In 2014, GreenerU worked with MassDevelopment to develop a program called Mass College Green, in which up-front financing was provided to pay for energy conservation measures. With no upfront capital investment, the college pays only for delivered energy savings over a five-year financing period and sees a net positive cash flow, resulting from energy cost savings. After the five-year payback period, the college will enjoy even greater cost benefits, realizing the entirety of the energy cost savings.
It was through this program that Mount Holyoke College—a liberal arts college for women in western Massachusetts—initially made investments in energy-efficiency improvements with GreenerU in 2015, solving a conundrum that had started more than 30 years prior.
Mount Holyoke College, founded in 1837, is a fairly typical northeastern campus. It relies on heat from a gas- or oil-fired boiler, which produces steam. Steam is then distributed through piping that connects to radiators in buildings across campus. Making adjustments to this single source of campus heat can be extremely challenging. In fact, it can be dangerous.
Steam plants such as Mount Holyoke’s have inherent limitations to their thermal efficiency. High-temperature flue gases are discharged to the atmosphere, representing wasted thermal energy. To reclaim a portion of this wasted energy, plant operators can install an “economizer” coil in the exhaust stream to transfer heat to the relatively cooler water entering the boiler, a project undertaken by Mount Holyoke in the summer of 1984. Unfortunately, the installed coil caused a build-up of pressure in the exhaust breeching. Flue gasses began to escape into the building, posing a health and safety hazard for plant operators. The economizer was torn out by Thanksgiving that year.
More than thirty years went by and the College remained wary of the issues they had experienced; however, the Mass College Green program provided an opportunity to partner with GreenerU and take a fresh look at the problem. Working closely with the plant’s engineers, the project team developed a solution that incorporated a bypass damper and sensor to detect when excess pressure needed to be released.
The economizer design had to be carefully balanced to safely bypass flue gases, yet provide enough energy recovery savings to make the project float, financially. Through four years, the economizer is outperforming the modeled energy performance and providing surplus cash savings to the College. The best part is that Mount Holyoke had no out-of-pocket expenses for design or construction and pays only for the actual energy savings, as measured by a Btu* meter on the economizer coil.
This improvement was part of a suite of energy conservation measures GreenerU performed at Mount Holyoke College as part of Mass College Green. At Kendade Hall, the College’s student center, GreenerU performed a lighting retrofit. Carr Laboratory underwent fume hood and variable air volume (VAV) rebalancing. And occupancy sensors and controls were installed in the Kendall Sports and Dance Complex.
All of these measures combined have performed better than expected. Now starting its fifth and final year, the Mass College Green financing program has enabled the College to pay back the cost of measure installation at 80% of the estimated “business as usual” costs. After 2020, all energy savings—to the tune of an average of $96,000 each year—are now Mount Holyoke College’s to keep.
*British thermal units