Applegate Housing, a 104 unit apartment complex in Bennington, Vermont is now heated with PDCs. When they were first built 40 years ago, each of the 23 individual buildings had a boiler that provided heat and hot water to the occupants. As years went by it became almost a full-time job keeping 23 separate boilers up and running all winter long, especially since many were at end of life. The 23 building units were also showing their age and poor energy efficiency.
It seemed that this could be the right time for a new approach, so a committee was formed to discuss options. The committee included people from Applegate Housing, Shires Housing, Housing Vermont, VEIC, engineers, energy conservation specialists and many others. After many meetings, all agreed on a plan that would add new windows, insulation and siding to all the buildings. Then a single biomass boiler burning semi-dry wood chips was installed in a new boiler house and was tied into newly buried pipes that now loop the complex, delivering hot water into each building.
Froling Energy was fortunate to get the contract to install a big biomass boiler and two LP boilers that will work in a peaking and backup role. Other contractors dug in the pipes and tied them into the heating systems in each of the 23 buildings. New indirect water heaters were installed in each unit as well—all heated by the central heating system.
The new biomass boiler is a Viessmann Vitoflex 300-RF Model KPT-540 which has a maximum output of 1.84 million BTU/hour. Everything was completed during the summer and fall of 2017.
The silo at Applegate holds 42 tons of PDCs—25% moisture content, screened, semi-dry wood chips—which are blown into the silo from a delivery truck.
April 2018 update: 50% energy cost savings reported by Applegate