Explain the difference between artificial, vacuum and plenum ventilation

Fill in the table.

	VENTILATION
ARTIFICIAL
VACUUM
PLENUM

6. Answer the questions:

1. What types of ventilation do you know?

2. Is vacuum ventilation a system whereby the internal air is extracted by suitable fans?

3. What is plenum ventilation?

Unit 10

Plenum Ventilation.

1. Memorize the following words and expressions:

Ø Control- контроль

Ø Incoming air- вхідний потік

Ø important feature- важлива риса

Ø Condition- стан

Ø Smoke and dust- дим і пилюка

Ø Correct temperature- правильна температура

Ø Humidity- вологість

Ø To install- встановити

Ø Expensive apparatus- цінні пристрої

Ø Air heaters- повітряні нагрівачі

Ø Washers- обмивачі

Ø Steam- водяна пара

Ø Ductwork- прохід (канал)

Ø Independent boiler- окремий котел

Ø Radiating surface- поверхня нагрівача

Read (he text, study it. Pay attention to new words.

Plenum Ventilation

Control over the incoming air is an important feature of this type of ventilation. Where the conditions are such that the surroundings are noisy and the air is fouled by smoke and dust the plenum system can be contemplated to provide clean air at the correct temperature and humidity. The air is drawn into the building by a fan. and is discharged through ductwork at suitable positions; conveniently placed outlets abstract the vitiated air through ducts con-trolled by an extraction fan of smaller power than the inlet fan. A slight pressure is created owing to a large rate of incoming air than that which is extracted, and consequently any leakage must be outwards.

The plenum system of ventilation is costly to install, owing to the necessity for expensive apparatus consisting of propulsion and extraction fans, air heaters, washers and filters (these vary according to circumstances), and distributing ductwork for the incoming air and outgoing air. A typical arrangement of plenum heating are : the air coming in is heated by a heater battery led from an independent boiler, feeding wrought-iron gilled tubes which have a good radiating surface. In summer, the air can be cooled by passing through the same battery fed by an ammonia refrigerating plant supplying cold water instead of hot water from the boiler. The ductwork is liable to convey sound unless special care is taken with the placing of the fans. These should be well away from the most important rooms, and even then the fan and motor should have an anti-vibration base of rubber or similar material to noise. Another good precaution is to provide flexible connections of leather between the ductwork and the inlets and outlets of the fan casing. The ductwork may be of light iron sheeting, circular in section or formed in brickwork or concrete. In new buildings it is possible to incorporate the various ducts in the general layout of the design but where the ductwork has to be applied to an existing building. The main ductwork should have means of access for cleansing purposes. In the cases of the inlet and outlet grilles, it is usual to make them decorative in character and detachable. From the foregoing description it will be seen that the plenum system is rather complicated and needs skilled attention for maintenance.

3. Answer the following questions:

1. What is an important feature of the plenum ventilation?

2. Is the air fouled by smoke and dust?

3. Can the plenum system be provide clean air at the correct temperature?

4. Can it provide the correct humidity?

5. What does plenum system of ventilation consist of?

6. What are the main components of this system?

7. The air coming in is heated by a heater battery, is not it?

8. Have gilled tubes a good radiating surface?

9. What is provided flexible connections of leather between the ductwork and inlets and outlets?

10. Where it is possible to incorporate the various ducts?

4. Complete the sentences: