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An operational cost minimisation model is established for a smart energy hub (S.E. Hub) consisting of a combined heat and power (CHP) unit, a heating, ventilation and air-conditioning (HVAC) system, and thermal and electricity storage units. The optimal operation of CHP is combined with the load management of HVAC under a time-of-use (TOU) tariff. The heat and power split ratio of CHP is dynamically determined during the operation. The scheduling of HVAC load and the charging/discharging of energy storage systems are also determined through the optimisation model. The energy management system can therefore shift the load demand and manage energy supply simultaneously. System operation requirements and environment factors including the outdoor air-temperature variation, seasonal variation, and battery degradation are considered. Comprehensive case studies are carried out to examine the effectiveness of the proposed strategy, from which insights are obtained for different energy management strategies and possible upgrade of S.E. Hub. Simulation results reveal that dynamic control of the CHP heat and power split ratio is an effective way to save the total operational cost, and a clear cost saving is shown through the proposed optimal operation strategy.

Abstract Bio-oil from biomass pyrolysis is a mixture of water and organic compounds, which can be used to prepare coal bio-oil slurry (CBS) by blending with coal. The water content in bio-oil has significant effect on the properties of CBS. 57 CBS samples with Shenmu coal concentration of 31–40 wt% and water content in rice husk bio-oil from 27.40 to 48.71 wt% were prepared. The rheology, thixotropy, characteristic viscosity, maximum solid concentration and static stability of the samples were tested. The results showed that the samples could be divided into two groups based on its rheological behavior: strong pseudoplastic and weak pseudoplastic CBS. During storage, all strong pseudoplastic samples were unstable but most of weak pseudoplastic samples were stable. With the increase of water content in bio-oil, CBS behavior changed from weak pseudoplastic to strong pseudoplastic and the transition occurred in the water content of about 45 wt%. Strong pseudoplastic CBS usually showed larger yield stress and thixotropic loop area compared with weak pseudoplastic ones. For all CBS samples, there was a water content in bio-oil where the characteristic viscosity of CBS was the minimum, and its value decreased with the increase in coal concentration.

Identifying the drivers of carbon dioxide emissions in the manufacturing industry is vital for developing effective environmental policies. This study adopts provincial panel data from 2000 to 2013 and uses nonparametric additive regression models to analyze the drivers of CO2 emissions in the industry. The results show that the nonlinear effect of economic growth on CO2 emissions supports the Environmental Kuznets Curve (EKC) hypothesis. Energy structure has an inverted “U-shape” effect owing to massive coal consumption in the early stages and the optimization of energy structure in the later stage. The inverted “U-shaped” impact of industrialization may be due to the priority development of heavy industry in the early stages and the optimization of industrial structure in the later stages. The impact of urbanization also exhibits an inverted “U-shaped” pattern because of mass consumption of steel and cement products in the early stages and the advancement in clean energy technologies at the later stages. However, specific energy consumption has a positive “U-shaped” impact because of the difference in the speed of technological progress at different times. Thus, the differential effects of these indicators at different times should be taken into consideration when discussing reduction of CO2 emissions in China's manufacturing industry.

Abstract The feasibility of an alternative CO 2 mitigation system and a methanol production process is investigated. The Carnol system has three components: (i) a coal-fired power plant supplying flue gas CO 2 , (ii) a process which converts the CO 2 in the presence of He from natural gas to methanol, (iii) use of methanol as a fuel component in the automotive sector. For the methanol production process alone, up to 100% CO 2 emission reduction can be achieved; for the entire system, up to 65% CO 2 emission reduction can be obtained. The Carnol system is technically feasible and economically competitive with alternative CO 2 -disposal systems for coal-fired power plants. The Carnol process is estimated to be economically attractive compared to the current market price of methanol, especially if credit can be taken for carbon as a marketable coproduct.

Abstract The mutual oxidation of n-pentane and NO2 at 500–1000 K has been studied at equivalence ratios of 0.5 and 1.33 by using an atmospheric-pressure jet stirred reactor (JSR). N-pentane, O2, NO, NO2, CO, CO2, CH2O, C2H4, and CH3CHO are simultaneously quantified, in-situ by using an electron-impact molecular beam mass spectrometer (EI-MBMS), a micro-gas chromatograph (μ-GC), and a mid-IR dual-modulation faraday rotation spectrometer (DM-FRS). Both fuel lean and rich experiments show that, in 550–650 K, NO2 addition inhibits low temperature oxidation. With an increase of temperature to the negative temperature coefficient (NTC) region (650–750 K), NO2 addition weakens the NTC behavior. In 750–1000 K, high temperature oxidation is accelerated with NO2 addition and shifted to lower temperature. Two kinetic models, a newly developed RMG n-pentane/NOx model and Zhao's n-pentane/NOx model (Zhao et al., 2018, Submitted) were validated against experimental data. Both models were able to capture the temperature-dependent NO2 sensitization characteristics successfully. The results show that although NO2 addition in n-pentane has similar effects to NO at many conditions due to fast NO and NO2 interconversion at higher temperature, it affects low temperature oxidation somewhat differently. When NO2/NO interconversion is slow, NO2 is relatively inert while NO can strongly promote or inhibit oxidation.

Abstract Atmospheric water harvesting technologies can be classified based on working principles, namely condensation technology, sorption technology and other technologies. Condensation technology utilizes various refrigeration technologies such as vapor compression cycle, thermoelectric cooling and adsorption/absorption cooling for condensing water vapor. Water harvesting processes can be operated as long as electricity is available. For other technologies, it can be further divided into innovative technologies and hybrid technologies. For innovative technologies, renewable energy powered VCC systems, solar chimney and geothermal cooling systems are used. Based on the above three categories, This paper summarizes these water harvesting technologies from perspectives of system configurations, test setups, simulation methods, performances analysis and important findings. Based on current review study, performances and research gaps of these technologies are compared and evaluated, and possible future research for atmospheric water harvesting in humid or dry climate regions are proposed.

Abstract The univariate sweeping tests for fuel injection pressure, injection timing and exhaust gas recirculation (EGR) rate were conducted on a three-cylinder gasoline extended range Atkinson cycle engine (ACE). The effects of above parameters on combustion, emission and performance of ACE were studied and some useful conclusions were obtained. In general, injection pressure has little effect on combustion and engine performance except at the injection advance of 280 deg, while its effect on emission is obvious. With injection pressure rising, NOx first increases and then decreases, while CO follows a reverse trend. Compared with injection pressure, injection timing has more significant effects. As injection timing is advanced, the max combustion pressure first increases and then decreases and the peaks appear around 300deg and 320deg. The lower EGR rate reduces BSFC and NOx with little influence on other emissions. At the EGR rate of 7%, NOx decreases significantly (up to 57.5%), CO, particle number (PN) and particle density are almost unchanged, and BSFC decreases by 4 g/(kW·h) at most. As EGR rate increases to 11%, only NOx further decreases, while other emissions become worse. Thus, a lower EGR rate (e.g., 7%) combining with reasonable injection advance (300deg) is suggested to improve ACE performance.