Hoval RoofVent CON-9, Design Handbook

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225
E
E
F
G
H
I
J
K
L
M
N
Total recirculation heat Q
R
(in kW)
Q
R
= V
R
· ρ · c · (t
ext
– t
room
)
t
ext
= extract air temperature in °C
Q
R
= 25'600 · 1.2 · 2.79 · 10
-4
· (22 – 20)
Q
R
= 17 kW
Required heat output total Q
H
(in kW)
Q
H
= Q
L
+ Q
V
– Q
R
– Q
M
Q
L
= fabric heat losses in kW
Q
M
= internal heat gains in kW
Use the following criteria for calculation of internal heat
gains (connected loads of machines and lighting): Operating
times, diversity, direct heat output through convection, indi-
rect heat output through radiation, etc.
Q
R
= 78 + 75 – 17 – 12
Q
H
= 124 kW
Required heat output per unit Q (in kW)
Q = Q
H
/ n
Q = 124 / 4
Q = 31 kW
Selection of coil type
■ First, use Table I6 to define the air inlet temperature at
the heating coil.
■ Using the required heat output per unit and the air inlet
temperature at the heating coil, select the required coil
type from Table I7 or Table I8.
At t
fresh
= -15 °C and t
ext
= 22 °C, the air inlet temperature at
the heating coil is 15 °C.
Select coil type B with 34 kW heat output at LPHW
60/40 °C and t
AI
= 15 °C.
Checking the ancillary conditions
■ Maximum mounting height
Select a different coil type or unit size if the actual
mounting height (= distance between the floor and
the bottom edge of the unit) is greater than maximum
mounting height H
max
(seeTable I7, Table I7).
■ Maximum floor area reached
Calculate the floor area reached per unit using the
selected number of units. If it exceeds the maximum
value listed in TableTable I4, increase the number of
units.
■ Compliance with minimum and maximum distances
Check the resulting distances based on the hall geometry
and arrangement of the units, using the information in
Table I9 .
Actual mounting height = 9.2 m
Max. mounting height H
max
= 17.4 m
→ OK
Floor area per unit = 52 · 45 / 4 = 585 m²
Max. floor area reached = 784 m²
→ OK
Minimum and maximum distances can be complied with
when units are arranged symmetrically.
→ OK
Definitive number of units
With a larger number of units, there is more flexibility of
operation. However, the costs are also higher. For an
optimal solution, compare both the costs and ventilation
quality of the system.
Select 4 LH-9s with heating coil type B. They ensure cost-
effective and energy-saving operation.
RoofVent
®
LH
Design example