Standalone hybrid system energy management optimization for remote village considering methane production from livestock manure

Recently, many efforts have been done to overcome increasing fuel consumption. One of the vital solutions is utilization of standalone renewable energy resources hybrid systems. This paper attempts to develop a cost-effective methodology to ascertain optimal design and energy management for a remote village. Different energy resources such as wind and solar, fuel cell, and energy storage systems are employed to satisfy total demands including agriculture, residential, school, and health center. Different hydrogen production methods are proposed to verify the efficiency of the developed methodology. In the proposed village, different waste types such as rice husk, maize straw, livestock, and residential wastes are used to generate the required hydrogen for fuel cells to generate electricity. The main objective of the proposed methodology is minimizing the total cost of the village including total costs of each Distributed Generation (DG), cost of natural gas consumption, penalty for interruption the demands, and cost of CO₂ emission. A Particle Swarm Optimization (PSO) algorithm is employed to solve the optimization problem by minimizing the total system costs while the customers required Loss of Power Supply Probability (LPSP) is satisfied. The suggested hybrid system not only increases the renewable energy penetration but also decreases the natural gas consumption. The results achieved in the course of the present study depict that utilization of energy produced from different types of wastes plays a significant role in conserving fossil fuels and overcoming the fossil fuels depletion. It is concluded from the results that there is about a 17.46% reduction in natural gas consumption when all available waste is utilized. In addition, considering 100% availability for the animal manure reduces the natural gas consumption by reformer from 2.373 to 1.605 million liters which means reduction of the natural gas consumption is 32.35%. The results conclude that H₂ produced by livestock waste is dominating among available wastes. However, there is about 18% reduction in the Cost of Energy (COE), when 100% availability is considered for this type of waste.     

Using demolition wastes from urban regeneration as sensible thermal energy storage material

Efficient use of solar energy in industrial applications calls for a cost‐effective thermal energy storage (TES) system. Packed bed is a viable technology for high‐temperature TES applications. The packing material acting as the TES material has to be sustainable with favorable thermal properties and compatible with the heat transfer fluid. Demolition wastes—leftovers from urban regeneration projects—in many countries are a big burden economically and environmentally. This paper aims to investigate the potential of using demolition wastes as sensible thermal energy storage (STES) material in packed bed column for industrial solar applications below 300°C. STES material samples have been prepared using binding additives with demolition waste dust. Chemical composition, mechanical strength, and thermal analysis tests have been carried out to determine suitability of STES samples. The DSC results showed that new STES samples had average specific heat capacity of 1000 to 1460 J/kg C in temperature range of 100°C to 500°C. The samples were thermally stable until 750°C under TGA analysis. These results showed that demolition wastes are potential low‐cost sensible heat storage material for applications up to 750°C. Furthermore, valorization of demolition wastes as sensible heat storage material is a sustainable approach in reducing fossil fuel consumption of high‐temperature industrial applications and avoiding the use of natural resources as packing material.     

垅型倾斜往复炉排危险废物焚烧炉的设计

焚烧是一种被广泛应用的危险废物处理技术。针对我国危险废物产生状况,提出一种无害化危险废物成型焚烧技术。该技术能同时焚烧固体废物和废液,并对烟气、飞灰和炉渣进行后期处理,实现危险废物的无害化处理。焚烧炉采用垅型倾斜往复炉,炉膛温度低时可喷油助燃,并从炉膛出口抽取部分烟气干燥成型后的固体废物。详细介绍了危险废物成型焚烧系统工艺流程、焚烧炉结构和设计计算方法,并以典型废物为设计燃料,给出了1 500 kg/h焚烧炉的计算结果。     

NOx reduction studies on a diesel engine operating on waste plastic oil blend using selective catalytic reduction technique

The constant escalation in the consumption of petroleum products has compelled researchers to discover for new alternative fuels which can be successfully incorporated in the existing automotive engines. Oil derived from waste plastics is one such alternative, which not only ensures longevity of fossil fuels but also assists in bringing down the hazardous impacts caused by the improper disposal of plastic wastes. This work focuses on the utilization of valuable energy of toxic non-biodegradable waste plastics to lucratively be used as an alternative fuel. An attempt was further made to reduce the NO_X emissions which increased with the use of waste plastic oil blend. The main objective of this experimental investigation is to study the performance & emission characteristics of a twin cylinder CRDI engine subjected to selective catalytic reduction (SCR) after-treatment technique. Different flow rates of ammonia as a reducing agent were tested and concluded that a flow rate of 0.5 kg/hr furnishes optimum results. A comparison of NO_X reduction efficiency was also made between SCR and EGR techniques. The comparison eventually indicated that SCR gives better NO_X conversion efficiency at higher loads without any adverse effect on the engine performance while operating on Waste Plastic Oil blend (P30).     

Integrated fossil fuel and solar thermal systems for hydrogen production and CO2 mitigation

In most current fossil-based hydrogen production methods, the thermal energy required by the endothermic processes of hydrogen production cycles is supplied by the combustion of a portion of the same fossil fuel feedstock. This increases the fossil fuel consumption and greenhouse gas emissions. This paper analyzes the thermodynamics of several typical fossil fuel-based hydrogen production methods such as steam methane reforming, coal gasification, methane dissociation, and off-gas reforming, to quantify the potential savings of fossil fuels and CO₂ emissions associated with the thermal energy requirement. Then matching the heat quality and quantity by solar thermal energy for different processes is examined. It is concluded that steam generation and superheating by solar energy for the supply of gaseous reactants to the hydrogen production cycles is particularly attractive due to the engineering maturity and simplicity. It is also concluded that steam-methane reforming may have fewer engineering challenges because of its single-phase reaction, if the endothermic reaction enthalpy of syngas production step (CO and H₂) of coal gasification and steam methane reforming is provided by solar thermal energy. Various solar thermal energy based reactors are discussed for different types of production cycles as well.     

Synergistic effect of hydrogen and waste lubricating oil on the performance and emissions of a compression ignition engine

The demand for energy is increasing every year. For a long time, fossil fuels have been used to satiate this energy demand. However, using hydrocarbon-based fossil fuels has led to an enormous rise of carbon dioxide levels in the atmosphere resulting in global warming. It is therefore necessary to look for alternatives to fossil fuels. The research carried out till date have shown biomass and waste-derived fuels as plausible alternatives to fossil fuels. The biomass feedstock includes jatropha oil, Karanja oil, cottonseed oil, and hemp oil among others and wastes include used cooking oil, used engine oil, used tire and used plastics etc. In this study, the authors aim to explore waste lubrication oil as a fuel for the diesel engine. The used lubrication oil was pyrolyzed and diesel-like fuel with 80% conversion efficiency was obtained. A blend of the fuel and diesel in the ratio of 80:20 on volume basis was prepared. Engine experiments at various load conditions was carried out with the blend. As compared to diesel, a 2% increase in thermal efficiency, 6.3%, 16.1% and 13.6% decrease in smoke, CO and HC emissions & 3.2% and 1.8% increase in NOx and CO₂ emission were observed at full load with the blend. With an aim to further improve the engine performance and reduce the overall emissions from the engine exhaust, a zero-carbon fuel namely gaseous hydrogen was inducted in the intake manifold. The flow rate of hydrogen was varied from 3 to 12 Litres per minute (LPM). As compared to diesel, at maximum hydrogen flow rate the thermal efficiency increased by 12.2%. HC, CO and smoke emissions decreased by 42.4%, 51.6% and 16.8%, whereas NOx emissions increased by 22%. The study shows that the combination of pyrolyzed waste lubricant and hydrogen were found to be suitable as a fuel for an unmodified diesel engine. Such fuel combination can be used for stationary applications such as power backups.     

Opportunities for heat exchanger applications in environmental systems

There is a worldwide interest in using pollution prevention methods to eliminate or lessen air, water, land and thermal pollution problems. Pollution prevention is designing processes that do not create pollution in the first place. Heat exchangers play an essential role in pollution prevention and in the reduction of environmental impact of industrial processes, by reducing energy consumption or recovering energy from processes in which they are used. They are used: (1) in pollution prevention or control systems that decrease volatile organic compounds (VOCs) and other air pollutant emissions; (2) in systems that decrease pollutants in wastewater discharges, the amount of the discharge and thermal pollution; and (3) used to recover energy in facilities that incinerate municipal solid waste and selected industrial hazardous wastes. Heat exchangers are also used in the heating, cooling and concentration of process streams that are part of many other pollution prevention or control related processes. In this paper, first presented is background information on the role of heat exchangers, their types, and a discussion of environment pollution problems. Next, the role of heat exchangers is outlined in the prevention and mitigation of the following pollution problems: air pollution from VOCs, sulphur oxides (SO_x), nitrogen oxides (NO_x); water pollution from industrial processes, thermal pollution, and land pollution resulting from municipal solid wastes or industrial hazardous wastes. Specific Research and Development needs for environmental heat exchangers are then summarized in the paper. It is hoped that this paper will challenge the heat transfer engineering community to further enhance the role of heat exchangers for pollution prevention and global sustainable development.     

Artificial Neural Network based prediction of performance and emission characteristics of a variable compression ratio CI engine using WCO as a biodiesel at different injection timings

Due to the increasing demand for fossil fuels and environmental threat due to pollution a number renewable sources of energy have been studied worldwide. In the present investigation influence of injection timing on the performance and emissions of a single cylinder, four stroke stationary, variable compression ratio, diesel engine was studied using waste cooking oil (WCO) as the biodiesel blended with diesel. The tests were performed at three different injection timings (24°, 27°, 30° CA BTDC) by changing the thickness of the advance shim. The experimental results showed that brake thermal efficiency for the advanced as well as the retarded injection timing was lesser than that for the normal injection timing (27° BTDC) for all sets of compression ratios. Smoke, un-burnt hydrocarbon (UBHC) emissions were reduced for advanced injection timings where as NO_x emissions increased. Artificial Neural Networks (ANN) was used to predict the engine performance and emission characteristics of the engine. Separate models were developed for performance parameters as well as emission characteristics. To train the network, compression ratio, injection timing, blend percentage, percentage load, were used as the input parameters where as engine performance parameters like brake thermal efficiency (BTE), brake specific energy consumption (BSEC), exhaust gas temperature (T_exh) were used as the output parameters for the performance model and engine exhaust emissions such as NO_x, smoke and (UBHC) values were used as the output parameters for the emission model. ANN results showed that there is a good correlation between the ANN predicted values and the experimental values for various engine performance parameters and exhaust emission characteristics and the relative mean error values (MRE) were within 8%, which is acceptable.     

Hydrogen production by coupling pressurized high temperature electrolyser with solar tower technology

Solar hydrogen production by coupling of pressurized high temperature electrolyser with concentrated solar tower technology is studied. As the high temperature electrolyser requires constant temperature conditions, the focus is made on a molten salt solar tower due to its high storage capacity. A flowsheet was developed and simulations were carried out with Aspen Plus 8.4 software for MW-scale hydrogen production plants. The solar part was laid out with HFLCAL software. Two different scenarios were considered: the first concerns the production of 400 kg/d hydrogen corresponding to mobility use (fuel station). The second scenario deals with the production of 4000 kg/d hydrogen for industrial use. The process was analyzed from a thermodynamic point of view by calculating the overall process efficiency and determining the annual production. It was assumed that a fixed hydrogen demand exists in the two cases and it was assessed to which extent this can be supplied by the solar high temperature electrolysis process including thermal storage as well as hydrogen storage. For time periods with a potential over supply of hydrogen, it was considered that the excess energy is sold as electricity to the grid. For time periods where the hydrogen demand cannot be fully supplied, electricity consumption from the grid was considered. It was assessed which solar multiple is appropriate to achieve low consumption of grid electricity and low excess energy. It is shown that the consumption of grid electricity is reduced for increasing solar multiple but the efficiency is also reduced. At a solar multiple of 3.0 an annual solar-to-H₂ efficiency greater than 14% is achieved at grid electricity production below 5% for the industrial case (4000 kg/d). In a sensitivity study the paramount importance of electrolyser performance, i.e. efficiency and conversion, is shown.     

Importance of Asphaltite Deposits in Southeastern Anatolia

Native energy sources of Turkey are quite limited, and the country is heavily dependent on the import of primary energy from abroad. The demand for electrical energy has increased very rapidly in Turkey due to the ongoing industrialization process and high population growth. Energy consumption in Turkey has continually increased over the past years and reached 82.2 million tons of oil equivalent (Mtoe) in 2000. This figure is expected to continue to grow and reach 115.2 Mtoe in 2005 and 153.9 Mtoe in 2010. In spite of the availability of all types of energy resources in Turkey, 66% of energy consumption is met with imports, as energy production is not sufficient to satisfy the demand for consumption. The primary energy sources of Turkey are hard coal, lignite, asphaltite, bituminous schist, hydropower, oil, natural gas, nuclear, geothermal, solar, wood, and animal and plant wastes. The required electrical energy of Turkey is primarily met from thermal and hydraulic sources, but, in addition to these, in recent times, asphaltite deposits in the Southeastern Anatolia Region of Turkey, roughly 79.969 million tons are found in the Sirnak and Silopi areas, and are mainly consumed in the residential sectors for heating due to its high calorific value (2876–5536 kcal/kg), are becoming important for Turkey to generate electricity energy. With the aim of this, it is planned to produce electrical energy after 2006 with the asphaltite taken out from Sirnak and Silopi region.     

Energy harvesting, reuse and upgrade to reduce primary energy usage in the USA

Two-thirds of input energy for electricity generation in the USA is lost as heat during conversion processes. Additionally, 12.5% of primary fuel and 20.3% of electricity are employed for space heating, water heating, and refrigeration where low-grade heat could suffice. The potential for harnessing waste heat from power generation and thermal processes to perform such tasks is assessed. By matching power plant outlet streams with applications at corresponding temperature ranges, sufficient waste heat is identified to satisfy all USA space and water heating needs. Sufficient high temperature exhaust from power plants is identified to satisfy 27% of residential air conditioning with thermally activated refrigeration, or all industrial refrigeration and process heating from 100 to 150 °C. Engine coolant and exhaust is sufficient to satisfy all air conditioning and 68% of electrical demands in vehicles. Overall, this study demonstrates the potential to reduce USA primary energy demand by 12% and CO₂ emissions by 13% through waste heat recovery. A detailed analysis of thermal energy demand in pulp and paper manufacturing is conducted to demonstrate the methodology for improving the fidelity of this approach. These results can inform infrastructure and development to capture heat that would be lost today, substantially reducing USA energy intensity.     

Potential of renewable energy sources and its applications in Yakushima Island

A study was carried out to see if the potential of renewable energy sources other than hy droelectric power, such as wind, photovoltaic, solar thermal, biomass and waste energy sources, can meet the current energy consumption in Yakushima. The current electricity consumption can be covered by wind and photovoltaic energy sources. The total potential of wind and photovoltaic energy sources is 5.4 times as much as the current electricity consumption. LP gas and kerosene can be replaced by solar thermal and biogas energy. The potential of plant biomass and municipal waste is not sufficient (approximately one third) to cover the rest of the fossil fuels (gasoline, diesel oil and heavy oil). Also, plant biomass and municipal waste must be converted into fluid form. This shortage can be covered by the po tential of wind and photovoltaic energy sources. We also investigated the possibility of tourism expansion using the potential of wind and photovoltaic energy sources. Taking into account three types of capacity (energy, accommodation and transportation), Yakushima can accept approximately four times as many tourists as the current number of tourists.     

Developing a conceptual model for the environmental management of power plant wastes

Despite the vital role of electricity in human life, the energy supply process produces all kinds of pollutants such as solid wastes. Unfortunately, due to the lack of specific charge of administration, lack of legal and statutory criteria for effective control, and lack of supervising organizations, in Iran the industrial wastes couldn’t be managed well. The quantity and quality of waste of power plants have been investigated, and then a questionnaire was sent to all stations. The results showed that the use of Mazut fuel and gas oil will increase the rate of wastes. In thermal-gas power plants, due to the consumption of natural gas and lack of water consumption in the production cycle, less wastes have been produced than the other thermal power plants. To determine and explain the factors affecting the production of waste in power plants, an interview was held in the presence of 40 experts in the field of power plant wastes, and after determining the factors affecting the rate of wastes in power plants, Analytical Hierarchy Processes (AHPs) were used for the weighing and prioritization of each of these factors. In the next step, according to the collected data, the conceptual model for the environmental management of power plants was provided. The most important factors in the production of wastes based on the type of fuel type are the type of power plant and the quality of water. Generally, power plant wastes are divided into three categories: ordinary, industrial, and hazardous. Ordinary wastes could be buried in the landfill of urban wastes. However, in the case of industrial and hazardous wastes, location for the landfill is necessary. Also, some wastes like clarifier sediments and combustion wastes could be reused in other industries in order to reduce the volume of these wastes and in some cases reduces the risk of as well.     

The kinetics of vaporization of a heavy metal from a fluidized waste by an inverse method

This study addresses the emission of heavy metals during the incineration of municipal solid waste. A global method was developed to determine the vaporization rate of the metal from the on-line analysis of exhaust gas. This method differs from direct models, which predict the time course of the metal concentration in the gas from the vaporization rate profile, but which are not practicable because this vaporization rate cannot be measured in real incinerators burning real wastes. The method is based on the determination of the global rate of release of heavy metal from the combustion of model wastes in a fluidized bed. It is an inverse method, which involves only the measured concentration of heavy metal in the exhaust gases and a model developed at the reactor scale. The thermal treatment of model wastes spiked with a metal was performed in a laboratory- scale fluidized bed. In fact, a solid matrix derived from real waste was dosed with Cd, Pb, or Zn and burned to simulate the metal’s release during the incineration of municipal solid waste. An on-line analysis system was linked to the gas outlet of the reactor, and the metal’s vaporization was tracked successfully by continuously measuring by inductively coupled plasma optical emission spectroscopy (ICP-OES) the relative concentration of the metal in exhaust gases. On the theoretical front, a bubbling bed model was developed and validated to calculate the metal’s vaporization rate from its concentration-time profile in the outlet gas. The inverse method consists in identifying these vaporization rates at the particle level from only the on-line diagnostic results and using the model, whatever the waste considered. The data obtained may be used in any process, in which wastes are heated rapidly (several hundreds of degrees per second), as in fluidized beds.     

塔式太阳能原位开采油页岩系统余热回收及参数优化研究

为减少油页岩原位开采过程中的化石能源消耗,构建塔式太阳能聚热页岩油原位开采系统模型,对集热场蒸汽参数和油页岩开采井间距进行优化,并在此基础上展开余热回收研究以提高系统综合能效。结果表明：通过对蒸汽参数和井间距进行优化,系统热效率η可由22.4%升至33.5%,再对生产井出口的蒸汽余热进行回收利用后,系统热效率η进一步提升(升至38.4%),页岩油生产成本C_p由306.0美元/t减少到174.7美元/t。     

中低温热源干燥系统的设计及试验

为解决工农业干燥过程中存在的干燥效率低、能耗高等问题,同时充分利用生产过程中产生的中低品位热能,设计了一种可控温湿度的中低温热源干燥系统,干燥系统由加热系统、排湿换气系统、温湿度控制系统和干燥室组成。介绍了其干燥工艺,分析了其运行性能和能耗情况,通过试验数据分析发现该干燥系统气流温度和速度分布均匀、能耗低,系统在整个干燥过程中的干燥速率为0.122 kg/(kg∙h),整个过程的能耗因子为391.2 kJ/kg。系统适用于以地热能和工业余热等中低温热能为热源的工农业干燥过程。     

Technologies to recover exhaust heat from internal combustion engines

The focus of this study is to review the latest developments and technologies on waste heat recovery of exhaust gas from internal combustion engines (ICE). These include thermoelectric generators (TEG), organic Rankine cycle (ORC), six-stroke cycle IC engine and new developments on turbocharger technology. Furthermore, the study looked into the potential energy savings and performances of those technologies. The current worldwide trend of increasing energy demand in transportation sector are one of the many segments that is responsible for the growing share of fossil fuel usage and indirectly contribute to the release of harmful greenhouse gas (GHG) emissions. It is hoped that with the latest findings on exhaust heat recovery to increase the efficiency of ICEs, world energy demand on the depleting fossil fuel reserves would be reduced and hence the impact of global warming due to the GHG emissions would fade away.     

An experimental investigation on engine performance and emissions of a single cylinder diesel engine using hydrogen as inducted fuel and diesel as injected fuel with exhaust gas recirculation

Fast depletion of fossil fuels is demanding an urgent need to carry out research work to find out the viable alternative fuels for meeting sustainable energy demand with minimum environmental impact. In the future, our energy systems will need to be renewable and sustainable, efficient and cost-effective, convenient and safe. The technology for producing hydrogen from a variety of resources, including renewable, is evolving and that will make hydrogen energy system as cost-effective. Hydrogen safety concerns are not the cause for fear but they simply are different than those we are accustomed to with gasoline, diesel and other fossil fuels. For the time being full substitution of diesel with hydrogen is not convenient but use of hydrogen in a diesel engine in dual fuel mode is possible. So Hydrogen has been proposed as the perfect fuel for this future energy system. The experiment is conducted using diesel–hydrogen blend. A timed manifold induction system which is electronically controlled has been developed to deliver hydrogen on to the intake manifold. The solenoid valve is activated by the new technique of taking signal from the rocker arm of the engine instead of cam actuation mechanism. In the present investigation hydrogen-enriched air has been used in a diesel engine with hydrogen flow rate at 0.15 kg/h. As diesel is substituted and hydrogen is inducted, the NO_x emission is increased. In order to reduce NO_x emission an EGR system has been developed. In the EGR system a lightweight EGR cooler has been used instead of bulky heat exchanger. In this experiment performance parameters such as brake thermal efficiency, volumetric efficiency, BSEC are determined and emissions such as oxides of nitrogen, carbon dioxide, carbon monoxide, hydrocarbon, smoke and exhaust gas temperature are measured. Dual fuel operation with hydrogen induction coupled with exhaust gas recirculation results in lowered emission level and improved performance level compared to the case of neat diesel operation.     

Performance analysis of an industrial waste heat‐based trigeneration system

The thermodynamic performance of an industrial waste heat recovery‐based trigeneration system is studied through energy and exergy efficiency parameters. The effects of exhaust gas inlet temperature, process heat pressure, and ambient temperature on both energy and exergy efficiencies, and electrical to thermal energy ratio of the system are investigated. The energy efficiency increases while electrical to thermal energy ratio and exergy efficiency decrease with increasing exhaust gas inlet temperature. On the other hand, with the increase in process heat pressure, energy efficiency decreases but exergy efficiency and electrical to thermal energy ratio increase. The effect of ambient temperature is also observed due to the fact that with an increase in ambient temperature, energy and exergy efficiencies, and electrical to thermal energy ratio decrease slightly. These results clearly show that performance evaluation of trigeneration system based on energy analysis is not adequate and hence more meaningful evaluation must include exergy analysis. The present analysis contributes to further information on the role of exhaust gas inlet temperature, process heat pressure, ambient temperature influence on the performance of waste heat recovery‐based trigeneration from a thermodynamic point of view. Copyright © 2009 John Wiley & Sons, Ltd.     

Development of new green-fuel production technology by combination of fossil fuel and renewable energy

A new system combining fossil fuel and renewable energy to produce methanol (environmentally benign) with a zero CO₂ emission process was studied. The objectives of this paper are to propose a practical process for the new system, to prove the zero CO₂ emission process for this new system using a system evaluation simulator, and to provide an economical evaluation. The system combining the electrolysis of water (producing both O₂ and H₂) using solar energy with the partial oxidation of coal and natural gas (Case 1) gives the best evaluation for CO₂ reduction and for energy conversion efficiency to upgrade the fossil fuel energy using solar energy. An economical evaluation shows that the product (methanol) cost is nearly the same as that for the conventional (commercial) methanol production process (29.5 yen/kg methanol) when the CO₂ recovery and disposal process is taken into account.