ORNL produces 3D-printed cooling smart wall23rd August 2020
USA: A leading US laboratory has demonstrated a first of its kind 3D-printed concrete smart wall cooling system.
The Empower wall, which measures 5ft (1.5m) by 8ft (2.4m), was 3D-printed at the Department of Energy’s Manufacturing Demonstration Facility at the Oak Ridge National Laboratory (ORNL) using an infrastructure scale additive manufacturing system called SkyBAAM that prints concrete.
SkyBAAM is described as being low-cost, cable-driven, field deployable with the possibility to be adapted for any construction site. It eliminates the need for a gantry system commonly found in large-scale additive manufacturing systems, and is said to be capable of being set up within hours at a construction site with minimal site preparation.
Inside the Empower wall is a thermal storage and active insulation system with a chiller that connects to the wall. Embedded pipes carry chilled water throughout the wall during low peak demand hours, cooling its interior temperature.
Active insulation surrounding the thermal storage can vary thermal conductivity on demand, transferring coolness stored in the interior of the wall to the occupied space when needed.
The Empower wall also uses model predictive control to optimise the operation of the active insulation and thermal storage based on the prediction of future conditions which can include weather or the occupant’s behaviour.
Based on the control predictions, the optimal charging/discharge rate for the wall and timing can be determined. The wall’s embedded sensors can then send a signal to the existing HVAC system to turn on or off.
“By working in concert with the active insulation, this control method minimises energy consumption and energy cost during peak demand times without compromising thermal comfort,” said Pijae Im, an ORNL buildings researcher.
A smart inverter powers the chiller connected to the wall and the pumps that transfer the cool temperature stored in the concrete to the wall’s surface. This inverter is connected to a battery that also stores energy from the building’s main power grid during low electricity demand times and allows the energy to be available when needed during peak demand times.
The smart wall concept will be validated when two additional Empower walls are built for installation in office buildings next year.
ORNL collaborated with the US Department of Energy’s Federal Energy Management Program (FEMP) to produce the walls, test functionality and reveal field validation results. The project is also supported by the Advanced Manufacturing Office and the Building Technologies Office in DOE’s Office of Energy Efficiency and Renewable Energy.