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Abstract The operation of Diesel engines on gaseous fuels, commonly known as dual fuel engines, uses Diesel fuel as the pilot fuel and gaseous fuel (methane and sometimes propane in the present work) as the main fuel. The gaseous fuel was inducted in the intake manifold to mix with the intake air. The investigation was conducted on a high speed indirect injection (Ricardo-E6) dual fuel engine and was concerned with the effects of exhaust gas recirculation (EGR) on the dual fuel engine combustion and emissions, in particular, the effects of intake air temperature and diluent admissions (N2 and CO2) on combustion and emissions. The use of diluents to displace oxygen (O2) in the intake air resulted in a reduction in the O2 supplied to the engine, increased the inlet charge thermal capacity (thermal effect) and, potentially, CO2 and N2 participated in the combustion process (chemical effect). In a separate series of tests, the temperature of the engine inlet charge was raised gradually in order to simulate the effect of mixing hot EGR with the engine inlet gaseous fuel air mixture. It was found that the admission of diluents resulted in reductions in the exhaust oxides of nitrogen (NOX). Higher inlet charge temperature increases the exhaust NOX but reduces the unburned hydrocarbon emissions. Finally, when carbon dioxide was added to the inlet gaseous fuel air charge, large reductions in NOX were observed.

Abstract A simple transient analytical approach has been adopted for developing an explicit expression for the water temperature of an indoor swimmingpool coupled to a panel of collectors. For qualitative assessment of the analytical results, computations have been made for the winter climatic conditions of Sri Nagar, India. The effects of several parameters, viz. inlet temperature, heat removal factors, collector, etc. on the performance of the proposed systems have been studied in detail. It is observed that (i) the proposed model agrees with the experimental results of the Australian passive solar swimming pool and (ii) the desired temperature for the indoor swimming pool can be achieved by the active method.

Abstract A mathematical model that describes a trailer scale biomass steam gasification system coupled with a solar collector heat source and a micro gas turbine is reported in this paper. This combined heat and power system is set to a prescribed output of 20 kW e and several system conditions have been optimized in a parametric study to minimize resource consumption rates. Biomass feeding rates under optimal conditions were found to range between 23 and 63 kg/h depending on the types of feedstock and other parameters. Water consumption is reduced through a condensation and recirculation process that is part of a heat recovery unit. Also, solar energy requirements have been reduced by means of a recuperator that extracts heat out of the combustion products. The overall system performance has been evaluated by a utilization factor which was found to range between 30% and 43%. The system has been compared to a baseline case of an air breathing gasification system of a similar scale. It was found that steam gasification produces the syngas with heating values over twice as high as those obtained by air gasification. Steam gasification also led to a 25% and 50% reduction in emission rates of contaminants like CO 2 and nitrogen oxides respectively relative to the baseline case.

Despite the high energy demand in the industrialized world and the pollution problems caused by widespread use of fossil fuels, the need for developing renewable energy sources with less environmental impacts are increasing. Biodiesel production is undergoing rapid and extensive technological reforms in industries and academia. The major obstacle in production and biodiesel commercialization path is production cost. Thus, in previous years numerous studies on the use of technologies and different methods to evaluate optimal conditions of biodiesel production technically and economically have been carried out. In this paper, a comparative review of the current technological methods so far used to produce biodiesel has been investigated. Four primary approaches to make biodiesel are direct use and blending of vegetable oils, micro-emulsions, thermal cracking (pyrolysis) and transesterification. Transesterification reaction, the most common method in the production of biodiesel, is emphasized in this review. The two types of transestrification process; catalytic and non-catalytic are discussed at length in the paper. Both advantages and disadvantages of the different biodiesel production methods are also discussed.

Abstract Heat sink lack of design is one reason that negatively affects the performance of Thermo-Electric Generator (TEG). As compared to conventional cooling systems used with TEG, Heat Pipe Heat Sink (HP-HS) has various points of interest. It is the most appropriate heat exchanger for medium temperature range under 300 °C. However, the performance of TEG with HP-HS could be affected by the fin space, fin length, fin height, fin materials and optimum geometry of HP-HS of the TEG cold side, which is still unknown. Thus, the aim of this study is to conduct an analytical and statistical study on the effects of fins space, fins length, fins height and fin materials parameters on the performance of TEG. In addition, the optimum geometry of HP-HS was investigated. The experimental study has been carried out with different dimensions of fin space, fin length and fin height, depending on the range determined based on previous studies. Besides, two materials were used namely aluminum (AL) and copper (CO). The multi-objective optimisation using response surface methodology (RSM) is applied to determine the optimum geometry of HP-HS to maximise the TEG power output (P), TEG efficiency (η), and to minimise HP-HS cost ($). The responses developed models were determined to be significant at 95% confidence level. It was found that an improvement in TEG performance as compared to literature was achieved. The maximum P and η after optimisation were 8.2 W and 3%, respectively. The percentage difference of TEG η as compared with the best previous results were, 36.7%. In addition, the CO HP-HS was found to be preferred over AL because of its lower costs per power output. CO was 8.75 USD/W, whilst, AL was 10.13 USD. Finally, this study shows an improvement in HP-HS cost, a reduction by 17.9% was achieved when compared with the estimated HP-HS cost in literature.

Abstract Biomass torrefaction is a thermal process, which is similar to a mild form of pyrolysis at temperatures ranging from 200 to 320 °C to produce energy densified solid fuel. The torrefied biomass is almost equivalent to coal and is termed as bio-coal. During torrefaction, highly volatile fraction of biomass including moisture and hemicellulose are released as vapors, providing energy enriched solid fuel, which is hydrophobic and brittle. In this study, bio-coal is produced from palm kernel shell (PKS) in a batch feeding reactor. The operating variables such as temperature, residence time and swiping gas flow rate are optimized. Around 73% yield of bio-coal with calorific value of 24.5 MJ/kg was achieved at optimum temperature 300 °C with residence time of 20 min and nitrogen gas flow rate of 300 mL/min. The thermal yield was calculated to be maximum of 94% for the bio-coal produced at 300 °C. The temperature and residence time of torrefaction are found to be the most sensitive parameters in terms of product yield, calorific value and thermal yield of bio-coal.

Abstract The experiment and simulation investigation of vehicle energy management (VEM) were carried out on a passenger car equipped with a turbocharged gasoline engine. The research results show that the vehicle takes on the characteristic of overcharge under urban conditions to guarantee the power by sacrificing economy. Exhaust energy after catalytic converter and the greater circulation heat transfer loss that account for more than one-third of total energy under New European Driving Cycle (NEDC) are wasted without being used, which indicates that the tested vehicle has great potential for recovering the waste heat. To solve these problems, the VEM model coupled multiple physical fields was developed and calibrated. Original turbocharger was reformed to hybrid turbocharger with the aid of simulation model, and its optimal control strategy based on equivalent consumption minimization strategy (ECMS) was designed. The one-dimensional numerical engine model was introduced into algorithms, which opens new windows for the development of VEM optimization strategies. After the transformation of hybrid turbocharger, the overcharge phenomenon under urban driving cycle has been eliminated. The main contribution to fuel saving comes from the reduction of pumping loss and alternator power consumption. The energy saving rate of hybrid turbocharger in different driving cycles ranges from 1% to 5%, which is mainly affected by the deterioration degree of overcharge on the economy of original machine and the characteristics of regeneration conditions in different driving cycles.