Typical industrial process cooling and
heating systems are operated as if they were undergoing full production capacity 24 hours
per day, seven days per week. This is usually
done due to minimal manpower staffing that can adjust system settings, as well as
unpredictable process spikes.
Over the
years, we have developed sequences of operation that successfully reduce energy
consumption, while smoothing the system operation, and minimizing manual inputs required
to keep the system tuned up. If a load should
change suddenly, our sequences are capable of responding to meet the needs of the load.
For
example, many control valves exhibit nearly linear response to the load when they are in
the 70% to 90% open range. However, these
valves typically spend a majority of their time in the 0% to 25% open range, where
response is not nearly so linear, and may in fact be quite non-linear. Our sequences, honed over many years of actual
field experience, evaluate the individual loads, and continually reset the associated
variables as required to keep the worst case valves in the 70% to 90% open range, where
they are most effective and waste the minimum amount of energy. If the worst case valve starts to stray above the
90% open range, the variables are quickly adjusted to meet the new loads.
These types
of sequences are very effective on normal office buildings as well as large
facilities that utilize a substantial amount of outside air and require control of the
humidity in the spaces, such as clean rooms
and wafer fabs, museums and libraries.
Depending
upon the location of the facility, for most of the year the need to dehumidify the fresh
air component of the circulating air is non existent, yet the cooling system, chiller
plant and reheat systems are typically run as if there were a continual need to
dehumidify, just in case there ever is a need to dehumidify. This is so wasteful it borders on neglect, but
until now, no one has focused on saving energy in these facilities, because no one had
developed fast response sequences of operation that aided system stability, were quick to
adjust to new loads and did not need substantial operator intervention.
As
an example of how systems can be designed to serve their loads while conserving energy,
the Lockheed Advanced Development Company (SkunkWorks) TES system reduced energy
consumption by approximately 1,400,000 kWh's annually when compared to the previous system
in place, with improved system temperature control. |