DIY solar water panels vs evacuated tubes


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Old 12-28-09, 12:08 PM
K
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DIY solar water panels vs evacuated tubes

Does anyone know the difference in efficiency from a DIY hot water collector from a evacuated tube collector?
 
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Old 12-31-09, 07:46 AM
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Hi kctpac

The evacuated tube collector has parallel rows of glass tubes connected to a header pipe, and these tubes have the air removed, therefore, the heat loss is minimal. However, reports suggest that the price (twice of any other option) is not justified in terms of efficiency (almost the same) and the evacuated tube collector has lots of problems with maintenace, snow, etc)
You can see the technical reports for all the types in this website
 
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Old 01-08-10, 07:54 AM
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Hot water, cost saving using solar

Interesting subject this.
Are you thinking of doing this to save money on hot water?
If you are, take a look at the cost of heating your hot water at the moment.
You will be surprised to discover just how little that hot water costs you over a year.
Then look at the cost of the panels and the control's, pipe work etc:
Divide one into the other and you will discover it will never pay for itself.
 
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Old 01-08-10, 10:55 AM
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I am using oil from a tankless forced hotwater system using 30-40 gallons per month. I want to get away from oil for $ reasons and reduce my carbon footprint.
 
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Old 01-08-10, 07:57 PM
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40 gallons a month is nothing. There are people that use 200 gallons.
 
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Old 01-10-10, 05:28 AM
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Do u lobby 4 the oil industry?
 
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Old 01-10-10, 05:36 AM
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The oil industry doesn't need lobbying. They are doing just fine.

Anyhow, I think he means 40 gallons a month just for hot water. Going with solar panels is not always about money as kctpac stated.

Those built in coils on the boilers are the worst way to make hot water. Going with an indirect tank alone will probably cut some of your usage down. I think when you have a built in coil, the boiler always keeps itself hot. So you will need to convert your boiler to cold start to save money when you switch over to solar panels. You may also be able to run your tank as a hybrid with the boiler as a back up. This gets past my knowledge of these systems. Have you been to the boiler forum about this issue at all? They will be able to shed a lot of light on what your system is doing and possibly ways to set it up to make sure you save as much as possible.
 
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Old 01-29-10, 06:49 PM
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i have evacuated tubes. i can tell you that to heat the small amount of hot water you use, they will not be cost effective. if you are thinking about the footprint, remember those tubes have their own footprint in the production process. just an fyi, i love my tubes, but, for the same reason as you have, installed them when i installed an endless pool ( small indoor exercise pool) to heat the pool. they work great. i have 75 tubes and it heats the floor and 2700 gallons in the pool. two days ago, i was dumping heat on a bright sunny day with snow on the ground (more light). and contrary to another post, there is no maintenance, at least on my array.
 
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Old 01-30-10, 11:20 AM
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In theroy the tubes are better but in practice they aren't. Their expensive, vulnerable to hail and snow cover. January in Wisconsin and I'm just about to bath in 100% solar heated water from my DIY flat panels. If I didn't know better it would seem impossible. PS To all you smart , yes I need it
 
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Old 01-30-10, 11:47 AM
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Hot water is the best solar application. It's used year round. Inexpensive if it's DIY. Mine paid for itself in 18 months, less if you figure savings for my tenant. Only vulnerable to the same problems as any type of water heater.
 
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Old 02-12-10, 01:54 PM
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Great insight

I am going to give that a try and thanks for sharing.

KG
 
 

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