A couple of years ago (when the financial crisis was just starting), we brainstormed about how we could bring down the utility bills in our State Laboratory. The Lab has always been electricity intensive, partly because of the workplace safety requirements etc. (e.g. the “hoods”) require more air exchange than a normal building. That means constantly bringing in 115 degree air and cooling it down to 78.
Since our initial assessment 3 years ago we’ve implemented several energy saving interventions. Some of the changes were operational (reprogramming exhaust fans) and adjusting the building settings when unoccupied to save energy. Last year these changes saved about $230,000, including a 17% reduction in electricity usage, 71% less in natural gas and a 30% drop in water. APS rewarded us with a check for $73,300 from their energy incentive program.
Our building management folks in the Lab figured out that the biggest energy efficiency enhancement of all would be if we could install an evaporative cooler in front of the air intake for the A/C unit, but that would have cost about $180K. So we used the $73K from APS and some other (non-state) Lab funds and ordered a swamp cooler for the Lab a few months ago. Last week our dream became a reality, and a crane hauled the large swamp cooler up to the roof of the Lab. The new cooler will have a sensor that knows when it’s more energy efficient to run the 20 HP cooler motor or the normal A/C system, depending on the dew point (the swamp will generally kick in when the dew point is in the mid 50′s and below). The project also includes temperature recovery coils which basically use the energy in the cool air leaving the building to reduce the temperature of the incoming air (reducing the electricity needed to cool the air).
The engineers estimate that the new swamp cooler and temperature recovery coils will save an additional $72,000 in annual utility costs (bringing our annual efficiency improvement to over $300,000 per year). Next, we’ll apply for another rebate from APS from the cooler and coil savings. If we get another rebate, we’d like to invest in the next efficiency item on the list- solar panels on the roof of the Lab. Good creative thinking and execution!