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Air curtain selection:
Entrances to many shops and public facilities are permanently open. Cold air intake from outside may result in draughts and heat loss. In such cases, we suggest application of the DEFENDER air curtain. The perfectly adjusted air stream protects against thermal loss while heating the air coming in from outside. Selection criteria for the relevant unit are given below.
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| Step 1. |
Door frame width should be lower than or equal to the air stream width. One DEFENDER unit for door width of 1 m.
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| Step 2. |
Mounting height
Mounting height and regulation
| Entrance height [m] | Ventilator speed | | 2,5 | 1 | | 3,0 | 2 | | 3,5 | 3 |
Table 1. Ventilator adjustments with reference to the unit mounting height
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| Step 3. |
The heating capacity should be adjusted to the ambient temperature indoors and wind force and direction outdoors; the main criterion for adjustment of the heating capacity is the internal temperature around the doors. The DEFENDER thermostatic controller will start up the heating in relation to the temperatures detected and the thermostat setting. Manual control of the heating capacity should take into account the feeling of thermal comfort indoors.
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| Step 4. |
Make adjustments with reference also to additional factors affecting unit operation (see table below).
Negative factors affecting curtain operation
| Positive factors affecting curtain operation | | Doors or windows permanently open, possibility of draught | Canopies or awnings over entrance mounted outside | | Permanent access to staircases, updraught effect | Revolving doors |
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