4 Warm air has a lower specific gravity than cold air. The resulting physical laws make it rise so that it accumulates beneath the ceiling of the room. This phenomenon is known by everyone who was ever worked on a ladder at ceiling level in a heated room during the winter. There exists a significant temperature difference between the ceiling and the floor. The higher the room, the greater this difference. A ceiling fan with the correct blade profile can send this huge “heat reservoir” back into the living space with no draught. Without any additional heating costs, the temperature at floor level is raised significantly. So the unit pays for itself within two to three heating seasons! These saving are generated automaticly. Because the radiator thermostats sense the now higher temperature, the associated heating system turns on later. Using the rule of thumb that a 1 °C rise in room temperature is equivalent to approximately a 6% increase in heating costs, it can be seen that a great deal of money can be saved with very little effort. In our example, the temperature difference is more than 6 °C*. As a result significant savings in heating costs are generated. 18 * (1+(0.115 * 3)) = 24.21 °C An example: In a 3-metre high room, the floor temperature is given at 18 °C. The temperature on the ceiling is calculated as follows: t Ceiling = tFloor * (1+(0.115 * h)) tCeiling = Ceiling temperature tFloor = Floor temperature h = Ceiling height This is valid regardless of external factors such as thermal insulation, solar radiation, etc. The average air temperature at the ceiling is calculated using the following (simplified) formula: *no air movement, changes of air and over a reasonable time period In every room a warm layer builds up under the ceiling. At floor level, the temperature drops considerably. The heat “sticks” to the ceiling. A ceiling fan with the appropriate blade profile brings the warm air lying under the ceiling back into the living space. Always operate at „max. speed“? As with many things, when using a ceiling fan for heat recovery in winter, the dosage is critical. At too high a fan speed there are draughts, which reverse the feedback of heat. At too slow a speed, the penetration depth is too low and the warm air does not reach the floor. For this reason, all our fans have speed control options. Using our regulating transformers you can exercise precise control up at to 5 speeds to ensure ideal, draught-free operation in your home. We offer our fans in 10 sizes, from a diameter of 75 cm to 212 cm. Thus you can find the right size for your personal use. The larger the fan, the slower it needs to rotate to move the same amount of air - with less wind noise and quieter operation. Forward or reverse? A fan can rotate either forwards or backwards. In forward, or summer, operation, the air is blown directly downward. Due to the low pressure above the fan, the air flows across the floor, up the walls and once again returns downwards via the fan. In reverse, or winter, operation the air is sucked from the ground, pushed against the ceiling and finds its way back down the walls across the floor under the fan where it is sucked up again. What is crucial here is that in reverse operation the airspeed in the living space is much lower than in forward operation and thus draughts appear less unpleasant. Deciding which direction of rotation is better for your application depends mainly on the height of the ceiling. With a ceiling height of more than about 2.6 m, a ceiling fan should operate forwards, even in winter; otherwise the airflow high above the floor is “torn away” and thus no optimum mixing with the warm layer can take place. In this case, the fan should rotate more slowly than in reverse operation. We recommend one of our controllers in this case. Summer operation During the warmer months, a ceiling fan is always operated in the forward direction. A high airspeed, in conjunction with the natural perspiration of the body creates a form of evaporative cooling. Just as in a car an individual at high temperatures feels pleasantly cooled with the windows open. But here again the cool wind should be used in moderation and sparingly. A ceiling fan in the bedroom which runs full speed all night can accelerate the cooling of the body and, at worst, even bring on a cold. Saving energy in both directions: The ceiling height and the speed of rotation determine a ceiling fan’s direction of rotation for bringing heat back to floor level. Forwards Reverse Save on your energy bills
RkJQdWJsaXNoZXIy NjQyNzA=