Optimize the Location of Embedded Pipes by Using Low-Grade Natural Thermal Energy/Waste Heat for Thermal Activated Façade

Abstract

The final effect of a thermal activated façade (TAF) wouldn’t only be influenced by the thermal character of the wall, dimensions and distance of the embedded pipes besides flow rate and temperature of the medium, but also by the location of the pipes. The location of the embedded pipes not only affects the final effect of thermoactivated, there is at the same time an obvious correspondence with the temperature of the medium. The simulations and lab investigations have concluded that the optimization the depth of embedded pipes, is necessary in order to use low-grade natural thermal energy/waste heat (LGTE) to achieve TAF. Using the bench mark of the “equivalent thermal resistance” (ER-Value), it is clear that the closer the pipes are located to the outside, the less energy grade is required. However, not all of the LGTE with higher temperature than outdoor air can be used for TAF. The limit of LGTE is the “Invalid Medium Temperature” (IVMT); although there is still a temperature difference between the medium and the outdoor environment, its thermal driving potential is not enough to form an effective heat transfer between the pipe and its surrounding per unit length, so that the medium circulation in the wall hardly contributes to changing the temperature gradient in the wall.