Electric Power From Any Heat Source - Really? Part 1

While working on another article, I stumbled across a few products that can convert heat directly into electricity. Hmmm....sounds like a great way to scavenge some watts back to our batteries when we are using our heaters. Especially the typical forced hot air RV furnace. Will this really work? let's take a closer look.

Likely, many of you have seen the "no moving parts" refrigerator/coolers that use "Peltier Effect" cooling modules. This uses power to cool one side of the module and heat the other. If you reverse the current flow, they will heat up instead of cool down. What we are doing, in essence, is heating up one side of the module and harvesting the electricity generated at the other, wire end. Most Thermoelectric generator modules use the "Seebeck Effect" a close cousin to Peltier.

Power Pot USB Charger

Not that much of this really matters. Simply put...heat goes in one side, electricity comes out the other. There are some existing products on the market now that take advantage of this effect. The first I found was a pot that you boil water in and it has a USB connector on it that will charge your cell phone and other small gadgets. It was called the "Power Pot." Yes, the name is funny, especially if you grew up in the 60's. It does work, but doesn't put out enough power to really make a dent in charging the RV house battery system. Right around 5 Watts at 5 Volts. The modules that make this happen will operate beginning at 250 degrees Fahrenheit to 600 degrees Fahrenheit depending on the module.

ThermoElectric Generator Module

Then there are the TEG (ThermoElectricGenerators) sourced from various companies. These are more in line with what I have in mind to test. They can be had in wattages and voltages ranging from a low of 1 Watt to a high of around 20 Watts. They'll also build custom TEGs and sell you separate modules to build it yourself. That's what I am looking into.

Atwood Style Exhaust Assembly

My concept is to wrap the inside furnace exhaust pipe with TEG modules then an insulating cover. As long as it doesn't affect the furnace or cause CO2 or Carbon Monoxide problems we may be able to significantly offset the furnace fan's draw. This can be a whopping 7.5 Amps or more! Wouldn't it be nice to not worry if your batteries will run your furnace overnight without going dead? If my experiments work, than we'll be able to do just that! Why waste heat dumped overboard? Recycle! Even if we cannot generate equal to or more than we use with the fan running, any power saved is a good thing.

Of course, it may not be COST effective. Stay tuned for Part 2 where I will be assembling various configurations and testing the concept. If it works, I'll have a good idea how much all this will cost. The modules I have been looking at are all around 40.00 dollars each. I believe between 2 and 6 modules will be enough. We'll see.

Be Seeing You...Down The Road,

Rich "The Wanderman"
www.thewanderman.com

The Need For Warmth - How Long Can I Run My Heater On Battery Power Alone

This Is Why You Need Heat!

    If you are like most RV owners, your propane fired forced hot air furnace uses a 12V blower fan to circulate the hot air. Depending on your battery capacity (1, 2 or more) you will likely be able to get through most nights. The usual draw is around 7.5 amps when the fan is running (perhaps a bit more or less depending on brand and size)

Common 2 Battery Installation (This One Is Mine)

If you have a single battery it is usually around 80 amp/hours in storage capacity. It's bad for the battery to be drawn down past 50% too often as the battery's life will be shortened. This means you have around 40 amp/hours to play with. 7.5 into 40 is around 5.3 hours of actual fan run time. In my case, with the thermostat set at 68 degrees Fahrenheit it runs for about 20 to 25 minutes every hour. So you can just about double your run time to about 10 hours. Bear in mind there are other draws on your battery overnight, so this is a best case scenario. With more batteries comes more capacity. Older batteries will not store as much power. And colder temperatures will reduce your storage capacity as well. Make sure your batteries are maintained properly and you should be able to keep the listed capacity for at least 2 years, maybe longer. Some loss will occur naturally, nothing to worry about.

I've heard of folks getting 7 or more years from their set of batteries if properly maintained!

Catalytic Heaters

You could install a catalytic heater which does not have a fan (Look at the Wave Series by Olympic) This is only limited by the available propane storage. It will require some ventilation. I have been toying with the idea of installing one of these since they are very close to using propane at 100% efficiency. I'd have to run a hose from the manifold to the heater AND figure out where to mount it to get the most coverage. Not really sure where that would be.

Typical RV Furnace

The fan on most, if not all furnaces,will actually run after the furnace flame has gone out. It will circulate the warm air while it is cooling down the furnace itself. Lots of heat from a typical RV furnace is lost to the outside air. Try standing outside next to your furnace exhaust one cool day. It can be pleasantly warm there! I've been working on a way to scavenge that waste heat and use it to do something useful. There are some new devices around that will convert heat into electricity, that would at least get something back. And/Or maybe run a coil of copper tubing around the exhaust pipe internally and circulate some water through it and into the hot water side of the plumbing system.

This is what I do in the winter....figure out what projects to research and develop for testing in the spring. It can get very interesting around my house when the midnight oil begins to burn. The whole Solar Charging Project began the same way.

Again, YMMV...but this should give you start.

Rich "The Wanderman"
www.thewanderman.com

Presto! - And Now You Have A perfectly Cooked Burger

    Many years ago I was finally allowed to go home after school without supervision. My Mom didn't want me to use the stove because it had a gas pilot that had to be lit and she was concerned something would go horribly wrong. At the time, I thought that was silly. In retrospect, she was right. With today's safety mechanisms it would likely have been OK, but then....not so much. Where is all this leading? Well a boy's gotta eat, so we found a solution that would allow me to cook a hot meal and be safe from accidental explosions.

The Hamburger Cooker

It's snowing here in Upstate new York today, so no work on the RV and being cooped up always gets me twitchy. I've been cleaning out the kitchen cabinets and stumbled across my old PRESTO! Hamburger cooker. This was the solution to my boyhood cooking problems. Still works! Man, does it make a tasty, perfectly cooked burger every time. Not even sure they are still available, but I'll wager they can be had cheaply on E-Bay or Craig's List or some similar online site. Likely, you could find one at a flea market or garage sale too.

How's it work? Well, it has two sides that come apart for easy cleaning. One side has the heating element embedded inside it. The cooking surface is a Teflon coated half burger shape. The other side has an top  aluminum "platter" with the other half of the burger mold and a bunch of drain holes. It fits into the bottom plastic housing that will catch any drippings. That makes for a juicy, not greasy burger. Bear in mind this predates the Fat Draining grills that are everywhere today.

Simply plug it in to preheat for a few minutes, put in your favorite ground beef (I like 80%/20% for this, though 90%/10% is OK as well)  or pre-made burgers, close the lid and latch. Depending on how you like your burgers, 3 minutes is rare, 4 minutes is medium, 5 minutes is well done. Open the lid and just like that a perfectly shaped, perfectly cooked burger. Everything but the cooking side is dishwasher safe. I usually just wipe out the Teflon coated cooking element side and it's clean. Pretty easy. Since it's small, it takes up very little space.


It uses 400 watts at 120V for 3-5 minutes translating to about 3.8 amp/hrs from a battery bank on an inverter. Obviously it's easily used with a generator or shore power. Like I've said before propane has to be bought, electricity can be made on the spot. Great for boondocking.

I'll bet you could also make other kinds of patties...chicken, veggie, lamb....with varying cooking times. I look forward to trying them all this coming RV season.

Be Seeing You...Down The Road,

Rich "The Wanderman"
www.thewanderman.com