User Manual

49
AUTOMATIC CONTROL
3 COOLING CONTROL BT Reason for energy savings
3.7 Different chillers selection control
The goal consists generally in maximizing the
chiller water temperature
0
Constant temperature control
With that a low chilled water temperature will
always be provided independent from the
demand. This results in an unnecessarily high
energy consumption at the chiller(s).
1
Variable temperature control depending on
outside temperature
With that the seasonally varying outside air
temperature is taken into consideration which
leads to higher chilled water temperatures when
appropriate. This results in reduced energy
consumption at the chiller(s).
2
Variable temperature control depending on the
load: This includes control according to room
temperature
With that the actual demand will be considerd.
This leads to a reasonably adjusted chilled water
temperature and by that to a substantial
reduction of the energy consumption.
3.8 Sequencing of different chillers (chilled water
generators)
This control function only applies to a system
with a set of different chiller sizes or chilled water
generator types including Free Cooling and/or
Renewable Energy Sources
0
Priorities only based on running time With that run times can be distributed as desired
amongst the various chillers.
1
Fixed sequencing based on loads only:
E.g. depending on the generators characteristics,
e.g. absorption chiller vs. centrifugal chiller
With that the different chillers can be operated
based on various load situations. This leads to a
certain improvement of the annual performance
factors.
2
Priorities based on generator efficiency and
characteristics:
The generator operational control is set
individually to available generators so that they
operate with an overall high degree of efficiency
(e.g. outside air, river water, geothermic heat,
refrigeration machines)
By considering actual efficiency and operating
situations the correspondingly fitting combination
can be operated which leads to improved annual
performance factors.
3
Load prediction based sequencing:
The sequence is based on e.g. COP and
available power of a device and the predicted
required power.
By considering actual efficiency and operating
situations and by predicting the expected future
consumption the various chillers can be run long
term in an optimal way.