Working Up

by Dwayne Phillips

I build a heater from two clay flower pots and some tea candles.

I saw this on the Internet (how many times have you heard that one) and decided to build my own.

It was very cold the week I did this, so that explains why I did it. I saw that you could build a heater with some candles and clay flower pots. Why not try?

This first photo shows my configuration: two tea candles (See NOTE below) set in a bread-making pan. The aluminum foil was to keep wax from spilling on my wife’s pan and causing domestic angst.

Candles in Pan

NOTE: I have no idea what makes a candle a “tea candle.” Beware what the big candle lobby can do in Congress.

The second photo shows the configuration after setting the smaller clay pot on top of the bread-making pan. The aluminum foil on top of this clay pot is necessary as it prevents the hot air from the candles from flowing out of the top of the pot. We want the small clay pot to become hot, so stop the flow of air.

Smaller Clay Pot in Position

The third photo shows the final heater configuration. The larger clay pot is now resting above the smaller clay pot. The hole on the larger clay pot is left open. Hot air will exhaust here.

The theory is simple. The candles, ooops, I mean, the tea candles will heat the small clay pot. Cold air flows up from the open bottom of the large clay pot across the surface of the small, hot clay pot. That air heats in the process and then exhausts through the open hole in the large clay pot.

I tested this. It works. I measured the temperature of the room air at 64 degrees F (no, I don’t spend a lot of money on central heat). I measured the temperature of the air exhausting from the large clay pot at 88 degrees F.

Larger Clay Pot in Position

Some of the web sites I saw on the Internet claimed that this heater would heat a small room. That didn’t happen in my experiment, but I believe that my configuration was too small to do that. Had I used larger clay pots and more tea candles, like I saw in several Internet demonstrations, I believe I could have generated enough heat.

Enough thermodynamics for this week.