Dishwasher Retrofit Saves Water, Energy

California Polytechnic State University in San Luis Obispo recently installed new efficient dishwashers in their dining facility and have begun reaping the rewards in water, energy and cost savings. Overall, it is estimated that the new dishwashers will result in annual savings of 736,920 gallons of water, 9,321 therms of natural gas and an annual cost savings of $16,647.

The project was spearheaded by student interns with the Alliance to Save Energy's Green Campus program. This project provides an excellent example of how water-oriented approaches provide multiple benefits and should be targeted by organizations whose primary goals aren't necessarily water conservation or river protection. Here's a press release from the Alliance to Save Energy describing the project:

Student interns with the Alliance to Save Energy’s Green Campus Program and California Polytechnic State University’s Campus Dining successfully identified and installed an energy and water efficient replacement of the campus main dishwashing machine, resulting in an annual savings of 736,920 gallons of water, 9,321 therms of natural gas and an annual cost savings of $16,647.

In early 2008 Green Campus interns responded to a request from Campus Dining to identify a replacement of the nearly fifty-year-old main dishwasher. Through extensive research the interns identified multiple energy efficient models that could meet the dishwashing demand for the campus’ main dining hall. Analysis of the possible replacements was completed through manufacturer’s specs, while the owner/maintenance manual was used to analyze the old machine.

While the models under scrutiny displayed little difference in electrical savings, due to more powerful pumps, significant savings were recognized in water and heating. Newer commercial dishwashing units use nearly half the water of the existing dishwasher, which in turn leads to a large savings of natural gas used to heat the water from an initial 60ºF to a final rinse temperature of 180ºF.

By October 2008, Green Campus completed its analysis and recommended Campus Dining move forward with procurement of the Stero STPCW-ER-21. Based on the students’ analysis, Campus Dining purchased the new dishwasher, which was installed over the 2009 spring break. Campus Dining is now in discussion with Green Campus to identify a replacement of the campus auxiliary machine. Green Campus interns are pushing for the most energy efficient model and looking to combine this model with the campus wide elimination of cafeteria trays.

Here's a link to a previous blog post which provides more information on the positive environmental effects resulting from the elimination of cafeteria trays.