• Energy Research
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Abstract Geological sequestration of CO 2 is an immediately available and technologically feasible means of reducing CO 2 emissions into the atmosphere, which is particularly suited to landlocked sedimentary basins. Geoscience, engineering, economic and public issues need addressing by governments and industry before proceeding with full scale implementation. Specific site selection should be based on a suitability analysis, a proper inventory of potential sites, an assessment of the fate of the injected CO 2 and a capacity determination, together with surface criteria such as CO 2 capture and transport. The suitability analysis, both at the basin and regional scales, is based on geological, geothermal, hydrodynamic, basin maturity, economic and societal criteria. The inventory of sequestration sites needs also identification of major CO 2 point sources and a cost benefit analysis. The potential for CO 2 escape and migration is a deciding factor in screening out unsafe sites. Site capacity should be determined based on in situ conditions and CO 2 properties and behavior. Transforming the geological space into the CO 2 space is an important step along the road map for selection of suitable CO 2 injection sites that allows the identification of safe large capacity sites. An example of application from the Alberta basin is presented.

Abstract Many countries committed themselves in the Kyoto protocol to reduce greenhouse gas (GHG) emissions. Some of these targeted emission reductions could result from a switch from coal-fired to gas-fired electricity generation. The focus in this work lies on Western Europe, with the presence of the European Union Emission Trading Scheme (EU ETS). For the switching to occur, several conditions have to be fulfilled. First, an economical incentive must be present, i.e. a sufficiently high European Union Allowance (EUA) price together with a sufficiently low natural gas price. Second, the physical potential for switching must exist, i.e. at a given load, there must remain enough power plants not running to make switching possible. This paper investigates what possibilities exist for switching coal-fired plants for gas-fired plants, dependent on the load level (the latter condition above). A fixed allowance cost and a variable natural gas price are assumed. The method to address GHG emission reduction potentials is first illustrated in a methodological case. Next, the GHG emission reduction potentials are addressed for several Western European countries together with a relative positioning of their electricity generation. GHG emission reduction potentials are also compared with simulation results. GHG emission reduction potentials tend to be significant. The Netherlands have a very widespread switching zone, so GHG emission reduction is practically independent of electricity generation. Other counties, like Germany, Spain and Italy could reduce GHG emissions significantly by switching. With an allowance cost following the switch level of a 50% efficient gas-fired plant and a 40% efficient coal-fired plant in the summer season (like in 2005), the global GHG emission reduction (in the electricity generating sector) for the eight modeled zones could amount to 19%.

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.

Ever-growing construction industries worldwide require energy saving, environmental friendly, inexpensive, and thermally efficient materials. Driven by this demand, we evaluated the thermal performance and economy of a newly developed PCM called local paraffin. These PCMs as potential thermal energy storage (TES) systems were extracted from Iraqi crude petroleum waste product and encapsulated in the building construction. Two identical test rooms were constructed by incorporating such paraffin (40% oil + 60% wax) on the roof and walls for determining its effect on the heat transfer over the temperature range of 40–44 °C. Experiments were conducted for achieving the controlled comfort temperature of 24 °C (below the PCM melting temperature). Room without PCM encapsulation was demonstrated to consume higher energy at 24 °C than the one with PCM. The energy economy of the PCM incorporated room was assessed by comparing the estimated electricity cost with the building that contains the traditional air conditioning system. Analytical calculation was performed to validate the experimental results. These paraffin based TES systems were established to be suitable alternative for efficient and green energy implementation in the building design for hot climate nations.

Abstract Energy conservation, pollution prevention, resource efficiency, systems integration and life cycle costing are very important terms for sustainable construction. The purpose of this work is to ensure a power supply for the north of the Solar Energy Institute building environment lamps by using wind power to comply with the green building approach. Beside this, the study is to present an energy analysis of the 1.5 kW small wind turbine system (SWTS) with a hub height of 12 m above ground level with a 3 m rotor diameter in Turkey. The SWTS was installed at the Solar Energy Institute of Ege University (latitude 38.24 N, longitude 27.50 E), Izmir, Turkey. NACA 63-622 profile type (National Advisory Committee for Aeronautics) blades of epoxy carbon fiber reinforced plastics were used. The system was commissioned in September 2002, and performance tests have been conducted since then. The performance analysis of the SWTS is quantified and illustrated in the tables, particularly for a reference temperature of 25 °C, 30th of October 2003 till 5th of November 2003 for comparison purposes. Test results show that when the average wind speed is 7.5 m/s, 616 W and 76 Hz electricity is produced by the alternator.

Airflow window is highly useful in conserving building energy, and lessens the comfort problems caused by glazing. In this study, the thermal performance of a natural airflow window was examined through the use of a dynamic model, developed based on the integrated energy balance and airflow networks. The validity of the model was first tested by measured data obtained from a prototype installed at an environmental chamber. The application in the subtropical and temperate climate zones were then examined with the typical weather data of Hong Kong and Beijing. The findings confirmed that the natural airflow window can achieve substantial energy saving in both cities, and the reversible window frame is only required for Beijing, a location with hot summer and cold winter. The space cooling load via fenestration in Hong Kong, a subtropical city, can be reduced to 60% of the commonly used single absorptive glazing. In Beijing, as an example of the temperate climate, this can be reduced to 75% of the commonly used double glazing configuration in the summer period, and the space heat gain can be improved by 46% in the winter period.

Abstract Performance and testing of an improved community size solar cooker have been carried out and compared with a hot box solar cooker with a single reflector. The cooker can meet the requirement of about 80 persons, therefore it is very suitable for hostels, temples, canteens, restaurants, etc. The economic analysis of the cooker has been carried out by considering the annual interest, maintenance cost and inflation in fuel prices and maintenance cost. The payback periods are in increasing order with respect to the fuels, firewood, coal, electricity, LPG and kerosene.

Abstract Under the condition of increasingly serious environmental pollution, rational energy policy plays an important role in the practical significance of energy conservation and emission reduction. This paper defines energy policies as the compilation of energy prices, taxes and subsidy policies. Moreover, it establishes the optimisation model of China’s energy policy based on the dynamic computable general equilibrium model, which maximises the total social benefit, in order to explore the comprehensive influences of a carbon tax, the sales pricing mechanism and the renewable energy fund policy. The results show that when the change rates of gross domestic product and consumer price index are ±2%, ±5% and the renewable energy supply structure ratio is 7%, the more reasonable carbon tax ranges from 10 to 20 Yuan/ton, and the optimal coefficient pricing mechanism is more conducive to the objective of maximising the total social benefit. From the perspective of optimising the overall energy policies, if the upper limit of change rate in consumer price index is 2.2%, the existing renewable energy fund should be improved.

Abstract As NH3 has received extra attention expected to play a key role as an H2 carrier with desirable physical and chemical properties, H2 production via NH3 decomposition becomes a promising way to supply H2 in a cost-competitive and eco-friendly manner. In this study, life cycle techno-economic and carbon footprint analysis is conducted to investigate the feasibility of the NH3 decomposition process in terms of economic performance and CO2 emissions. In particular, the life cycle NH3 supply chain for H2 production is considered including production, transportation, and decomposition back to H2. Based on the classification of NH3 into three different types depending on how the chemical is produced, NH3 price and CO2 emissions are evaluated. In addition, using a commercial process simulator, the decomposition process is modeled and techno-economic analysis for the whole process for H2 production reveals that NH3 price is the most influential economic factor and the H2 production cost can compete with renewable-based H2 but it is still higher than fossil fuel-based H2 production. Moreover, H2 supply via NH3 decomposition is projected based on a domestic implementation plan in the Republic of Korea resulting in estimation of NH3 price, H2 production cost, and corresponding CO2 emissions in the future.