Energy recovery ventilator definitions, Recommended roof openings – COOK ERV User Manual
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B
A
D
C
F
E
Energy Recovery Ventilator Definitions
Bearing, external - Flanged or pillow block bearing used with rotating shaft models.
Bearing, internal - Sealed ball bearing used with fixed shaft models.
Bulb seal - The seal used for both the circumferential seal and the inner seal in the cassettes. They are constructed of
neoprene and configured to seal against the wheel band in the case of the circumferential seal, and against the wheel
face in the case of the inner seal. These seals are noncontact in that there is a slight gap between seal and sealing
face to allow the wheel to turn at high RPMs without overtorquing motor or causing seal damage. These seals have an
integral clip and are clipped to the cassette face panel cutout (circumferential) or to the post (inner).
Cassette - The steel structure that houses the wheel. Typically ERV cassettes are of punched sheet metal panelized
construction.
Energy Enthalpy Wheel - A generic name for an energy conservation wheel. The term enthalpy refers to an air
stream’s total energy (temperature and humidity level).
Exhaust Air - The air stream leaving an ERV that is exhausted to the outside. Exhaust air is building return air that has
been run through the wheel.
Heat Wheel - Synonymous with enthalpy wheel, energy conservation wheel, or total energy recovery wheel. Some
heat wheels are sensible only wheels and should not be confused with total energy recovery wheels.
Latent Energy - Latent energy in the context of wheel discussions is the work done by the wheel to transfer moisture
from one air stream to another. Latent work is accompanied by humidity changes in the air streams.
Media - The chemical composite part of the wheel which actually performs the latent and sensible exchange.
Outdoor Air - The air stream entering an ERV that is brought in from outside. Outdoor air becomes supply air after
going through the wheel.
Purge - A small segment of supply air defined by the gap between the inner seal on the outdoor air edge of the center
post and the supply air edge of the center post. The purge angle is adjustable. The purge captures the small amount
of supply air captive in the wheel when the wheel moves from return to supply and routes it to return to minimize cross
contamination.
Return Air - The air stream entering an ERV that is returned from the building. Return air becomes exhaust air after
going through the wheel.
Sensible Heat - Sensible energy in the context of wheel discussions is the work done by the wheel to transfer heat
from one air stream to another. Sensible work is accompanied by temperature changes in the air streams.
Sensible Wheel - A wheel that does only sensible work, i.e., where only heat is transferred from one air stream to
another and the resultant moisture level remains unchanged.
Supply Air - The air stream leaving an ERV that is supplied to the building space. Supply air is outdoor air that has
been run through the wheel.
Recommended Roof Openings
All dimensions in inches.
Unit Size
Recommended Roof Openings Arrangement V & C
A
B
(Arr. V)
B
(Arr. C)
C
D
E
F
F
(Coil Units)
1500
1-5/8
41
29
18
1-1/2
45-3/4
50-3/4
86-3/4
2500
1-3/4
43
29
20
1-5/8
48-1/2
48-1/2
84-1/2
3500
2-1/2
49
33
22
2
57
61
97
4500
2-1/2
49
35
22
2
63
66
102
5500
2-1/2
55
35
26
2
63
66
102
7000
2-1/2
68
42
31
2
76-1/2
76
112
8500
2-1/2
68
42
31
2
76-1/2
76
112
10000
2-1/2
74
45
38
2
81
96
132