“Super storms, super typhoons, super nor westers ,super weather events are happening around the world with some regularity, not to mention the odd earthquake here and there just to add to the mix” says Ian Kempthorne of K&L Nurseries, Canterbury New Zealand. “Some people say it’s due to global warming but I'm not so sure, but in the last year our nursery has taken on the biggest and most challenging project yet, to have a fully sustainable, renewable heating system for our cut flowers which we grow Gerbera and Roses."
The idea first came from the fact K&L were paying $1800 carbon tax per load of coal (30 ton) which was supposed to go to green technology. According to Ian, the old coal boiler at best was 60% efficient. (ie 40% of the coal burnt went out the chimney as waste). K&L were in line for a major re-fit of the boiler and decided to look into a biomass boiler to heat the crops, as they felt the cost, tax and availability of good coal at that stage was not that certain.
“After my father in law had a trip to Europe looking at boilers we decided on a boiler from Austria with 40 years experience in Biomass boiler manufacturing. Having talked to lots of people in NZ most of the faults with wood boilers are fuel handling and moisture content. Polytechnik has engineered a boiler that feeds wood in with a ram design and dries the wood before it fires it, which allows the burner to handle 20 to 60% moisture content of the fuel. Due to large furnace and moving grate system it has good control on a wide range of fuel types. Flexibility is the key to it all and the sophisticated computer controls the boiler indicates this system has one of the best emissions of any boiler in the country.” Says Ian.
“The project hasn't been running long, we fired up in early June 2013 so it wasn’t the best time for fine tuning. Due to lots of factors we were over budget and behind on schedule but are very pleased with the performance of the boiler. With earth quake building requirements, special mesh, steel specs it has been quite a job to get done.”
The other major project to go with the boiler was the need for a large thermal storage tank. After looking at wood and steel tanks, (which we would have to have large foundations to hold up to 400 tons!) K&L have installed a lined in ground tank to hold the hot water (400,000 litres) , this keeps the boiler at or above 90% efficient. The boiler is smaller than the output the nursery needs but can draw from thermal storage to supply the full needs of the nursery. “The programming of the computer can be done by Polytechnik’s “ big brother” as I like to call them in Austria and tuning can be done via the internet.” Says Ian.
“With uncertainty over carbon and fossil fuel use we see ourselves being well placed to have a point of difference for our product in a ever-changing and environmentally sensitive world we live in.”
By : Ian Kempthorne, Director K&L Nurseries, Christchurch New Zealand for GrowerNews.co.nz
For more information on Polytechnik and the K&L project visit the on line project review at http://www.polytechnik.com/ENG/projects/thermal-energy-plants/-up-to-1000kw/kl-nurseries.php