Abstract
•A novel building envelop based on spatial distribution of material to form the periodic lattice architecture.•For a given relative density of the lattice, the unit-cell size governs the mode of heat transfer.•The unit-cell orientation plays a significant role in defining the thermal performance of the lattice based structures.•Conductive mode of hear transfer dominates the thermal transmittance of the polymer lattices.
A continuous increase in energy prices and the growing concern about global warming has created an urge to increase the energy efficiency of residential buildings. In this paper, the reduction of heat loss by incorporating porosity in a monolithic material was studied. To this aim, various sizes of the polymer-based lattice panels were developed using a triangular unit cell. A new technique based on moulding was used to develop commercial size (1 m2) panels which were not possible with normal 3D printers. A novel, experimental results-based, scaling law was used to predict the thermal performances of these polymer lattice-based panels. Besides, the thermal performance of these lattice-based panels was also investigated using an in-house built calorimeter box and a commercial guard hot box chamber by exposing them to a temperature difference of around 30 °C. It was observed that the scaling up of the unit cell size to manufacture commercial-size panels did not affect its U-value, even though the heat transfer through the lattice cell heavily depends on the unit cell size. It was also observed that the hydraulic diameter of the polymer-lattice structures of value less than 8 mm leads only to a conductive mode of heat transfer. The effect of testing parameters such as sensor location and the temperature gradient across lattice on the U-value of the polymer lattice was also characterised and made recommendations for achieving the higher thermal resistance of the lattice panels to make them suitable for energy-saving in building applications.