Edina Realty

Initial System: The Edina Realty building is a five story office building located in Roseville, Minnesota. The building contained a VAV system supplied by two rooftop units (RTU’s) with gas heating and DX cooling. A lighting upgrade had recently been completed.

Issues: The Owner had indicated that many of the tenants were complaining about lack of control of heating and cooling with some areas rising above 80 degrees F. One of the tenants had already left and another was threatening to leave. NewMech utilized Xcel Energy grant money to complete a recommissioning study on the building which identified the following problems.

• Existing RTU’s were undersized and could not meet building cooling demands.
• The RTU’s were 15 years old and at the end of their useful life.
• Many of the existing VAV boxes and controls were not operating correctly.
• The building was severely out of balance with some areas receiving no supply air.
• The recirculation system between the supply and return was not operational.
• Economizers were not working correctly.
• Return air grills were obstructed.

Solutions: NewMech installed two new 30 ton high efficiency RTU’s. The units were sized to provide the correct amount of cooling required for the building. The balancing, recirculation, economizing and return air problems were all corrected as part of the project. New controls were installed with setback capabilities.

Results: The project was executed with one weekend shutdown largely eliminating interruptions of Edina Realty’s operation. NewMech also worked to procure $ 5,470 in rebates for the project and 1.5% financing*. The total project cost after rebates was $112,780. The high payback on high efficient equipment and controls was 3.6 years (base equipment replacement cost was $69,780). Below is a summary of the overall savings on the project.

* Financing was procured through a special rate provided by the Utility Company.