Three large Northern Air® destratification fans are slowly rotating in a sports facility in Norddjurs Municipality.
They have had a major impact on the facility’s operations and energy consumption. How? By continouosly destratifying the room and making use of the heat trapped at ceiling level.
The destratification fans have secured a significant reduction in the inlet air temperature, a balanced temperature between floor and ceiling and significant energy savings.
Technical Manager in the municipality, Karl Juul, explained what the challenges were. Prior to finding a destratification solution, he said: “We find it difficult to maintain a certain temperature in our large sports facilities. We pump large amounts of hot air into the room. But since hot air rises, we still have problems with temperature differences between floor and ceiling level.”
Karl Juul was presented with a solution consisting of destratification fans. Specifically Northern Air® HVLS fans to be used in the ceiling. The municipality then decided to implement this solution in several of their large sports facilities. In the first project, they placed three destratification fans in Toubro Sports Center.
In this particular sports facility, there’s 11 meters to the ceiling. And Karl Juul was instantly impressed with the effect on the temperature:
“I admit, I was a little skeptical to begin with. But just half an hour after the installation I could feel a completely different temperature down by the floor. All the heat normally trapped at the ceiling was instantly felt at floor level. When measuring, we could see the temperature at floor level quickly increased by 3-4 °C.”
All in all, Norddjurs Municipality has achieved energy savings of 31% across their facilities by implementing destratification fans, according to Technical Service Manager Karl Juul.
To maintain a desired temperature, the ventilation system previously supplied hot air between 6.30 AM and 12.30 PM and again from 4.00 PM to 10.30 PM. In total, almost 13 hours a day, which required a lot of energy.
“After installing the destratification fans, we’ve been able to reduce the operating hours of the ventilation system from 13 to 8 hours a day. At the same time, we’ve also managed to lower the inlet air temperature. In the past, we supplied the hall with 46–49 °C air. Now, since the fans help destratify the room and exploit the existing heat much better, we’ve lowered the inlet temperature just 24,5 °C. Even in January with an outdoor temperature of just 3 °C. And we are still working on lowering it further. This is a change that has significantly reduced our energy consumption,” says a very satisfied Karl Juul.
Karl Juul also explains how the municipality strives to maintain a certain temperature of 18.5 °C in their sports facilities. Before they installed the destratification fans in the ceiling, the temperature at floor and ceiling level were very different. According to Karl Juul:
“Today, they’re almost the same. Sometimes the tempereture is completely equalixes. We see fluctuations of less than 0,4 °C. between floor and ceiling now, so it looks very promising for the future.”
“We find it difficult to maintain a certain temperature in our large sports facilities. We pump large amounts of hot air into the room. But since hot air rises, we still have problems with temperature differences between floor and ceiling level.”
After installing the destratification HVLS fans, Karl Juul also experimented with another drastic change. He lowered the desired temperature from 18,5°C to 16,8°C in the sports halls.
The response from the users was almost comical, as they asked Karl: “So, you have turned up the heat, huh?!” To which Karl, with a smile on his face, could reply: “Actually, quite the contrary…”
Example of Northern Air® HVLS destratification fans installed in a sport facility.
“I have only words of praise for Nordicco and their giant fans. The collaboration has worked flawlessly from the beginning and their systems have fully lived up to our expectations,” says Karl Juul and continues:
“Going into the future, I expect that the destratification fans will help us to further reduce the consumption of district heating. I also expect that we can keep operating with a lower inlet air supply temperature which will reduce our electricity consumption. Not to mention the added benefit of us getting a significantly better indoor climate and happy users.”
Based on his experience, he gladly recommends others who have large premises and facilities with high ceilings to look at the opportunities for detratification using the slowly rotating ceiling fan. Destratification ensures that no heat goes to waste and combats temperature differences in a room.
“Here we are, on the threshold of winter and the temperature is slowly falling outside. And I note that I now only need to raise the inlet air supply temperature by 0,5 °C for every 5 °C the temperature falls outside”, he concludes.
After the destratification fans were installed, Karl Juul made sure to be at people’s disposal in the sports hall and to answer questions from users and staff. This way, user involvement could be achieved in relation to the installation and the function of the fans.
Users of Toubro Sports Centre vary from football and handball players to people who play badminton and basketball. The destratification fans therefore benefit a wide range of users of the sports hall in addition to the staff. Thus, Karl has also optimized by using different operating settings based on which group of users are in the hall. For instance by pausing the fans during badminton training sessions.
Example of Northern Air® HVLS fans installed in a sport facility.
In winter, the destratification fans benefit because of the energy savings they could achieve. This was an important goal for the municipality. The warm air supplied to the hall rises and amasses under the ceiling. During the colder months, the Northern Air® HVLS fans slowly push the air down into the occupation area by running in “reverse mode“. This way, thermal equalization, also known as temperature equalization is ensured across the room. And therefore it is possible to use a lower supply temperature. This results in lower energy consumption and reduced CO2 emissions. Furthermore, comfort is increased because the air is circulated and it feels warmer at the ground.
Conversely, the summer setting “forward mode” is used in the Toubro Center when it is hot outside. This way, the temperature sensation can be significantly reduced because the destratification fans create a so-called “chill factor”. By feeling a breeze you feel a cooling effect, although no energy is used to actually cool the air. Fans running in “forward mode” press the air directly downwards and this is how this cooling effect is created. This is not only to great benefit of users but is a much more environmentally friendly alternative than actually cooling the space.
The indoor climate is improved. Pockets of heavy and stagnant air are removed due to air circulation. The pressure on other ventilation systems, such as air conditioning, can also be reduced this way. Ultimately, destratification fans ensure energy savings and are a far more economically and sustainable choice than cooling.
A destratification fan is also known as an HVLS fan. HVLS stands for ‘High Volume Low Speed’ and refers to what the fan does. It circulates enormous amounts of air at low rotational speed. HVLS fans are mechanical ceiling fans with a diameter between 2 and 7 meters.
By moving large volumes of air, one of the main benefits of HVLS fans is their ability to balance out the temperature between floor and ceiling level. This process is also known as destratification. When destratifying a room, you efficiently equalize humidity and temperature differences between floor and ceiling level thus preventing any heat from going to waste at ceiling level. This phenomenon is particularly relevant in spaces with high ceilings, because hot air rises.