Our old friend of over thirty years, Heikki Hyytiainen, came to Wild Acres this year in Little Switzerland as a speaker and presenter at the annual Masonry Heater Association retreat. Heikki was our first significant contact in Europe who graciously introduced Doug Wood and Albie Barden to the world of Finnish Contraflow heaters in the winter of 1979. In the spring of 1979, Albie invited Heikki to the States to lead the first hands-on workshop of Finnish Contraflow heaters in North America. More than a dozen masons and others attended this first workshop in Lincolnville, Maine over thirty years ago. The heater, with only one recent firebox repair, is still in service. Heikki was instrumental in introducing us to our Finnish Castings suppliers with whom we have worked for the past three decades.
Heikki, although trained as an architect and also working as the editor of a Finnish magazine called Muoto (Form) started with a research interest in masonry heaters and then became much more deeply involved with masonry heaters when he formed his own small manufacturing and design company in Finland called Tulisydan Oy. For the past fourteen years, Heikki has been the head of the masonry heater organization in Finland and for the past decade and longer Heikki has been working to refine the design of a mason friendly, user friendly, relatively low cost, high efficiency, clean burning firebox cassette and core system which anyone could use and from which expect excellent results. Recently, Heikki produced ten units of his design as a pre-production prototype run and sent two of these units to the States. One was to be built and displayed and fired at Wild Acres and one was to be sent to an EPA approved testing lab in Washington State for emissions testing.
At Wild Acres, we built up the cassette core in two days with several professional masons in attendance and then started firing the unit. Heikki immediately noted from the large amounts of moisture boiling out of the ends of the logs that the wood was not dry. Given the short time of the Wild Acres event, we knew as well that we would have to burn the unit very aggressively to dry out the clay mortar in order to create an atmosphere in which the unit could burn cleanly and well. Once we were able to dry out the unit itself and find better wood, we were able to get the unit to burn much more satisfactorily. No fewer than seven other projects including three other heaters, a cooker, a bake oven and a smoker and a “rocket” Contraflow heater were also being built in a workshop format, so the attendee population was widely dispersed around all of these projects during the event. A cleaner burning and cooler burning masonry smoker was built and used which grabbed the attention of everyone there along with the annual building of a bake oven which produced pizzas for the annual outdoor party in the work area at the end of each Wild Acres session.
Heikki also gave a ninety-minute PowerPoint presentation on the history and state of the art of wood burning and masonry heaters in Finland. With handheld cameras, the presentation was recorded on video and will likely be available through the MHA Web site in the future. Before his presentation, I was unaware that Heikki has fifteen different wood fired appliances at his summer cottage in Finland. These include indoor and outdoor ovens, saunas, fireplaces, cookstoves, etc. His curiosity and need to perfect a way to burn wood cleanly and well have clearly been a driving force in his life for a long long time. I also learned from Heikki that he advises against storing wood inside the home as he is concerned about the mold that can dry out on the wood fuel and enter the house atmosphere and affect children’s health. He advised that wood should be split and immediately put under cover in an outdoor well-ventilated wood shed and then brought into the home as it is needed. It is clear that the wood species available in Finland are primarily white birch and softwoods, more prone to quick rot than many New England hardwood species, but his input was significant and welcomed.
The first half of his presentation was historical and cultural and the second half of his presentation addressed the more technical questions and challenges of our times. He described clearly the problems of particulate emissions and how to work to lower the emissions of both large and ultra fine particles. He described in detail how wood burns and gasifies and how it is necessary to capture and burn the gases in a manageable and clean way and then presented graphs and drawings showing how Contraflow heaters were once built and how his new research is showing how they should be best built today for maximum efficiency and lowest particulate emissions.
The current design he has worked out uses a thick inner heat exchange wall and a thick slightly separate outer or veneer wall with a total wall thickness of close to 10 inches. He pointed out that in a well-insulated modern modest Finnish home, that such a heater can be fired once a day every other day and keep the house toasty and warm. Americans are not yet building such modest high efficiency homes in great numbers but it was hopeful to see from his work, how a high efficiency system such as the one he has developed as a core, could be adapted to work cleanly and efficiently in our current North American house designs. Particularly impressive was a graph that showed a nearly unchanging steady stream of heat output over a twenty-four hour period when using one of his designs.
In addition to a long history of masonry heater designs, Heikki also showed us photos and told stories of several commercial artisan bake ovens that he had built, many in a workshop format, throughout Scandanavia. One of the ovens, which he designed and built in a workshop format, he described as a two-tier Finnish Contraflow design. The fire is lit in the afternoon and burns until it is out two or three hours later. The heat is stored in the mass and evens out over night. The baker comes in the next morning and then bakes all day long, doing as many as seven loads of bread. Heikki said that this Swedish oven can bake 500 kg of bread from one two hour firing of 70 kg of wood.
After Wild Acres, Heikki stayed a day with Tom Trout and then flew out of Ashville to Washington. Albie drove twelve hours to New Jersey and left his fully loaded truck there and then flew out of Newark to join Heikki and Tim Seaton in Spokane and Colville, for a week of testing at Ben Myren’s lab. The first core was packed up and crated for a rest in New Jersey and then came home to Maine with Albie where at some point in the future we hope to reconstruct the system for our crew here and do some more testing with it.
This trip, I predict, will prove to have been a very important trip for the future of masonry heaters in North America. His contributions here and in Finland have been very significant and we are very grateful that he agreed to spend another two weeks with us here in the States during this past April. Keep your eyes peeled here and on the MHA Web site for news about Heikki’s video recorded presentation and look as well for an informal report on our testing experience in Washington State at Ben Myren’s lab.