Operating Characteristics of a Small Cryogenic Stirling Engine With a Displacer

The green house effect by carbon dioxide issue would make better recognizing the importance of efficient use of energy in terms of high energy conservation measures. Accordingly, attention is drawn to the Stirling cycle machine, which is a perfect Freon free and efficient machine. Most Stirling engines operate in temperature ranges in which the temperature difference between the heat source and heat sink is between 100 K and 700 K, with the room temperature being at the lower end of the operating temperature range. However, information available on engines that utilize the room temperature as the heat source and the ultra-low temperature of liquid nitrogen as the heat sink is scarce. Engines that operate within such temperature ranges are called cryogenic heat engines. If their practical applications are realized, energy that has hitherto been wasted during the use of ultra-low-temperature media can be recovered in the form of electrical energy. We have designed and developed a 500 W class Stirling machine as a cryogenic engine. This paper presents some operating characteristics.