I thought Stirling engines can offer great advantages if used in cars, but it never crossed my mind using such an engine in a heating boiler for your household. Evita is the name of the latest boiler made by Remeha, a Dutch company, using a Stirling engine to produce electricity and upload it to the grid.
The energy savings that Evita does are worth mentioning, because besides producing hot water the classic way, by burning methane, it measures the home’s demand for hot water, and if it is lower than the electricity production, it starts the Stirling engine by burning gas beneath it.
The company brags 25% savings on the electricity bill and a CO2 reduction of about 60% (a ton per year). If used in a home that usually consumes around 2,000 cubic meters a year, the Evita can actually save 410 euros.
Remeha also says that their Evita boiler has an efficiency of over 140%. I’m a little confused with that, but by that they probably also include the electricity provided to the grid, with the associated savings. Anyway, it’s a boiler that pays for itself in a few years, and that is quickened by the subsidies that governments and local authorities provide in some countries, of up to 4,000 euros for purchasing the Evita, for example.
Evita has a testing history of a few years. In that time, it was installed in various homes in the Netherlands with a great amount of success. However, it does its best in homes with medium to high heat and hot water consumption.
Thus, a Stirling engine normally considered a pretty inefficient way of transforming heat into electricity, does a certain amount of good to the environment. And the most beautiful part from that point of view would be if the methane is supplied from a biogas digester, rather than from fossil sources.
Thanks to Cata for mentioning the Evita to us.