Return air ducts in the ceiling plenum of the floor below
discharge from the building and at the fresh air intake
the roof shall be insulated. Sound attenuator shall be
into the building. The run-around coil system shall be
provided, as needed, to connect the return ductwork to
capable of connecting to a microprocessor controller that
the return fan or air-handling unit, in order to minimize
in turn can be connected to a direct digital control (DDC)
noise and vibration.
Building Automation system.
Enthalpy Wheels: A desiccant-impregnated enthalpy wheel
Fan Coil Units. For perimeter spaces, provide four-pipe
with variable speed rotary wheel may be used in the
fan coil units with cooling coil, heating coil, MERV 10
supply and exhaust systems.
filters, internal condensate drain, and overflow drain. Unit
shall have self-contained microprocessor controls and
Sensible Heat Recovery: For sensible heat recovery, a cross-
shall be capable of connecting to and interoperating with
flow, air-to-air (z-duct) heat exchanger shall recover the
a BACnet or LONWORKS Direct Digital Control (DDC)
heat in the exhaust and supply air streams. Z-ducts shall
Building Automation System. Fan coil units shall be
be constructed entirely of sheet metal. Heat-wheels may
capable of operating with unit- mounted or remote-
also be used for sensible heat recovery. Unit shall have
mounted temperature sensor. Installation of fan coil units
variable speed drive for controlling the temperature
above ceiling is not permitted.
leaving the unit.
Kitchen Ventilation Equipment. Products of combustion
have individual zone thermostatic control capable of
from kitchen cooking equipment and appliances shall be
connecting to a self-contained microprocessor that can
delivered outdoor of building through the use of kitchen
interface with a BACnet or LONWORKS Direct Digital
ventilation systems involving exhaust hoods, grease ducts
Control (DCC) Building Automation System.
and make-up air systems where required. Commercial
kitchen equipment applications shall be served by a Type
Heat Recovery Equipment. Heat recovery equipment
I hood constructed in compliance with UL 710 and
shall operate at a minimum of 70 percent efficiency. The
designed in accordance with code having jurisdiction.
heat recovery equipment must be capable of connecting
Grease ducts shall be constructed of black steel not less
to a microprocessor controller that in turn can be
than 1.4 mm (0.055 in, No. 16 gauge) in thickness or
connected to a direct digital control (DDC) Building
stainless steel not less than 1.1 mm (0.044 in, No. 18
Automation System. Pre-filters shall be provided in all
gauge) in thickness. Make-up air systems serving kitchen
heat recovery equipment.
exhaust hoods shall incorporate air-side heat exchange
Heat Pipe: For sensible heat recovery a run-around type
to recover energy from the exhaust stream to be used for
heat pipe shall use refrigerant to absorb heat from the
heating the supply air stream.
air stream at the air intake and reject the heat back into
Motors. All motors shall have premium efficiency as per
the air stream at the discharge of the air-handling unit.
ASHRAE Standard 90.1. Motors that are 0.37 kW (1/2 hp)
System shall have solenoid valve control to operate under
and larger shall be polyphase. Motors smaller than 0.37
partial load conditions.
kW (1/2 hp) shall be single phase. For motors operated
Run-around Coil: A glycol run-around coil may be used
with variable speed drives, provide insulation cooling
with control valves and a pump for part load conditions.
characteristics as per NFPA.
The run-around coils shall be used at the exhaust
139
MECHANICAL
ENGINEERING
5.8
HVAC Components
Revised March 2005 PBS-P100
Previous Page
