Design
D - 21
3) Flow in area determination
From the flow in area required, calculated in 1), and the effective flow in area calculated in 2)-C), it is necessary to
fulfill the following two conditions.
1) The overall effective flow in area ‚ret must be greater than the required flow in area Sr.
2) For a layout with 3 or more rows, the smallest value of the area of two adjoining walls Se
12
.
Se
23
.
Se
34
.
Se
41
shall be
greater than 25% of Sr. min (Se
1
.
Se
23
.
Se
34
.
Se
41
) 0.25×Sr
*Where these conditions are not fulfilled, apply the following measures and re-investigate.
●Increase the upstand height
●Install a blow out duct return to item 5-
●Change the foundations to a cat walk
●Increase the opening rate in the walls
●Lower the height of the walls return to item 5--2)
●Increase the distance from wall to unit
Correction of cooling capability
As a result of this criterion, the temperature of the intake air in this combined installation is expected to rise by 3
o
C
during cooling.
Obtain the reduction in cooling capability for each unit from the characteristics for that model type.
(2)Verandah installation criterion
If an outdoor unit is installed on a verandah, where it is surrounded by walls on 5 sides, it is necessary to design the
layout taking short circuits and maintenance space into mind. For installation on each floor of a building is evaluated in
the same way in accordance with the criteria.
1Design points
1) Do not allow the exhaust air from an outdoor unit to create a short circuit, causing the capability of the system to
reduce remarkably.
2) Do not install a gallery on the exhaust outlet.
(Installing a gallery reduces the wind quantity by over 10%)
3) Create an environment in which exhaust air from the outdoor unit will not cause trouble.
4) Satisfy the local regulations regarding operating noise from outdoor units.
5) The distance to the adjacent building should be at least 10m.
6) The design external air conditions are 35
o
CDB or less.
7) Make sure to provide maintenance space.
2 Necessary flow in area
1) For an installation as shown in Figure 1, the shaded area shown in Figure 1 is the flow in area.
2) The necessary flow in area for one outdoor unit is 5m
2
for 8, 10 HP, 10m
2
for 13~20HP, so the shaded area is the
necessary flow in area.
5. Criteria for positioning the outdoor unit
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