Höhlenmensch14 Feb 2019 13:52I don’t want to start a fundamental debate with technical comparisons here, but just ask a question that arises from my laziness … (researching is quite extensive—and the more you learn, the more complicated it gets).
I’ve already looked at the documentation from different companies and noticed that tube vacuum collectors tend to be in a higher price range than conventional flat-plate collectors.
Looking at the technical data, I feel like I need to study it all over again.
To explain: I want to start by trying out a collector that I install myself to see how much hot water I can generate. Then, multiplying that and implementing it on a larger scale in a professional installation should allow me to calculate in advance what the whole thing would cost, which shouldn’t be a problem.
So far, I am quite skeptical about the payback calculations I have seen. (–When thinking about photovoltaics, I already gave up for this reason.)
My problem is that the pitch of my gable roof faces DIRECTLY west.
Is that even enough to make the investment worthwhile?
The tube collector is supposed to perform better in this respect, as it can make better use of side radiation.
But when I look at the efficiency figures from the companies, I notice that for differences of around 7%, they act like one system is boiling the water and the other is almost cooling it ;-)
Has anyone had experience if the better sensitivity to side radiation really provides a significant advantage?
In the long run, the flat-plate collector is probably simpler than the tubes, since I see that spare parts are also offered for the tubes ?! – For me, this raises the question: does the vacuum degrade? After how long?
Even though this is a trial, I would prefer not to set up two test installations.
Thanks in advance for any tips,
a believer in the wisdom of the crowd. ;-)
I’ve already looked at the documentation from different companies and noticed that tube vacuum collectors tend to be in a higher price range than conventional flat-plate collectors.
Looking at the technical data, I feel like I need to study it all over again.
To explain: I want to start by trying out a collector that I install myself to see how much hot water I can generate. Then, multiplying that and implementing it on a larger scale in a professional installation should allow me to calculate in advance what the whole thing would cost, which shouldn’t be a problem.
So far, I am quite skeptical about the payback calculations I have seen. (–When thinking about photovoltaics, I already gave up for this reason.)
My problem is that the pitch of my gable roof faces DIRECTLY west.
Is that even enough to make the investment worthwhile?
The tube collector is supposed to perform better in this respect, as it can make better use of side radiation.
But when I look at the efficiency figures from the companies, I notice that for differences of around 7%, they act like one system is boiling the water and the other is almost cooling it ;-)
Has anyone had experience if the better sensitivity to side radiation really provides a significant advantage?
In the long run, the flat-plate collector is probably simpler than the tubes, since I see that spare parts are also offered for the tubes ?! – For me, this raises the question: does the vacuum degrade? After how long?
Even though this is a trial, I would prefer not to set up two test installations.
Thanks in advance for any tips,
a believer in the wisdom of the crowd. ;-)
B
boxandroof14 Feb 2019 14:22Large-scale installation, payback period, trial self-installation? What exactly are you planning?
You are building and need or want to install solar thermal (ST) on the roof, either for domestic hot water generation or heating support, or you want to retrofit?
Generally, solar thermal is rarely economically viable compared to photovoltaics; it is usually the least unfavorable option to justify keeping the gas heating system.
If your gable roof is fully facing west, you also have an east side, and in that case, I would cover both sides with photovoltaics.
You are building and need or want to install solar thermal (ST) on the roof, either for domestic hot water generation or heating support, or you want to retrofit?
Generally, solar thermal is rarely economically viable compared to photovoltaics; it is usually the least unfavorable option to justify keeping the gas heating system.
If your gable roof is fully facing west, you also have an east side, and in that case, I would cover both sides with photovoltaics.
Höhlenmensch15 Feb 2019 00:55Sorry for the poor description of my planning.
I am not planning to build, but I have a house where everything is functioning.
From an environmental perspective and to save costs, I have noticed many upgraded roofs, which led me to consider that I should also behave somewhat future-oriented.
Like many others, I noticed this summer while using my garden hose that the sun actually provides a significant amount of energy.
As a do-it-yourself builder with experience in various trades, I want to set up a collector, connect it to a storage tank, and test on different sunny days to what extent and volume I can produce my shower water more cost-effectively. If this leads to a positive result, I can install a larger system completely on my roof.
Unfortunately, I do not have a south-facing location for installation, which makes me skeptical whether the effort is actually worthwhile.
Manufacturers and installation companies always maintain that it is worth it, even if it only results in a cup of warm coffee in the end. I have found that the saying “trial makes wise” often holds true.
For example, with my heating system, I found that simply turning it off has the greatest saving effect, which was denied by all the professional companies.
In summer, my heating (oil) is off and I shower using electric heating.
Regarding the collector, I am considering whether it is worth investing a bit more in the experiment (tube collector), as its performance might partly compensate for my west-facing orientation.
I could try using two different collectors (flat plate and tube) on a trial basis, but for such an experiment I didn’t want to invest too much, since if the experiment does not meet my expectations, no one would buy the unwanted collector. (Maybe that is an idea after all—I should take a look on eBay).
Best regards and good night :-)
I am not planning to build, but I have a house where everything is functioning.
From an environmental perspective and to save costs, I have noticed many upgraded roofs, which led me to consider that I should also behave somewhat future-oriented.
Like many others, I noticed this summer while using my garden hose that the sun actually provides a significant amount of energy.
As a do-it-yourself builder with experience in various trades, I want to set up a collector, connect it to a storage tank, and test on different sunny days to what extent and volume I can produce my shower water more cost-effectively. If this leads to a positive result, I can install a larger system completely on my roof.
Unfortunately, I do not have a south-facing location for installation, which makes me skeptical whether the effort is actually worthwhile.
Manufacturers and installation companies always maintain that it is worth it, even if it only results in a cup of warm coffee in the end. I have found that the saying “trial makes wise” often holds true.
For example, with my heating system, I found that simply turning it off has the greatest saving effect, which was denied by all the professional companies.
In summer, my heating (oil) is off and I shower using electric heating.
Regarding the collector, I am considering whether it is worth investing a bit more in the experiment (tube collector), as its performance might partly compensate for my west-facing orientation.
I could try using two different collectors (flat plate and tube) on a trial basis, but for such an experiment I didn’t want to invest too much, since if the experiment does not meet my expectations, no one would buy the unwanted collector. (Maybe that is an idea after all—I should take a look on eBay).
Best regards and good night :-)
N
nordanney15 Feb 2019 09:22A west-east orientation is actually quite good for a photovoltaic system with a high own consumption rate. Personally, I would consider that more than south-facing. To be honest, I wouldn’t even consider south-facing at all ;-)
N
nordanney15 Feb 2019 10:25Nordlys schrieb:
You seriously want to put solar panels on an old building with an oil heating system?! What does the type of heating have to do with photovoltaics? Even with the current feed-in tariff and a well-planned self-consumption strategy, a reasonably designed photovoltaic system—especially if not sold by an opportunist—pays off in 7 to 10 years.
When regarding the grid feed-in? Will the original poster still experience that?
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