Engineered Systems - June 2008 - (Page 21)

CaseInPoint ing it down the road to a new foundation. Early on, the CCAT committee decided to use radiant in-ﬂoor heating and had PEX (crosslinked polyethylene) tubing installed in the newly poured basement slab. This tubing, manufactured by Uponor Inc., would eventually carry warm water from a yet-to-be-determined heating source to warm the slab as well as the people and environs above. Next, CCAT called in a local expert Stephen Bohner, who co-owns Alchemy Construction Incorporated, also of Arcata, to help decide exactly how to heat the lecture-library room in the basement and the upper level, which would provide living quarters for the director of CCAT and the HSU students who live and work there. Soon thereafter, Bohner recommended the Phoenix Solar 119-gal, 130,000 Btuh water heater as a perfect ﬁt with CCAT’s sustainable mission. Manufactured by Heat Transfer Products, the Phoenix combines domestic hot-water storage (from a solar collector panel) with a 97%efﬁcient, gas-ﬁred backup — all in one unit. The sealed-combustion, direct-vent Phoenix Solar delivers both high-efﬁciency space heating and domestic hot water, using state-of-the-art condensing boiler technology and a modulating, load-matching gas burner. The Phoenix Solar would feed both the 1,550-sq ft basement with its radiant ﬂoor heating, as well as the radiators that would heat another 1,550 sq ft upstairs. In addition, the unit would also provide domestic hot water for the entire house. HOW THE SYSTEM WORKS A ﬁrm believer in closed-loop systems, Bohner separated the Phoenix Solar’s auxiliary heating port for the domestic hot water from the space heating system via a Taco X-Pump Block, a heat exchanger that is also an all-in-one unit. The auxiliary ports of the Phoenix Solar feed domestic hot water to the X-Pump Block. Using its internal heat exchanger, two pumps and control logic, the X-Pump Block relies on an outdoor reset to control the amount of hot water sent to the radiant tubing loops. Bohner explained how the system works, “We monitor indoor temperatures by running thermostat wire to each room in the house. We monitor outdoor temperatures with an outdoor sensor on the north side of its exterior. When there is a call for heat, the X-Pump Block mixes and delivers the correct water temperature — based on the outside temperature — to the radiant manifold.” Individual room zoning is accomplished at the radiant manifold via thermal actuators, also made by Uponor. “When a zone calls for heat,” Bohner said, “those actuators pop their heads and warm water ﬂows through the PEX loops attached to them. Again, the colder it is outside, the warmer the water delivered to the room needing heat.” Finally, Bohner chose another all-in-one unit, the Oventrop Regusol EL-130 solar pumping station, to move water from the solar collectors to the radiant loops whenever that water is hotter than the water inside the Phoenix Solar. “Linking the Taco X-Pump Block and Oventrop EL130 with the new Phoenix Solar was a great way for us to easily integrate a solar thermal system into the newly remodeled CCAT.” LIVING CLASSROOM To date, the three student-residents, having never run out of hot water, are very happy with the new system. CCAT offers university students and the general public tours, workshops, and opportunities for hands-on involvement. They don’t just preach sustainable products; they actually live with them to discover whether or not they like them. CCAT provides classes on solar thermal, solar electric, and now — with the move and the renovation — radiant ﬂoor heating. What appears to be a single-family residence is actually a university’s “recycled” live-in classroom and center for sustainability education. A 119-gal, 130,000-Btuh solar water heater played a key role in the building’s sustainable radiant heating design. “It is like a live-in classroom for sustainability,” said Bohner. “CCAT is preaching sustainability, so they liked the idea of the Phoenix Solar because it would allow them to actually ‘walk the walk, as well as talk the talk.’” Heat pump-based HVAC and control system contributes to bright IdeA(s) The new headquarters of Integrated Design Associates (IDeAs) Inc. is a testament to the company’s commitment to helping architects design the best and most energy efﬁcient buildings. The new IDeAs headquarters is the ﬁrst commercial ofﬁce building in the U.S. designed to meet a net-zero energy/net-zero carbon emissions goal. Johnson Controls designed and installed a unique heat pump-based HVAC and control system, which is a key contributor to minimizing the building’s energy consumption. IDeAs is a consultancy that provides electrical engineering and lighting design services for projects such as educational and medical facilities, ofﬁce and retail spaces, and restaurants and apartments. When the company bought a 7,200-sq-ft former bank branch to house its new headquarters, David Kaneda, principal, saw an opportunity to bring the concept of a zero-energy building to life. The goal was to transform a 1960s-era windowless concrete bank into a highly efﬁcient and comfortable building using a full complement of sustainable design techniques and technologies. The result is an ofﬁce building that uses renewable energy from photovoltaics to meet 100% of its energy requirements, burns no fossil fuels, and produces no net greenhouse gas emissions. MAXIMIZING EFFICIENCY, MINIMIZING COSTS Johnson Controls designed the HVAC system to maximize performance, energy efﬁciency, and IAQ, while keeping the construction costs comparable to more traditional designs. The energy efﬁciency for the HVAC system and building envelope is estimated to be 40% below the 2005 California Title 24 energy requirements. The design incorporates a geothermal heat pump, which takes adw w w. esmag a zine . c o m 21 http://www.esmagazine.com

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Engineered Systems - June 2008 Contents Editor’s Note Letters To The Editor Back2Basics HVAC Challenge Case In Point Commissioning Efficiency Incentives HydroTech Building Automation Energy Wiz HVACR Designer Tips Notre Dame Tackles the Heat State Of The Arts Time For A Transplant? Project Delivery: What Can IPD Do For You? Issues & Events Computers & Software Products Application Checklist Glossary Classifieds Advertiser Index Tomorrow’s Engineer

Engineered Systems - June 2008

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