2.7.5.2 APPLICATIONS
2.7.5.2.1 All applications, listed under paragraph 2.7.4.1(a), can be
evaluated for steam heating, depending upon the availability of steam at
appropriate pressure and the system complexity, if any, involved with the
steam condensate return.
2.7.5.2.2 The use of steam shall also be considered for:
(a) Air Handling Units: To preheat the mixed air up to 12.5 to 15 degrees C
(55 to 60 degrees F), that is, to match with the cooling coil leaving air
temperature.
(b) Heating and Ventilation Units: To heat the outdoor air as determined
either by room thermostat or a discharge air temperature sensor.
2.7.5.2.3 See Article 2.3.1 for the type of steam heating coils.
2.7.5.2.4 Extensive use of the duct mounted steam reheat/heating coils shall
be avoided to alleviate the problems of
(a) Steam Condensate Return
(b) Lack of space available above the suspended ceiling for installation of
steam traps, 300 mm (12 inches) minimum, and for dirt leg additional 150 mm
(6 inches).
(c) Trap Maintenance
(d) Objectionable noise due to steam whistling, condensate flow, and water
hammering
2.7.5.3 EQUIPMENT
(a) Unit Heaters, Heat Exchangers, and Radiators
(b) Air Handling Units
(c) Heating & Ventilation Units
controlled. Wherever the steam heating equipment is used in a space, cooled
by the mechanical refrigeration, a single thermostat, to avoid the possible
occurrence of simultaneous cooling and heating, shall control the space
temperature.
2.7.6 ELECTRIC HEATING
shall be considered only if the heat generated by the fossil fuels is not
available.
2.7.6.2 APPLICATION: The electric heating should be considered for:
(a) Emergency Generator Rooms
HVAC DESIGN MANUAL
2-16
HVAC SYSTEMS AND EQUIPMENT
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