AAON M1-011 - Manual (Page 34)

34
11. AAONAIRE
®
Heat Wheel
The AAONAIRE
®
Heat Wheel is a “total energy”
recovery wheel, which means that it can transfer both
sensible and latent energy, that is, heat and moisture,
from one air stream to another. The heat wheel is a
disc composed of spirally wound desiccant matrix
material. The wheel is divided across the center when
installed, and rotated by an electric motor at up to 60
RPM so that one half of the matrix material is exposed
at one moment to the exhaust air stream, and at the
next moment to the ventilation supply air stream. With
a heat wheel, efficiencies of 70 to 85% are achievable
for both sensible and latent energy transfer.
Figure 11 below shows the basics of a heat wheel.
For installation, maintenance, performance, or other
information, consult the AAONAIRE
®
Setup
Information booklet that came with your AAONAIRE
®
heat wheel.
Cleaning
The need for cleaning of the heat wheel will be
determined by the operating schedule, climate, and
regular contaminants of the conditioned space. The
AAONAIRE
®
Heat Wheel is “self-cleaning” in that the
smallest particles will pass through, and larger
particles will land on the wheel surface, and will then
be blown clear as the wheel rotates into the opposite
direction of laminar flow. The primary cleaning need
will be to remove oil based aerosols that have
condensed on energy transfer surfaces. These oily
films can clog micron sized pores in the desiccant
material reducing the wheel’s efficiency. It can take
several years in a reasonably clean environment such
as a school, or an office building, for measurable
efficiency loss to occur. Dirtier air, such as that from a
kitchen, industrial or machine shop, or a smoke filled
room in a bar, will reduce efficiency in a much shorter
period of time.
To clean the wheel, remove the segments from the
wheel frame, and brush foreign material from the face.
Soak the segments in a non-acid based coil cleaner,
or another alkaline detergent, and warm water.
Massaging the matrix with your hands will increase the
cleaning action. Rinse well, and shake excess water
away before reinstalling. For applications where
frequent cleaning is required, it is advisable to keep a
second set of wheel segments on hand. While a set is
soaking, or being cleaned, the spare set can be
replaced in the wheel.
HGBP line connects to
ASC fitting between
TXV and distributor
HGBP
Valves
2 nd Stage
Comp.
HGBP Lines
Factory Piping
Field Piping
Figure 10.2, HGRH with External HGBP Piping
TXV TXV
1 st Stage
Condenser Coil
2 nd Stage
Condenser Coil
1 st Stage
Comp. Reheat Coil
1 st Stage
Evaporator Coil
2 nd Stage
Evaporator Coil
HGRH
Valve
Check Valve
Filter Drier
Isolation
Valves
Filter
Drier