Net Zero Impact completed installation of its largest hybrid solar-thermal system to date at Addison on Fourth near Seattle’s International District.
Net Zero Impact will supply heat and hot water to the building’s 254 apartments and studios, as well as to new retail storefronts.
The building, originally constructed as a hotel in 1911, has been renovated by Goodman Real Estate. The renovation replaced steam-generated heat provided by Seattle Steam with Net Zero Impact’s hybrid solar system – including solar-thermal tubes, high-efficiency boilers and automated system controllers.
The expected savings on energy costs are estimated at $60,000 per year, nearly a two-thirds reduction. With available federal tax credits and local grants, Goodman Real Estate expects to recoup its solar investment within three years.
Sun-generated steam from 450 Net Zero Impact solar-thermal tubes reaches a temperature of 212 degrees, pre-heating water for two new boilers that deliver heat to existing radiators throughout the structure. Solar-heated water, at a temperature of approximately 120 degrees, will also be piped throughout the building for domestic use.
In addition to the rooftop solar tubes, the following equipment and renovations were part of Net Zero Impact’s project:
- Two 98 percent, high-efficiency domestic hot water boilers
- Automated electronic controllers to manage the entire heating system
- A complete rebuild of the condensation system for existing radiators
- Installation of hot water tanks, piping, pumps and new gas lines
- A complete exhaust system upgrade
- New temperature valves for the century-old radiators
The solar thermal tubes, manufactured by Kingspan Solar, transform direct and diffuse sunlight into useful heat in the form of hot water. Capturing the sun’s energy in less-than-sunny environments is a important to customers in the Pacific Northwest. Inside each Kingspan air-evacuated tube, solar radiation is collected, concentrated and transferred to an insulated manifold.