Data Sheet

Technical System Catalogue/Climate control
Sample calculation
3 - 66
Step 1: Raise the water inlet temperature
The temperature in the cold aisle is precisely definable and
identical throughout, thanks to optimised temperature
distribution.
 Increasing the air intake temperature also increases
the waste air temperature.
 Increasing the air intake temperature improves the
performance of free cooling.
Possible energy saving in the production of chilled
water: up to 26%.
Q
total
(Q
sens.
) 80 kW (80 kW) – 79.9 kW (79.9 kW)
T
air; hot
(rel. humidity) 26 °C (45%) – 31 °C (32%)
T
air; cold
(rel. humidity) 15 °C (89%) – 19.8 °C (62.2%)
T
water; inlet
10 °C – 15 °C
T
water; return
15 °C – 20 °C
P
electr.
for cold water 190 MWh/a – 139 MWh/a
–26%
Step 2: Reduce the volumetric air flow
For a constant air volume flow rate, the cooling output
improves with airside temperature difference.
 By reducing the volumetric air flow, the return waste air
temperature is increased,
Possible energy saving in the operation of the fans:
up to 60%.
Q
total
(Q
sens.
) 79.9 kW (79.9 kW) – 88.4 kW (88.4 kW)
T
air; hot
(rel. humidity) 31 °C (32%) – 36 °C (25%)
T
air; cold
(rel. humidity) 19.8 °C (62.2%) – 19.7 °C (64.6%)
V
air
(ext. press.) 22000 m
3
/h (80 Pa) – 17000 m
3
/h (20 Pa)
P
electr.
for CRAC fan 3.6 kW – 1.5 kW
–60%
Step 3: Reduce the throughput
The speed of the pump may be reduced because a smaller
amount of cooling water is required to provide the same
cooling output if the return water temperature is increased.
Possible energy saving in the operation of the pump:
up to 14%.
Potential saving in the production of chilled water:
up to 17%.
Q
total
(Q
sens.
) 88.4 kW (88.4 kW) – 80 kW (80 kW)
T
air; hot
(rel. humidity) 36 °C (25%) – 36 °C (25%)
T
air; cold
(rel. humidity) 19.7 °C (64.6%) – 21.3 °C (54.2%)
T
water; inlet
15 °C – 15 °C
T
water; return
20.6 °C – 23.5 °C
V
water
(P
electr.
) 13.6 m
3
/h (3 kW) – 8.1 m
3
/h (2.3 kW)
P
electr.
for cold water 143 MWh/a – 125 MWh/a
–17%
Summary
Energy saving:
 Fans: 19 MWh/a
 Pumps: 6 MWh/a
 Cold water production: 65 MWh/a
 Overall: 90 MWh/a
Cost saving with Rittal aisle containment:
up to 36%.
Q
total
(Q
sens.
) 80 kW (80 kW) – 80 kW (80 kW)
T
air; hot
(rel. humidity) 26 °C (45%) – 36 °C (25%)
T
air; cold
(rel. humidity) 15 °C (89%) – 21.3 °C (54.2%)
V
air
(ext. press.) 22000 m³/h (80 Pa) – 17000 m³/h (20 Pa)
T
water; inlet
10 °C – 15 °C
T
water; return
15 °C – 23.5 °C
V
water
(P
electr.
) 13.8 m
3
/h (3 kW) – 8.09 m
3
/h (2.3 kW)
P
electr.
for CRAC fan 3.6 kW – 1.5 kW
P
electr.
for cold water 190 MWh/a – 125 MWh/a
P
electr.
Total 248 MWh/a – 158 MWh/a
–36%