SBIR Phase I: High Efficiency Multi-fluid Jet Refrigeration

这个小型企业创新研究第一阶段项目将展示一种高效的超音速喷射器蒸汽压缩技术，该技术可以在高冷凝器温度（100-120华氏度）下将低至中等等级的热能（200-400华氏度）转化为有用的制冷（20 -50华氏度）。所提出的多流体射流冷却器通过使用具有相对低潜热的推进剂连续夹带和压缩具有相对高潜热的不混溶低温制冷剂来最大化传热效率。初始原型的效率比传统的单流体喷射器高出400%。Phase i研究将在冷凝器温度升高的情况下扩展这些增益。具体的研究重点是：1)高效的射流喷嘴，以超音速膨胀高摩尔质量，低比热比的推进剂，而没有使用传统喷嘴设计时观察到的膨胀/压缩损失；2)将亚音速制冷剂混合到超音速推进剂中，使其动能损失最小，避免制冷剂的音速窒息；3)最大压力恢复扩压器利用弱的斜压缩波代替强的正常激波将混合超音速流过渡到亚音速。双流体喷射器压缩技术的潜在应用包括天然气驱动的空调、集中式太阳能热电厂、低成本的热电联产电厂和热驱动海水淡化。该项目的更广泛影响/商业潜力是减少与世界相关的经济和气候负担？美国对空间冷却的需求日益增长。空调是美国高峰时段用电的主要用途，也是商业建筑最大的能源支出。全球650亿美元的空调设备市场正以每年5%的速度增长；由于它是由电力驱动的机械蒸汽压缩循环主导的，电网的压力——以及由此延伸到环境和经济——也同样在上升。一种安静、清洁、可靠且具有成本效益的热驱动解决方案将大大降低这些风险。不幸的是，目前的技术存在效率低、外形大、需要昂贵的水冷式冷凝器的问题。最初的研发工作已经证明，在中等环境条件下，使用低成本组件构建的优化流体对的喷射器蒸汽压缩机的运行效率可以与电动压缩机相媲美。然而，大众市场的采用需要在极端的外部温度下高效运行。第一阶段的研究将通过最大限度地减少非混相流体对在超音速膨胀和压缩过程中产生的不可逆损失，最大限度地提高冷却功率和排放压力（从而在高冷凝器温度下可操作）。项目成果将有利于高超声速航空电子和低大气喷气推进的邻近领域

This Small Business Innovation Research Phase I project will demonstrate a highly efficientsupersonic ejector vapor compression technology that converts low-to-medium grade thermal energy(200-400F) into useful refrigeration (20F-50F) at high condenser temperatures (100-120F). The proposedmulti-fluid jet cooler maximizes heat transfer efficiency by using a propellant with relatively low latent tocontinuously entrain and compress an immiscible low temperature refrigerant of relatively high latentheat. Initial prototypes have 400% higher efficiencies than conventional single-fluid ejectors. Phase Iresearch will extend these gains while operating at elevated condenser temperatures. Specific researchfoci are: 1) Highly efficient jet nozzles to supersonically expand a high molar mass, low specific heatratio propellant without the expansion/compression losses observed when using conventional nozzledesigns; 2) Mixing of subsonic refrigerant into the supersonic propellant with minimal kinetic energy lossby avoiding sonic choking of the refrigerant; and 3) Maximum pressure recovery diffusers utilizing weak,oblique compression waves instead of strong, normal shock waves to transition the mixed supersonic flowto subsonic velocity. Potential applications for the two-fluid ejector compression technology includenatural gas powered air conditioning, concentrated solar thermal chiller plants, lower cost combinedheating power and cooling plants, and thermally-driven water desalination.The broader impact/commercial potential of this project is reduced economic and climate burdenassociated with the world?s growing demand for space cooling. Air conditioning is the leading usage forpeak-time electricity in the U.S. and largest energy expense for commercial buildings. Globally, the$65billion air conditioning equipment market is growing at 5% p.a.; and because it is dominated by theelectrically-driven mechanical vapor compression cycle the strain on electrical grids - and by extensionthe environment and economy - is rising likewise. A quiet, clean, reliable and cost effective heat-drivensolution would greatly reduce these risks. Unfortunately, status quo technologies suffer low efficiencies,large form factors, and require expensive water-cooled condensers. Initial R&D efforts have proven anejector vapor compressor using optimized fluid pairs built with low cost components can operate atefficiencies competitive with electric compressors when operating in moderate ambient conditions. Massmarketadoption, however, requires efficient operation at extreme outside temperatures. Phase I researchwill maximize cooling power and discharge pressure (thus operability at high condenser temperatures) byminimizing irreversible losses incurred during supersonic expansion and compression of the immisciblefluid pairs. Project findings will benefit adjacent fields of hypersonic avionics and low atmosphere jetpropulsion