Carrier 30HXC Series, Инструкции по установке, эксплуатации и обслуживанию

Страница: 26 / 50

26
7 - APPLICATION DATA
7.1 - Unit operating range
Evaporator 30HXC Minimum Maximum
Evaporator entering water temperature °C 6.8* 21
Evaporator leaving water temperature °C 4** 15
Condenser (water-cooled) 30HXC Minimum Maximum
Condenser entering water temperature °C 20*** 45
Condenser leaving water temperature °C 25 50
Outside ambient operating temperature 30HXC °C 6 40
* For application requiring operation at less than 6.8°C, contact Carrier for unit
selection using the Carrier electronic catalog.
** For application requiring operation at less than 4°C, the units require the use of
antifreeze.
*** Units operating at full load and below 20°C condenser entering water
temperature require the use of a head pressure control with analogue water
control valves (see paragraph on head pressure control).
Maximum ambient temperature: for transport and storage of the units the
minimum and maximum allowable temperatures are -20°C and +70°C. It is
recommended that these temperatures are also applied for transport by
container.
† For operation in ambient temperatures down to -18°C the unit must be equipped
with option 28.
Notes
1. Evaporator and condenser ∆T = 5 K
2. For start-up at full load with a condenser water entering temperature below
20°C, a three-way valve must be used to maintain the correct condensing
temperature
3. Maximum condenser water leaving temperature 50°C (at full load)
4. For low evaporator leaving temperatures <+4°C and >-6°C order option 5
Legend
A Standard unit operating at full load.
B Standard unit operating at reduced load.
C Units operating with head pressure control with analogue water control
valve .
For transient operating modes (start-up and part load) the unit can operate
down to a condenser water temperature of 13°C.
Additional operating range for high condensing temperature units and
non-reversible heat pumps.
Evaporator leaving water temperature, °C
Condenser w
ater entering temper
atur
e, °C
20
25
30
35
45
15
13
50
58
15 10 5 4 °C
A
C
B
13
7.2 - Minimum chilled water flow
The minimum chilled water flow is shown in the table on the next
page. If the flow is less than this, the evaporator flow can be
recirculated, as shown in the diagram. The temperature of the
mixture leaving the evaporator must never be less than 2.8 K
lower than the chilled water entering temperature.
Legend
1 Evaporator
2 Recirculation
7.3 - Maximum chilled water flow
The maximum chilled water flow is limited by the maximum
permitted pressure drop in the evaporator. It is provided in the table
on the next page. If the flow exceeds the maximum value, two
solutions are possible:
•
Select a non-standard evaporator with one water pass less
which will allow a higher maximum water flow rate.
•
Bypass the evaporator as shown in the diagram to obtain a
highter temperature difference with a lower evaporator flow
rate.
For maximum chilled water flow rate
1
Legend
1 Evaporator
2 Bypass