"To recover heat is hardly a problem. The challenge is to find the technology that can deliver the high temperatures we need. With SPPs heat pump we can now heat water to over 120 °C with recovered heat". - L.M Horvli - TINE Meierier, buyer of the first SPP HighLift Heat Pump
When gas is compressed, it heats up and correspondingly when decompressed it cools down. This is the simple principle behind the Stirling engine, on which the SPP HighLift heat pumps are built. Operating with a gas in a single phase also gave inspiration to the company name Single-Phase Power, as well as the ability of the technology to do temperature lifts of 100oC and above gave the name HighLift to the heat pump technology.
Having its origin all the way back in the beginning of nineteenth century, the history of the modern Stirling engine starts in the late 1930ies with the effort by Philips N.V. to find a replacement for batteries. Since then, many inventors have used Stirling engines for various applications. The SPP team has worked with this technology for more than 10 years based on their hypothesis that the simple principle would also work for variety of temperature ranges.