The best time to save energy
When is the best time to save energy in industrial
refrigeration?
Energy can be saved when opportunities exist. During
summer operation, a little energy can be saved because the majority of
refrigeration plants operate at full capacity. Cool weather will give us an
opportunity to save energy. The following energy saving measures can be
implemented:
- Optimized
condensing
pressure
- Optimized part load
operation
- Optimized hot gas
defrosting
During periods of cool weather, condensing pressure
should float to follow fluctuation of wet bulb temperature. However, every
refrigeration plant has a minimum allowable condensing pressure. It is very
important to keep this pressure as low as possible because a refrigeration plant
will operate longer at optimum condensing pressure and more energy can be saved.
Many refrigeration plants have a minimum condensing pressure of 110 -
120 psig to provide adequate hot gas defrosting. My research has shown
that the majority of refrigeration plants can be defrosted at condensing
pressure of 70 - 80 psig. This is not back pressure regulator
setting. This is minimum allowable condensing pressure. During winter operation,
condensing pressure of many refrigeration pants can be lowered by 30 -
40 psig. This is a huge energy saving. Usually, lower condensing
pressure saves up to 50% of total energy savings. If you do
defrosting at condensing pressure higher than 100
psig, most likely this pressure can be lowered and energy can
be saved.
This fall I continue my campaign of free energy savings
for industrial refrigeration plants. Initial part of remote tuning up is free
because it does not require a visit to the plant. Usually, at this stage of
optimization I help end users to reduce minimum condensing pressure by
10 - 20 psig. A typical energy saving of this step is
$20,000 - 50,000. No investment is required. However, remote
tuning up requires participation of operating engineers in initial optimization
of a refrigeration plant operation. Anybody interested in this tuning up, please
contact me.