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Energy Audit Case Study II
This energy audit case study is a sanitized part of an energy audit, it
is only one element of a comprehensive
energy audit report conducted by Kelcroft E&M Limited.
Date: February 2005
Location: Central, Hong Kong
Type: Composite Commercial Building
A Kelcroft energy audit uncovered several opportunities to conserve waste energy, lower operating expenses and save money. One particular discovery, is an interesting an example because Kelcroft philosophy, namely details matter.
It
also demonstrates that a relatively small modification
can create substantial savings over time.
The Kelcroft energy audit uncovered an alarming
fact, the entire
building’s central chilled water plant was regularly started
every Sunday to serve a single room.
Synopsis
The building was fitted with a standard plant arrangement, a central chilled water air conditioning system, comprising:
- air-cooled liquid chillers
- chilled water pumps (2 duty/1 standby)
- pressure compensated bypass valve
- common riser serving fan coil units
- control on/off 2-port control valve
Building Characteristics
Building operation were outsourced to a building management
company, plant stop/start operations was conducted manually.
One tenant required air-conditioning for a
single room (approx. 500 sq.
ft.).
Therefore the building management company started the
chilled water plant, including pumps and ancillaries, and operated same
for four hours, every Sunday to provide comfort cooling.
The system turndown ratio was unable to cope with the "load"
creating gross energy inefficiency. The control system was hunting, and
causing operational instabilities.
Numerical Analysis
Energy auditing is economics driven; the goal to identify
feasible energy and cost savings.
Calculations indicated that corrective action
would save more than
HK$40,000 per annum, with a payback period of less than one year. In
addition, a corrective action would save more than 2,400 Kg carbon
dioxide emitted every year.
Other savings accrue, extended life of
the equipment and
reduced maintenance costs.
Conclusions
The air-conditioning system had been operated inefficiently,
causing stability (hunting) problems, and calculations validated the
significant waste of energy.
Since operating requirements, characteristics
are not static, and vary
throughout the lifespan
of a building, is a timely reminder to conduct an annual energy audit.
What Next?
Next you might like to learn more about Kelcroft's energy auditing services, click one of the following links to learn more:
1. Order your Kelcroft energy audit today
2. Learn more about Kelcroft's energy and green business services
3. Click here to read energy audit audit case study I
4. Click here to read energy audit case study III
For further information regarding energy efficiency and energy
conservation call Mr John Herbert telephone (852) 2335 9830, facsimile
(852) 2335 9862 or
email us