On Thursday, 4 June, the Foundry Division of the Institute of Manufacturing Technology held its traditional historical smelting event. Alongside the historic furnace, a foundry tour with a quiz, and plenty of food and drink, this year’s programme featured a Stirling engine.

The foundry specialists received the heat engine as a gift in 2016 from Štěpán Vaněk, who had built it himself. The engine was invented by the Scottish engineer Robert Stirling in 1816 as a potential rival to the steam engine. Its principle is simple: a heat source at the bottom warms the air, causing it to expand and push a piston upward. As the air cools at the top, it contracts, and the piston moves back down. Due to its relatively low power output, practical applications of the Stirling engine remained limited, mainly to low-power domestic uses such as water pumping.

As visitors to the historical smelting event noted while learning about the invention, it offers an efficient way to make use of waste heat. “I use them in barbecue grills. The heat from the grill powers a Stirling engine, which then turns the meat above the grill,” one visitor explained, describing a practical application.

The main attraction, of course, was the smelting itself in the historic furnace. The tradition was established more than twenty years ago at the Foundry Division by Professor Karel Stránský, who dedicated his life to archaeometallurgy.