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.