Saturated steam (>121°C and >205 kPa) is widely used in the medical sterilization process known as autoclaving. However, solar-driven steam generation at such high temperature and pressure requires expensive optical concentrators. We demonstrate a passive solar thermal device mostly built from low-cost off-the-shelf components capable of delivering saturated and pressurized steam to drive sterilization cycles even under hazy and partly cloudy weather. Enabled by an optimized ultra-transparent silica aerogel, the device utilizes an efficient thermal concentration strategy to locally increase the heat flux and temperature obviating the need for active optical concentrators. With almost 2× higher energy efficiency (47%) than those previously reported at 100°C, the device demonstrated successful sterilization in a field test performed in Mumbai, India. In addition to enabling passive sterilization, this work promises the development of solar thermal energy systems for saturated steam generation in energy conversion, storage, and transport applications.

饱和蒸汽（> 121°C和> 205 kPa）被广泛用于医疗灭菌过程，称为高压灭菌。然而，在如此高温和高压下产生太阳能驱动的蒸汽需要昂贵的光学集中器。我们演示了一种被动式太阳能热设备，该设备主要由低成本的现成组件构成，即使在朦胧和部分多云的天气下，也能输送饱和和加压的蒸汽以驱动灭菌周期。通过优化的超透明二氧化硅气凝胶，该设备利用有效的热集中策略来局部增加热通量和温度，从而消除了对有源聚光器的需求。与先前在100°C时报道的能量效率相比，该设备的能效提高了近2倍（47％），该设备在孟买进行的现场测试中显示出成功的灭菌效果，印度。除了能够进行被动灭菌外，这项工作还有望开发用于能量转换，存储和运输应用中的饱和蒸汽产生的太阳能系统。