The principle of operation of air-heat curtains is as follows: air is taken from the upper area of the lobby, heated in heaters up to 50 °C, fed by a fan into the air distribution chamber and then released through the uniform distribution duct at the door. The air is discharged through cracks or holes in the duct. The resulting jet creates a vertical air curtain. The air can be released from the bottom at the door or from the side to the desired height. Air is supplied to the air curtain from the supply ventilation without additional heating.
According to the principle and effect of the curtain, there can be gate and mixing types. In the first case, the curtain maximally or completely prevents (blocks) air access to the enclosed space; the air velocity from the installation to create such curtains should be high (up to 25 m/s). Such curtains are arranged at low outdoor temperature and frequent opening of doors. In mixing type installations, the rushing cold air is mixed with the heated air of the heat curtain. As a result, warm air enters the room through the door and the curtain, which does not create a feeling of cold blowing.
1. What is the reason for the location of outdoor air intake devices in ventilation systems?
2. Name the main types of fans by type and design.
3. What is the reason for the mandatory installation of the filter in front of the heat exchange equipment (heaters and coolers)?
4. Give an example in which cases it is advantageous to use electric air heaters.
5. What are the advantages of using water heaters?
6. Why the range of air velocity in heat exchange equipment is strictly limited?
7. What is the fundamental difference between water (water-glycol) and freon air coolers?
8. What measures are envisaged to reduce noise in ventilation systems?
9. Which device is used to prevent air flow when the fan is turned off?
10. In which places of the building are provided air heat curtains with heated air?