My furnace is just about shot.

It’s a 70s-era oil furnace that came with the house. It smells funny, it sucks oil down like a breast-fed three-year-old, and it’s burning a serious hole in my pocket.

Since I’ve got to do something about it, I figured I’d go one step better than a simple upgrade, and put in a heat pump. Heat pumps are one of the coolest things invented in the last few centuries. (My own personal standard of coolness is the bicycle, which I consider to be the closest man has come so far to a perfect machine, with the exception of the friction brakes. All braking should be energy recapture.)

When I realized that a heat pump is effectively 200-300% efficient (compared to production of heat), I started to wonder if it could be made even more environmentally friendly by doing away with the electrical motor entirely. A little research uncovered gas-engine-powered heat pumps, but I wanted to go even farther – bicycle power.

The most popular consumer-grade bicycle generator outputs around 200 watts of electricity. If I assume that the generator efficiency is around 60% (based on data on wikipedia), and we use direct-drive of the compressor, then effective power output of the cyclist is about 330 watts.

If I was REALLY hard-core, I can imagine bicycling 2 hours, every day, for a total power generation of:

330 watts * 2 hours * 365 days = 240 kWh per year.

A two-ton heat pump from Goodman (the SSZ16, for those of you following along from home) draws 1.7 kW at 47 degrees F (the typical measurement point). If, theoretically, a one-ton unit drew only half that (it doesn’t), and we took some advantage (not much) from avoiding the electric motor and using direct drive from the bicycle, we *might* be able, with two cyclists, to run a heat pump in real time.

Wow. For a near-perfect machine, that’s a lot of wasted power.

In an upcoming post, I’ll be looking into ways we can establish a mental framework for evaluating our energy usage, and other aspects of our “inconvenience“.