# Creating a Portable Ceramic Space Heater that Works with No Electricity.

## 01/29/13

"I can't help quoting you, cause everything that you said rings true." - About Morrissey.

Doctor Aaronson, Omaha, Nebraska's OTHER Oracle. Dr. Michael Aaronson is a kidney physician specializing in Nephrology and hypertension.

Using a ceramic space heater powered by a candle to generate convective heat (corners), a hand crank to generate heat from a light bulb (center stage), and a low voltage DC blanket powered by a portable, electrical battery allows a family comfort and warmth during a power outage. Note: when the candle heaters are placed appropriately (at the edges of the blanket), the heat stays in a king-sized zone.

The concept of using convective heat by means of a candle warmer to keep you warm and toasty when the power goes out is the final component of our 3-part-package to avoid the hotel when you have lost your electricity. It's time to hunker down folks!

Dr. Aaronson hopes Mr. Morrissey is feeling better. Get well soon!

Let's review: first, we showed you how to create heat from a light bulb using a hand crank. Second, we showed you how to power a heating blanket with a battery using a low voltage DC current. We will now describe a way to create a ceramic space heater sans electricity using a candle and a flower pot as shown below.

A ceramic flower part (code word: terracotta) heated by a jar candle creates, in effect, a space heater that keeps you warm when you have no power and it is cold outside.

Please note: don't get burned when playing with fire. Keep these apparati out of the reach of children. Know what you are doing. If you don't want to make one of these yourself, purchase the Kandle Heeter Candle Holder (or 3 of them like I did) so that you know your heating machine has been built correctly. First, the manufacturer has made many of these warming candles. Second, it appears that he has "open-sourced" the process, giving the reader howto instructions, which is unbelievably great and worthy of respect. I purchased 2 Kandle Heeters and 1 Glow-warm electric candle which uses an infra-red light bulb rated at 50 watts and plugged into an electrical outlet to create warm heat.

Close up of the Glow Warm Electric Candle in action. The infrared lightbulb creates 50 watts of heat which warms the apparatus which warms you.

Disclaimer: How is it possible that this apparatus can create "more" heat than a candle by itself can? If you read on, you will see why the system works. That said, these are my opinions -- the opinions of America's Medical Blogger and your simple country nephrologist de jour. I do not pretend to be a physicist. I (about me) went to Bowdoin College in Brunswick, ME and majored in Biochemistry with a minor in Psychology. My goal here is altruistic. My goal here is to help keep you warm. That said, please don't get lost in the language (as I explain in my blog The Need for Medical Jargon Justified Using the 18 Omaha, Nebraska Snow Words). At the end of the day, this system does indeed work, because it uses the same principles as a ceramic space heater, because it is a ceramic space heater (see below).

How does a ceramic space heater work? According to Wikipedia: Ceramic heaters are space heaters that generate heat by passing electricity through heating wires embedded in ceramic plates. It takes from 1000-1500 watts of electricity to do this. Since we do not have that kind of power when the electricity goes out, we need to come up with another approach.

It turns out that a candle can provide the "electrical equivalent" you need to create a functional space heater. Instead of plugging a space heater into a wall outlet to get the electricity you need to create heat, the candle serves as the "source" of the heat.

A ceramic space heater. Contrast this with our candle heater shown below:

The oil candle, made by LampLight, powers the flower pot warming system. The heat of the candle warms the steel bolt directly above it which gets hot and transfers thermal energy or heat to the terracotta flower pots.

Which type of candle should you purchase to run your portable ceramic space heater? It turns out there are different candles you can buy to heat your candle heater. You can buy a jar candle, a lamplight reusable oil candle, or a disposable restaurant grade oil candle. Note that the "hottest" candle is the one that has its flame constantly near the apparatus. That said, for the sake of clarity, using information available on the internet via wikipedia, we will use the standard, dollar store, taper-type, paraffin wax candle in our calculations to "prove" that the system can generate a significant amount of heat. So it can be argued that we are UNDERESTIMATING the amount of heat that this candle warmer will generate...

From Wikipedia: a modern candle typically burns at a steady rate of about 0.1 grams/minute, releasing heat at roughly 80 watts.

I plan to show you how the 80 watt number is derived and why the candle heater works.

Heat is released from a burning candle. However, for reasons that will become crystal clear, candle heat from a burning candle is not concentrated enough to make a noticeable difference to a person or family near the candle to create warmth. That's where the concentrator shown below comes in:

Close-up view of the Kandle Heeter. The candle heats the steel inner core.

Side view of the heating apparatus.

The heat from a burning candle is 600 degrees Fahrenheit. The heat rises and warms the steel nuts and bolts to 550 degrees Fahrenheit. This heat is subsequently transferred to the 3 flower pots starting at the innermost terracotta pot and moving outward. By the time the heat has reached the outermost pot, the surface temperature of the outer pot is approximately 180 degrees.

I will use the following equation to explain why this system works:

$HP=0.001\cdot \left({T}_{s}-{T}_{o}\right)\cdot A$

= temperature at the outermost surface of the ceramic flower pot (Fahrenheit)

= temperature outside of the house (Fahrenheit)

A= the surface area of the flower pots.

We first must appreciate the goofy terminology that is used when heat is described. We will start by calculating the amount of "horse power" generated by the system. We will convert that number to BTU. We will convert that number to Watts generated per candle heating system.

In order to determine the horse power generated by the system, you multiply the constant 0.001 times the difference between the temperature at the outer surface of the flower pot which we determined to be 180 degrees by measuring it and the temperature outside which last time the power went out at my house was 5 degrees. We multiply this by the surface area of the system which is 0.611 square feet as shown:

HP = 0.001 x (180 degrees - 5 degrees) x 0.611 square feet

HP = 0.106 horsepower (or one tenth of one horse)

Next, in order to make the math work, we must convert horsepower to BTU per hour as is shown:

1 HP = 2545 BTU/hour

0.106 HP x 2545 BTU/HP = 269.77 BTU

BTU does not have a lot of meaning to me. So let's get rapidtables.com to help us convert BTU per hour to watts so we can show that we are releasing around 80 watts of energy in the form of heat:

260.77 BTU -> 79 Watts per candle heating system.

To put this into perspective, consider that the hand crank generates around 12 Watts of heat as we described in part 1. The heating blanket generates 36 Watts of heat as we described in part 2. So this system does quite well at 80 Watts of heat generated. Power up 3 of them and you are at 270 Watts of warm, where you need it, heat that keeps working as long as you have available paraffin or jar candles.

Left: candle warmer heated by an infrared bulb. Center: candle warmer heated by a jar candle. Right: candle warmer heated by a reusable oil lamp.
The Kidney Consulting Oracle of Omaha Nebraska USA.
www.michaelaaronsonmd.com Doctor Michael L. Aaronson attended Bowdoin College. He received his medical training in Connecticut and Minnesota and is board certified in internal medicine and nephrology. His practice area includes Nebraska and Iowa. He is an assistant clinical professor of medicine. He has published many research articles. Dr. Aaronson works in Omaha, Nebraska in the Nephrology / Kidney Division. He blogs about relevant topics to keep you and your family happy and healthy using the wisdom of MORRISSEY.

What is the secret of success to create a flower pot space heater that works similar to a ceramic space heater that you can buy at Walmart? The answer is many.
1. Remember the wisdom presented in the "snow words" blog above. It took me a while to appreciate that a flower pot is made of terracotta which is another name for ceramic. Ceramic is ceramic. The flower pot happens to be ready-made ceramic shaped in a way that it easily works well when cleverly put together to concentrate the heat generated by a candle heating a piece of steel.
2. A candle by itself doesn't concentrate heat or warm Michael's bones because there isn't enough surface area to allow for the "horse power" required to keep you warm. If you do the math using the equation provided above, you will see that a candle in and of itself provides minimal heat.

A candle flame has a small surface area.

Helpful hint: when you are alerted that a storm is coming, power up the candle heaters so that they can warm up and be fully functional when / if the power goes out. It is important that you are prepared before you lose power.

Helpful hint #2: To maximize your return on investment, if you use solar power or wind energy, you can charge a Duracell battery and use that to light an infrared bulb which powers your candle warming system and keeps you warm while offsetting the cost of your electrical, gas, and oil bill. We use the GlowWarm electric candle as a nightlight / heat source when the power is working.

Conclusion: candles can be a great source of heat, especially when the power is out and you have no other options. Just as a blanket keeps you warm by concentrating the heat from your body, a candle warmer concentrates the heat from a candle. Consider using this approach to stay comfortable as you weather the storm.