摘要：An adjustable ejector expansion device for a CO2 heat pump water heater (HPWP) is proposed to improve the system performance. It has been designed to investigate experimentally the effects of the motive nozzle throat area of the ejector, entrained flow pressure, back pressure and primary flow pressure on the entrainment ratio. Experiments based on different motive nozzle throat areas were conducted and the results of the prototype ejector using CO2 as working fluid are presented. The results show that an adjustable ejector can achieve high performance and work well in a wide range of working conditions.

摘要：水系锌离子电池具有低成本、高安全的特点,有望应用于大规模储能.然而,锌负极的循环稳定性仍不理想,且水系电池缺少合适的亲水隔膜,这限制了水系锌离子电池的实际应用.在本文中,我们报道了一种可用于水系电池的分级多孔的聚偏二氟乙烯-双三氟甲磺酰亚胺锂(PVDF-LiTFSI)(PVDF-Li)隔膜.均匀混合的LiTFSI盐降低了PVDF的结晶性,使隔膜具有优异的机械强度,并形成分级的孔隙结构.这种LiTFSI诱导的分级多孔结构有助于实现Zn2+的快速传输和锌的均匀沉积,同时保证隔膜在水系电解液中具有优异的润湿性.这种先进的PVDF-Li隔膜能显著抑制锌枝晶的生长,提高水系锌离子电池的循环寿命.因此,使用PVDF-Li隔膜的Zn||V2O5电池的初始容量达324 mA h g-1,比传统玻璃纤维隔膜高27%,且容量保持率也得到大幅提升.该研究设计了一种功能隔膜来调控正负极反应的均匀性,这为高性能水系电池的开发提供了新的思路.