The Integrated Hvac System - Lifebreath 350DCS Operation And Installation Manual

The Integrated HVAC System

The HRV has become an integral component of the
HVAC system. Figure A shows an HRV unit providing
fresh air directly to the return air plenum of a rooftop
heat/cool unit.
In the balanced airflow system, the HRV exhaust
removes stale room air (eg. from lunch room, storage
or copy area) and returns to the space an equal
amount of fresh outdoor air, making the use of
an economizer obsolete in conjunction with an
HRV.
Many buildings have ceiling return air plenum as in
Figure B. Fresh air from the HRV can be introduced
directly into the ceiling space but this should occur
near the air handler's intake.
In installations where it is satisfactory to provide
general
ATTENTION
These Illustrations are examples. Be
sure to verify the duct configuration
of intake exhaust on and the unit you are
installing.
STALE AIR
EXHAUST
FRESH AIR
SUPPLY
STALE AIR
EXHAUST
FRESH AIR
SUPPLY
RETURN AIR DUCT
HRV/ERV UNIT
B.D.
HRV/ERV FRESH
AIR SUPPLY
ROOF DECK
CEILING RETURN AIR PLENUM
HRV/ERV UNIT
HRV/ERV FRESH
AIR SUPPLY
21
exhaust from the space, the air to be exhausted may
be taken directly from the return air plenum to the
HRV as it is drawn back to the air handler. Fresh air
supplied by the HRV is then introduced directly into
the return air plenum but at a location closer to the
air handler. The air handler would have a constant
running blower to effectively distribute the fresh air
and remove the stale air. Balancing dampers would
be located in both the HRV supply and exhaust ducts
between the return air plenum and the HRV.
NOTE: At no time should the air handler T.E.S.P. on
the return duct exceed that of the HRV .
CAUTION
When interlocking
an HRV/ERV, care must be taken to ensure
the fans of both units operate in the correct
rotation.
ECONOMIZER
ROOFTOP
UNIT
SUPPLY DUCT
or BREATHER T
B.D.
STALE AIR
EXHAUST TO ERV
ECONOMIZER
ROOFTOP
UNIT
12" BREATHER
SUPPLY DUCTWORK
SPACE
B.D.
B.D.
STALE AIR EXHAUST
a rooftop unit with