Talk title: "Back to the Future – Installing hydronics and air-to-water heat pumps to get fossil fuels out of buildings"
Galen Staengl is a mechanical engineer whose career in renewable energy was shaped early on by his father, a serial renewable-energy entrepreneur. In this talk from the Westford Symposium, he makes the case for hydronic heating and cooling systems paired with air-to-water heat pumps as a practical path to getting fossil fuels out of buildings. He traces the history of hydronic heating from early furnace designs through the steam era, walks through a real case study of soldered pipe joints that failed X-ray inspection, and shares design details from a multifamily project using air-to-water heat pumps and PEX distribution. Along the way he covers the refrigerant cycle and pressure-enthalpy diagrams, why heat pump capacity and efficiency drop at low outdoor temperatures, glycol and freeze protection, and war stories comparing two-pipe, three-pipe, and four-pipe hydronic systems.