PlumbingandMechanical Solar Thermal Report Spring 2012 : Page 5Left: Mast & Brunk installers Jose Fernandez (left) and Gerardo Rodriguez work on part of Cedarwood's 25-panel solar thermal system. Right: Two 500-gallon tanks store water heated from the solar panels. The system includes an AIC heat exchanger, Wilo pumps and PAW pump stations. where additional energy savings and LEED points could be achieved.” Rosenberger’s extensive experience with solar thermal systems in California and Germany’s RSF Solar, combined with his connection to EMU, made Altadena a natural choice to design Cedarwood’s solar hot water system. “Hans’ family has been a longtime supporter of EMU, which gave immediate credibility to his offer to design and install a hot water solar system for our new dorm,” Kurtz notes. “At the time there were only a few contractors in the area installing solar domestic systems and few with the depth of experience that Hans was able to demonstrate. It also was helpful to have a single contact to design the system, source the components, supervise installation and ultimately provide the financial vehicle to take advantage of available incentives.” Part of that financial vehicle is a power purchase agreement, typical in the solar energy industry, where Altadena Energy & Solar owns and maintains the solar thermal system and EMU purchases heat units from Altadena. The university doesn’t have the capital outlays of purchasing the solar panels and other equipment, yet can still realize tax benefits. Existing building design The primary goal was to have the dorm ready for the 2009-2010 academic year, with the secondary goal being the completion of the solar thermal system, Rosenberger says. Since the roof and mechanical room were already completed, the 1,000-sq.-ft., 1,100-gallon solar thermal system design needed to be adapted to the existing building for roof support, pipe chases, tank locations, etc. “Estimation of the hot water demand and simulation of the system design were the two most challenging aspects of the engineering,” he notes. “Because the dorm was a LEED project, a lot of emphasis was placed on reducing demand, as well as meeting that demand with the most benign system design as is possible. “For the solar design, this system was challenging because the physical layout of the system outstripped our solar simulation software. Our system is comprised of three fields (West, South, East) on two hydraulic loops (W-S, E-S) and multiple tanks. That situation could not be simulated exactly with our design software.” Chris Mast , president of mechanical contractor Mast & Brunk, adds: “The issue of over-temperature mitigation is significant. A fan-coil unit for removing excess heat was considered during design planning, but has not been implemented as of yet. Currently, a solenoid drain-off valve is used to dump excessive hot water.” The system was installed over the course of five months to avoid conflict with the dorm residents during the school year. The system started testing in spring of 2010, and was commissioned for service that July. Mt. Crawford, Va.-based Mast & Brunk, which has worked with EMU and The Troyer Group on various projects for nearly 17 years, installed the 25 Sunearth EC40 panels for the indirect glycol system in about two days with a team of four to five men, says Mast. Mechanical systems installed in the dorm include: PAW pump stations; an AIC double-wall, brazed-plate heat exchanger; and two 500-gallon storage tanks arranged as pre-heat to three A. O. Smith Cyclone 90+ AFUE water heaters to supplement the solar domestic system. The Spring 2012 Solar Thermal Report 5 Photo credit: Mast & Brunk (left); Altadena Energy & Solar (right) Publication List Using a screen reader? Click Here |
