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TERI Information Digest on Energy and Environment
Year : 2002, Volume : 1, Issue : 1
First page : ( 48) Last page : ( 56)
Print ISSN : 0972-6721.

Energy conservation, consumption, and utilization

 


[108]Energy efficiency and building construction in India
Tiwari P. 2001A comprehensive optimization model for energy accounting in house construction in India has been developed in this paper. The main concern of the paper is energy consumption in building construction in India. The techniques of construction evaluated are commonly used pucca techniques as well as low-cost construction techniques. An assessment of the magnitude of energy consumption, if housing shortages have to be met, shows that a huge amount of energy would be consumed in the housing sector alone. The associated levels of carbon dioxide emissions associated with this construction would also be prohibitively high. Finally, the paper concludes with recommendations for structural changes in the energy and construction policy in India to minimize energy consumption in building construction.
(3 figures, 7 tables, 11 references)
Building and Environment36(10):1127–1135
Institute of Policy and Planning Sciences,
University ofTsukuba, Tsukuba 305–8573, Japan
<tiwari@sk.tsukuba.ac.jp>

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[109]Heat exchanger connection in substations
Zsebik A and Sitku Gy. 2001Nowadays a large number of district heat utilities are faced with excessive cost pressure if they intend to offer district heat at prices comparable to the heating cost of individual heating systems. The return temperature in district heating networks has a great impact on the economy of district heat. Transmission capacity, pumping demands, heat losses, efficiency in case of cogeneration, utilization of industrial waste heat, solar, and geothermal energy for district heating are all dependent on this parameter. One way to obtain lower return temperature is the suitable connection of heat exchangers in substations. Based on mathematical modelling and simulation, this article shows the temperature differences between three types of heat exchanger connections - serial, parallel, and two-step - and their economic impact. The paper concludes that parallel and two-step connections are better than the serial connection with bypass pipe. It is also recommended that before the modernization of substations, the critical heat demand (based on the actual technical and economic data) should be determined. Depending on the results, parallel or two-step connection substations can be realized.
(6 figures, 2 references)
Energy Engineering98(5):20–28
Department of Systems and Control Engineering,
Technical University of Budapest, H-1111 Budapest, Mhegyetem rkp. 3, Hungary
<zsebik@rit.bme.hu>

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[110]Increasing fuel efficiency and reducing harmful emissions in traditional cooking stoves
Still D and Winiarski L. 2001A set of design principles, which can be adapted to many cook-stoves without changing their outward appearance, in order to increase their fuel efficiency and reduce harmful emissions, has been discussed in this paper. The design principles discussed are (1) insulating everywhere around the fire and hearth except where it touches the pot(s), (2) forcing the hot gases to rub against the outside of the pot(s) by creating small channels with narrow gaps that follow the shape of the pot(s) - otherwise flames will just warm the escaping air, (3) providing intense heat to the pots by placing the pot near the hot flames, (4) using metal pots rather than ceramic pots, (5) increasing the speed of the hot gases as they hit the pots as faster hot flue gases punch through the still air that surrounds the pot(s). This paper also describes a set of cook-stoves, which are based on these principles, and are now proving very successful in Nicaragua, Honduras, El Salvador and Guatemala.
(5 figures)
Boiling Point47(Aut):36–39
Aprovecho Research Center,
80574 Hazelton Road, Cottage Grove, Oregon 97424, USA
<apro@efn.org>

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[111]Thermodynamic behaviour of an air-conditioning system employing combined evaporative-water and air coolers
Tashtoush B, Tahat M, Al-Hayajneh A, Mazur VA, Probert D. 2001Harnessing waste-heat or insulation, in order to energize a sorp-tion system can improve the economics of operating the associated cooling machine. In this paper the performance of an open-absorption system, using waste-heat, has been investigated. A computer simulation program for the behaviour of an open-absorption system suggests that the performance of the CEC (combined evaporative cooler), i.e. an IEC (indirect evaporative cooler) together with a DEC (direct evaporative cooler), was better, by more than 20%, than that of either direct or indirect cooling cycle. The CoP of the combined system rose upon increasing the heat-supply temperature. However, it did not function if the heat-source temperature was less than 34 °C. The CoP and the refrigerating effect of the cycle rose upon increasing the cooling-air temperature. Such systems are practical means for achieving solar-cooling air conditioning.
(10 figures, 13 references)
Applied Energy70(4):305–319
Department of Mechanical Engineering,
PO Box 3030, Jordan University of Science and Technology, Irbid, Jordan
<bourhan@just.edu.jo>

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[112]Energy requirements and conservation potential in industrial sector in Karnataka
Ramachandra TV and Subramanian DK. 2001Energy is essential for industrial production as this sector constitutes a major consumer of commercially produced energy. An improvement in energy efficiency in this sector would result in a slower rate of energy consumption. This paper discusses the industrial energy scene in Karnataka, India, and the possibilities for energy conservation. An analysis of the energy consumption data of Karnataka shows that the per capita consumption of energy is low (compared with 32 countries in the world). However, for the industrial sector, energy per state domestic product is at least 10-20 times higher compared to that of industrialized countries. This implies inefficiency in energy utilization. Detailed investigation of the industrial sector, through analysis of specific energy consumption, industry-wise and year-wise for a seven year period reveals that about 28% energy could be saved in the industrial sector. This, when quantified, accounts for saving of 2.25 MTOE of energy or 1541 million kWh electrical energy per year in Karnataka. Such a saving is equivalent to the energy output of 300 MW electric power generating units. Therefore, energy budgeting, auditing and conservation techniques should be initiated at the earliest.
(1 figure, 3 tables, 8 references)
International Journal of Ambient Energy22(1):35–46
Energy Research Group,
Centre for Ecological Sciences, Indian Institute of Science, Bangalore - 560 012, India
<cestvr@ces.iisc.ernet.in>

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[113]Finite time thermodynamic optimization of an irreversible heat pump system using the Lagrangian multiplier method
Kaushik SC, Kumar P, and Jain S. 2002This paper presents finite time thermodynamic analysis and optimization using the Lagrangian multiplier method for a vapour compression heat pump system with external and internal irreversibility. An expression for the CoP of the heat pump system is derived at minimum power input and given output heat flow rate condition for the system. It is shown that external irreversibility in the heat pump, due to finite temperature difference or finite heat transfer between the cycle fluid and source/ sink reservoirs, causes the endoreversible CoP to be lower than the reversible CoP. The internal irreversibility of the heat pump system is characterized by a single irreversibility parameter (R s) representing non-isentropic compression in terms of the ratio of entropy differences. The presence of this parameter in the equations for minimum input power and coefficient of performance of the system clearly shows that a real heat pump system needs more input power and has a lower coefficient of performance than an endoreversible heat pump system.
(2 figures, 4 tables, 10 references)
International Journal of Ambient Energy22(2):105–111
Centre for Energy Studies,
Indian Institute of Technology-Delhi, Hauz Khas, New Delhi-110 016, India
<kaushik@ces.iitd.ernet.in>

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[114]Energy optimization studies in a dairy industry ice bank tank
Kumar PR, Balaji SR, Lal DM, Kalanidhi A. 2001In the dairy industry, ice bank tanks are used for chilling water to 1 °C. The chilled water is then used for cooling milk from its arrival temperature of between 5-12 °C down to a temperature of 4 °C and also for cooling during the pasteurization process. An ammonia based vapour compression system is used to chill the water. The load on the plant is not constant throughout the day since the arriving milk temperature and quantity are not fixed. Hence, during part load conditions, ice builds up considerably in the ice bank tank. This results in reduced heat transfer rates and other flow problems. However, the ice build-up to a certain level is beneficial, as it helps to meet sudden demands from the load side. Beyond this level, though, problems occur as more ice is accumulated. In the present work, the load from the chiller, pasteurized and thermal resistance due to ice builds up on the evaporator coil is calculated for a week. This has been undertaken to determine the additional energy spent in storing cold in the form of ice blocks. An ice flake thickness of 50 mm is considered to be the optimum. Further build-up can be controlled by operating the compressor for the time needed according to the load. This paper brings out a method to prevent the ice layer thickness exceeding 50 mm by running the compressor according to load fluctuation, thereby achieving a power saving.
(4 figures, 2 tables, 11 references)
International Journal of Ambient Energy22(4):181–187
Department of Mechanical Engineering,
Anna University, Chennai, India

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[115]An experimental study of the thermal performance of an earth-air-pipe system in single pass mode
Thanu NM, Sawhney RL, Khare RN, Buddhi D. 2001The thermal performance of an earth-air-pipe system constructed at Gulmohar farmhouse, Gurgaon, India has been studied in this paper. It has been used in a single pass mode to condition three bedrooms, a living room, a dining room, and a kitchen of a farmhouse. The performance of the earth-air-pipe system was first evaluated prior to the construction of the farmhouse. Accordingly, the temperature and relative humidity at suction and delivery points of the earth-air-pipe system were monitored in three seasons, i.e. summer, monsoon and winter. After the construction of the farmhouse was completed, the performance of the earth-air-pipe system in question, along with performance of one of the living rooms of the farmhouse, was evaluated. The temperature and relative humidity of a conditioned room (living room of the farmhouse), delivery point of the earth-air-pipe system (located in the living room), suction point of the earth-air-pipe system (the hut in which blower of the earth air-pipe system is placed) and ambient air were measured. The cooling and heating potential of the earth-air-pipe system is estimated. The coefficient of performance of the installed system during summer, monsoon, and winter was found to be 7.9, 1.9 and 2.1, respectively. It is concluded that good thermal comfort conditions can be created reasonably in the building with such a system.
(19 figures, 7 tables, 10 references)
Solar Energy71(6):353–364
School of Energy and Environmental Studies,
Devi Ahilya University, Khandwa Road, Indore-452 017, India
<rlsawhney@hotmail.com>

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[116]Development of a kinetic model for dressing throatless rice husk gasifier
Jain AK, Sharma SK, and Singh D. 2001Gasification of rice husk and the application of producer gas as a renewable energy source is practised for quite some time now. The designing of the gasification reactor is usually based on an arbitrary choice of specific gasification rate. This approach is not scientific and very precise as wide variation occurs in the reported values of optimum specific gasification rate. In the current study, a model has been proposed correlating the reaction kinetics of thermal degradation of rice husk with fuel bed height, husk density, maximum temperature in the gasifier reactor, and design capacity of gasifier. Using the model, a down draft throatless gasifier for generation of producer gas for a 10 kW engine was designed and fabricated. The performance evaluation tests on the gasifier indicated that at a specific gasification rate of 190 kg/h/m2, the gasifier efficiency was the maximum. The model was used to find out the reactor diameter using the literature performance data on throatless rice husk gasifiers. The reactor diameter determined using the model is compared with the actual values. The proposed model is a preferred choice for the designing of batch operated down draft throatless rice husk gasifier reactor compared to the gasifier designing using specific gasification rate approach.
(3 figures, 2 tables, 14 references)
Indian Chemical Engineer43(3):167–171
School of Energy Studies for Agriculture,
Punjab Agricultural University, Ludhiana- 141 004, India

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[117]Energy use in commercial buildings in Hong Kong
Yu PCH and Chow WK. 2001Most of the commercial buildings in Hong Kong are provided with MVAC (mechanical ventilation and air conditioning) system for thermal comfort since natural ventilation is not possible in these high-rise buildings. Electricity is the main source of energy to drive the MVAC systems, which accounts for 60% of the total energy use (electrical) in Hong Kong. In this paper, energy performances of 20 commercial buildings, covering the common types have been studied. The monthly electricity billing data as well as the results from computer modelling were analyzed. Correlation equations of energy use with building envelope parameters, such as overall thermal transfer value, building size, envelope heat gain, and the annual chiller load were derived. The results are useful for building envelope design, energy audit and legislative control of energy use in commercial buildings. The chiller load per unit floor area of the conditioned spaces in a commercial building, which is believed to be a good index for energy cost estimation, has been found to be inversely proportional to the building size; i.e. the bigger the building the smaller the energy cost per unit floor area.
(4 figures, 2 tables, 19 references)
Applied Energy69(4):243–255
Department of Building Services Engineering,
The Hong Kong Polytechnic University, Hung Horn, Hong Kong, China
<bewkchow@polyu.edu.hk>

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[118]Estimation of process side thermal efficiency of fired heaters
Chakravarthy SSS, Bhatnagar BR, Malhotra S, Vohra AK, and Gill BS. 2001Fired heaters are the major energy consumers in refinery and petrochemical plants. The initiative to ensure that these heaters run close to their design efficiency is tremendous. Heater operating efficiency is an estimation of the net heat being transferred from fuel oil/gas to the process fluid. The present paper focuses on the development of a computer package for calculation of process side thermal efficiency. The results of the efficiency calculations have been reported for a typical crude furnace. The same are compared against DESIGN-II processes simulator calculations and have been found to be within +5% error. The above programme is based on semi-empirical approach and can be used for estimating the absorbed duty without detailed investigation on the flue gas side. It can also generate the TBP (true boiling point) curve based on the temperature, pressure, and absorbed duty.
(1 figure, 2 references)
Indian Chemical Engineer43(3):196–199
Environment Department,
Engineers India Ltd, PTI Building, PO Box No 730, 4 Sansad Marg, New Delhi - 110 001, India
<bsgill@eil.co.in>

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[119]Analysis of energy conservation opportunities in glass manufacturing facilities
Gopalakrishnan B, Plummer RW, and Alkadi NM. 2001This article describes the nature of the energy conservation opportunities found in glass manufacturing facilities. The Industrial Assessment Center at West Virginia University has conducted the energy assessments at the glass manufacturing facilities between 1996 and 1999. Energy savings of 280 000 MBtu (millions of British thermal units), and a cost saving of 1 080 000 dollars were determined, resulting in a payback on investment of less than 6 months. Assessment methodologies and tools are discussed. The most significant energy conservation opportunities are found to be related to insulation of heat generating surfaces, preheating the combustion air in boilers, and heat recovery and distribution.
(4 tables, 36 references)
Energy Engineering98(6):27–49
Department of Industrial and Management systems Engineering,
West Virginia University, USA

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[120]A mathematical model for fixed dome type biogas plant
Raheman H. 2002This paper describes the development of a mathematical model for determining the dimensions of a fixed dome type Deenbandhu model biogas plant, the most popular model constructed in India. The developed model could estimate the different dimensions within an absolute variation of six per cent. This will help the designers to determine the dimensions of various capacities of a Deenbandhu model biogas plant for different hydraulic retention times to suit the local climatic conditions.
(3 figures, 6 tables, 5 references)
Energy27(1):25–34
Agricultural and Food Engineering Department,
Indian Institute of Technology, Kharagpur-721 302, India

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[121]Calculating yearly heat consumption using the specific heat demand coefficient
Zsebik A and Benyo I. 2001When analysing the efficiency of energy management, one often needs to determine the expected heat consumption from the known nominal or design heat demand. In other cases, the design heat demand needs to be determined from the actual heat consumption data of several years. In order to facilitate the above tasks, this article describes: (1) an adequately accurate formula for outdoor temperature distribution and air temperature duration function (through which the expected heat consumption can be determined), and (2) a formula for the relative value of space heating demand, whose integral determines the so-called specific heat demand coefficient. Using the specific heat demand coefficient the expected heat consumption can be determined from the design heat demand or vice versa.
(2 figures, 2 references)
Energy Engineering98(6):50–57
Department of Systems and Control Engineering,
Technical University of Budapest, H-1111 Budapest Muegyeten rkp. 3, Hungary
<zsebik@rit.bme.hu>

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[122]Comparison of externally fired and internal combustion gas turbines using biomass fuel
Ferreira SB and Pilidis P. 2001There is a difference of opinion regarding the relative merits of gas turbines using biomass fuels. Some engineers believe that the internal combustion gas turbine coupled to a gasifier will give a higher efficiency than the externally fired gas turbine using pretreated biomass that is not gasified. Others believe the opposite. In this paper, a comparison between these schemes is made, within the framework of the Brazilian perspective. The exergetic analysis of four cycles is described. The first cycle is EGFT (externally fired gas turbine), the second uses gasified biomass as fuel BIG (biomass integrated gasifier)/GT (gas turbine), each of them with a combined cycle as a variant EGFT/ CC (combined cycle) and BIG/GTCC. These four are then compared to the NGT (natural gas turbine) cycles - NGT and NGT/CC - in order to evaluate the thermodynamic cost of using biomass. The comparison is carried out in terms of thermal efficiency and in terms of exergetic efficiency and exergy destruction in the main components. The present analysis shows that the EFGT is quite promising. When compared to the NGT cycle, the EFGT gas turbine shows poor efficiency, though this parameter practically equals that of the BIG/GT cycle. The use of bottoming steam cycle changes the figures and the EFGT/ CC - due to its higher exhaust temperature - results in high efficiency compared to the BIG/GTCC. Its lower initial and maintenance cost may be an important attraction.
(4 figures, 5 tables, 14 references)
Journal of Energy Resources Technology123(4):291–296
CAPES/Brazil,
SoE-Cranfield University, MK43 OAL Bedfordshire, UK
<S.B.Ferreira.1998@Cranfield.ac.uk>

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[123]Scope of carbon dioxide as a natural refrigerant for replacements of CFCs
Haider GN and Sarkar SC. 2001Most of the conventional refrigeration systems use CFCs (chlo-rofluorocarbons). The ozone layer in the stratosphere, which protects life on earth from the sun's harmful ultraviolet radiation, is getting depleted due to the use of CFCs and other harmful substances. The problem threatens not only human beings, but also the plant and animal kingdom on the earth's surface. In view of this alarming problem, a replacement of CFCs by eco-friendly refrigerants becomes an urgent necessity. Carbon dioxide, the old refrigerant in its new form, appears to be a viable alternative refrigerant for the future in the context of CFC phase out and waste gas utilization. This paper is a state-of-the-art report concerning the various possible alternative refrigeration cycles based on carbon dioxide as a natural refrigerant in environmental protection.
(1 table, 18 references)
Journal of Energy in Southern Africa12(3):408–410
Advanced Centre of Cryogenic Research,
POJadavpur University, PB No 17005, Kolkata-700 032, India
<scs@cal2.vsnl.net.in>

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[124]Removal of carbon dioxide from biogas for methane
Jana S, Chakrabarty NR, and Sarkar SC. 2001Biogas generally contains about 60%-65% methane, 35% carbon dioxide and a small amount of other impurities. The presence of carbon dioxide does not contribute any fuel value for the gas but lowers its total calorific value. Removal of carbon dioxide from the gas mixture not only helps reduce the greenhouse gas but also enriches the fuel value of biogas to a great extent. Removal of carbon dioxide from biogas can be achieved in several ways such as chemical separation, membrane separation, cryogenic separation as well as adsorption separation, the latter playing a vital role if suitable adsorbent material and adsorption-desorption devices are available. This paper makes an experimental study on the feasibility of enrichment of methane in biogas using indigenously developed coconut shell based active carbon on a gas adsorption system, specially designed for the purpose. It is shown that it is feasible to increase the calorific value of biogas following the method and the adsorbent.
(2 figures, 5 references)
Journal of Energy in Southern Africa12(3):412–414
Advanced Centre of Cryogenic Research,
POJadavpur University, PB No. 17005, Kolkata - 700 032, India
<scs@cal2.vsnl.net.in>

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[125]Fixed bed pyrolysis of the rapeseed cake
Sensoz S, Yorgun S, Angin D, Qulcuoglu E, Ozgimen D, Karaosmanoglu F. 2001The fixed bed atmospheric pressure pyrolysis and nitrogen swept pyrolysis of the rapeseed cake obtained from cold extraction press have been investigated. Experiments were performed in the Heinze retort at a 7 °C per minute heating rate, with a 500 °C final temperature varying sweep gas velocity (50, 100, 150, 200, 250, 300 cm3/min) under nitrogen atmosphere. Liquid, gas, and char yields were determined, pyrolysis conversion was calculated. The liquid, char, and gas products were found to be environmentally friendly fuel candidates.
Energy Sources23(10):873–876
Istanbul Technical University,
Faculty of Chemical-Metalurgical Engineering, 80626 Maslak, Istanbul, Turkey
<filiz@itu.edu.tr>

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[126]Energy savings in indoor swimming-pools: comparison between different heat-recovery systems
Johansson L and Westerlund L. 2001In indoor swimming-pool facilities, the energy demand is large due to ventilation losses with the exhaust air. Since water is evaporated from the pool surface, the exhaust air has a high water content and specific enthalpy. Because of the low temperature, the heat from the evaporation is difficult to recover. In this paper, the energy demand for the conventional ventilation technique in indoor swimming pools is compared to two different heat-recovery techniques, the mechanical heat-pump and the open absorption system. The mechanical heat-pump is the most widely used technique in Sweden today. The open adsorption system is a new technique in this application. Calculations have been carried out on an hourly basis for the different techniques. Measurements from an absorption system pilot-plant installed in an indoor swimming pool in the northern part of Sweden have been used in the calculations. The results show that with the mechanical heat pump, the electrical input increases by 63 MWh/year and with the open absorption system by 57 MWh/year. However, a mechanical heat pump and an open absorption system decrease the annual energy demand from 611 to 528 and 484 MWh respectively, which correspond to decreases of approximately 14% and 20%, respectively. The electricity input will increase when using heat-recovery techniques. Changing the climate in the facility has also been investigated. An increased temperature decreases the energy demand when using the conventional ventilation technique. However, when either the mechanical heat-pump or the open absorption system is used, the energy demand is increased when the temperature is increased. Therefore increasing the temperature in the facility when using the conventional technique should be considered the first measure to reduce the energy demand.
(19 figures, 1 table, 9 references)
Applied Energy70(4):281–303
Department of Mechanical Engineering,
Lulea University of Technology, Division of Energy Engineering, Lulea, Sweden
<larsj@mt.luth.se>

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[127]Optimal efficiency as a design criterion for closed loop combined cycle industrial cogeneration
Roy S. 2001In comparison to conventional industrial cogeneration plants, the CLCC (closed loop combined cycle cogeneration) system has the advantage that it needs virtually no enhancement in steam handling capability of the existing plant, both in terms of steam pressure as well as volume flow rates. An optimal design procedure is introduced in this paper for configuration of a CLCC system between existing steam headers of an industrial setup. While aiming primarily at maximization of generation efficiency for the CLCC configuration, the design approach simultaneously attempts to configure a suboptimal number of units for each item of cogeneration equipment. The suboptimal (integer) number of units is maintained within a specified suboptimal margin of the corresponding optimal (real) number of units that emerges from efficiency maximization. The design procedure relies heavily on a database including all available makes of cogeneration equipment. Consequently, the approach is very much market dependent, as illustrated adequately by a suitable case study.
(7 figures, 2 tables, 21 references)
IEEE Transactions on energy conversion16(2):155–164
Department of Electrical Engineering,
Indian Institute of Technology-Delhi, Hauz Khas, New Delhi - 110 016, India

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[128]Validation of road transport statistics through energy efficiency calculations
Zachariadis T and Samaras Z. 2001The paper presents an approach to validate vehicle-kilometre statistics of motor vehicles by comparing them with official energy consumption data. The comparisons were carried out for the 15 European Union countries by computing the energy efficiency and the fuel economy of individual vehicle categories and comparing them with real-world data and model calculations. The major outcome of the study was that estimates of vehicle-kilometres are often unreliable and yield unrealistic energy efficiency and specific fuel consumption results. Based on these conclusions, some basic guidelines are given for energy and road transport analyses: use fuel economy estimates based on measurements of in-use cars under actual driving conditions, collect as many travel data as possible and check their consistency with the aid of energy balances.
(7 figures, 6 tables, 24 references)
nergy26(5):467–491
Laboratory of Applied Thermodynamics,
Department of Mechanical Engineering, Aristotle University, 54006 Thessaloniki, Greece
<zisis@eng.auth.gr>

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