The performance of a novel window with energy-saving potential in cold regions of China

The thermal insulation performance of a building's windows can have an important role in its energy-saving capability. In this work, we proposed a novel, energy-saving insulated window (ESIW) and investigated its winter insulation ability by conducting temperature, comfort, energy and entropy analyses of a house outfitted with the ESIW system. The natural indoor temperature of houses with ESIW(A) structure windows was generally higher than that with some single-layer functional glasses. Furthermore, it costs less, and therefore demonstrated the highest cost benefit performance. Then, four different ESIW structures (A to D) were designed and tested. The inner ESIW(D) system with 3-cm insulator thickness and an 8-cm air layer had 4.3% superior performance in energy saving relative to the outer ESIW(A) system, which was comprised of 2-cm insulator thickness and an 8-cm air layer. The lower the insulation level, the greater the energy loss with a decrease in the predicted mean vote of occupants. While the predicted percentage dissatisfied of occupants, entropy of energy loss (S_g), and entropy difference of the whole insulation system (ΔS_iso) would be increased. Finally, the period from 22:00 to 8:00 appears to be the optimal time interval for the use of a roller curtain.