Worldwide, buildings consume over 40% of the total commercial energy, and 36% of this amount is dedicated to heating and cooling of buildings. Therefore, building environment control systems require efficient thermal management (Ürge-Vorsatz et al., 2015). An ideal thermal management that could lower the energy load for cooling and heating respectively would combine passive strategies for thermal control, which are characterized by low cost, straightforward implementation, and energy efficiency, with the on-demand control of heating and cooling, specific for active thermal management strategies. This research was inspired by the capability of cephalopod skin to change the color in a dynamic manner, and such mechanism was applied for infrared radiation.
The scientific challenge of building an efficient platform for thermal control was addressed by using block copolymer materials in the development of nanocomposites with dynamically tunable thermal infrared properties. This has resulted in polymer-based materials capable of controlling a heat flux of 40 W/m2 with transient mechanical input of <3 W/m2 and capabilities for reflecting infrared radiation in a static manner as good as the reference material of the space blanket developed by NASA in 1960.
In indoor spaces, more than 50% of total heat exchange between the human body and the environment takes place through infrared radiation, with a maximum of human skin infrared emission around the wavelength of 9 microns. The prepared polymer-based materials modulate transmission and reflection of infrared radiation in a wide range of frequencies from near infrared to far infrared (up to 25 microns wavelength), thus being capable to modulate the heat exchange of the human body through radiation and the materials can be scaled to large surfaces on the order of square meters. Thus, the polymer nanocomposites manage 60-70 % of the metabolic heat flux from sedentary individuals and can modulate changes in the individual body temperature within a setpoint temperature range of 8 °C. This increase in the setpoint temperature translates into use of air conditioning for cooling/heating with a significantly lowered load, which would further translate into a 3 % decrease of global energy consumption.
