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FAQ – questions and answers about destratification ceiling fans

Reducing hall heating costs with industrial ceiling fans


Which fan is the right one for our hall?

In order to be able to select the right fan type, find here the most important criteria:

– hall height: you can choose from a wide variety of devices for hall heights up to 10m, 12m, 16m or 20m (even higher halls can be operated with height-shifted mounting).
– is it necessary to have splash-water and dust proof IP54?
– need of contact protection (z.B. ball-impact or protection from the forklift)?
– need of visual protection?

We will be happy to advise you without obligation.

Should an industrial ceiling fan run forwards and backwards?

The reverse run of the ceiling fans is used in living rooms. In our case, i.e. in industrial halls and in big commercial areas this does not make sense.
In summer and in winter the air flow direction should be downwards.
The efficiency would be reduced in reverse run, due to the air flow over the complete ceiling and all over the walls. The desired effect would not be achievable.

How loud are the fans in actual practice

We put emphasis on a most quiet as possible design of our fans. Please note, that our indications in dB(A) are mesured at 1m distance from the fan.

Basically, the type of the fan is an important factor for the volume:

– housing fans have a greater noise development in relation to the performance.
– our fans with safety guards are significantly quieter. This type of fan is often used without problems in tennis halls, where disturbing noises cannot be accepted.
– our open ceiling fans (without guard) are extraordinarily quiet.

Are ceiling fans with a high diameter suitable for the recirculation of warm air?

Ceiling fans with a very high diameter from 3 to 5 meter are originally developed for a summer use.
Recirculation of warm air and temperature compensation is quite possible. One advatage could be in a 1.000m2-hall, if only one big fans should be installed.
We also see disadvantages and therefore do not sell fans with those high dimensions for the recirculation of warm air:
In the winter months, it is important that the recirculation of the air goes as unnoticed as possible. Undesired air flow must be avoided. To equip a hall of 1.000m2, we use therefore six fans with a diameter of 1,4m. A close cone is conducting the warm air to the floor.  This is how you can achieve the temperature compensation in the complete hall faster and evenly.
One single ceiling fan with a diameter of 5m causes an enormous air flow and will not achieve places a little further away or disfigured areas.
The diameter and the technical design of our fans are selected as follows:
To achieve with the highest level of safety temperature compensation with as little investment and power consumption as possible.

We need a short height because of a crane runway.

The open ceiling fans 03.214 und 03.224 are equipped with a short height 44cm (instead of 69cm).

If properly performed according to our instructions, it is possible to reduce the heigt of the fans 03.210 03.215 even further.

Three chains of 1m lenght are supplied with the closed fans. It is possible to shorten those chains as needed. Please be careful to keep a minimum distance of 30cm from the upper edge of the motor and the ceiling.

Can we hang the ceiling fans lower on a chain?

With the open ceiling fans with rod installation (i.e. 03.210) it is technically not possible and should absolutely not be tried. If properly implemented, it is possible to change the rod into a longer one.

Our closed ceiling fans, for instance the type 03.291, is delivered with three chains per fan with 0,8m each for mounting. In compliance with the accident prevention regulations and our assembly instructions, the use of longer chains is possible if the implementation is professional.

Is dust stirred up by the ceiling fans?

With our stepless speed controller you can precisely set the air flow of the fans for special requirements. The warm air reaches the floor hardly noticeable. In general it is completely unproblematic to offer an additional group.

What are the safety requirements of the fans?

Our ceiling fans are constructed for industrial use at a height of 10 or 20m. Screw connections and other connections are secured several times and are designed for continuous operation. All our open ceiling fans are equiped with an additional safety wire to ensure a direct connection from the engine axle to the hall ceiling.

Especially for safety reasons, all our open ceiling fans are only delivered completely assembled (except for the wings).

Regular tests at independent testing institutes are an important basis for us, although our own requirements usually go beyond that.

Regulator and controler

When do we need speed regulators?

The fans are always running at the highest speed when you do not use a apeed regulator. This could be suitable, if your hall heat is about 10m. Otherwise, the fan is ensuring, that the warm air is reaching the ground without draughts und that the fans are not consuming more than necessary. Sometimes it is necessary to use more speed controler to  balance different hall heights or different use areas (stock/workiung points).

When do we need a controller recirculation warm air 03.431?

Basically, the temperature compensation works without a controller recirculation warm air 03.431.

But continuous operation of the fans is mostly not reasonable
High temperature differences are often compensated within several minutes. This is the reason why the fans should not run continously.
The controller recirculation warm air automatically ensures that the fans are not running too long or too short. In most cases it is sufficient to have one device per hall.

Other inexpensive control options
Other inexpensive, although not so perfect ways to regulate the fans:
– Coupling of the fans to the hall heating system. The fans are just running as long as warm air is coming into the room. This can be optimized with a delay or time relay.
– Interval switch 03.436 to define an interval with working time and break time. Easy setting with two trimmer.
– A simple room thermostat near the ceiling switches the fans on, when a set temperature at the ceiling is achieved.

Why are the speed controller and the controller recirculation hot air not in one device?

This has two reasons:

1.) You will mostly need one controller recirculation hot air and several speed controller for one hall. Especially if you have different room heights and different use of hall areas, you should adjust with several speed controller.

2.) In our view it does not make sense to combine the two devices in order to reduce the speed depending on the temperature difference. There is only one optimal speed: Warm air reaches the ground without disturbing air movements. If you reduce the speed of the fans a bit more, the warm air is just circulating in the upper area and the cold air at the ground area will not move.

Is it possible to run the fans even slower after installation?

Our speed controllers have an internal way to adjust the minimum speed. Follow the instructions.

Further questions

Are changes to the hall heating necessary after installation?

No. The room thermostat of your hall heating is recognizing the advantage and will switch to a energy saving modus.

You can examine together with the heating specialist, if there are existing any further kind of optimization of the hall heating system, f.i.:
– Reduce preheating time
– Extend night-time subsidence
– Remove or shut down distribution channels
– Reset the blinds: The air flow must not be adjusted horizontally to the employees in front of the hot air outlet.
– Increase the airflow

Does hot air recirculation also make sense when gates are often opened?

Fans for the recirculation of hot air are especially useful when you often open the hall door. The inrushing cold air is building a „cold air lake“ at the ground which is often harmful for the employees, the maschines and the devices.
Our fans dissipate the „cold air lake“ in a short time and the temperature is compensated. You can optimate the regulation of the fans in relation to the hall doors depending on local conditions:

1.) Switches at the door can ensure that the warm air is not leaving the room. This is accomplished through turning off the fans during the opening time.
2.) If the employees near open doors are affected by incoming cold air, the fan is able to significantly improve the situation.
3.) As soon as the door is closed again, the fans could restart (primarily for thermostat control) and dissolve the cold air lake.

Is it possible to warm also poorly heated adjoining rooms?

This often works very well: Place the fan with chain suspension at the ceiling of the warm air hall just in the near of the door opening to the cold area. Orient the fan at the bottom of the door opening. The fan 03.291 can be operated in any position and leads up to 18.000m³ warm air into the cold part of the hall.

We not only want to lower heating costs, but also higher room temperatures.

By using ceiling fans, you have two advantages: More heat in the occupied zone and reduction of the heating costs.
You can choose with the room thermostat of the hall heating, what should be the focus:  Set the room thermostat a little higher, for instance 2 degrees. If the compensation of the temperature gains 5 degrees of heat without any use of other energy, you still have 3 degrees to decrease the heating costs.

How can I easily estimate the heating cost savings?

1). Heating cost savings by the compensation of the temperature difference between the ceiling and the floor.
Measure the temperature in the heating period and at normal operation at approximately 40cm under the ceiling (T1) and 40cm above the floor (T2)

Calculate: (T1-T2-1): 2*6 = Percentage of the savings.
Example: T1 = 27° T2 = 18°
(27-18-1):2*6 = 24% of the heating costs savings by the compensation of the temperature difference.
Think about the outside temperature during the measurement: At an outside temperature of 5 ° (weighted mean), you get an estimate of the average heating period. At lower outside temperatures, the temperature difference increases, as does the heating requirement and the potential savings.

2.) Savings by a lower temperature loss at the ceiling of the hall.
The savings result from the lower temperature at the hall ceiling. More precisely it behaves proportionally to the now smaller difference between the inside and outside temperature.

One example: At an outside temperature of 2°C, the ceiling fans reduce the temperature at the ceiling from 27°C to 20°C:
Calculation: 100 – (difference after / difference before * 100)
Calculation example: 100 – (18 / 25 *100) = 28
The loss of transmission at the ceiling could be reduced by 28%.

3.) Further savings through the use of ceiling fans.
You can examine together with the heating specialist, if there are existing any further kind of optimization of the hall heating system, f.i.:
– Reduce preheating time
– Extend night-time subsidence
– Remove or shut down distribution channels
– Increase the airflow
– ….

What is the hole amount of power consumption of industrial destratification in practice?

Here’s an example:
The installations includes 10 ceiling fans 03.210 with 75W each. The fans are installed in 7m height and the run with 80%. The Controller recirculation hot air switches the system on for an average of 3 operating hours per working day.
From this is calculated the power consumption as follows:
10 x 75 x 0,8 x 3 / 1000 = 1,8 kilowatt hours per working day.

How long does it take to distribute the warm air of the ceiling to the hall?

Our planning instructions are designed in a way, that the temperature stratification is removed within 10 minutes. You can therefore profit within this short time from 100% of the advantages and savings. The fast temperature compensation is also important to dissolve the cold air lake within a few minutes after having opened the hall gates.

Are there any ways to improve your offer?

Please ask for bulk prices or second hand devices.
Sometimes we can offer new devices with little scratches, damaged packaging or like that. They are tested and of course delivered with the full guarantee.

You could start with a lower number of fans as proposed in the planning.
Even one fan which brings the warm air to the floor is extremely valuable. With 50% of the planned quantity you could achieve 75% of the possible advantages. In most cases it only takes more time to compensate the temperature. We would be pleased to advise you.

Reduce the number off and the installation costs by increasind the air performance/rotation speed per device.
This could be done in warehouses, which are only entered for a short time or in event halls during the preheating time.

Are there any obstacles concerning the installation of destratification concepts?

Obstacle: Bright radiators which produce exhaust gases which accumulate at the ceiling
If you heat your hall with “bright radiators” and if they dispense the exhaust gases at the ceiling, the air circulation could be harmful. Please ask your installation company or the manufacturer concerniung the exhaust situation at your hall.

Obstacle: Harmful production gases, which accumulate at the ceiling of the hall.
In this case, the air circulation could be harmful. The conditions must be checked by specialists on a case-by-case basis.

Obstacle: Fire alarm concept
With warm air recirculation the air of the hall is mixed almost completely. This is how it hast o function for a optimal warm air heating. Your fire alarm concept has to be prepared for this and should work optimally. Please check, if in case of fire, the system should switch off the elements of the hall heating and the recirculation of warm air.

Do you offer installation?

We cannot offer installation. The installation is simple and can be done by any specialist. We will provide you with the device planning, free of charge and without obligations. We are happy to advise you on any questions relating to the implementation. If you would like to purchase our devices from an installation specialist, they will receive special purchase prices.

Planning instructions

Planning instructions tennis