Specifications

Cat 604-5 33
Application Considerations
Application Considerations
Location Requirements
Daikin Magnitude units are designed only for indoor, weather-
protected, non-freezing area consistent with the NEMA 1
rating on the chiller, controls, and electrical panels.
Equipment room temperature for operating and standby
conditions is 40°F to 104°F (4.4°C to 40°C).
Optimum Water Temperatures and Flow
A key to improving energy efficiency for any chiller is
minimizing the compressor pressure lift. Reducing the lift
reduces the compressor work and its energy consumption per
unit of output. The chiller typically consumes more energy
than any other component in the chiller system. Therefore, the
optimum plant design must take into account all of the
interactions between chiller, pumps, and tower.
Higher Leaving Chilled Water Temperatures
Warmer leaving chilled water temperatures will raise the
compressor's suction pressure and decrease the lift, improving
efficiency. Using 45°F (7°C) leaving water instead of 42°F
(5.5°C) will significantly reduce chiller energy consumption.
Evaporator Temperature Drop
The industry standard has been a 10°F (5.5°C) temperature
drop in the evaporator. Increasing the drop to 12°F or 14°F
(6.6°C or 7.7°C) can improve chiller efficiency and reduce
pump energy consumption.
Reduced Evaporator Fluid Flow
Several popular chiller plant control practices including
Variable Primary Flow systems advocate reducing the
evaporator fluid flow rate as the chiller capacity is reduced.
This practice can significantly reduce the evaporator pumping
power while having little effect on chiller energy consumption.
The Magnitude chiller can operate effectively in variable
evaporator flow systems as long as the minimum and
maximum tube velocities are taken into consideration when
selecting the chiller. See section Variable Fluid Flow Rates and
Tube Velocities‚ page 35.
If it is decided to vary the evaporator water flow rate the rate
of change should not exceed 50% per minute and should not
exceed the minimum or maximum velocity limits.
Condenser Entering Water Temperature
As a general rule, a 1°F (0.5°C) drop in condenser entering
water temperature will reduce chiller energy consumption by
two percent. Cooler water lowers the condensing pressure and
reduces compressor work. One or two degrees can make a
noticeable difference. The incremental cost of a larger tower
can be small and provide a good return on investment.
Condenser Water Temperature Rise
The industry standard of 3 gpm/ton or about a 9.5°F (5.3°C)
delta-T works well for most applications.
Reduced Condenser Fluid Flow
Several popular chiller plant control practices also advocate
reducing the condenser fluid flow rate as the chiller load is
reduced. This practice can significantly reduce the condenser
pumping power, but it may also have the unintended
consequence of significantly increasing compressor power
since the leaving condenser water temperature is directly
related to compressor lift and power. The higher compressor
power will typically be larger than the condenser pumping
power reduction and will result in a net increase in chiller plant
energy consumption. Therefore, before this strategy is applied
for energy saving purposes it should be extensively modeled or
used in an adaptive chiller plant control system which will take
into account all of the interdependent variables affecting
chiller plant energy. If it is decided to use variable condenser
fluid flow, the Magnitude chiller can operate effectively as
long as the minimum and maximum tube velocities are taken
into consideration when selecting the chiller.
Chilled Water Temperature
The maximum temperature of water entering the chiller on
standby must not exceed 105°F (46.1°C). Maximum
temperature entering on start-up must not exceed 90°F (32°C).
Minimum chilled water leaving temperature without antifreeze
is approximately 38°F (3.3°C).
Piping
Piping must be adequately supported to remove weight and
strain on the chiller's fittings and connections. Be sure piping
is adequately insulated for job conditions. Install a cleanable
20-mesh water strainer upstream of the evaporator and
condenser. Install enough shutoff valves to permit draining
water from the evaporator or condenser without draining the
complete system.
Note: This product, in its standard configuration, is equipped
with a shell and tube
evaporator with carbon steel shell and
copper tubes. The water or other fluid used in these
evaporators must be clean and non-corrosive to the materials
used in the evaporator. Daikin makes no warranty as to the
compatibility of fluids and materials. Non-compatible fluids
may void the equipment warranty. If the compatibility of the
fluid with the evaporator is in question, a professional water
quality consultant should administer the proper testing and
evaluate compatibility.