Smart air movement for thermal comfort

In a warming planet, there is a need for limiting the increase in the energy demand for space cooling. Air movement is an energy efficient means to provide thermal comfort in warm environments, minimising or completely avoiding the use of more energy-intensive air conditioning. While the heat generated from a human body does not vary, the forced convection accelerates the heat transfer between the parts of the body skin hit by the air flow and the surrounding thermal environment.  

Ceiling fans are among the most adopted sources of air movement in buildings, and they are usually manually operated. However, within H2020 4RinEU project, a smart algorithm was developed by Eurac Research to automatically adapt the rotational speed based on the air temperature and relative humidity measured in the room, and the occupants’ activity level. This algorithm was initially implemented by Vortice into a commercial device, and then, in H2020 Cultural-E project, both technological development and algorithm validation with human participants were performed. 

Key innovation figures

Vortice Nordik eco ceiling fan before and after the redesign

The key technological step forwards are better integration of the ceiling fan within the HVAC system and hence building energy concept, and the improvement of the ceiling fan body to reduce the blade-to-ceiling distance and integrate a sensor for automatically estimating the occupants’ activity level. 

The ceiling fan is fully integrated with the HVAC system to unleash energy savings potential in the summer season while ensuring a stable and high level of thermal comfort, and it will learn from the occupant’s control preferences and coordinate its action with cooling and ventilation systems for an energy efficient, comfortable and healthy indoor environment. Dynamic building simulations have been used to estimate the energy and comfort performances in different scenarios. The use of connection protocols enables to ensure the effectiveness of the integrated system in the real buildings. 

Without jeopardizing the fans’ performances (i.e. air flow generated), the blade-to-ceiling height was reduced to 30cm to enable the installation of the ceiling fans also in rooms with internal height down to 250cm, which is a common situation in recent and brand new residential buildings in Europe (blade-to-floor distance must always be 230cm or more for safety purposes). Further development of the fan unit was focused on embedding a movement sensor to enable the automatic identification of the activity level which otherwise must be manually selected by the user. In any case, a complete manual operation of the fan is always possible (i.e. rotational speed and flow direction directly chosen by the user overriding the automatic control logic).

Testing & prototypes

View of the experimental setup with ceiling fan installed in the Façade System Interaction Lab at Eurac Research.

Testing and prototyping aimed at validating the algorithm with human participants and improving technological aspects of the fan unit. 

The former were performed by Eurac Research and UniVE personnel within the Eurac Research Façade System Interactions Lab. This lab comprises two identical 30m2 environmental chambers in which air and surface temperatures, relative humidity and air flow rate can be accurately controlled, and furnishing can be adapted to the project’s needs.

Tests with 30 human participants were performed to assess the effectiveness of the algorithm under various thermal conditions and also to consider further scenarios (manual control and reverse flow mode). The results show that the satisfaction level with automatic and manual control was almost identical, therefore highlighting the effectiveness of the automatic algorithm. 

Technology development

If you want to know more about the Smart air movement for thermal comfort, you can check out the following publications.