Section 03 · 4 pages
Heat uphill
A machine that moves heat rather than making it.
Every page in this section
- Three or four units for oneA heat pump does not make heat, it moves it, which is why its output can exceed the energy put in without breaking anything.
- The cold endPerformance falls as the outside gets colder, which is exactly when the heat is wanted, and that trade is the whole engineering argument.
- The refrigerant problemThe working fluid is itself a greenhouse gas in most units, and replacing it changes the pressures the machine must handle.
- District heatAt city scale the same physics runs through a pipe network instead of a garden, with very different economics.