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[en] Highlights: • Resorption cycle is proposed for the air conditioners (ACs) of electric vehicles (EVs). • Intermittent working modes of the cycle won’t consume the electricity of on-board batteries. • Resorption working pair of CaCl2-NH4Cl-NH3 has reasonable energy density and high COP. • Energy consumption of resorption AC is reasonable if compared with conventional AC of EVs. - Abstract: Conventional compression type air conditioners (ACs) consume a large part of the electricity of batteries on-board of electric vehicles, and that will make the cruising mileage shorter. Sorption and resorption cycles, which are intermittent, may solve this question by the energy storage phases. Both sorption and resorption cycles are analyzed and compared, and both of them have simpler structure if compared with conventional AC for that only two heat exchangers are required. The equilibrium performance analysis shows that resorption working pairs has higher energy density and coefficient of performance (COP) than that of sorption working pairs when the high temperature salt of resorption cycle is same with the halide of sorption cycle. The experimental Clapeyron curves are studied, and CaCl2-NH4Cl-NH3 has best performance. Compared with MnCl2-CaCl2-NH3 and MnCl2-NH4Cl-NH3, the energy density and COP of CaCl2-NH4Cl-NH3 improves by 160% and 35% at least, respectively. The performance of CaCl2-NH4Cl-NH3 is also compared with that of CaCl2-NH3. They have similar smallest energy density, and CaCl2-NH4Cl-NH3 has higher COP if consider the working conditions in the whole year. The energy required for the electric car with a resorption AC is 0.23–0.265 kWh/km, which is acceptable if compared with the results of conventional AC.
[en] Highlights: • An innovative sorption system is proposed to reduce nitrogen oxides emission. • Nanoparticle of carbon coated aluminum plays dual roles in the beginning and end of this system. • The lowest annual required mass of composite sorbent is one quarter of that of urea solution. • Cost of sorption SCR system by using carbon coated aluminum is much lower than that of adblue. - Abstract: A novel sorption system is proposed to reduce nitrogen oxides (NOx) emission, which is regarded as an alternative solution to conventional urea selective catalytic reduction (SCR) technology. Nanoparticle, i.e. carbon coated aluminum (Al@C) plays dual roles at the beginning and end of this system. One is used to prepare novel fuel blend, which is expected to reduce NOx emission due to low fuel consumption. The other is selected for developing composite sorbent for ammonia storage reactor. NOx emission of a diesel engine is tested in terms of various fuel blends. Based on these testing results, working performance of novel sorption SCR system is evaluated. It is indicated that the lowest annual required mass of composite SrCl2 with Al@C is about 98 kg, which is one quarter of urea solution. Comparably, the highest annual required volume of urea solution is 25.6% higher than that of composite SrCl2 with Al@C. Annual required mass ranges from 98 kg to 475 kg whereas annual required volume is in the range from 243 L to 446 L. Feasibility of novel sorption SCR system is further verified, which reveals vast potentials for reducing NOx emission in terms of conversion efficiency and cost.
[en] Highlights: • A small-scale pumpless Organic Rankine Cycle (ORC) system is established. • The maximum power output is 232 W when the hot water inlet temperature is 95 °C. • The highest energy and exergy efficiency are 2.4% and 13.7%. • Pumpless ORC may become one alternative solution to low grade heat utilization. - Abstract: A small-scale pumpless Organic Rankine Cycle (ORC) system driven by the low temperature heat source is established to investigate the overall performance. Hot water temperature from 75 °C to 95 °C is adopted for performance analysis whereas the environmental temperature is about 25 °C. Refrigerant R245fa is selected as working fluid, and scroll expander is employed for power generation. One worth noting fact is that pumpless ORC system shows great potential for low temperature heat recovery. Experimental results indicate that the maximum power output is 232 W, which is obtained at 95 °C hot water inlet temperature. Correspondingly, the average power output is 204 W which is lasted for 6.6 min, revealing the high stability for power generation. For different hot water inlet temperature, the highest energy and exergy efficiency of the system are 2.4% and 13.7%. Besides, performance of novel pumpless ORC system is compared with that of our previous prototype. It shows a remarkable improvement in terms of power output, energy efficiency and exergy efficiency. Power generation process is able to keep constant for 95% of the cycle time. As a result, pumpless ORC may become an alternative solution to low grade heat utilization when compared with conventional small-scale ORC.