Carel MCmultizone, User Manual

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37
ENG
“MCmultizone” +030221981 - rel. 2.3 - 09.12.2014
cabinet
distribution
maint
enanc
e
12.1 Sizing an MC system
When sizing an MC system, several factors must be considered: air fl ows,
fl ow speed, presence of cooling coils, dimensions of the room where
the humidifi er will be installed. For correct sizing, given the relative
complexity of the factors involved, the applications should be designed
using the documents provided by CAREL.
To calculate the humidifi cation requirements of a certain space, a series
of factors need to be considered:
•
volume of the local (m3);
•
current conditions of the room: temperature (°C) and relative humidity
(% rH);
•
desired conditions in the room: temperature (°C) and relative humidity
(% rH);
•
characteristics of the materials inside (quantity, hygroscopic factor,
number of people);
•
time required to reach steady operation;
•
inlet of outside air (infi ltration, occasional opening of doors or
windows);
•
air change (m3/h);
•
outside design conditions: temperature (°C) and humidity (% rH);
•
condensation on the cooling coil.
Note : If there is no fresh air inlet, once the required relative humidity
value is reach the humidifi cation system will not need to work
much to maintain the humidity level.
Consequently, to save running costs when high capacities are required,
check the time required to reach steady operating conditions.
12.2 Sizing the compressor
Careful attention needs to be paid to sizing the compressor. The air
consumption is determined by the capacity of the installation and not
by the maximum fl ow-rate of the cabinet. Consequently, the number
of atomising heads in the installation and their fl ow-rate need to be
considered. The air fl ow-rate of each head may have the following
values:
MCAA2 MCAB2 MCAC2 MCAD2 MCAE2
Nm 3 /h 3.43 5.08 6.86 8.64 12.7
CFM 2 3 4 5 7.5
The air consumption for all heads is equal to:
- 0.41 m3/h per litre of water at an operating pressure of 2.1 bars;
- 1.27 Nm3/h per litre of water at atmospheric pressure;
- 0.75 CFM per litre of water at atmospheric pressure.
The table below describes the specifi c consumption for each individual
head in Normal m3/h and CFM (Cubic Feet per Minute), referred to
atmospheric pressure:
Calculation example:
Installation of 18 MCAC2 heads supplied by a 230 l/h cabinet.
V = C
head
x n = 6.86x18 = 123.5 Nm3/h = 2058 l/m
(referred to the rated data of the compressor)
where:
V = volume of air taken in by the compressor or introduced into the room
by the installation (Nm3/h)
C
head
= air consumption of each head (Nm3/h)
n = number of heads
Note : In order to guarantee the right air fl ow-rate in all conditions,
the size should be overrated by 10%.
12.3 Sizing air/water lines between cabinet &
distribution system
The pipes or hoses carrying air and water to the atomising heads must
be made from copper or plastic. DO NOT USE GALVANISED STEEL PIPES
as these may release impurities that block or damage the heads. When
supplying the cabinet with demineralised water, only use plastic or
stainless steel pipes. If the cabinet is supplied with demineralised water
(aggressive), Tefl on or liquid Tefl on must be used as the sealant.
In alternative to the above, polypropylene hoses can be used, which
allow faster and simpler connections by welding.
To determine the diameters of the air/water outlet lines, refer to the tables
below. Make sure that the inside diameter of the pipes/hoses selected is
as described in the table under the item “ID”.
Always make sure that the rated pressure of the pipes/hoses is suitable
for the operating pressure of the installation, in any case PN8 or higher
diameter pipes/hoses are recommended.
12. DESIGNING A SYSTEM
system
fl ow-rate l/h
type of heads line length
A B C D E 5 m 10 m 25 m 50 m
no. heads installed per
type
air water air water air water air water
ID mm ID mm ID mm ID mm ID mm ID mm ID mm ID mm
30 11 8 6 4 3 15 12 20 14 20 15 25 18
60 22 15 11 9 6 20 12 25 14 30 15 30 18
120 44 30 22 18 12 30 12 30 14 35 15 40 18
230 85 58 43 34 23 35 12 40 14 45 15 55 18