Central air tempering system

Outside air for the entire building is drawn in through a central build up unit. The outside air is tempered, heated and cooled, to maintain a con­stant 55F (12,8 C) supply for all zone systems. The tempering unit also contains a bank of modium efficiency prefilters. To assure close control of temperature and help eliminate the possibility of coil freeze up, a present steam coil with internal face and bypass damper sections is used. Steam pressure is maintained on the coils at all times and shut off only when out­side temperature is above freezing. The precool coil is a standard chilled water coil with three-way bypass valve control.

THEME 8.

AIR-HANDING UNITS.

1. Define what system is described:

1. It supplies a varying amount of constant temperature conditioned air to meet the prevailing space load.

2. These systems are very simple to design and reliable to operate.

3. Recognizing that both systems have good features and limitations, a group of hybrid systems evolved.

2. Compare the both systems: Constant Volume Variable Temperature Systems and Variable Volume Constant Temperature Systems.

WORDS TO BE STUDED AND MEMORIZED: