
Chiller Optimisation Showing where to Save
The brand of Vitasoy is not only a household name of beverages in Hong Kong,
but equally well known worldwide. The existing plant has been in operation since
1980’s and its operation requires chiller units which cool mainly office space
as well as some manufacturing and storage areas. The cost of operating the
chillers contributes significantly to Vitasoy’s overheads.
To further enhance the energy efficiency, CLP conducted Chiller Optimisation
Services on all four chiller units by using comprehensive and non-invasive
measurement techniques to determine the actual performance of each unit over
time. From site measurement, CLP discovered that the coefficient of performance
(COP) for one of Vitasoy’s air-cooled chillers had deteriorated significantly,
from the manufacturer’s specified level of 2.32 to 0.68. This chiller could not
help the other 3 chillers sharing the heat load as it was only running at around
10 to 20% efficiency most of the time and also worsen to direct the flow of
chilled water into this insufficient cooling plant.

Replacing an Inefficient Chiller Unit Increases the COP Significantly
With site verification and recommendation from CLP, Vitasoy decided to
replace the inefficient chiller unit and was completed in January 2015. Since
the COP for the new unit is 3.2, Vitasoy can save roughly 80% energy cost
through this chiller replacement alone. The company expects the payback period
within a year and a half.
Manually Sequence for Optimum Efficiency for Added Savings
Through measurements taken from different chiller units during various part
load conditions, CLP further recommended that Vitasoy manually sequence the
operation of the four chiller units to attain even better energy efficiency
without adding any investment cost.
If some chillers would give superior performance than others in full load or
part load conditions, it should be switched on first and for most of the time.
The operator is also reminded to keep existing chiller units full load as far as
practicable before switching on additional units in part load conditions.
Therefore, another 5% in energy savings are expected to achieve.
"Improving efficiency levels is critical to our bottom line and an essential
part of our drive to protect the environment. CLP’s Chiller Optimisation
Services was extremely effective in addressing the area to enhance efficiency,”
said Mr. Herbert Lee, Senior Manufacturing Manager, Vitasoy.