Hey guy /diy/generates! Helping my dad clean out an old shed behind a house he just bought, and there were several finned radiators in there. You know the ones for hot water, right? Basically a copper tube with a shitload of washers soldered on them? Well, my girlfriend is a pinerest addict, and she shows me stupid shit all the time, but I remembered a pool heater built from black PVC, and I got an idea. I have a pretty decent sized garage, (20x 24 ft) and I was thinking about adding heat anyway. Here is my idea: Take a plastic barrel, insulate the fuck out of it for heat storage, run one of these fuckers on the roof with a pump constantly running a water/mthanol mix thru it, into the tank sucking the water from the bottom. have another feed run by a separate pump towards the top pushing the same mix through the radiators. Use a relay with a thermostat to control the pump feeding the radiators, and some other setup to measure the water in the coil to control that pump so I'm not cuirulating cold water in the tank when the sun goes down. It wouldn't be my main system, just something to help. Any thoughts?
>>1014270
>any thoughts
Paragraphs are underrated.
trying to do this from my phone because internet is still out from the last storm. It's a bitch.
>>1014277
Well there's your answer.
>>1014270
i read that fucking mess once, not doing it again. i have no idea what you want
you have "many rads" from a car? truck? old central air unit?
are you planning to heat or cool the fucking pool
no, hot water radiators for a house. basically a piece of copper pipe with fins soldered to it with a metal cover. I have 8 of them 6 ft long each.
coil will be used to heat water going into a barrel. barrel will be insulated.
water drawn off of barrel through radiators to heat garage area. redundant system, not primary.
>>1014295
OP wants to install a radiant heating system in his garage using old vehicle radiators. He wants to store most of the water on the roof in a tank so it's heated by sunlight. He wants to use methanol/water blended for some odd reason, probably because he thinks methanol will hold heat better. He wants to use a photo cell to shut the pump off when the suns not out, probably because he thinks that it'll keep the tank from losing heat at night.
>>1014302
Could work, but it will be less efficient than a conventional solar heater. A lot of heat could be lost because the only thing separating the hot water from the cold exterior is a 1mm plastic tube, causing massive losses, specially in winter. I would suggest to do some research on better designs.
>methanol/water blended for some odd reason, probably because he thinks methanol will hold heat better.
Maybe to avoid freezing?
Water has a 75.41 J/mol*K heat capacity, while methanol has 79.5 J per mol*K. I don't think it'll be a massive difference, but could be a slight improvement, 50/50 mix freezes at around -35 C btw.
Add a photo sensor and a comparator to the pump circuit and you're good to go, it will stop the thing at night or when it's cloudy. A thermostat could be added to stop water from circulating though the radiators if the temperature inside the tank is lower than in the shed, making sure it only heats the shed up.
>>1014302
Methanol is probably to reduce mildew.
>>1014270
This is a thing around the world. There's 100s of DIY stuff on how to do it online. Google some.
You just need water, nothing else unless there's chance of freezing then you add antifreeze to the closed loop side that is being heated by the sun.
These thing are deceptively simple to make, don't over think it. Just get good flow and install some T&P valves.
methanol is a lot cheaper for me. Most of the farmers aroung here use it from distillation for their grain dryers, and yes it's was because of freezing. My google-fu is admittedly weak, because all I could find was stuff for sale.
>>1014270
It's theoretically sound (and, in fact, functionally identical to a thermal mass air conditioner idea I've been mulling over blowing the cash on for the last two years), but you should check how much heat you can store in your barrel; it's almost certainly not going to be enough to last very long.
For reference, the 8x4x4' tank I'd be using holds about 15MJ (~14,000BTU) per 1°C. A 55 gallon drum will hold a little under 900kJ.
I can get methanol for roughly 1.50 a gallon USD. Coolant is approimately 9.
This is similar, only the ones I got are rusty on the stamped metal. They've never been installed.
>>1014315
Oh wait, I forgot methanol is much less dense, so no, adding methanol will only help to avoid freezing at the cost of heat energy storage per volume.
>>1014270
Yeah. Learn to do simple heat loss calculations. R value, temp difference between inside and outside. Figure required BTUs or Joules needed.
Now calculate the solar energy per square meter at your location during the heating season, times the efficiency of the collector you will be using. Now calculate the number of square meters of collector you will need to heat the space you have. And the required energy storage (store heat during the day for heating at night).
Cheap metal/plastic collectors are much less efficient than other types, so you will need more collector area. But they are cheap. Evacuated tube collectors are expensive, but more efficient. So you will need less area.
>>1014270
These black pipes are actually bullshit just look them up on YouTube everyone says its a scam. I could imagine. How much heat domyou want to capture with that tiny surface area ?
>>1014343
They're designed to dissipate heat outward. The fins would be a hindrance to their economy if you wanted to retain or absorb heat.
I made an out door pool heater once from copper pipe and a galvanised steel box.
The box was about 1500mm x 1000mm x 120mm. I had two 22mm copper pipes running down each side of the inside of the box. Imagine this box is open on one of its biggest faces.
Then between the 2 x 22mm headers ran a series of 15mm copper lines. All painted black.
I know someone who works in window manufacture so managed to get a triple glazed unit to cover the assembly.
It got so hot one of the glass panels shattered.
>>1014340
Holy jesus,the savings.
I used 100m of us rated irrigation pipe and just coiled it around the shed roof next to the pool and added a pump in summer you can't put you hand next to the hot water outlet in the pool I used black pipe to catch more heat
>>1014302
Could methanol be to prevent corrosion maybe?
