Austrian company OkoFEN has brought to market the first residential electricity producing pellet boiler, the Pellematic Smart_e. The boiler uses a pellet-condensing module from an earlier pellet boiler design, the Pellematic Smart and outfitted it with with a Microgen Stirling Engine. The engine uses a heated/cooled helium hydraulic system. The result of these two technologies is a unique boiler that is capable of outputting 14 kW (47,770 Btu/h) of thermal energy and 1 kW of electricity.
The Pellematic Smart_e can save households’ money on both heat and electricity bills. Switching from oil, propane, or electricity to pellets usually results in substantial savings. The heat is used for space heating of the living area and domestic hot water generation. Plus with the added Stirling Engine, the electricity you produce in your own house can offset part of a home’s monthly electricity bill. A full load of 24 hours can produce 24 kWh of electricity at 1kW.
At 24 kWh per day, the Pellematic Smart_e could generate enough electricity for most or all of a home’s average daily electricity needs. However, in order to create this electricity, the boiler must run at full capacity, which can create a substantial amount of excess heat. The surplus heat may be stored while the electricity is still produced but even with the heat storage capabilities, some of the heat may be lost, and the efficiency of the boiler falls. For the Pellematic Smart_e to meet the electricity needs of a house, it would have to extend far beyond the heating needs of that house.
“The issue is the large 14:1 ratio between thermal and electricity on this unit, and the (likely) narrow output curve,” explains Norbert Senf, one of the judges for the Wood Stove Design Challenge, “In a thermal electricity generating station, you get about a 2.5:1 ratio.”
Although it is perhaps not the most efficient when it comes to producing electricity, OkoFEN’s innovative boiler demonstrates the potential of this hybrid technology. The success of this product is likely to lead to further industry advancements to manufacture and distribute pellet boilers capable of producing even greater amounts of electricity.
For more information check out OkoFEN’s website here
Also, their FAQ page here