Estimation on oil demand and oil saving potential of China's road transport sector

China is currently in the stage of industrialization and urbanization, which is characterized by rigid energy demand and rapid growth of energy consumption. Therefore, energy conservation will become a major strategy for China in a transition to low-carbon economy. China's transport industry is of high energy consumption. In 2010, oil consumption in transport industry takes up 38.2% of the country's total oil demand, of which 23.6% is taken up by road transport sector. As a result, oil saving in China's road transport sector is vital to the whole nation. The co-integration method is developed to find a long-run relationship between oil consumption and affecting factors such as GDP, road condition, labor productivity and oil price, to estimate oil demand and to predict future oil saving potential in China's transport sector under different oil-saving scenarios. Monte Carlo simulation is further used for risk analysis. Results show that under BAU condition, oil demand of China's road transport sector will reach 278.5 million ton of oil equivalents (MTOE) in 2020. Oil saving potential will be 86 MTOE and 131 MTOE under moderate oil-saving scenario and advanced oil-saving scenario, respectively. This paper provides a reference to establishing oil saving policy for China's road transport sector.     

Two-phase pressure drops in a helically coiled steam generator

An experimental investigation regarding two-phase diabatic pressure drops inside a helically coiled heat exchanger have been carried out at SIET thermo-hydraulics labs in Piacenza (Italy). The experimental campaign is part of a wide program of study of the IRIS innovative reactor steam generator. The test section consists of an AISI 316 stainless steel tube, 32 m length, 12.53 mm inner diameter, curved in helical shape with a bend radius of 0.5 m and a helix pitch of 0.8 m, resulting in a total height of the steam generator tube of 8 m. The explored operating conditions for two-phase flow experiences range from 192 to 824 kg/m² s for the mass flux, from 0 to 1 for the quality, from 1.1 to 6.3 MPa for the pressure, from 50 to 200 kW/m² for the heat fluxes. A frictional two-phase pressure drops correlation, based on an energy balance of the two-phase mixture and including the 940 experimental points, is proposed. Comparison with existing correlations shows the difficulty in predicting two-phase pressure drops in helical coil steam generators.     

Coconut oil extraction by the traditional Java method: An investigation of its potential application in aqueous Jatropha oil extraction

A traditional Java method of coconut oil extraction assisted by paddy crabs was investigated to find out if crabs or crab-derived components can be used to extract oil from Jatropha curcas seed kernels. Using the traditional Java method the addition of crab paste liberated 54% w w^?1 oil from grated coconut meat. Oil extraction using crab paste carried out under controlled temperatures and in the presence of antibiotics showed that enzymes from crab played a dominant role in liberating oil from grated coconut meat and aqueous J. curcas kernel slurries when incubated at 30 °C or 37 °C. However, at higher temperature (50 °C), thermophilic bacterial strains present inside crabs played a significant role in the extraction of oil from both oilseeds tested. A thermophilic bacterial strain isolated from crab paste and identified based on 16s rRNA sequence as Bacillus licheniformis strain BK23, when added as starter culture, was able to liberate 60% w w^?1 oil from aqueous J. curcas kernel slurry after 24 h at 50 °C. Further studies of BK23 and extraction process optimization are the challenges to improve Jatropha oil extraction yield and process economy.     

Decentralized/stand-alone hybrid Wind–Diesel power systems to meet residential loads of hot coastal regions

In view of rising costs, pollution and fears of exhaustion of oil and coal, governments around the world are encouraging to seek energy from renewable/sustainable energy sources such as wind. The utilization of energy from wind (since the oil embargo of the 1970s) is being widely disseminated for displacement of fossil fuel produced energy and to reduce atmospheric degradation. A system that consists of a wind turbine and Diesel genset is called a Wind–Diesel power system.The literature indicates that the commercial/residential buildings in Saudi Arabia consume an estimated 10–40% of the total electric energy generated. In the present study, the hourly mean wind-speed data of the period 1986–1997 recorded at the solar radiation and meteorological station, Dhahran (26°32′N, 50°13′E in the Eastern Coastal Region of Saudi Arabia), has been analyzed to investigate the potential of utilizing hybrid (Wind–Diesel) energy conversion systems to meet the load requirements of a hundred typical two bedroom residential buildings (with annual electrical energy demand of 3512 MWh). The long term monthly average wind speeds for Dhahran range from 4.2 to 6.4 m/s. The hybrid systems considered in the present case study consist of different combinations/clusters of 150 kW commercial wind machines supplemented with battery storage and Diesel back-up. The deficit energy generated by the Diesel generator (for different battery capacities) and the number of operational hours of the Diesel system to meet a specific annual electrical energy demand of 3512 MWh have also been presented. The evaluation of the hybrid system shows that with seven 150 kW wind energy conversion system (WECS) and one day of battery storage, the Diesel back-up system has to provide 21.6% of the load demand. Furthermore, with three days of battery storage, the Diesel back-up system has to provide 17.5% of the load demand. However, in the absence of battery storage, about 37% of the load needs to be provided by the Diesel system. The study also places emphasis on the monthly average daily energy generation from different sizes (150 kW, 250 kW, 600 kW) of wind machines to identify the optimum wind machine size from the energy production point of view. It has been noted that for a given 6 MW wind farm size (for 50 m hub height), a cluster of forty 150 kW wind machines yields about 48% more energy as compared to a cluster of ten 600 kW wind machines.     

Field test of a solar seawater desalination unit with triple-effect falling film regeneration in northern China

Based on the mechanism of falling film evaporation condensation, a new four-stage distillation unit with triple-effect regeneration has been designed, constructed and field tested. The seawater desalination system is driven by 80 m² all-glass vacuum tube solar collection system with an additional 1 kW wind power system to provide electricity for pumps. The field testing and monitoring of the system had been carried out under the real weather condition for 2 years. The results show that the water production of the system for per unit of solar collector area could reach up to more than 12 kg/m²/day under the fine weather conditions. Water production of the system was stable in long period and the annual production could reach to 250 tons in northern China. The economic performance of the system is also discussed. The cost of water production is estimated approximately 4.6 Dollar/ton for the 15-year service life.     

Palm-based biofuel refinery (PBR) to substitute petroleum refinery: An energy and emergy assessment

As the most active palm industry cluster in the world, Malaysia produces enormous amount of biomass from the industry. This work studies the possibility of creating a renewable and sustainable source of energy by fully utilizing an area of land to provide liquid biofuel for the country. Palm-based biofuel refinery (PBR) proposed in this study has the ultimate goal to displace petroleum fuels and fulfill domestic energy demand. It fully utilizes indigenous palm biomass to fulfill 35.5% of energy demand in the country by using land area of only 8% of current palm cultivation. The operation concept of PBR is similar to petroleum refinery in which a single source feedstock (crude petroleum) can be processed to multiple products. In PBR, products from an oil palm plantation will be converted to various biofuel end products. Renewable biofuel such as biodiesel and bioethanol can be produced from crude palm oil and lignocellulosic residues. Energy and emergy assessment were made in this work to evaluate the sustainability and efficiency of PBR. Biofuel produced from PBR has a high energy equivalent of 31.56 MJ/kg as 1 ha of land can produce 182,142 MJ annually. Although there are still obstacles to be overcome, it is important for Malaysia to develop its own energy supply from indigenous resources as an initiative not only for security but also lower carbon emission.     

Understanding energy systems change in Canada: 1. Decomposition of total energy intensity

Between 1995 and 2010, the total energy intensity (E/GDP, PJ/Gross Domestic Product in 2002$) of the Canadian economy declined by 23% or − 2.64 MJ/$. To understand why, the Logarithmic Mean Divisia Index (LMD-I) method was used to decompose a large body of government statistical data supporting the observed E/GDP decline. The analysis shows that (a) 48% (1.27 MJ/$) of the decline was associated with an inter-sector structural change in the economy (i.e. an increased contribution to the total GDP of the low energy-using commercial and institutional sector compared with the high energy-using manufacturing and heavy industry sectors); (b) 24% (0.62 MJ/$) was attributed to the impact of the Canadian GDP growing faster than population; (c) 22% (0.58 MJ/$) of the decline was associated with an overall decrease in business energy intensity. A deeper analysis of business sectors shows a positive impact of 0.4 MJ/$ from increased energy intensity in the oil and gas sector, offset by a 0.98 MJ/$ decline due to energy intensity declines in the other business sectors; (d) 6.3% (0.17 MJ/$) of the decline was associated with an improvement in the energy intensity of households, mostly from residential energy use rather than personal transportation energy use. These results provide insights for policy makers regarding those aspects of the Canadian economy that contribute to, or work against, efforts to transform energy systems toward sustainability.     

The environmental impacts of green technologies in TX

Using detailed electricity consumption and solar generation data from homes in an Austin TX neighborhood between 2013 and 2015, we calculate the environmental benefits of electric vehicles and rooftop solar panels. We estimate time-varying electric grid marginal emissions and water consumption rates in ERCOT through a regression based analysis, and find that emissions and water consumption rates are lowest at high demand times due to those hours' reliance on cleaner natural gas generators. We utilize these emissions and water consumption rates to estimate the avoided GHGs and water consumption from grid electricity that solar panels provide. For electric vehicles, we estimate the net effect of this technology, given the avoided gasoline consumption but increase in grid-related charging. We find that, on average, solar panels avoid approximately 75% of yearly grid-related emissions (0.7 tons CO₂/year per kW of solar capacity) and yearly grid-related water consumption (400 gal/year per kW of solar capacity), where the benefits depend on the orientation of the panels. We also find that electric vehicle deployment results in avoiding up to 70% of fuel-related emissions (3.5 tons CO₂/year) and 60% of fuel-related water consumption (1400 gal/year), though the benefits significantly decrease with the efficiency of the counterfactual vehicle.     

Cogeneration potential in the Columbian palm oil industry: Three case studies

The palm oil mills are characterized by the availability of considerable amounts of by-products of high-energy value such as empty fruit bunches (EFB), fibers, shells and liquid effluents with high content of organics called palm oil mill effluent (POME). A palm oil mill produces residues equivalent to almost three times the amount of oil produced by biomass, showing a huge potential for increasing the power efficiency of the plants and installed power, mainly by the use of by-products in cogeneration plants with high steam parameters and by reducing steam consumption in process. The objective of this paper is to present the results of the study about the cogeneration potential for three representative palm oil mills located in two important palm oil producing regions in Colombia (South-America), fifth palm oil producers of the world. The sizing of the cogeneration system was made assuming it operation during the greatest possible number of hours throughout the year (based on the seasonal availability of fruit) considering parameters for the steam at 2 MPa and 350 °C, using a condensing-extraction turbine. The balance of mass and energy was made by using the Gate Cycle Enter Software, version 5.51, to estimate the potential of electricity generation. The results showed that for fresh fruit bunch (FFB) processing capacities between 18 and 60 t FFB h⁻¹, it is possible to have surplus power ranging between 1 and 7 MW, if the plants are self-sufficient in electric energy and steam for process. With an average Capacity Factor (approximately 0.4), it is possible to expect a generation index of 75 and 160 kWh t⁻¹ FFB when the processing plant is operating or shutdown, respectively, 3 or 4 times better than when a traditional system with a back-pressure steam turbines is used. This analysis used up to 60% of EFB produced in plant as fuel, considering its value as fertilizer for the palm crop. Several economic conditions were considered to estimate the economic and technical feasibility of cogeneration systems in palm oil mill for Colombian palm oil sector.     

Experimentation on a cogenerative system based on a microturbine

The paper reports on experimental results of an energetic characterization of a cogenerative plant. The generator is a microturbine Turbec T100-CHP integrated in a heat recovery system. For operation in standard conditions the maximum electrical and thermal power generated are, respectively, 105 and 167 kW. Experimental tests were run by varying the electrical power produced between 50 and 110 kW with 10 kW stepping. For each step the set-point of the water temperature at the outlet of the recuperator was varied in the range 60–80 °C with 5 °C stepping. In every operating condition the measurement system allows the real-time calculation of the quantities needed for the energetic characterization of the plant, such as efficiency indices and PES (primary energy saving index). It is seen that performances remain essentially constant in the range 80–110 kW. A moderate decrease is then observed until about 60 kW, while a further reduction of the electrical power implies a clear worsening (PES decreases from about 30% to 16% in the tested range). Furthermore, environmental impact has been investigated with respect to gaseous and acoustic emissions. In particular the concentration of pollutants in exhaust gases, except for NO_x and CO₂, strongly increases by reducing the electrical power output.     

延迟焦化装置的能耗分析及节能优化实践

中国海油惠州炼油分公司420× 104t/a延迟焦化装置通过停用解吸塔上重沸器3.5MPa蒸汽、停用柴油汽提塔1.0MPa汽提蒸汽、降低循环比、采用先进控制(APC)提高加热炉热效率、降低高压水泵和罐区减渣原料泵电耗、提高水的回用率、加大装置处理量等工艺优化措施,装置综合能耗比设计能耗39.03kg标油/t原料降低3kg标油/t原料.为了进一步降低装置能耗,达到国内其他先进装置的能耗水平,该装置在2011年利用检修时机,通过加热炉节能改造降低排烟温度、利用柴油低温热发生0.45MPa蒸汽、焦化富气压缩机叶轮更换、焦炭塔区特阀汽封线改造等节能改造措施.加热炉热效率由89％提高至91.5％,节约3.5MPa蒸汽用量约6.5t/h,同时减少了燃料气、蒸汽和电的消耗,使装置能耗总体降低3.16kg标油/t原料.装置节能改造每年可增加4000万元的经济效益.     

Performance of a dual-purpose solar continuous adsorption system

A conceptual design and performance of a dual-purpose solar continuous adsorption system for domestic refrigeration and water heating is described. Malaysian activated carbon and methanol are used as the adsorbent–adsorbate pair. The heat rejected by the adsorber beds and condensers during the cooling process of the refrigeration part is recovered and used to heat water for the purpose of domestic consumption. In a continuous 24-h cycle, 16.9 MJ/day of heat can be recovered for heating of water in the storage tanks. In the single-purpose intermittent solar adsorption system, this heat is wasted. The total energy input to the dual-purpose system during a 24-h operation is 61.2 MJ/day and the total energy output is 50 MJ/day. The latter is made up of 44.7 MJ/day for water heating and 5.3 MJ/day for ice making. The amount of ice that can be produced is 12 kg/day. Using typical value for the efficiency of evacuated tube collector of water heating system of 65%, the following coefficient of performances (COP's) are obtained: 44% for adsorption refrigeration cycle, 73% for dual-purpose solar water heater, 9.1% for dual-purpose solar adsorption refrigeration and 82.1% for dual-purpose of both solar water heater and refrigerator.     

Hydrogen production with integrated microchannel fuel processor for portable fuel cell systems

An integrated microchannel methanol processor was developed by assembling unit reactors, which were fabricated by stacking and bonding microchannel patterned stainless steel plates, including fuel vaporizer, heat exchanger, catalytic combustor and steam reformer. Commercially available Cu/ZnO/Al₂O₃ catalyst was coated inside the microchannel of the unit reactor for steam reforming. Pt/Al₂O₃ pellets prepared by ‘incipient wetness’ were filled in the cavity reactor for catalytic combustion. Those unit reactors were integrated to develop the fuel processor and operated at different reaction conditions to optimize the reactor performance, including methanol steam reformer and methanol catalytic combustor. The optimized fuel processor has the dimensions of 60 mm × 40 mm × 30 mm, and produced 450sccm reformed gas containing 73.3% H₂, 24.5% CO₂ and 2.2% CO at 230–260 °C which can produce power output of 59 Wt.     

A gasoline fuel processor designed to study quick-start performance

A fast-start capability is a key requirement for on-board fuel processors for automotive fuel cell systems operating on gasoline fuel. This paper reports on the design and fabrication of a suitable fuel processor having this capability and discusses estimates of the start-up fuel consumption for the laboratory unit. Also discussed are the start-up strategy and the results of a start-up simulation, which showed that the fuel processor can deliver 90% of the rated hydrogen capacity in 60 s, producing a product gas that contains >30% hydrogen and <50 ppm carbon monoxide. The start-up fuel consumption was estimated on the basis of the thermal mass of the fabricated components; the 10-kW_e laboratory unit was estimated to require >2.9 MJ of fuel energy.     

Steam condensing – liquid CO2 boiling heat transfer in a steam condenser for a new heat recovery system

In a new waste heat recovery system, waste heat is recovered from steam condensers through cooling by liquid CO₂ instead of seawater, taking advantage of effective boiling heat transfer performance; the heat is subsequently used for local heat supply. The steam condensing – liquid CO₂ boiling heat transfer performance in a steam condenser with a shell and a helical coil non-fin tube was studied both numerically and experimentally. A heat transfer numerical model was constructed from two models developed for steam condensation and for liquid CO₂ boiling. Experiments were performed to verify the model at a steam pressure range of 3.2–5 kPa and a CO₂ saturation pressure range of 5–6 MPa. Overall heat transfer coefficients obtained from the numerical model agree with the experimental data within ±5%. The numerical estimations show that the boiling local heat transfer coefficient reaches a maximum value of 26 kW/m² K. This value is almost one order higher than that of a conventional water-cooled condenser.     

Modelling and analysis of air-cooled reciprocating chiller and demand energy savings using passive cooling

The study presents modelling and analysis of air-cooled chiller system in an office building at Central Queensland University in Rockhampton, Australia. EnergyPlus, building energy simulation software, has been used to model and to simulate the energy savings. Base case cooling energy has been compared with measured data. The simulated results show a reasonable agreement with the measured data. As a passive cooling means, the effect of economiser usages and pre-cooling have been simulated and analysed to assess annual demand savings for an energy intensive office building at Rockhampton, Australia. It was found that implementation of the pre-cooling and economiser system could save 115 kW/m²/month and 72 kW/m²/month total cooling energy and 26 kW/m²/month and 42 kW/m²/month chiller energy, respectively.     

Feasibility of pico-hydro and photovoltaic hybrid power systems for remote villages in Cameroon

Pico-hydro (pH) and photovoltaic (PV) hybrid systems incorporating a biogas generator have been simulated for remote villages in Cameroon using a load of 73 kWh/day and 8.3 kWp. Renewable energy systems were simulated using HOMER, the load profile of a hostel in Cameroon, the solar insolation of Garoua and the flow of river Mungo. For a 40% increase in the cost of imported power system components, the cost of energy was found to be either 0.352 €/kWh for a 5 kW pico-hydro generator with 72 kWh storage or 0.396 €/kWh for a 3 kWp photovoltaic generator with 36 kWh storage. These energy costs were obtained with a biomass resource cost of 25 €/tonne. The pH and PV hybrid systems both required the parallel operation of a 3.3 kW battery inverter with a 10 kW biogas generator. The pH/biogas/battery systems simulated for villages located in the south of Cameroon with a flow rate of at least 92 l/s produced lower energy costs than PV/biogas/battery systems simulated for villages in the north of Cameroon with an insolation level of at least 5.55 kWh/m²/day. For a single-wire grid extension cost of 5000 €/km, operation and maintenance costs of 125 €/yr/km and a grid power price of 0.1 €/kWh, the breakeven grid extension distances were found to be 12.9 km for pH/biogas/battery systems and 15.2 km for PV/biogas/battery systems respectively. Investments in biogas based renewable energy systems could thus be considered in the National Energy Action Plan of Cameroon for the supply of energy to key sectors involved in poverty alleviation.     

Energy consumption pattern of a decentralized community in northern Haryana

A survey of household energy consumption pattern has been carried out in a village, Bibipur, district Jind, Haryana, India, during 2004. The households surveyed covered heterogeneous population belonging to different income groups, education groups and social groups. Studies were made on the total energy available, total energy required and energy consumption in different sectors domestic, agricultural, transport, rural industries and miscellaneous uses. The total energy available from all the sources (animate, biomass/non-conventional and inanimate sources) in the village is 468,205 MJ and the requirement for all the activities and from all the resources is 592,220 MJ. There is a big gap between energy supply and demand for the village. There is more availability of non-conventional energy resources as compared to conventional energy resources and some resources are unexploited. Therefore, to meet the balance of energy demand and supply, non-conventional resources should be exploited.In domestic sector, maximum energy is used in cooking (52.1%) and 45% of it is supplied from non-conventional energy sources and 10% from conventional energy sources. Calculations were made by considering all the energy resources for average per capita energy consumption and it was 20.02 MJ/day per capita. Electricity is used mainly for lighting and power, while gas is preferred for cooking.In agricultural sector, energy consumption for different activities was calculated and it was found that maximum energy consumption is in irrigation (41.7%) and minimum in transplanting. In agricultural sector, maximum energy comes from conventional energy sources (about 60%) and from non-conventional energy sources it is only about 30%. From the study, it was found that maximum population having good economic conditions like electricity very much as an energy source followed by LPG, biogas, coal, firewood and agricultural residues.     

Optimum temperatures in a shell and tube condenser with respect to exergy

This paper focuses on evaluation of the optimum cooling water temperature during condensation of saturated water vapor within a shell and tube condenser, through minimization of exergy destruction. First, the relevant exergy destruction is mathematically derived and expressed as a function of operating temperatures and mass flow rates of both vapor and coolant. The optimization problem is defined subject to condensation of the entire vapor mass flow and it is solved based on the sequential quadratic programming (SQP) method. The optimization results are obtained at two different condensation temperatures of 46 °C and 54 °C for an industrial condenser. As the upstream steam mass flow rates increase, the optimal inlet cooling water temperature and exergy efficiency decrease, whereas exergy destruction increases. However, the results are higher for optimum values at a condensation temperature of 54 °C, compared to those when the condensation temperature is 46 °C. For example, when the steam mass flow rate is 1 kg/s and the condensation temperature increases from 46 °C to 54 °C, the optimal upstream coolant temperature increases from 16.78 °C to 25.17 °C. Also, assuming an ambient temperature of 15 °C, the exergy destruction decreases from 172.5 kW to 164.6 kW. A linear dependence of exergy efficiency on dimensionless temperature is described in terms of the ratio of the temperature difference between the inlet cooling water and the environment, to the temperature difference between condensation and environment.