Biomass project to bring a new energy era to UNH

The University of New Hampshire’s first large-scale biomass boiler system is currently under construction on the Durham campus.

Located directly across the street from Wildcat Stadium, the new Northwest Heating Plant, being built by Froling Energy, is expected to provide heat and hot water to four buildings and 10 greenhouses in the neighborhood of the Thompson School of Applied Science.

This winter, the new wood chip boiler and two new liquid propane gas backup boilers will be the sole source of heat for these buildings. A key part of the project is to run pipes underground to create a small district heating system serving Putnam Hall, Barton Hall, Cole Hall, the Veterinary Diagnostic Lab and the 10 MacFarlane greenhouses.

UNH’s central combined heat and power plant provided heat to these buildings for many years but the long pipe run out to the Thompson School area was failing. Instead of spending money on replacing the old pipes, it was decided to create a new separate district heating system fueled by one of New Hampshire’s key renewable fuels — wood chips.

UNH officials calculate that the plant will consume 750 tons of semi-dry wood chips, equivalent to over 70,000 gallons of No. 2 fuel oil and over 91,000 therms of natural gas. The screened wood chips — known as PDCs — have 25 percent to 30 percent moisture content, made from sustainably harvested trees sourced from forests in southwest New Hampshire and central Massachusetts.

The biomass boiler is a 2.45-million BTU/hour output Viessmann Vitoflex 300-UF that employs gasification technology,
oxygen sensor-based combustion controls and a multi-cyclone in the stack to make this one of the most efficient, reliable and cleanest burning wood chip-fired boiler systems available.

A 45-ton capacity vertical PDC storage silo also is being built in the boiler house. PDCs are delivered a bit like oil: from a truck that pumps it through a hose and into a tank. But with PDCs, a blower truck blows them through a 5-inch diameter hose into the silo. The simplicity of this delivery method significantly reduced the project’s cost, officials said.

The plant is expected to be operational in October, with completion in December.

Categories: Energy and Environment