Healthy sport in energy-efficient sports halls

After a long break due to the pandemic, sports of all kinds are finally being played again in sports halls, independent of the weather. Together with Isabel Janowsky and other researchers from the IABP, Prof. Philip Leistner from the Institute for Acoustics and Building Physics (IABP) at the University of Stuttgart, is researching the indoor climate and energy-efficiency of sports halls. The goal is to promote the health and well-being of those playing sports in such halls, while simultaneously saving energy and resources in the operation of sports facilities. The project will be funded for 18 months by the Federal Institute of Sports Science (BISP).

Prof. Philip Leistner and his team from the Institute for Acoustics and Building Physics (IABP) at the University of Stuttgart have already examined many sport and fitness studios, gyms and weight rooms in terms of the properties that enhance performance and healthy conditions, optimally combined with an economical use of energy and resources. As part of a project funded by the German Federal Institute for Sport Sciences (BISP) over a period of 18 months, and supported by sponsors and sports facility operators across Germany, they are committed to carrying out an integrated examination of sports halls of various ages and with varying technical equipment over the winter and summer months.

The scientists' main goal is to create human space models that can be used as the basis for planning guidelines for new buildings and existing sports facilities, and ultimately for intelligent systems that can be used to regulate heating, ventilation and air conditioning in sports halls in such a way that the people who play sports there are always provided with an environment that is perceived as healthy and comfortable, while at the same time ensuring that the buildings, rooms and facilities remain energy efficient. As a result, not only are the visitors happy, but the sponsors and operators too.

"While a lot of thought has been given to the design of office spaces, data on healthy and energy-efficient sports rooms is very sparse and the requirements are sometimes very general," says Leistner. Sometimes, the comfort levels for spaces with a low activity level are also applied to sports halls. However, he also believes that fixed usage temperatures should be challenged, for example, as these consider neither the type of sport being played - from yoga classes to gymnastics, to weight training or team sports - nor the number of athletes and how they are dressed. The fact that most halls do not have air conditioning might save energy, but on hot summer days like those we are experiencing now, this is anything but a guarantee for a healthy indoor climate. In terms of ventilation, the pandemic has also raised questions about whether rooms should be equipped with air purification systems, and how old systems, in particular, will cope with this.

Isabel Janowsky, lead scientist in this field at the IABP, emphasizes that regulating the indoor climate only in accordance with outdoor temperatures ignores many other options for creating a comfortable environment in combination with energy efficiency. She continues: “Due to their use, sports halls experience rapid temperature changes, because those playing sports release lots of energy.” Furthermore, air temperature, air circulation and humidity all play a role in our perception of an environment as comfortable. For example, those training experience even relatively low temperatures as uncomfortably warm if the humidity is high, because evaporative cooling only has a negligible cooling effect on the skin. And in spaces where strenuous activities are carried out over longer periods of time, such as when treadmills are used, it might be better to use digital temperature regulation via air circulation rather than only influencing the temperature of the air. In previous studies, Stuttgart researchers were able to show that that if fitness rooms where people are playing sport have an air temperature of up to 22°C, air circulation speeds of up to just 0.15 m/s are experienced as comfortable, while with temperatures of above 24 °C, a higher air circulation speed is preferred.

The researchers from the Institute of Acoustics and Building Physics would also like to highlight an interesting point: fitness clubs in Germany alone have over 11 million members. When training on the cycle ergometer, rowing machine, stepper & Co, they produce a lot of power, amounting to an estimated 50 GWh annually – pure regenerative energy that could be put to good use.