Thermal protection protects from entering the outside of cold air in winter and hot - in the summer. To achieve the maximum effect, it is necessary to correctly make a thermal curtain, and even even in winter, with a frequent door opening or gate, it will be possible to maintain a comfortable temperature, without making additional energy consumption.
The heat curtain is used to maintain a dealer temperature in the house. In winter, cold air will not penetrate, and in the summer - warm.
The principle of operation of any air-thermal protection is the same. When operating a powerful fan, a high-speed flow is created, which does not give warm air to exit through open doors out of the room, and cold - fall inside.
Air-thermal curtains are used in stores, cafes, restaurants, industrial and storage facilities, that is, where many visitors. So that they work efficiently, it is necessary to correctly make their calculation.
The heat curtain also protects insects, dust and dirt into the room.
The operation of the air-thermal curtain and in the summer, this equipment helps to maintain cool air, obtained due to the operation of the air conditioner, and also does not allow to penetrate into the room insect and dust, it is necessary to simply correctly calculate the required curtain parameters.
When choosing an air-thermal curtain, such parameters are calculated:
- length;
- calculation of heating power;
- stream speed;
- installation type, it can be horizontal or vertical;
- management method using a thermostat or remote control;
- Heat source, it can be hot water or electricity.
Determine the necessary length of the air-thermal curtain
To make the specified calculation, it is necessary to take into account the width of the doorway, the height on which air-thermal protection will be installed, and the air flow rate. The flow rate is directly proportional to the height of the opening. So that the work of the veil is effective, it must be located as close as possible to the doorway.
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The scheme for determining the parameters of the thermal curtain.
If there was a need to establish air-thermal protection in a large opening and a single curtain, it is set to several pieces, having them close to each other. It is necessary to take into account the wind strength on drafts, if there are several inputs and outputs in the room. If there is no possibility to install an air-thermal veil over the doorway, then it can be installed vertically.
Standard length of this equipment - from 600 to 2000 mm. The most common are models of 800-1000 mm long, they correspond to the width of the standard doorway.
Selection of heating power of thermal curtain
This equipment is not a heater, and therefore, if we talk about the power of heating, the calculation is most likely subjectively, as it is an energy-saving device, which prevents the inhibitory air in summer and cold air in winter in the winter. In the technical characteristics of the air-thermal curtain indicate the difference in the temperature of the bleached and suction flow. Each model has already made the optimal selection of the heater power. Some manufacturers of the same models of thermal curtains are produced with different capacities with heaters, and therefore you can always make the correct selection of the required power.Air performance calculation
Calculation of heat flux speed: a - air flow through an open opening during the cold season. B - airflow created by the wind from the street. C is the total air flow through an open opening, taking into account the wind from the street.
In order to correctly calculate the speed of the heat flux, it is best to invite a specialist. Air performance is the main parameter. From this indicator depends the flow rate and the installation height of the curtain.
For example, in order to effectively protect the doorway with a width of 0.8-1 m, whose height is 2-2.5 m, it is necessary to install a veil, the performance of which is 900-1200 cubic meters / h. At the outlet of the curtain, the air velocity will be from 8 to 10 m / s, and near the floor - 2.5-3.5 m / s.
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The selection of equipment with the necessary airflow speed is based on such data:
- For each model there is a recommended installation height, but in specific cases it is necessary to take into account the strength of wind and drafts, to make the appropriate amendments. This is especially true in premises that have a large area and several inputs and outputs;
- The speed of the air flow from the curtain hole directly depends on the diameter of the rotor and the speed of its rotation. The rotor length is more than 800 mm not used, as it is difficult to solve technologically. If the curtain has large sizes, the engine is installed in the middle, and the Rotors are on the sides. This reduces the cost of equipment, but the airflow failure appears in the center.
- Manufacturers indicate the distribution of air flow rates at different distances from the installed equipment. Do not recommend installing a veil that generates too large air flow, as this will lead to large loss of warm air;
- The calculation shows: In order to work normally this equipment, the speed of the output flow at the floor level should be more than 2.5 m / s.
Air flow rates distribution diagram.
Example of calculation:
We carry out air calculation, which comes through the doorway, M3 / C,
LPR = VHV,
V - air speed, m / s;
N and B - height and width of the doorway, m.
Calculate the amount of air, M3 / C, which is necessary to protect against cold air to the room,
Lzov = LPR / J (B / B + 1)
j - airflow coefficient = 0.45;
b - the width of the channel through which air flows, m.
Calculation of thermal power of the heating element, kcal / h,
Quap = 0,24ls (TZ - TNach),
TNAH - air temperature during his fence, ° С
TZ - temperature of the flow of warm air, ° C;
Covered control
You can control the heat curtain with the remote control that can be remote or built-in.
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On the specified hardware must be at least two switches that allow the heater and the fan. More expensive models have the possibility of stepwise control of the power of the heater and the rotational speed of the fan.
This equipment can be controlled using a remote or built-in control panel. Usually, small curtains have built-in control panels, and industrial curtains are controlled remotely, since it will be hard to get to their buttons.
Some models are additionally completed with a thermostat, which makes it possible to turn off the heating elements or fully this equipment when the temperature setpoint is reached.
In industrial models, limit switches are often used, which makes it possible to include heat protection only when the door is opened. Thus, electricity is saved. For ordinary doors, this method of savings does not apply, since it is necessary to exit on operating parameters 5-10 seconds, and during this time the doors are already closed.
To protect against overheating, almost all models have several degrees of protection: without turning on the fan, the heating element is not connected, when the temperature is reached, the power of 80-110 ° C is turned off.
Vertical protection, in contrast to the horizontal, is installed on the side of the doorway. It does not differ from the horizontal, and its height should be at least 3/4 of the height of the opening.
Electricity or hot water as a heat source
Mainly, electricity acts as a heat source, but there are models where hot water performs, it is served from the heating system.
Such systems are more difficult to install, but this is compensated by low costs at high equipment power. Usually such models are used in industrial buildings, where there are open doorways of a large area.