Direct Sunlight-Activated Phase Change Materials for Controlled Heat Storage and Triggered Release

  • The invention provides a solution to utilize phase change materials to controllably store solar energy and release it in the form of heat on demand
  • The new materials exhibit the absorption of visible light (530-625 nm) instead of UV to undergo phase transition and store latent heatThe new materials exhibit the absorption of visible light (530-625 nm) instead of UV to undergo phase transition and store

Advantages

  • The photo-controlled phase transition by the absorption of the natural solar spectrum is achieved for the first time, without the need for high-intensity UV light sources, which distinguishes this invention from the previous work
  • The photo-controlled phase transition solves the problem of uncontrolled loss of thermal energy by preserving the liquid phase as well as the stored latent heat for an extended period of time and over a wide range of temperatures, even at subzero temperatures.

Potential Applications

The proposed device in this invention will be installed on a rooftop and connected to a boiler system. The device will store solar energy during the day, controllably release it at night or when needed, and transfer the heat to water, providing space heating and hot water for buildings. We anticipate that 1 kg of PCMs is able to heat 3 L of water from room temperature to 56 °C, offering a comparable performance to that of commercial boiler systems. Harnessing solar energy and storing heat in a controllable fashion will enhance the energy efficiency of buildings by reducing the consumption of electricity, oil and gas via diurnal or seasonal energy load shifting, which will significantly reduce energy expenses in residential or commercial buildings.