The biomass heating system for the Santa Fe Community College will add a one megawatt biomass boiler (3.4 million BTU per hour) to the College's heating system. This new boiler will supply approximately 80-90 percent of the College's total heating demand, and will be housed in a newly built 800-square foot building near the existing boiler room.
The natural-gas boilers will remain in place for backup, and will provide some additional heat during the coldest days of winter. The heat generated by the new boiler will be distributed throughout the campus via the existing network of pipes on the campus. The domestic hot water and the swimming pools will also be heated with biomass. The Early Childhood Development Center is not affected by the biomass system.
Layout of the System
Adjacent to the new boiler room, a 1,000 square-foot, covered biomass fuel-handling area will be built. This area will receive loads of woodchips, and will feed the fuel automatically into the boiler. The profile of the additions are planned to be no higher than the surrounding buildings, and will be of comparable design and finish. Changes to the plumbing will not be visible from outside the buildings.
Fuel for the System
We conducted a biomass fuel study for a 50-mile radius surrounding the college, and identified more than a dozen sizable biomass fuel sources. These included green waste at solid-waste disposal sites, wood slabs, chips and sawdust from wood-products manufacturers, and small-diameter timber and slash from forest thinning projects. Which of these sources will be tapped for fuel for our project has yet to be determined.
Water Vapor Exhaust
Biomass fuel contains moisture, and in very cold weather a plume of water vapor will rise from the exhaust stack. The thickness and height of the plume will vary depending on the outdoor temperature and relative humidity. The dry climate and low relative humidity in Santa Fe means that water vapor plumes will generally be less pronounced than in regions with a wetter climate. The plume can also be reduced or eliminated if necessary by bypassing the boiler's economizer, but doing so reduces the system's thermal efficiency.
Air Emissions from the Biomass Heating System
Emissions from the system will be well below the level that requires a permit from the New Mexico Air Quality Bureau (NMAQB), and in fact they are even below the level at which notification is required. The NMAQB bases their requirements on the emissions that would result if the system were operated at peak load, 24 hours per day year-round with the emission-control system bypassed. The SFCC system will operate about 4,800 full-load-equivalent hours per year, or less than 55% of the time, and will have a multi-cyclone system for removing particulate emissions from the exhaust.
Comparable Systems in Operation
There is a biomass system in operation at the Jemez Mountain Schools in Gallina, NM, but it is 50 percent larger than the planned SFCC system, and uses a different fuel-handling system. In Austria, a country roughly one-fourth the size of New Mexico, there were 843 biomass-fired district heating systems operating as of January 2005.
Project Schedule
The system had its ceremonial inauguration in December 2005 and will be in operation soon.
For more information on this project, contact:
Mark Sardella, Local Energy
1442 South Saint Francis, Suite B
Santa Fe, New Mexico 87505
www.localenergy.org
Tel: (505) 982-9800