Everywhere, it seems, interest is picking up in the Stirling engine. The prestigious Jet Propulsion Lab recently reported that the Stirling is one of the two most promising alternative automobile engines for the future, offering silence, long life, improved mileage, and greatly reduced pollution. Ford Motor Company announced it has installed an experimental Stirling in a sedan for testing as part of its current research effort on the Stirling. The Energy Research and Development Administration recently entered an eight year $110 million contract with Ford for development of a Stirling automobile engine. In Sweden, work is said to be progressing very well toward the development of a Stirling suitable for delivery vans and other vehicles.

By no means is all of the current interest in this old engine related to powering road vehicles. In Athens, Ohio a great deal of development work is being done on a Stirling powered heat pump for home heating. In this application, gas or other fuel is used to run a small Stirling engine, which in turn drives a conventional heat pump to heat or cool a home. This may seem like a complicated way to provide heat when compared with the conventional method of simply burning the gas and using that heat directly. But the fact is that the Stirling heat pump approach provides a great deal more heating for the same amount of gas, because it makes a more efficient use of the high temperature flame of the gas. Even at today’s gas prices, it is anticipated that such devices could pay for themselves in gas bill savings in three or four years.

In Holland, where the revival of interest in the Stirling engine first began about forty years ago, air liquifying machines based on the Stirling cycle are being produced and sold world-wide.

In India, South America, and other places around the world, the Stirling is receiving attention as a potential power source for pumping irrigation water and doing other farm chores; because, unlike the gasoline engine, it can use almost any combustible substance for fuel, including sticks and straw. As the price of oil continues to rise, the multifuel capacity of the Stirling becomes one of its most important virtues.

Nor is all the current interest in the Stirling solely for utilitarian purposes; hobbyist Norris Bomford spent several years developing a Stirling engine to propel his graceful rowing skiff over the lakes and rivers of England. The engine, which pushes his craft at a gentle three to four miles per hour, is so quiet that builder Bomford can indulge in his two favorite recreations at the same time — boating and listening to classical music on a portable record player.