Fact: chiller plants use up more than half of an HVAC system’s electrical load. So, it goes without saying that if you want to improve the energy output of your facility, you should be looking to optimize one apparent but often overlooked detail: the chiller itself.
In theory, enhancing the efficiency of your chiller plant may seem like a straightforward process. The goal is simply to make sure that the byproduct (i.e., chilled water) and its corresponding waste heat are both circulated properly. However, the challenge lies in the chiller’s designed temperature differential. Often, a plant may operate at a lesser optimal level than its original design, making it more difficult to remediate the waste heat.
Despite its challenges, chiller optimization is not entirely impossible. What then are the options for making a condenser water system function much more efficiently? Here are 5 strategies facility owners and managers can employ for maximum chiller optimization.
One of the most common solutions to optimizing a chilled water system is to introduce VFDs or Variable Frequency Drives. These are devices that regulate the electrical frequency of a motor, thus providing an opportunity to save on energy.
One efficient way of introducing VFDs to save energy is through cooling tower fans. This works by stabilizing temperature control as well as through the determining effects of Fan Laws. Said law takes into account the speed and percentage of one fan and draws it against another one that is operating at full capacity.
One may also explore the energy savings opportunity in variable speed pumping through other VFD options such as fitting chillers and chilled water pumps. These devices are generally considered as traditional solutions. Unfortunately, they are often overlooked in favor of other strategies.
When it comes to maximizing chiller plant efficiency, running multiple devices at the same time is beneficial. Granted of course that you do this by running said pieces of equipment at part-load (the optimum capacity these devices run on). By doing so, you’ll be saving far more energy for your facility by balancing the water flow into your chiller.
See, here’s the thing: operating multiple devices at a lower speed or lesser load translates to more efficiency. This is done in comparison to the energy input required from operating equipment functioning at their full capacity. Running multiple devices will maximize the heat transferred and reduces the chances of fluctuating pressure during the process. The end result: more efficiency in your operations.
Naturally, this solution is meant for facilities with more complicated processes and far more demanding output requirements. Those with more simplistic requirements might not be able to run multiple chillers at their ideal capacities simultaneously.
Another overlooked detail is the weather condition where facilities are located. In the winter, a facility can rely on the temperature outside to operate more efficiently. See, most devices are designed to operate on an average temperature of 45F. At this temperature, proper dehumidification can take place and supply the required air temperature to the facility.
What a facility manager can do then is to offset the need for water chillers during colder seasons. This can be done by implementing a temperature reset control that automatically eliminates the need for a chiller during colder seasons. Not only will this save energy, but it will also keep the facility from over-dehumidification and unnecessary cooling.
Despite very compelling reasons to employ this strategy, this is still not a traditionally used technique for energy efficiency efforts. However, lately, newer buildings have started to see the benefits of implementing this.
Some of these methods, of course, will work better for some facilities than others. The best course of action is to consider the components as well as the financial restrictions, the geographical location (to determine the climate), and the state of the water chiller. From here on, it will now be a matter of testing and finding out which method or strategy works best for a particular set of specifications. It’s always best to find a solution that is tailored to one’s specific requirements and capacities.