Related Research and Development
Vuilleumier Heat Pump (VHP)
Based upon the thermodynamic principles of the Vuilleumier Cycle, first patented in 1918, the VHP is a heat engine directly coupled to a heat pump. The system moved a working gas, helium, between three chambers within a closed system. Two displacers reciprocate within a cylinder to move the working gas between separate hot, warm, and cold chambers while fuel is burned to produce a high-temperature heat source.
NASA/US Air Force
From the early 1960s to the late 1970s, the U.S. Air Force and NASA built small Vuilleumier Cycle based systems for cryogenic cooling applications.
Bosch and Viessman (BVE)
In the early 1990’s, a joint venture between Bosch and Viessman developed three VHP machines, each tested for over 6,500 hours. Some of these projects evolved into larger scale (10-20 kW) domestic HVAC projects. While many of these prototype systems demonstrated efficient heating performances (COP > 1.3), none were completed to full commercialization.