Carel FLSTDMAHUE, Руководство пользователя

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ENG
“FLSTDMAHUE” +030220961 - rel. 1.1 - 28.08.2019
46
Screen index Display description Selection
Gfc14 Priority 0: temperature
¦ 1:humidity
¦ 2: no priority
There are two possible critical conditions, due to simultaneous requests for
1.
cooling and humidification;
2. heating and dehumidification.
Cooling and humidification
ADIABATIC HUMIDIFIER
CONTROL PROBE
Case Return / Room Supply
1 Simultaneous
request for
cooling/
humidification The cascade control ramp
acts on the humidity
request, which becomes
the higher of the two
values and any limits that
compensate for the value
(*) The humidifier controls
based on the supply
humidity control probe,
the cooling coil attempts
to meet the temperature
requirements
2 Cooling only The cascade control
ramp acts to satisfy the
humidity request due to
temperature control Humidity control only
3 Humidification
only Humidity control only Control on humidity
probe, however
maintaining supply
temperature within limits
(Gfc35)
(*) When the humidity reaches the set point, case 2 applies, while if reaching the
temperature set point, case 3 applies.
See par. 9.5 for simultaneous heating and dehumidification.
9.13 Indirect evaporative cooling - IEC
Note: the return temperature probe must be installed to activate IEC.
Definition
The possibility of heat recovery in temperate climates is further increased by
the indirect evaporative cooling technique. One possible operating diagram,
illustrated in the figure, shows how the air is humidified before being
expelled: its temperature decreases, meaning this cooler air can be used to
exchange heat with the outside air, which is in turn cooled without variations
in its moisture content (humidity).
T
1
H
1
T
2
H
2
T
3
H
3
T
4
H
4
6
1
2
3
4
5 7 8
Fig. 9.m
Key
1 Summer cooling rack - IEC 7 Droplet separator
2 Humidification rack in winter - DEC 8 Reheating coil
3 Summer cooling rack T1,H1 Outside temperature/humidity
4 Humidification rack in winter T2,H2 Return temperature/humidity
5 Heating and cooling coils T3,H3 Supply temperature/humidity
6 Heat recovery unit T4,H4 Exhaust temperature/humidity
To measure the efficiency of heat recovery unit, see the chapter on “Heat
recovery”..
Enabling
The following need to be enabled/set:
1.
indirect evaporative cooling - IEC;
2.
the IEC limit probe to be installed position after the droplet separator,
where present;
3.
the analogue output for the adiabatic humidifier request (pressurised
water line 2);
4. the analogue output for the humidification rack control in summer
(pressurised water line 1).
Screen index Display description Selection
Ha14a Enable IEC NO/YES
Rec.-IEC delay 0 s
Ha14b IEC settings:
Humidification
Alternating ¦ IEC + Humidification
Dehumidification Stop IEC ¦ IEC + coil
Hb23c IEC limit probe Position ≠ 0
Hb68 IEC Position ≠ 0
Hc03a Bypass damper with
IEC active Always force closed ¦ no forced closing
Screen index Display description Def Min Max UOM
Gfc32a IEC activation delta
Heat recovery unit + IEC
0 0 15 °C
IEC only 0 0 20 °C
Delta at 100% 0 0 20 °C
IEC diff. 0 0 20 °C
The drawings below refer to the following:
Heat re IEC D4
IEC only D3
Delta at 100% D2
IEC diff. D1
Activation
The following conditions are required for activation:
1.
cooling request;
2. on/off heat recovery unit with pleat exchanger or run-around coil (not
enthalpy wheel);
3.
following conditions are required based on return temperature, outside
temperature and saturation temperature;
4. no humidification request;
5.
no dehumidification request.
Also see the chapter on “Heat recovery” for the conditions in which heat
recovery is activated.
Conditions for activation by temperature
The controller activates IEC in two cases:
1.
the heat recovery unit is already active (a) and the conditions for
activation of IEC are satisfied (b);
a) ExtT- RetT > delta_recov
b) RetT- SatT > D2
Psychrometric diagram
0
5
10
15
20
25
30
35
40
45
-5 0 5 10 15 20 25 30 35 40 45 50 55
DBT °C
x g
/k
g
Specific
humidity
ExtT
SatT
SatT+D1 SatT+D2
{
Delta
recovery
{
D2
SetT
RetT
Key
RetT Return temperature
ExtT
Outside temperature
SatT Saturation temperature