Bard 920-0074 qwserv Manual De Usuario
Manual 2100-533A
Page
Page
6 of 12
ENERGY RECOVERY VENTILATOR
MAINTENANCE
MAINTENANCE
GENERAL INFORMATION
The ability to clean exposed surfaces within air moving
systems is an important design consideration for the
maintenance of system performance and air quality.
The need for periodic cleaning will be a function of
operating schedule, climate, and contaminants in the
indoor air being exhausted and in the outdoor air being
supplied to the building. All components exposed to the
airstream, including energy recovery wheels, may
require cleaning in most applications.
systems is an important design consideration for the
maintenance of system performance and air quality.
The need for periodic cleaning will be a function of
operating schedule, climate, and contaminants in the
indoor air being exhausted and in the outdoor air being
supplied to the building. All components exposed to the
airstream, including energy recovery wheels, may
require cleaning in most applications.
Rotary counterflow heat exchangers (heat wheels) with
laminar airflow are “self-cleaning” with respect to dry
particles. Smaller particles pass through; larger
particles land on the surface and are blow clear as the
flow direction is reversed. For this reason the primary
need for cleaning is to remove films of oil based
aerosols that have condensed on energy transfer
surfaces. Buildup of material over time may eventually
reduce airflow. Most importantly, in the case of
desiccant coated (enthalpy) wheels, such films can close
off micron sized pores at the surface of the desiccant
material, reducing the efficiency with which the
desiccant can adsorb and desorb moisture.
laminar airflow are “self-cleaning” with respect to dry
particles. Smaller particles pass through; larger
particles land on the surface and are blow clear as the
flow direction is reversed. For this reason the primary
need for cleaning is to remove films of oil based
aerosols that have condensed on energy transfer
surfaces. Buildup of material over time may eventually
reduce airflow. Most importantly, in the case of
desiccant coated (enthalpy) wheels, such films can close
off micron sized pores at the surface of the desiccant
material, reducing the efficiency with which the
desiccant can adsorb and desorb moisture.
FREQUENCY
In a reasonably clean indoor environment such as a
school, office building, or home, experience shows that
reductions of airflow or loss of sensible (temperature)
effectiveness may not occur for ten or more years.
However, experience also shows that measurable
changes in latent energy (water vapor) transfer can occur
in shorter periods of time in commercial, institutional
and residential applications experiencing moderate
occupant smoking or with cooking facilities. In
applications experiencing unusually high levels of
occupant smoking, such as smoking lounges, nightclubs,
bars and restaurants, washing of energy transfer
surfaces, as frequently as every six months, may be
necessary to maintain latent transfer efficiency. Similar
washing cycles may also be appropriate for industrial
applications involving the ventilation of high levels of
smoke or oil based aerosols such as those found in
welding or machining operations, for example. In these
applications, latent efficiency losses of as much as 40%
or more may develop over a period of one to three years.
school, office building, or home, experience shows that
reductions of airflow or loss of sensible (temperature)
effectiveness may not occur for ten or more years.
However, experience also shows that measurable
changes in latent energy (water vapor) transfer can occur
in shorter periods of time in commercial, institutional
and residential applications experiencing moderate
occupant smoking or with cooking facilities. In
applications experiencing unusually high levels of
occupant smoking, such as smoking lounges, nightclubs,
bars and restaurants, washing of energy transfer
surfaces, as frequently as every six months, may be
necessary to maintain latent transfer efficiency. Similar
washing cycles may also be appropriate for industrial
applications involving the ventilation of high levels of
smoke or oil based aerosols such as those found in
welding or machining operations, for example. In these
applications, latent efficiency losses of as much as 40%
or more may develop over a period of one to three years.
NOTE: Sensible
performance only
is shown for
winter application.
performance only
is shown for
winter application.
TABLE 3
WINTER HEATING PERFORMANCE — (INDOOR DESIGN CONDITIONS 70°F DB)
t
n
e
i
b
m
A
.
D
.
O
E
T
A
R
N
O
I
T
A
L
I
T
N
E
V
B
D
F
s
e
e
r
g
e
D
.
f
f
E
%
0
8
M
F
C
0
5
4
.
f
f
E
%
1
8
M
F
C
5
7
3
.
f
f
E
%
2
8
M
F
C
0
0
3
T
L
V
S
R
H
S
L
V
T
L
V
S
R
H
S
L
V
T
L
V
S
R
H
S
L
V
5
6
0
3
4
2
4
4
9
1
6
8
4
5
2
0
2
0
4
6
1
5
8
3
0
2
6
1
8
2
3
1
2
9
2
0
6
0
6
8
4
8
8
8
3
2
7
9
0
5
0
4
0
8
2
3
0
7
7
0
4
2
3
6
5
6
2
3
8
5
5
5
0
9
2
7
2
3
8
5
8
5
4
1
5
7
0
6
0
2
9
4
4
5
1
1
0
6
8
4
5
8
9
3
5
7
8
0
5
0
2
7
9
6
7
7
7
4
4
9
1
0
0
1
8
1
6
5
6
9
3
5
1
0
8
4
6
3
1
3
5
6
6
1
1
5
4
0
5
1
2
1
0
2
7
9
0
3
4
2
5
2
1
0
1
1
0
2
8
4
2
9
1
0
0
1
8
2
4
6
6
8
5
4
1
0
4
0
8
5
4
1
4
6
6
1
1
6
1
9
2
0
5
1
2
1
1
4
8
9
9
0
3
2
0
2
7
9
0
7
9
7
0
5
7
1
5
3
0
1
0
7
1
8
0
6
3
1
2
0
4
3
5
7
1
4
1
1
8
4
1
1
3
9
6
2
0
4
3
1
1
8
9
2
9
1
4
0
2
0
3
0
4
4
9
1
2
5
5
5
1
8
8
8
3
0
0
2
6
1
2
2
1
3
1
8
7
0
3
0
6
9
2
1
7
2
6
0
1
3
3
3
2
5
2
0
7
8
1
2
6
9
4
7
1
4
7
3
4
5
2
2
8
1
2
6
7
4
1
3
6
4
3
0
8
5
4
1
5
5
9
1
1
4
2
6
2
0
2
0
0
3
4
2
0
4
4
9
1
0
6
8
4
0
5
2
0
2
2
0
4
6
1
8
4
8
3
0
0
2
6
1
4
8
2
3
1
6
1
9
2
5
1
0
3
7
6
2
4
8
3
1
2
6
4
3
5
5
7
2
2
2
2
4
0
8
1
2
3
2
4
0
2
8
7
1
2
1
6
4
1
8
0
2
3
0
1
0
6
1
9
2
8
2
3
3
2
2
3
8
5
0
0
3
4
2
3
8
6
9
1
7
1
6
4
0
4
4
9
1
1
4
9
5
1
9
9
4
3
5
0
9
5
1
3
2
7
2
5
2
8
1
3
6
5
2
3
6
2
3
2
3
1
2
2
0
0
5
0
6
0
1
2
9
6
2
7
1
1
9
7
3
0
0
2
0
4
3
6
1
2
7
2
4
0
8
6
0
5
3
8
2
4
6
9
2
2
7
8
3
5
0
8
6
2
2
8
9
5
8
1
2
8
0
4
5
-
0
5
4
6
3
0
6
1
9
2
0
9
2
7
5
7
3
0
3
4
0
6
4
2
1
7
7
5
0
0
3
4
2
6
2
9
9
1
4
7
3
4
0
1
-
0
8
8
8
3
4
0
1
1
3
6
7
7
7
0
0
4
2
3
4
4
2
6
2
6
5
1
6
0
2
9
5
2
4
5
2
1
2
6
6
6
4
LEGEND
VLT = Ventilation Load – Total
HRS = Heat Recovery – Sensible
VLS = Ventilation Load – Sensible