Diffuse ceiling ventilation

The experiments are carried out in a climate chamber located at the Department of Civil Engineering Aalborg University. The objective of the experiments is to evaluate the performance of the system combining diffuse ceiling ventilation and thermally activated building construction (TABS) in terms of thermal comfort and energy performance. 20 cases with different boundary conditions are conducted varying on climate condition heat load. TABS water temperature and flow rate with or without diffuse ceiling.

This work presents an energy assessment of the natural ventilation performance within buildings located on both hot-temperate and mild-temperate conditions such as the existing along the central region of Mexico. With the assistance of a coupled thermalairflow simulation program, simulations are run without and with natural ventilation, respectively. Thereby, the consumption of air-conditioning presented in this region is validated with data from literature when natural ventilation is not applied.

This paper presents and analyses the performance of an integrated system with diffuse ceiling ventilation and a thermally activated building construction. A full-scale experiment is carried out in a hot box with an office setup. The performance of the integrated system is evaluated under different boundary conditions, considering different weather conditions, internal heat loads, TABS activation modes and with/without diffuse ceiling. The measurement results indicate that the diffuse ceiling plays a beneficial role improving thermal comfort in the occupied zone.

Diffuse ceiling ventilation is a novel air distribution concept, where the space above a suspended ceiling is used as a plenum and fresh air is supplied into the occupied zone through perforations in the suspended ceiling panels. Due to the low momentum supply, the airflow in the room is driven by buoyancy force generated by heat sources. The previous studies indicate that the diffuse ceiling ventilation system can effectively eliminate the draught risk in the occupied zone and provide a comfortable indoor environment even with low-temperature supply.

Diffuse ceiling ventilation is a novel air distribution device that combines the suspended acoustic ceiling with ventilation supply. A diffuse ceiling distributes the supply air above the acoustic tiles and has proven performance in laboratory experiments. To study the performance in real conditions a classroom was retrofitted with mechanical ventilation and a diffuse ceiling. The employed ceiling comprises active panels penetrable to air and impenetrable passive panels.