Meet the Contestants; Hiisi

With the first Wood Stove Decathlon only a couple weeks away, we are profiling the remaining teams in the competition. Take this opportunity to learn more about the design teams and their stove’s innovative features.

“It’s so Hiisi, anyone can do it!” The Finnish stove is marketed as easy to use, inspiring the homonymic name Hiisi. The Hiisi is Finnish company’s Tulikivi's smallest hybrid heat-retaining fireplace and is especially well suited to modern low energy construction projects. The upcoming 2015 wood emissions restrictions in Germany has challenged Tulikivi engineers and innovators to meet the high standards. After years of development the stove is ready meet the world's tightest emissions standards set for 2015 and to compete in the Wood Stove Decathlon this November.

Lab technician Onni Ovaskainen and a Hiisi prototype

The Hiisi differs from standard room-heating stoves in that typical wood stoves are not normally heat-retaining units. The Hiisi's heat-retaining soapstone releases heat more slowly, and in the form of soft, pleasant radiant heat and it can heat water. This is a major design point since this stove won't over heat new energy efficient homes. These types of homes are quickly becoming the norm so Tulikivi has worked to minimize the convection heat into the room using thermal radiation and a double glass door. Despite its compact size, the Hiisi is a hybrid fireplace, meaning that both pellets and wood can be burned in their firebox without the need for any further equipment, accessories or even electricity.

The model that Tulikivi is bringing to Washington D.C. has already been sold in Europe for the past 5 months. Only taking a brief pause to celebrate Hiisi’s success, Tulikivi is getting ready to launch the next generation of Hiisi models this coming January. The new model promises to burn even cleaner than the original.

Tulikivi hopes that their Hiisi stove will help promote the benefits of residential biomass heating. They work hard to ensure that consumers are aware of these benefits. While selling these masonry heaters in the US, Tulikivi educates their consumers of the long tradition of masonry heating and the pros and cons of thermal mass radiant heat compared to dry hot convection heat. Over the past two years, insight from consumers and Tulikivi’s importer network has led to developmental and design changes to get the look and feel of the Hiisi just right.

We are looking forward to seeing Hiisi in action at the Wood Stove Decathlon November 16-19, 2013. Vote for your favorite stove at Popular Mechanics. 

Pellet Boiler Also Makes Enough Electricity to Power Home

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