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Abstract: This is the first research paper on data center from Finland. The objectives of this study are to evaluate air management and energy performance of cooling system and investigate the possibilities of energy saving and reuse in the data center. Field measurements, particularly for long term''s IT and facility powers, were conducted. Different performance metrics for the cooling system and power consumption were examined and analysed. Key problem areas and energy saving opportunities were identified. The electrical end use breakdown was estimated. Results show that IT equipment intake conditions were within the recommended or allowable ranges from ASHRAE. The Power Usage Effectiveness (PUE) value for a typical year was about 1.33. Noticeable recirculation of hot air was not observed, but extreme bypass air was found. The air change rate was set much bigger than the recommended ASHRAE''s value. There was no heat recovery system. The air management and heat recovery issues therefore need to be addressed. Fan speeds (Computer Room Air-Conditioning Unit) should be reduced and the ventilation rate should be minimized. Further, a simulated heat recovery system was presented demonstrating that the data center could potentially provide yearly space and hot water heating for 30,916m2 non-domestic building. [Copyright &y& Elsevier]

Abstract: Energy saving estimation model (ESEM) use normal distribution (Gaussian) probability theory to predict potential savings for previously determined system improvements. Those improvements are low/high cost investments based on data gathered during one year monitoring of typical hypermarket facility HVAC system. The consumption of electrical energy and natural gas has been monitored and system segments with largest amount of energy consumption have been marked. Gathered data pointed out to fan units as the biggest energy consumers and suggested that system energy-saving improvement must be focused on fans energy consumption control. This paper deals with ESEM inputs and outputs in order to provide correct financial estimation of specific investment. [Copyright &y& Elsevier]

Abstract: In this paper an energy balance and a greenhouse gas profile has been formulated for the county of Wexford, situated in the south east of Ireland. The energy balance aims to aggregate all energy consumption in the county for the year 2006 across the following sectors; residential, agriculture, commerce and industry, and transport. The results of the energy balance are compared with the previous energy balance of 2001 where it is found that the residential sector is the biggest emitter of CO2 with 38% of total emissions with the transport and industry/commerce sectors sharing second place on 28%. Consumption of oil is seen to have increased significantly in nearly all sectors, accounting for over 70% of the total final energy consumed (TFC) while the total primary energy requirement (TPER) sees oil consumption accounting for 91% of all fuels consumed. To take into account the contribution of agriculture in total GHG emissions the gases CH4 and N2O will be estimated from the agricultural and waste sectors. The results show that methane contributes 25% of total GHG emissions with agriculture being the primary contributor accounting for 36% of total emissions. [Copyright &y& Elsevier]

Abstract: Numerical simulations are essential to the understanding of the long-term geological storage of CO2. Physical modelling of geological storage of CO2 has been based on Darcy’s law, together with the equations of conservation of mass and energy. Modelling and simulations can be used to predict where CO2 is likely to flow, to interpret the volume and spatial distribution of CO2 under storage conditions, and to optimise injection operations. The state of the art of physical modelling and numerical simulation of CO2 dispersion is briefly reviewed in this paper, which calls for more accurate and more efficient modelling approaches. A systematic evaluation of the numerical methods used and a comparison between the streamline based methods and the grid based methods would be valuable. Multi-scale modelling may prove to be of great value in predicting the long-term geological storage of CO2, while highly accurate numerical methods such as high-order schemes may be employed in numerical simulations of CO2 dispersion for local transport calculations. [Copyright &y& Elsevier]

Abstract: Window design, especially glazing choices, is a critical factor for determining the effectiveness of passive solar design. Windows are like a knife has two side; one is useful and the other is harmful. In this paper the effects of windows’U-value, window orientation and windows size on annual heating and cooling energy demand is studied considering the both energy and investment costs. The study has been performed for three different climate zones; Amman, Aqaba and Berlin. Four types of windows have been studied; single glazed, double glazed L, double glazed H and triple glazed. The results show that heating load is highly sensitive to windows size and type as compared with cooling load. Also, it is shown that with a well-optimized glazed window energy saving can be reached up to 21%, 20% and 24% for Amman, Aqaba and Berlin, respectively. [Copyright &y& Elsevier]

Abstract: Numerous studies have focused on improving energy efficiency in commercial buildings. Engineers and researchers have developed complex methods to improve energy efficiency, but buildings are often managed by non-specialised technicians who need understandable and cost-effective actions to implement in their buildings. This paper presents basic actions on which to base improvements in energy efficiency in commercial buildings in operation. Furthermore, obtained results and details of the implementation of these techniques in various buildings in the Universitat Politècnica de València are presented. [Copyright &y& Elsevier]

Abstract: Energy saving methods can be employed to reduce energy consumption in buildings, or improve indoor thermal conditions. An example of those methods is the use of permeable coverings, but there are other important parameters like thermal inertia. To understand and predict these energy saving procedures, one may employ different software resources. In the present paper a review of existing software resources is carried out, and, as a consequence of this review, HAM tools were selected to simulate the indoor environment of school buildings. Results show that parameters like thermal inertia can interfere in the solar heat gains, changing the building time constant. Other parameters, like air changes per hour or the use of permeable coverings, present a clear enhancement of indoor environment conditions. [Copyright &y& Elsevier]

Abstract: Improvements in energy efficiency of electrical equipment reduce the greenhouse gas (GHG) emissions and contribute to the protection of the environment. Moreover, as system investment and energy costs continue to increase, electric utilities are increasingly interested in installing energy-efficient transformers at their distribution networks. This paper analyzes the impact of the environmental cost of transformer losses on the economic evaluation of distribution transformers. This environmental cost is coming form the cost to buy GHG emission credits because of the GHG emissions associated with supplying transformer losses throughout the transformer lifetime. Application results on the Hellenic power system for 21 transformer offers under 9 different scenarios indicate that the environmental cost of transformer losses can reach on average 34% and 8% of transformer purchasing price for high loss and medium loss transformers, respectively. That is why it is important to incorporate the environmental cost of transformer losses into the economic evaluation of distribution transformers. [Copyright &y& Elsevier]

Abstract: In the cold climate of continental Europe the correction of thermal bridges in buildings is a mandatory issue, as in these areas they produce not only heat losses but frequently also condensation and mould growth. In mild Mediterranean climate thermal bridges also cause an increase in energy consumption, but usually do not present condensation effects. In Italy, the current regulations for new buildings only recommend but do not impose the thermal bridge correction, which usually needs extra costs during construction and refurbishment phases. This paper presents a study on the effects of thermal bridges for two building types (terraced houses and semi-detached houses) and three current envelope solutions in Italian climate, which may be considered representative of mild Mediterranean climate. The buildings are characterised by reinforced concrete frameworks and clay block walls; the thermal performance of the envelopes complies with Italian regulations for new constructions. In a first step the impact of thermal bridges on both heating and cooling energy demand is studied; then the economic convenience of correcting such thermal bridges is assessed by calculating the discounted payback period referred to the additional costs of construction and refurbishment. [Copyright &y& Elsevier]

Abstract: The purpose of this paper is to investigate the reasons for ever growing energy consumption in buildings and to give enhanced supervision strategies for reduction of building energy consumption compared to regular ones. A case study of Ningbo city was used to make a detail analysis. Several factors were determined as the reasons for ever growing building energy consumption including climate change, household electricity load increase, the growth of real estate, fast-growing household electrical appliances, high energy consumption in existing buildings, changes in industrial structure and the lack of enhanced government supervision. Then the discussion of suitable countermeasures shows that only enhanced supervision strategies are currently applicable. Finally, it is concluded that enhanced government supervision strategies, including the establishment of a strict control system for new built buildings through information integration and encryption, establishing an energy efficiency supervision system of large-scale public building and a carrot-and-stick approach with added expert checklist for the building application of renewable energy, showed great advantages in promoting building energy efficiency in Ningbo, compared with other cities. These supervision strategies are applicable in other cities as they are in the similar situations in the enforcement of building energy efficiency. [Copyright &y& Elsevier]

Abstract: This paper proposed a new solar assisted air source heat pump system with flexible operational modes to improve the performance of the heating system. A mathematical model was established on the solar assisted air source heat pump system for building heating with a heating capacity of 10kW, and an air source heat pump unit was developed to validate the model. The effect of the solar collector area on the performance of the system running in Nanjing was studied. The results showed that the COP of the heat pump unit was enhanced with the increase of the solar radiation density during the typical sunny day in the heating season. In addition, the COP also increased in proportion to the solar collector area. Compared with the case when the solar collector area was 0m2, the COP increase of the heat pump and the energy-saving rate were 11.22% and 24% respectively when the solar collector area was 40m2. Meanwhile, the solar equivalent generation power efficiency could reach 11.8%. [Copyright &y& Elsevier]

Abstract: Electric lighting consumes 19% of total electricity production worldwide. Open-plan offices constitute the majority of office stock, in which most office workers perform their daily tasks, and hence the lighting in those offices has significant impact on, not only energy usage, but also occupants’ productivity. This paper presents a unique lighting optimization approach for open-plan offices that is capable of tuning task lighting to each occupant''s preference in the most energy-efficient fashion. Exploiting individual controllability of the advanced networked lighting systems, each luminaire can be dynamically actuated at a different level to realize various lighting configurations without any physical rewiring. This research formulates lighting actuation into a linear programming problem and finds the optimal light outputs for each of the luminaires that collaboratively deliver specified lighting to each workstation while using the least amount of energy. Simulations using our lighting optimization approach have shown its versatility in providing proper workstation-specific task lighting under different requirements compared to business-as-usual practices. Energy savings are generated from tuning the light levels to occupants’ needs as well as keeping unoccupied areas unlit or minimally lit with this approach. [Copyright &y& Elsevier]

Abstract: Energy-efficient and power-aware designs have played important roles in modern computing systems to reduce the power bills for server systems or prolong the lifetime of embedded devices. Moreover, systems with multiple heterogeneous processing units have been widely adopted to enhance the computing capability or reduce the power consumption. This work explores how to synthesize a heterogeneous multiprocessor platform or select processing units with the partitioning of real-time tasks so that the energy consumption is minimized. Given a set of processing unit types, characterized by the power consumption for maintaining activeness and executing jobs, this paper proposes an efficient and effective algorithm to allocate processing units with energy-efficient task partitioning. When the constraint on the numbers of allocated processing units is not specified, we show that the algorithm is with a -approximation factor, in worst cases, for processing unit types with a variety of power consumption models, where n is the number of tasks. The approximation factor is asymptotically optimal for polynomial-time approximation algorithms unless . Moreover, we also present how to deal with specified maximal numbers of allocated processing units to minimize the energy consumption. Simulation results show that the proposed algorithm is effective for energy consumption minimization. [Copyright &y& Elsevier]

Abstract: Time-critical jobs in many real-time applications have more than one feasible interval. Such jobs can be executed in any of their feasible intervals. Given a schedulable set of multiple feasible interval (MFI) jobs, energy can be saved by carefully selecting the executing interval for each job. In this paper, we explore the energy minimization problem for real-time systems in which jobs have more than one feasible interval. The static and dynamic energy management schemes are both investigated to minimize the energy consumption while preserving the system’s feasibility. Focusing on EDF scheduling algorithm, we first study reducing the dynamic power consumption of a single CPU. We show that the static optimal speed assignment problem is NP-Hard and propose a simulated annealing (SA) based approach to solve it. Then, we develop several on-line greedy algorithms to exploit run-time slack by reselecting a job’s executing interval on-the-fly. In addition, a leakage-aware version is discussed to improve the overall energy efficiency. Simulation results show that all proposed schemes achieve significant improvements of energy efficiency while the system remains schedulable. [Copyright &y& Elsevier]

Abstract: Liquid Crystal Display (LCD) technology has evolved and developed over the past decades to replace Cathode Ray Tube (CRT) display technology as the market leader. This is evident, with global market figures for liquid crystal displays surpassing $75 Billion in 2008. Current End-of-Life (EoL) disposal for LCD screens is typically landfill or incineration, this form of disposal restricts the ability to recover potentially reusable materials from waste LCD screens e.g. steel, aluminium, copper etc. Thus to conserve raw materials and to protect the environment it is essential to replace the traditional flow of products from manufacturer to landfill with a recycle and recover approach. While the recycling methods for CRTs are well established, however those of LCDs are as yet in their infancy. However to reduce consumption of natural resources and reduce quantities of waste going to landfill, recycling process must be encouraged and developed. This paper aims to address the challenges facing EoL treatment of LCD units by analysing LCD build types, structures and component material to establish traits which may make EoL treatment less of a challenge. Analysing this data will lay the foundation to developing a balanced recovery system meeting the needs of economic viability and environmental conservation in future work. [Copyright &y& Elsevier]

Abstract: The purpose of this paper is to identify the relations between transportation energy consumption and its impacted factors. We first analyze the current status of transportation energy consumption in China. Then, the logarithmic mean Divisia index (LMDI) technique is used to find the nature of the factors those influence the changes in transportation energy consumption. We find that: (1) In 2006, the transportation energy consumption increased by 7.63 times against that in 1980. (2) Up to 2006, the oil consumed by transportation accounted for 49.6% of that in the whole country, which almost equaled to the net oil import. (3) In the light of the increasing energy consumption intensity, the energy-utilization effectiveness of transportation sector has been declining gradually. (4) The transportation activity effect is the most important contributor to increase energy consumption in the transportation sector and the energy intensity effect plays the dominant role in decreasing energy consumption. [Copyright &y& Elsevier]

Abstract: Energy performance of non-residential buildings and in particular of office buildings used as bank branches is very limited. This paper presents new data from 39 representative bank branches and results from a more in-depth analysis of information from energy audits in 11 typical bank branches throughout Greece. The data was used to derive practical energy benchmarks and assess various energy conservation measures. Accordingly, the average annual total energy consumption is 345kWh/m2. The breakdown of the different end-uses reveals that HVAC averages 48% of the final energy consumption, lighting averages 35% and other office and electronic equipment average 17%. The most effective energy conservation measures reach annual energy savings of 56kWh/m2 by regulating the indoor set point temperature, while the use of HF electronic ballasts and CFL lamps may save about 22kWh/m2 and 29kWh/m2 with and without the use of the external marquee sign, respectively. [Copyright &y& Elsevier]

Abstract: As states in the U.S. adopt new energy codes, it is important to understand the benefits for each state and its building owners. This paper estimates life-cycle energy savings, carbon emission reduction, and cost-effectiveness of conventional energy efficiency measures in new commercial buildings using an integrated design approach. Results are based on 8208 energy simulations for 12 prototypical buildings in 228 cities, with 3 building designs evaluated for each building–location combination. Results are represented by easy-to-understand mappings that allow for regional and state comparisons. The results show that the use of conventional energy efficiency technologies in an integrated design framework can decrease energy use by 15–20% on average in new commercial buildings, and over 35% for some building types and locations. These energy reductions can often be accomplished at negative incremental life-cycle costs and reduce a building''s energy-related carbon footprint by 9–33%. However, generalizing these results on energy use, life-cycle costs, and carbon emissions misses exceptions in the results that show the importance of location-specific characteristics. Also, states do not appear to base energy code adoption decisions on either potential energy savings or life-cycle cost savings. [Copyright &y& Elsevier]

Abstract: Along with high-speed economic development and increasing energy consumption, the Chinese Government faces a growing pressure to maintain the balance between energy supply and demand. In 2009, China has become both the largest energy consumer and CO2 emitting country in the world. In this case, the inappropriate energy consumption structure should be changed. As an alternative, a suitable infrastructure for the implementation of renewable energy may serve as a long-term sustainable solution. The perspective of a 100% renewable energy system has been analyzed and discussed in some countries previously. In this process, assessment of domestic renewable energy sources is the first step. Then appropriate methodologies are needed to perform energy system analyses involving the integration of more sustainable strategies. Denmark may serve as an example of how sustainable strategies can be implemented. The Danish system has demonstrated the possibility of converting into a 100% renewable energy system. This paper discusses the perspective of renewable energy in China firstly, and then analyses whether it is suitable to adopt similar methodologies applied in other countries as China approaches a renewable energy system. The conclusion is that China’s domestic renewable energy sources are abundant and show the possibility to cover future energy demand; the methodologies used to analyse a 100% renewable energy system are applicable in China. Therefore, proposing an analysis of a 100% renewable energy system in China is not unreasonable. [ABSTRACT FROM AUTHOR]

Abstract: One of the central variables in bottom-up energy efficiency and saving calculations is the energy consumption baseline. In the evaluation of energy efficiency measures, developing this baseline is a challenging task, which may involve serious problems, especially if the energy service of the analysed subject has changed while the energy efficiency measure was being implemented. In this paper we present a formalised concept of the process of developing the baseline that is flexible enough to deal with various difficulties, such as changes in the levels of the energy services involved. We also discuss the most relevant options for deriving the necessary variables. [ABSTRACT FROM AUTHOR]

Abstract: School buildings constitute a major part of the non-residential building stock, though due to their operational characteristics, they represent a low percentage of the overall energy balance of the building sector. Although health and productivity of pupils and teachers is strongly affected by the indoor environmental quality of their school, poor indoor air quality has been reported in published literature, even so for recently constructed school buildings. The same applies for the energy consumption, with large amounts of energy being wasted because no energy saving measures are applied for the operation of schools. This paper presents the outcome of a study on the energy performance of Hellenic school buildings. The general features of the contemporary building stock are presented along with the results from an energy survey in 135 Hellenic schools. The derived energy consumption benchmarks are compared with published literature. Finally, the energy performance and indoor environmental quality of a representative sample of schools in metropolitan Athens are assessed in a holistic approach to the “energy efficiency – thermal comfort – indoor air quality” dilemma. The IEQ assessment was based on an objective evaluation by monitoring crucial indoor conditions and a subjective occupant evaluation using standardized questionnaires. The potential of several energy conservation measures is evaluated in terms of energy savings and reduction of greenhouse gas emissions along with the related payback periods. [ABSTRACT FROM AUTHOR]

Abstract: This paper explores the potential of reducing the annual energy consumption of a central air-conditioned building through advanced evaporative cooling systems. The building considered is a typical three floor library building of a University. The regenerative evaporative cooling technology is coupled with the liquid cooled water chiller system to accomplish the energy conservation objective. Comparisons of the regenerative evaporative cooling are made with simple evaporative cooling to bring out the importance such a system. The well-known building simulation software, TRNSYS is used to carry out the heat load calculations and the dynamic simulations of the building. Annual energy consumptions of different components of the air-conditioning system are estimated for the existing water chiller system as well as for both coupled evaporative cooling systems (simple and regenerative). The annual energy consumptions, the indoor temperature, the relative humidity and the thermal comfort index ‘PMV’ are compared for all the three different air-conditioning systems. The coupling of direct and regenerative evaporative cooling technologies with water chiller system has shown, respectively, 12.09% and 15.69% savings in annual energy consumption of the building, while maintaining PMV between −1 and +1 for most of the hours in the year. [ABSTRACT FROM AUTHOR]

Abstract: The energy saving opportunity of supermarket refrigeration systems using subcooler between the medium-temperature (MT) refrigeration system and the low-temperature (LT) refrigeration system has been identified in the previous work. This paper presents a model-based comprehensive analysis on the subcooler design. The optimal subcooling control is discussed as well. With optimal subcooler size and subcooling control, the maximum energy savings of integrated two-temperature supermarket refrigeration system using R404A or R134a as working fluid can achieve 27% or 20%, respectively. The load ratio of MT to LT system and the operating conditions have considerable impact on the energy savings. [ABSTRACT FROM AUTHOR]

Abstract: The impact of natural ventilation of a roof cavity on improvement of the thermal environment and reduction of cooling load of a factory building is discussed. A computer program was developed with the logic in a companion paper to observe the effect of cavity ventilation on the operative temperature of the occupied zone in the factory. Comparisons were made between factories with a cavity roof and a single roof in the Japanese climate. Results showed that the cavity roof was superior to the single roof in lowering the operative temperature by about 4.4°C. When the factory was air conditioned, the cooling load reduction reached approximately 50% during the summer to maintain an operative temperature of 26°C. Results showed that a naturally ventilated cavity roof has excellent potential for improving the indoor thermal environment and energy savings of factory buildings without complicated cooling installations and life time power consumption. [ABSTRACT FROM AUTHOR]

Abstract: This paper develops a bottom-up model of space and water heating energy demand for new build dwellings in the Irish residential sector. This is used to assess the impacts of measures proposed in Ireland''s National Energy Efficiency Action Plan (NEEAP). The impact of the housing construction boom, which resulted in 23% of occupied dwellings in 2008 having been built since 2002, and the subsequent bust, are also assessed. The model structure treats separately new dwellings added to the stock after 2007 and pre-existing occupied dwellings. The former is modelled as a set of archetype dwellings with energy end use affected by the relevant set of building regulations that apply during construction. Energy demand of existing dwellings is predicted by a simpler top down method based on historical energy use trends. The baseline scenario suggests residential energy demand will grow by 19% from 3206ktoe in 2007 to 3810ktoe in 2020. The results indicate that 2008 and 2010 building regulations will lead to energy savings of 305ktoe (8.0%) in 2020. Had the 2008 building regulations been introduced in 2002, at the start of the boom, there would be additional savings of 238ktoe (6.7%) in 2020. [Copyright &y& Elsevier]

Abstract: Energy usage and energy efficiency are of increasing concern in Mexico, electricity generation principally depends upon fossil fuels. On one hand, the stocks of these fuels have been confirmed to be critically limited. On the other hand, in process of electricity generation by means of these fuels, a number of poisonous by-products adversely affect the conservation of natural eco-system. This paper focuses on estimation of energy consumption, energy savings, reduction of emissions of CO2 for use of urban and rural household appliances in Mexico between 1996 and 2021. The analysis concentrates on six major energy end uses in the residential sector: refrigerators, air conditioners, washing machines, TV set, iron and heater. It is estimated that by 2021 there will be a cumulative saving of 22,605GWh, as a result of the implementation of government programs on energy efficiency that represents a cumulative reduction of CO2 emissions of 15,087TgCO2. It means that Mexico can reduce in 5650MW the generation capacity of national electricity system, which is to avoid burning 40.35MM barrels of oil. The findings can be useful to policy makers as well as household appliances users. [ABSTRACT FROM AUTHOR]

Abstract: The paper focuses on investigating thermal-transients effects, associated to intermittent use of internal combustion engine (ICE), on fuel economy and hydrocarbon (HC) emissions of series hybrid solar vehicles (HSVs). An offline, non-linear constrained optimization is set-up to individuate the ICE power trajectory that simultaneously minimizes fuel consumption, suitably operates the battery and fully exploits daily solar contribution. The results highlight the importance of including thermal transients in HSV energy management. The combined effects of engine, generator and battery losses, along with cranking energy and thermal transients, produce non-trivial solutions for the engine/generator group, which should not necessarily operate at its maximum efficiency. [Copyright &y& Elsevier]

Abstract: This paper presents a strategy for a simple demand controlled ventilation system for single family houses where all sensors and controls are located in the air handling unit. The strategy is based on sensing CO2-concentration and moisture content in the outdoor air and exhaust air. The CO2-concentration is used to ensure adequate ventilation during occupancy and the moisture content is used to ensure adequate removal of moisture produced in the house. The ventilation rate can be switched between two flow rates: a high rate and a low rate. The high flow rate is based on existing requirements in the Danish building regulations and the low flow rate is based on minimum requirements in indoor air quality standards. Measurements were performed on an existing single family house where the controls were installed on the existing mechanical ventilation system. The results showed that the ventilation can be reduced to the low rate 37% of the time without significant changes in the CO2-concentration and moisture level in the house. In theory this gives a 35% saving on electric energy for fans. [ABSTRACT FROM AUTHOR]

Abstract: This paper quantifies the theoretical limit of energy consumption for the removal of 20 representative organic contaminants (9 chlorinated alkyl hydrocarbons, 3 chlorinated alkenes, 3 brominated methanes, 5 aromatic hydrocarbons and their derivatives) in the United States Environmental Protection Agency (U.S. EPA) Priority Pollutant List by physical procedures. The general rules of the theoretical limit of energy consumption with different initial concentrations at 298.15K and 1.01325×105 Pa by NRTL, UNIQUAC and Wilson models are obtained from the thermodynamic analysis with our previously established method based on the thermodynamic first and second law. The results show that the waste treatment process needs a high energy consumption and the theoretical limit of energy consumption for organic contaminant removal increases with decreasing initial concentrations in aqueous solutions. The theoretical limit of energy consumption decreases with the more C–H bonds being replaced by C–Cl or C–Br bonds in chlorinated methanes, ethanes, ethenes or brominated methanes except for 1,1,2,2-tetrachloroethane, and the energy consumption for the removal of chlorinated methanes is higher than that of chlorinated ethanes with the same C–H bonds being replaced by C–Cl bonds. For the removal of chlorinated ethenes, brominated methanes and benzene and its derivatives studied, the energy consumption has corresponding relationship with solubility and the energy consumption is higher for the removal of organics with higher solubility. [ABSTRACT FROM AUTHOR]

Abstract: The improvement of energy efficiency is seen as one of the most promising measures for reducing global CO2 emissions. However, the emission reduction potential may seem different from the industrial plant and policy-maker’s perspectives. This paper evaluates the influences of process heat conservation on CHP electricity production, primary energy consumption and CO2 emissions from both the mill site and national perspectives. The results indicate that heat conservation in an industrial process may lead to varying results in primary energy consumption and CO2 emissions, depending on the form of marginal heat production used at the mill site. In the CHP process, reduction of the heat load lowers electricity production, and this reduction may have to be compensated for at the national level. Therefore, the energy conservation potential in industry has to be evaluated by taking into account the connections to the outside society, which means that a wider system boundary than a mill site has to be used. This study demonstrates by theoretical analysis and case mill studies the magnitude of the effects of system boundary definition when evaluating the contribution of an individual energy efficiency investment towards fulfilling the commitment to reduce CO2 emissions at the national level. [Copyright &y& Elsevier]

Abstract: In this paper an analysis of energy use and energy conservation in the Malaysian rubber producing industries is presented. It has been found that rubber industries consume a substantial amount of energy. Excessive use of energy is usually associated with many industrial plants worldwide, and rubber plants are no exception. This study is based on the realization that enormous potential exists for cost-effective improvements in the existing energy-using equipment. Through the method of a walkthrough energy audit, power rating, operation time of energy-consuming equipment/machineries and power factor were collected. The data were then analyzed to investigate the breakdown of end-use equipment/machineries energy use. The results of the energy audit in the Malaysian rubber and rubber producing industries showed that the electric motor accounts for a major fraction of total energy consumption followed by pumps, heaters, cooling systems and lighting. Since the electric motor takes up a substantial amount of the total energy used in rubber industries, energy-savings strategies such as the use of high efficient motors, and variable speed drive (VSD) have been used to reduce energy consumption of motors used in rubber industries. Energy-savings strategies for compressed-air systems, boilers, and chillers have also been applied to estimate energy and cost savings. It has been found that significant amount of energy and; utility bills can be saved along with the reduction of emission by applying the foretold strategies for energy using machineries in the rubber industries. [Copyright &y& Elsevier]

Abstract: Internal exhaust gas recirculation (EGR) is an effective strategy to reduce pumping loss and improve fuel economy using mixture dilution than traditional external EGR. In this paper, the internal EGR was obtained by exhaust gas trap (EGT) using the negative valve overlap (NVO) method. The effects of EGT on the part-load characteristics, including energy conversion, combustion and emission characteristics were studied in a direct injection spark ignition (DISI) engine. The experimental results showed that EGT can save fuel consumption by 5–16% due to reduced pumping loss and improved combustion efficiency, while it also can increase the engine cyclic variation and combustion duration. The engine cyclic variation increases with increasing of the EGT level; this can be overcome by advancing spark timing to stabilize the combustion. The flame propagation and compression combustion occurred simultaneously when high EGT level and high compression ratio were adopted; the combined combustion can reduce combustion duration but increase the engine cyclic variation. The stratified mixture using the two-stage injection strategy can reduce the engine cyclic variation and shorten the combustion duration so as to improve the thermal efficiency. Moreover, the second injection mass ratio and timing take an important effect on the combustion and emission characteristics in DISI engines using EGT strategy. [Copyright &y& Elsevier]

Abstract: We have been developing technologies for energy saving in the residential sector. Recently, we have been concentrating our resources specifically into the development of polymer electrolyte fuel cell (PEFC) cogeneration systems. The system has excellent energy saving characteristics. However, the total amount of energy saved depends on how the system is operated. The characteristics of residential energy consumption are more complicated than in industrial use and depend on individual living patterns. It is therefore not easy to develop a control method for a system that can be generally applied across a wide variety of residential use. In this paper, we propose a system configuration and operation planning method developed for a residential PEFC cogeneration system. Using an operation planning method we developed, we demonstrate that our system provides higher energy savings than the conventional method. The energy saving rates are 15.9% under a large heat demand, 18.4% under a relatively high electrical demand and low heat demand, 1.3% under relative low electrical and heat demands. [Copyright &y& Elsevier]

Abstract: This paper employs annual data from 1971 to 2006 to examine the causal relationship between aggregate output, electricity consumption, exports, labor and capital in a multivariate model for Malaysia. We find that there is bidirectional Granger causality running between aggregate output and electricity consumption. The policy implication of this result is that Malaysia should adopt the dual strategy of increasing investment in electricity infrastructure and stepping up electricity conservation policies to reduce unnecessary wastage of electricity, in order to avoid the negative effect of reducing electricity consumption on aggregate output. We also find support for the export-led hypothesis which states Granger causality runs from exports to aggregate output. This result is consistent with Malaysia pursuing a successful export-orientated strategy. [Copyright &y& Elsevier]

Abstract: As a renewable energy utilization system, the electric-driven seawater source heat pump district heating system is gaining popularity in some coastal areas. However, under what conditions can the system achieve its energy-saving effect and how to evaluate its energy-saving potential are not clear in practice. In this paper, an expression of the critical COP value of the heat pump unit for energy-saving (COP h,c ) is derived through the comparison of the system and the conventional boiler house district heating system in the energy consumption respect. On the other hand, the actual COP values of the heat pump unit (COP h,a ) are calculated by an experimental data regression model on the basis of the manufacturer''s dataset. The comparison of the values of COP h,c and COP h,a makes the energy-saving judgment of an electric-driven seawater source heat pump district heating system and its energy-saving potential, if it has, readily available. It was found that both the heating district radius and the natural conditions of the seawater are the most important factors that determine the energy efficiency of the system. And through comparison, it was also found that the type of the fuel of the boiler has significant impact on the crucial index value of COP h,c . [Copyright &y& Elsevier]

Abstract: This paper analyses how to apply mist pre-cooling coupled with condensing temperature control to enhance the coefficient of performance (COP) of an air-cooled chiller system and hence achieve electricity savings. A modified DOE-2.1E chiller model was developed to predict the change of chiller COP due to various set points of condensing temperature and pre-cooling of air stream entering the condenser. The model was calibrated by using manufacturer’s data and used to estimate the annual electricity consumption of a chiller system serving an office building under four operating schemes: traditional head pressure control (HPC); HPC with a fixed mist generation rate; condensing temperature control (CTC) with a fixed mist generation rate; CTC with an optimal mist generation rate. It was estimated that using optimal mist control with CTC could achieve a 19.84% reduction in the annual electricity consumption of the system. Considerations when using mist pre-cooling to maximize electricity savings have been discussed. [Copyright &y& Elsevier]

Abstract: The Louisiana Home Energy Rebate Offer (HERO) is a residential energy conservation program established in 1999 to provide rebates for qualified applicants to build new homes that are more energy efficient or improve the energy efficiency of existing homes. Energy conservation programs require careful evaluation because of the high cost to implement the measures and the expectation that they will reduce energy use. The purpose of this paper is to demonstrate that residential energy conservation measures in a hot and humid climate can be evaluated using the International Performance Measurement and Verification Protocol (IPMVP), a best practice methodology commonly used in industrial and commercial performance-based contracts, but rarely, if ever, applied to residential programs. Using a random sample of 60 HERO participants, we were able to construct statistically significant electricity consumption baseline models for 90% of households. We determined that more than half of the sample participants consumed more electricity after their efficiency improvement, with an average net household savings of 172kWh/yr, about 1% pre-retrofit consumption. A description of the baseline model construction, preliminary program evaluation, and recommendations are provided. All program conclusions are considered preliminary until a larger and more comprehensive study is conducted. [Copyright &y& Elsevier]

Abstract: In order to respond to climatic change, many efforts have been made to reduce harmful gas emissions. According to energy policies, an important goal is the implementation of renewable energy sources, as well as electrical and oil combustion savings through energy conservation. This paper focuses on an extensive review of the technologies developed, so far, for central solar heating systems employing seasonal sensible water storage in artificial large scale basins. Among technologies developed since the late 1970s, the use of underground spaces as an energy storage medium – Underground Thermal Energy Storage (UTES) – has been investigated and closely observed in experimental plants in many countries, most of them, as part of government programmes. These projects attempt to optimise technical and economic aspects within an international knowledge exchange; as a result, UTES is becoming a reliable option to save energy through energy conservation. Other alternatives to UTES include large water tanks and gravel–water pits, also called man-made or artificial aquifers. This implies developing this technology by construction and leaving natural aquifers untouched. The present article reviews most studies and results obtained in this particular area to show the technical and economical feasibility for each system and specifics problems occurred during construction and operation. Advantages and disadvantages are pointed out to compare both alternatives. The projects discussed have been carried out mainly in European states with some references to other countries. [Copyright &y& Elsevier]

Abstract: This paper revisits the causal relationship between coal consumption and real GDP for six major coal consuming countries for the period 1965–2005 within a vector autoregressive (VAR) framework by including capital and labour as additional variables. Applying a modified version of the Granger causality test due to Toda and Yamamoto [Toda HY, Yamamoto T. Statistical inference in vector autoregressions with possibly integrated process. J Econom 1995;66:225–50], we found a unidirectional causality running from coal consumption to economic growth in India and Japan while the opposite causality running from economic growth to coal consumption was found in China and South Korea. In contrast there was a bi-directional causality running between economic growth and coal consumption in South Africa and the United States. Variance decomposition analysis seems to confirm our Granger causality results. The policy implication is that measures adopted to mitigate the adverse effects of coal consumption may be taken without harming economic growth in China and South Korea. In contrast, for the remaining four countries conservation measures can harm economic growth. [Copyright &y& Elsevier]

Abstract: In this paper, we investigate the relationship between carbon emissions, income, energy and total employment in selected OPEC countries for the period of 1971–2002. We mainly focus on the link between energy use and income. Employing the autoregressive distributed lag (ARDL) approach, we find that there is a cointegrating relationship between the variables in Saudi Arabia only. The long run forcing variables for income are determined to be employment and energy for Saudi Arabia. In Indonesia, Algeria, Nigeria, and Venezuela, there is no cointegration between income and energy. Secondly we question the long run Granger causality between carbon emissions, energy use, and income. Our results suggest that none of the countries need to sacrifice economic growth to decrease their emission levels. Indonesia and Nigeria may contribute to emissions reduction via energy conservation without negative long run effects on economic growth. [Copyright &y& Elsevier]

Abstract: This paper presents a novel low-power majority function-based 1-bit full adder that uses MOS capacitors (MOSCAP) in its structure. It can work reliably at low supply voltage. In this design, the time-consuming XOR gates are eliminated. The circuits being studied are optimized for energy efficiency at 0.18-μm CMOS process technology. The adder cell is compared with seven widely used adders based on power consumption, speed, power-delay product (PDP) and area efficiency. Intensive simulation runs on a Cadence environment and HSPICE show that the new adder has more than 11% in power savings over a conventional 28-transistor CMOS adder. In addition, it consumes 30% less power than transmission function adder (TFA) and is 1.11 times faster. [Copyright &y& Elsevier]

Abstract: With the development of distributed generation (DG) technologies and the implementation of policies to encourage their applications, building combined heat and power (BCHP) is expected to play a greater role in the commercial buildings in the future. BCHP is a promising efficiency improvement and carbon mitigation strategy, but careful selection of technology and operation mode is required to achieve a reasonable system performance according to energy consumption characteristics of buildings and technical features of equipments. This paper analyzed energy consumption characteristics of four typical commercial buildings in Japan and simulated the energy system performances of four mostly widely adopted DG technologies under different operation mode conditions for the four buildings studied. Various scenarios were evaluated and compared regarding energy utilization efficiency, energy saving and environmental effects, as well as economic efficiency. Results show that the hotels and hospitals are more attractive for BCHP because of their stable thermal load demands and a favorable heat-to-power ratio, which is the most compatible match with available DG technologies. Furthermore, some DG technologies are more suitable for a certain type of building than others because of their technical features more matching with the building’s energy consumption characteristics, as well as the user’s motivation of selecting BCHP. In Japan, during selecting DG technologies, the prior order is gas turbines (GT), gas engines (GE), diesel engines (DE) and phosphoric acid fuel cells (PAFC) for the hotels, PAFC, GE and GT, DE for the hospitals, PAFC, DE, GE and GT for the stores, as well as DE, PAFC, GE and GT for the offices. [Copyright &y& Elsevier]

Abstract: In the last years, the growing demand for air conditioning has caused a significant increase in demand for primary energy resources. Solar-powered cooling is one of the technologies which allows to obtain, by using the renewable solar source, an important energy saving compared to traditional air conditioning plants. The paper describes different technical installations for solar cooling, their way of operation, advantages and limits. The objective of the present study has been to analyze the technical and economic feasibility of solar absorption cooling systems, designed for two different application fields: industrial refrigeration and air conditioning. The possibility to replace or integrate the existing plants is studied, by considering the refrigeration requirements of a company, which works in meat manufacturing, and the heating and cooling demands of a hotel located in a tourist town in Italy. In the first case, the system comprises an absorption chiller coupled to solar flat plate collectors, whereas the second application is about a hybrid trigeneration plant, known as thermo-solar trigeneration; this option allows having greater operational flexibility at sites with demand for energy in the form of heating as well as cooling, for example in a hotel. In this way the authors could compare different results obtained by a technical and economic experimental analysis based on existing users and evaluate the advantages and disadvantages in order to suggest the best solution for the two studied cases. [Copyright &y& Elsevier]

Based on a large sample for the German commercial and services sector, this paper econometrically assesses the relevance of various types of barriers to energy efficiency at the sectoral level and across fifteen sub-sectors. The results at the level of entire sectors suggest that the lack of information about energy consumption patterns and about energy efficiency measures, lack of staff time, priority setting within organizations, and – in particular – the investor/user dilemma are all relevant barriers. Allowing for sector-specific differences in the relevance of these individual barriers yields a more heterogeneous picture. The numbers and types of relevant barriers vary across sub-sectors, and the majority of sub-sectors are subject to relatively few barriers. The statistically most significant barriers are found for the sub-sector of public administrations. These findings are robust, independent of whether the definition of an organization's energy efficiency performance includes only measures that have actually been realized or also those that are being planned. For planned projects, however, organizations appear to underestimate internal priority setting as a barrier to energy efficiency. [Copyright &y& Elsevier]

Abstract: Insights into the past Energy Research and Technology Development (ERTD) expenditures allows policy makers to better set priorities for current and future ERTD funding as well as to analyze the exact impact of ERTD investments to the development of energy technologies. However, despite numerous attempts in the past, there is currently no comprehensive, validated database that includes disaggregated data on public and private ERTD expenditures in the EU-27 for different technology groups. One of the main aims of the Scientific Reference System for New Energy Technologies and Energy End Use Efficiency (SRS NET & EEE) FP6 project is to enhance the availability, quality and completeness of data on public and private ERTD expenditures, disaggregated for energy technologies and energy end-use efficiency options in the EU-27. The aim of the paper is to outline the main data gathering procedures and results from the “SRS NET & EEE” project, as well as the related policy implication. [Copyright &y& Elsevier]

Abstract: There is an obvious and indisputable need for an increase in the efficiency of energy utilisation in buildings and in the energy supply system within communities. Heating, cooling and lighting appliances in buildings account for more than one third of the world''s primary energy demand. In turn, building stock is a major contributor to energy-related environmental problems and CO2 emissions. There are great potentials to be obtained through a more efficient supply of energy and rational use of energy in buildings. An optimisation of the exergy flows in buildings and related supply structures, similar to other thermodynamic systems such as power stations, can help in identifying the potential of increasing efficiency in energy utilisation. Through analyses, it can be shown that calculations based on the energy conservation and primary energy concept alone are inadequate for gaining a full understanding of all important aspects of energy utilisation processes. The high potential for a further increase in the efficiency of; for example, boilers, cannot be quantified exclusively by performing energy analyses—the energy efficiency is close to 100%; however, this potential can be demonstrated by using an exergy analysis, whereby the exergy efficiency of a common gas boiler is about 8%. It is necessary to work out new and more efficient ways to supply energy to satisfy the demand for energy services. This paper outlines the international co-operative work in the general framework of the International Energy Agency (IEA), the ECBCS Annex 49 “Low Exergy Systems for High Performance Buildings and Communities” [Annex 49, Energy Conservation in Buildings and Community Systems—Low Exergy Systems for High Performance Buildings and Communities, homepage: http://www.annex49.com, 2007]. [Copyright &y& Elsevier]

Abstract: The main functions of the heat-pump air conditioning system driven by gas engine (GEHPAC) are to maintain the room temperature and control the humidity of the room. In summertime, the air can be reheated by the waste heat water from the gas engine, while the air can be reheated and humidified by the waste heat water in winter. Reducing or displacing electrical heating requirements can achieve the greatest opportunity for significant energy savings. This paper, therefore, aims to improve the energy performance of the AC system by using the waste heat from the gas engine. The mathematical model for the second heat exchanger, the sprayed room, the mixed air, was used to research the GEHPAC. Explicitly, we investigated the influence of various factors including the outdoor air temperature and humidity in summer and winter. Results from the analysis show that the GEHPAC can save more energy than the electricity engine heat pump. The GEHPAC runs beautifully in part load mode. PERx is higher in winter than in summer. The maximum PERx is over 1.6 in summer, while over 1.9 in winter. The GEHP which can control the room humidity can be used in more areas than the common GEHP. [Copyright &y& Elsevier]

Abstract: The main methods for improving the efficiency or power of the combined cycle are: increasing the inlet temperature of the gas turbine (TIT), inlet air-cooling, applying gas reheat, steam or water injection into the gas turbine (GT), and reducing the irreversibility of the heat recovery steam generator (HRSG). In this paper, gas reheat with recuperation was applied to the regular triple-pressure steam-reheat combined cycle (the Regular cycle) by replacing the GT unit with a recuperated gas-reheat GT unit (requires two gas turbines, gas recuperator, and two combustion chambers). The Regular cycle with gas-reheat and gas-recuperation (the Regular Gas Reheat cycle) was modeled including detailed modeling of the combustion and GT cooling processes and a feasible technique to reduce the irreversibility of its HRSG was introduced. The Regular Gas Reheat cycle and the Regular Gas Reheat cycle with reduced-irreversibility HRSG (the Reduced Irreversibility cycle) were compared with the Regular cycle, which is the typical design for a commercial combined cycle. The effects of varying the TIT on the performances of all cycles were presented and discussed. The results indicate that the Reduced Irreversibility cycle is 1.9–2.15 percentage points higher in efficiency and 3.5% higher in the total specific work than the Regular Gas Reheat cycle, which is 3.3–3.6 percentage points higher in efficiency and 22–26% higher in the total specific work than the Regular cycle. The Regular Gas Reheat and Reduced Irreversibility cycles are 1.18 and 3.16 percentage points; respectively, higher in efficiency than the most efficient commercially-available combined cycle at the same value of TIT. Economic analysis was performed and showed that applying gas reheat with recuperation to the Regular cycle could result in an annual saving of 10.2 to 11.2 million US dollars for a 339MW to 348MW generating unit using the Regular cycle and that reducing the irreversibility of the HRSG of the Regular Gas Reheat cycle could result in an additional annual saving of 11.8 million US dollars for a 439MW generating unit using the Regular Gas Reheat cycle. [Copyright &y& Elsevier]

Abstract: Energy-consumption data collected from two equipment-retrofit projects before and after the retrofits was used to develop a model that estimates energy savings from retrofit projects. The computation method used in the model is based on Artificial Neural Networks (ANN). The model integrates weather variables, specific equipment-usage and occupancy data, and building-operation schedules into the pre-retrofit energy-usage pattern. It then estimates the energy usage of the pre-retrofit equipment in the post-retrofit period by using weather data, occupancy, and building-operation schedules in the post-retrofit period. The difference between the recorded energy usage of the post-retrofit equipment and the predicted energy usage of the pre-retrofit equipment in the post-retrofit period is the estimate of energy savings. For the two retrofit projects used in the ANN model, the coefficient of correlation varied from 0.957 to 0.844; the root mean square error varied from 6.81% to 16.4%; and the mean absolute error varied from 5.31% to 9.95%. Additionally, the sensitivity of the model to the input variables was analyzed with one of the retrofit project data. Dry bulb temperature, wet bulb temperature, and time (representing building-occupancy and equipment-operation schedule) were determined as the most effective variables in the ANN model. The research and findings are presented in this paper. [Copyright &y& Elsevier]

Abstract: The compressor is an important auxiliary for fuel-cell (FC) operation. Growing fuel-cell system efficiency involves an optimal fuel cell energy management and the air management is a key issue. Thus, a good modelling for static and dynamic operation of all components of the FC system, and in particular of the compressor, is required. The difficulties, due to a lack of information about the performance of compressors, demand predictive and modern approximation methods to be used for compressor modelling. To overcome these issues, the paper proposes and presents a moving least squares (MLS) algorithm for obtaining a surrogate model of the centrifugal compressor. The experimental data provided by manufacturers are used for this task. The results can be used for the development of an off-design model or the overall dynamic simulation of the behaviour of a FC system. [Copyright &y& Elsevier]