Ultra-transparent aerogels are designed for better and lower cost solar collectors

We may hear a lot about photovoltaic panels, but solar collectors are also useful-these devices collect heat from sunlight and are used in applications such as home heating. Now, MIT researchers have announced the development of a new material that can make them cheaper and more efficient than ever.

Currently, solar collectors usually include a series of reflectors that focus sunlight onto a central collection device. The device again contains a transparent glass plate on top of the black heat-absorbing material, with a vacuum in the gap between them. Such an arrangement may be expensive and complicated, however, most of the accumulated heat may "escape" through the glass panel. With this in mind, a team at MIT has developed a silicone aerogel to replace glass.

The material is transparent enough to allow a lot of sunlight to pass through, but it also has a high enough insulation value to keep the heat inside. When the MIT research team tested a collector containing aerogel on the roof when the outdoor temperature in winter was below 0ºC, the internal heat-absorbing material could maintain a temperature of 200ºC.

Aerogels are composed of "rich and cheap" ingredients, initially a rapidly drying liquid. What is left is a material mainly composed of air. Due to the rapid drying process, the space between the silica particles is very small. This quality makes it more transparent than other insulating aerogels, with a light transmittance of more than 95%-in contrast, the aerogels previously developed can only reach about 70%.

Researchers now hope that once the technology develops further, solar collectors incorporating aerogels can be used to heat water in pipes and then pump the water through home heating systems. However, before this, the cost of the drying process needs to be reduced-there is currently a need for a special device called a critical point dryer, which is not suitable for commercial scale production of collectors.

The researchers recently published a paper on the study in the journal ACS Nano.