Unlocked Mind Newsletter / Unlocked Mind Media
3 dimensional visualization skills are important to develop the imagination, so a good way to develop this ability is to build and work with three dimensional things. Here we share the various projects our staff have done.
It is our hope that you will see the logic (or the lack of logic) used to make your own heat strips as an example of the kind of thought and analysis that goes into our script review services.
Notice: The content presented here is for entertainment purposes only. Readers who decide to construct or modify the items mentioned here do so at their own risk and peril.
This project started when more heat was wanted in our basement shop area. The excess heat from the boiler running made the temperature in the basement about 60 degrees, which is not bad, given that the rest of the building is heated to about 72 degrees, so coming and going from the basement was uncomfortable. Installing an extra hot water radiator from the boiler in the basement was considered, but too much work. We wanted to try something easier before going through that much trouble. Using an electric space heater was also ruled out since it would be too wasteful ... We had to find a way to capture some of the heat (and money) that was literally going up the chimney.
Note: This idea works best with older gas fired appliances. The newer condensing boilers, furnaces and hot water heaters have lower vent temperatures meaning this idea might not work well, or at all.
The solution we discovered was to make aluminum heat sinks out of regular aluminum flashing, and to install the heat sinks on all the metal vent pipes going to the chimney, check the temperature, and see what would happen.
The temperature went up from 60 to about 65 degrees ... not a bad increase for just a few dollars, and without any future energy expenditures for running a space heater, or installing an additional radiator off the boiler.
Here is what you will need to make your own heat strips:
Container of heat transfer compound. You only use the heat transfer compound on vent pipes on boilers or furnaces that run during the winter, meaning you can leave the heat strips in place. For cooler temperatures in summer, you would remove the heat strips from hot water heater vent pipes and clothes dryer vent pipes. While thermal transfer efficiency is lower without using the heat transfer compound, there is no messy goop to clean up and collect dust during the summer months.
1. a bunch of rare-earth magnets. You can order these for cheap on E-bay. You might have to wait a month for shipping from China, so plan your order early so the magnets arrive before you need them.
2. Roll of regular aluminum flashing.
CAUTION: Aluminum flashing is sharp, especially when you start cutting it up. The stuff is stiff, and dangerous to work with without wearing work gloves. Be warned - One careless slip of the hand, and the flashing can cut you to the bone. Wear the work gloves ... You will be glad you did once you see how slippery and springy working with it can be.
3. work gloves to work with the sharp edges of the aluminum flashing. Leather gloves are best.
4. Tin snips
5. Hand held wide jaw sheet metal clamp/bender
6. Pair of regular pliers
7. Optional: High temperature Epoxy glue to hold the magnets to the heat fins. See below for details.
CAUTION: You will notice no drills are mentioned here. You don't want to drill into gas fired vent pipes, because it could let the deadly carbon monoxide gas enter your breathing space, no matter how careful you think you can seal up any holes in the pipe. Energy efficiency is no good if you or your family is not alive to enjoy the benefits of the work, or to pay those lower energy bills.
First, locate all the exposed metal vent pipes you have, and estimate how much pipe surface area you have. This will determine how many heat strips you will have to make. Use a damp rag and wipe the dust and dirt off the pipes so they are nice and clean. Rusty vent pipes should be replaced immediately.
CAUTION: Never touch hot vent pipes. Serious burns, injury or death may result. Wait for pipes to be cool before touching them. If in doubt, turn off appliance and wait 24 hours before you touch the pipes.
Make Vs. Buy: There are companies out there that sell pre-made heat strips, but they are expensive. By making your own, more financial benefits are earned since your initial cash outlay is much lower than paying a higher price for the manufactured strips. Also, by making your own heat strips, you can make more strips to take advantage of the whole length of pipe you have instead of having to buy fewer and more expensive strips and not seeing any temperature increase for the greater expenditure.
Next, measure how wide your hand held sheet metal clamp/bender are. The wider the better, but to make the project easier, they should be at least 6 inches wide. You want the pieces of the flashing to fit within the jaws of the bender, so the bends are nice and flat and make good contact with the vent pipes, as shown in the picture below.
[picture of sheet metal in the clamp]
Remember that a heat sink works by conduction, and passes its heat by convection (is this a science lesson?). Some of the heat from the vent pipe is conducted to the heat strip, which in turn heats a larger volume of air passing by the pipe. Since the aluminum flashing is thin, there is not much material available for it to conduct a large amount of heat, so the fins of your heat strips can only be about 2 inches long. Longer fins will start to cool off, meaning having longer fins would be a waste of material if they are not allowed to heat up and pass the heat to the air. The benefit of the thinner material is that it heats up faster, and passes heat to the air faster than a heavier heat sink would.
Next, cut the flashing into rectangles, as shown below. As mentioned above, each side is about 2 inches, and the center section should be about 1 to 1.5 inches wide. The center channel is where the magnets will hold the heat sink to the pipe.
[picture of flat piece of flashing]
Next, use the benders to bend the metal into a channel shape, as shown below:
[picture of channel shape]
next, use the tin snips to make a series of cuts into each side of each channel. About half inch wide work best, as shown below:
[picture of cuts being made in the channel shape]
Next, bend every other piece, to give the air room to move past so it can collect the heat. Use the pliers to bend the fins in and out. Remember, the edges will be very sharp! Your heat strip should look like the one below:
[picture of strip with bent fins]
Now you have to decide how you want to mount the heat strips. For easy to reach places, you can just hold the strip up, and place the magnets in the center channel so it stays in place. If you think you may have trouble reaching around to put the magnets on the strip, you may want to use the Epoxy glue to bond the magnets to the strip before it is put in place. If you don't have a large piece of sheet metal handy, you can put a sheet of newspaper over the (metal) washer or dryer, and use the Epoxy glue to put the magnets in place. Let the glue dry/cure overnight before putting the fins in place.
CAUTION: Do not place the heat strips in areas where people could touch them, for example in areas around valve handles, etc. Place them out of the reach of children and curious adults who may touch them, and cut themselves on the sharp edges.
[picture of heat strip on a pipe]
That's about it. Once your strips are in place, take a temperature reading, and see how high your temperature increases. While a few degrees may not seem like a lot, remember that you did not have to pay extra for the increased heat temperature, and you help keep some of your money from being wasted by going up the chimney.
We would like to know your results. Let us know how this project idea worked for you.