performance indices are compared, the RBF-based model is a more accurate predictor than the MLP model.

‣ Energy management of commercial buildings - A case study from a POET perspective of energy efficiency

Xia,Xiaohua; Zhang,Jiangfeng; Cass,William
Fonte: Journal of Energy in Southern Africa Publicador: Journal of Energy in Southern Africa
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2012 Português
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This paper aims at analyzing the energy management activities for commercial buildings of a financial service company in South Africa by energy efficiency in terms of performance, operation, equipment and technology (POET). The sustainability of a general energy management program is discussed within this POET framework. As an application of this discussion to the commercial building scenario, the award winning energy management program of this financial service group company is featured from the POET perspective of energy efficiency. The case study shows that the POET based framework can not only cover all major energy management activities, but also identify further energy efficiency improvement opportunities.

‣ Energy consumption and economic growth nexus: Panel co-integration and causality tests for Sub-Saharan Africa

Fatai,Basiru Oyeniran
Fonte: Journal of Energy in Southern Africa Publicador: Journal of Energy in Southern Africa
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/11/2014 Português
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This study reassesses the causal relationships between energy consumption and economic growth in 18 Sub-Saharan Africa countries over the period 1980-2011. The Panel Unit Root Test results show that variables (both exogenous and endogenous) are stationary at their first difference with individual effects and individual linear trends, while the results of panel co-integration tests show that energy consumption and economic growth do have a stable long-run equilibrium relationship. There is unidirectional causality from energy consumption to economic growth in East and the Southern Africa Sub-region, which supports the growth hypothesis. As a result, the related authorities in the regions should take a special interest in different sources of energy and invest more in this sector, make suitable policies in this regard and find new alternative and cheap sources of energy. But, there is no causality between energy consumption and economic growth in Central and the West Africa Sub-region, which is in line with the neutrality hypothesis. In other words, both energy consumption and economic growth are neutral with respect to each other. Our results confirm the inconclusive nature of a causality relationship between energy consumption and economic growth.

‣ Electrical performance results of an energy efficient building with an integrated photovoltaic system

Ziuku,Sosten; Meyer,Edson L.
Fonte: Journal of Energy in Southern Africa Publicador: Journal of Energy in Southern Africa
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2010 Português
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A 3.8 kW rooftop photovoltaic generator has been installed on an energy efficient house built at the University of Fort Hare, Alice campus, South Africa. The system, located on the north facing roof, started generating electrical power in February 2009. In addition to providing electrical energy, the photovoltaic panels also act as the building roofing material. An instrumentation and data acquisition system was installed to record the indoor and outdoor ambient temperature, indoor and outdoor relative humidity, wind speed and direction, solar irradi-ance, electrical energy produced by the solar panels and the household energy consumption. This paper presents the initial results of the electrical performance of the building integrated photovoltaics (BIPV) generator and energy consumption patterns in the energy efficient house.

‣ Modelling energy supply options for electricity generations in Tanzania

Kichonge,Baraka; John,Geoffrey R; Mkilaha,Iddi S N
Fonte: Journal of Energy in Southern Africa Publicador: Journal of Energy in Southern Africa
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2015 Português
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The current study applies an energy-system model to explore energy supply options in meeting Tanzania's electricity demands projection from 2010 to 2040. Three economic scenarios namely; business as usual (BAU), low economic consumption scenario (LEC) and high economic growth scenario (HEC) were developed for modelling purposes. Moreover, the study develops a dry weather scenario to explore how the country's electricity system would behave under dry weather conditions. The model results suggests: If projected final electricity demand increases as anticipated in BAU, LEC and HEC scenarios, the total installed capacity will expand at 9.05%, 8.46% and 9.8% respectively from the base value of 804.2MW. Correspondingly, the model results depict dominance of hydro, coal, natural gas and geothermal as least-cost energy supply options for electricity generation in all scenarios. The alternative dry weather scenario formulated to study electricity system behaviour under uncertain weather conditions suggested a shift of energy supply option to coal and natural gas (NG) dominance replacing hydro energy. The least cost optimization results further depict an insignificant contribution of renewable energy technologies in terms of solar thermal, wind and solar PV into the total generation shares. With that regard...

‣ Harnessing Nigeria's abundant solar energy potential using the DESERTEC model

Akuru,Udochukwu B; Okoro,Ogbonnaya I; Maduko,Chibuike F
Fonte: Journal of Energy in Southern Africa Publicador: Journal of Energy in Southern Africa
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2015 Português
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The DESERTEC project, a European Union (EU) initiative to harness solar energy by means of Concentrated Solar Power (CSP) from Africa for use in Europe, shows the enormous potential that exists in alternative energy sources for the sub-region once there is political will. The Trans-Mediterranean Renewable Energy Corporation (TREC), a network of scientists and politicians who have taken it upon themselves to solve Europe's energy problem using sun from Africa, conducted three studies which evaluated the potential of renewable energy resources in the Middle East and North Africa (MENA), the expected needs for water and power in EU-MENA between now and 2050 and issues relating to the construction of an electricity transmission grid connecting the EU and MENA (EU-MENA-Connection), with a formula to turn the North African desert sun into electricity and transport same to Europe. This paper harnesses the TREC fact-finding studies in order to estimate how much the same ideas can be applied in many other parts of the world, Nigeria in particular. Investigation reveals that this association exists with huge potentials for an energy-starved country like Nigeria in harnessing her abundant hot sun in the north, which could go a long way in meeting the energy needs in that part of the country and beyond. Other benefits include unlimited supplies of clean electricity...

‣ Impact of renewable energy deployment on climate change in Nigeria

Akuru,Udochukwu B; Okoro,Ogbonnaya I; Chikuni,Edward
Fonte: Journal of Energy in Southern Africa Publicador: Journal of Energy in Southern Africa
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2015 Português
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It is well known fact that the rate of industrial growth of any country is a function of the amount of energy available in that country and the extent to which this energy is utilized. The burning of fossil fuels to generate energy is a dirty process. Greenhouse gas (GHG) emissions result when fossil fuels are produced and consumed and these emissions contribute to climate change. Nigeria as a country is highly vulnerable to the impacts of climate change because its economy is mainly dependent on income generated from the production, processing, export and/or consumption of fossil fuels and its associated energy-intensive products. Hence, it is on this premise that this paper is researched to review the energy sources being used in Nigeria and investigate its impact to climate change. Findings reveal Nigeria's over-dependence on fossil-generated energy with associated adverse environmental effects, among other things. Recommendations for the integration of renewable energy into Nigeria's energy mix, beyond other measures, have been offered, especially with reference to the salient environmental benefits that accrue to it.

‣ An energy system planning model for the industrial sector in Nigeria

Njoku,PC
Fonte: Journal of Energy in Southern Africa Publicador: Journal of Energy in Southern Africa
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2008 Português
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This paper reports the energy system modelling projection in the industrial sector of Nigeria. It is carried out to provide a long term perspective on the Scenario buildings for the industrial energy system of Nigeria. The projections have inter-sectoral consistency only to the extent those of the Federal Republic of Nigeria have to the inter-industrial linkages, which are no doubt important. However, it appears that input-output tables have not been instructed and regularly impeded and expanded as part of the planning scenarios that have been generated on the contested demand, which is to assume constant energy intensity in future years. The basis for projecting energy demand in the industrial sector is to estimate the likely changes in energy consumption intensity and the ratio of energy consumption to value added. It is considered expedient and pragmatic to use a scenario for constructing an optimal level forecast, projecting a desirable energy equilibrium pattern for the year 2010.

‣ SADC's response to climate change - the role of harmonised law and policy on mitigation in the energy sector

Barnard,M
Fonte: Journal of Energy in Southern Africa Publicador: Journal of Energy in Southern Africa
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2014 Português
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The negligible levels of energy-related GHG emissions attributable to the Southern African sub-region translates into the sub-region contributing relatively little towards global climate change. Notwithstanding, the member states comprising the Southern African Development Community (SADC) are among the most vulnerable to the trans boundary effects of global climate change. Existing SADC climate change policy documents highlight the important role of the energy sector in climate change mitigation. Furthermore, various international, African Union and SADC legal instruments stress the crucial role of harmonised law and policy as climate change adaptive measure. It is the central hypothesis of this paper that harmonised sub-regional law and policy aimed at regulating SADC member states' mitigation efforts in the energy sector is a crucial climate change adaptive strategy. This hypothesis is based on the mandates for the formulation of a SADC climate change action plan and for mitigation in the energy sector. These mandates are contained in the texts of the SADC-CNGO Climate Change Agenda, 2012 and the Southern Africa Sub - Regional Framework on Climate Change, 2010 respectively. It is the main aim of this paper to investigate recent developments in the formulation of harmonised SADC law and policy on climate change in general and law and policy pertaining to mitigation in the energy sector specifically. In achieving the stated aim...

‣ Solar water heater contribution to energy savings in higher education institutions: Impact analysis

Popoola,Olawale M; Burnier,Clément
Fonte: Journal of Energy in Southern Africa Publicador: Journal of Energy in Southern Africa
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2014 Português
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This paper focuses on the impact of Solar Water Heaters (SWH) at a higher institution of learning. An energy audit was conducted for the evaluation of the energy conservation measure: energy conoduction Energy is a key element in the development of any country or institution; as a result any shortage in energy will have a serious effect on the economy and social aspect of such country or institution. South Africa has, in recent years, experienced high economic growth as well as a rapid expansion in the elsumption analysis, correlation of consumption with weather; financial criteria, payback period and needed solar heater system (SWH) to determine the energy that may be termed as wastage or can be saved. The method of investigation includes assessment of the hot water usage within the institution campus and residencies, analysis of bills, metering and development of a software model for the analysis of energy use, system needed and environmental variables. This renewable measure (SWH) showed a high potential of energy and financial savings for higher education institutions especially those with residences