Fort Kent, Maine
At the University of Maine at Fort Kent, Harriman designed a system to integrate a wood pellet fired boiler into an existing building heating system. The project involved replacement of an existing oil fired steam boiler in the Sports Center with a wood pellet fired hot water boiler. The second oil fired steam boiler was converted to hot water to serve as a backup for the wood pellet fired boiler. Conversion of the Sports Center boiler plant from steam to hot water also involved replacement of air handling unit heating coils, replacement of the domestic hot water heating system, removal of the steam to hot water heat exchanger and installation of a primary/secondary hot water piping system.
Fuel storage and delivery was accomplished by installing two pellet silos within an existing coal bin adjacent to the boiler room. Each silo is equipped with a pellet auger which discharges into a temporary storage bin. Pellets are then transferred from the temporary storage bin to the boiler by a series of pellet augers. The pellet silos were sized to provide 2-3 weeks of fuel storage during the coldest part of the winter. Also, since each pellet silo has an independent auger, the fuel storage system has built in redundancy in the event that one of the pellet augers failed. Additionally, in the unlikely event that both pellet augers failed, the Owner could manually fill the temporary storage bin with bags of pellets as an additional level of redundancy.
In addition to heating the Sports Center, the project involved installing underground hot water piping between the Sports Center and the nearby Lodge Building. The scope of this work involved replacement of one of the oil fired hot water heating boilers in the Lodge Building with a plate-and-frame heat exchanger and running hot water heating piping from the boiler room to the new underground piping. Not only does this conversion allow the Sports Center boiler plant to provide heating for the Lodge Building during the heating season, but it also allows the Lodge Building to provide domestic water heating for the Sports Center during the remainder of the year.
Photography by JS Photography