diy solar

diy solar

My first diy solar water heater

x4dow

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Dec 30, 2020
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Started making my own solar heating panels for my inflatable hottub

Looking forward to test them out in the summer :

2x 4'4' panels with 66 meters 13/16mm irrigation tubing each.

Powered by 18W12v pump on a thermostat swithh and a 60w panel hooked to a small " solar generator "

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Started making my own solar heating panels for my inflatable hottub

Looking forward to test them out in the summer :

2x 4'4' panels with 66 meters 13/16mm irrigation tubing each.

Powered by 18W12v pump on a thermostat swithh and a 60w panel hooked to a small " solar generator "

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Started making my own solar heating panels for my inflatable hottub

Looking forward to test them out in the summer :

2x 4'4' panels with 66 meters 13/16mm irrigation tubing each.

Powered by 18W12v pump on a thermostat swithh and a 60w panel hooked to a small " solar generator "

View attachment 34525View attachment 34526View attachment 34527View attachment 34528View attachment 34529
What's your expectation for performance? What's your total investment for making this?
 
What's your expectation for performance? What's your total investment for making this?
I bought stuff new, so spent about 200 bucks total. from what i've seen online, considering the sun isnt that hot here in the uk, this thing should at least half my electricity usage in the summer. Considering the tub can use up to 60-70 a month in the summer, this should pay itself in 4-5months.
If you just have hose laying around, you can make a more basic version for less than 10-20 bucks.
 
Had my first trial run today.
Only 18C/65F outside. Hottub Water was at 28c/82f, ran it for 2 hours, water gone up to 30C/86F. Looking promising for my firs ttry, considering its a reasonable mild early spring day in the UK
 
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Quick update. this system has actually been working "TOO WELL". water been consistently going over 40C (104F) during the day in the last sunny days. Might reverse the thermostat to actually STOP when incoming water temperature is bigger than X, instead of what is at the moment (Start when temperature inside the box over X)
 
Impressive!

I wonder if two thermostats in series would be the solution?

One to stop when the tub gets hot
Second to not pump in cold water from the heater
 
Amazing work! Very promising results, so great that you’re able to use the sun to bring the hot to the tub.

I’ve always wondered what people do to throttle back the amount of power generated by this.

There are https://en.wikipedia.org/wiki/Smart_film
But the cost per surface area might not make sense. Also most are marketed to block solar infrared heat, and it’s not clear to me that switching states changes the infrared transparency. Just a random silly thought.

Cheers on the developing system!
 
Impressive!

I wonder if two thermostats in series would be the solution?

One to stop when the tub gets hot
Second to not pump in cold water from the heater
Yes.
Although there are also thermostats that have 2 sensors and allow you to do that in 1.


However I don't want to stop the system if the water is too hot, as these boxes are all black and sealed, if the water stops flowing, the pipes would probably melt.
 
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