Does solar water heating make any economic sense?

jackswift said:
Why would anyone need a tank of hot water during the summer anyway? A shower heats water as it comes out dishwashers, washing machines heat water.
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You might be hand washing dishes, washing babies, cleaning a range of things, and its alot easier in hot water than cold. Maybe having a bath to help with aches and pains, or just because you want to. You might like washing in cold water, but I'd guess you are in the minority.
 
Maybe not a whole tank, but certainly some. And yes, I prefer to wash my hands with hot water. :)
 
I guess the point is if you have a full tank of hot water and 2-4 people in the house, you will save alot of money compared to 2-4 people using an electric shower. Electric showers are inefficient - i guess it depends on the number of people in the house and how often you take showers - but a recent discussion on this forum proved that heating water with oil (no matter the price) would work out cheaper than using electricity.

As regards my solar panels, I used a company in Macroom, Co. Cork - Solaris Energy. 6SQ metres of German made Flat panels built into roof with a 300 litre tank. On average water drops about 1 degree an hour during the night etc - so it's often 60 degrees at 10pm and 50 degrees at 8am the following morning - more than enough for several showers
 
We also used this company in Macroom, and have found them totally unsatisfactory in their back up. No response to phone calls or emails when the system looses pressure etc. So we could not recommend them as a reputable company to deal with.

As this post seems to indicate, the cost of solar installations is way to expensive in Ireland to warrant installation except on an green basis. Our tanks looses about the same overnight. WOuld we install solar again if we were at the beginning of the process? NO as pay back is to long. optimistic

PaddyH said:
I guess the point is if you have a full tank of hot water and 2-4 people in the house, you will save alot of money compared to 2-4 people using an electric shower. Electric showers are inefficient - i guess it depends on the number of people in the house and how often you take showers - but a recent discussion on this forum proved that heating water with oil (no matter the price) would work out cheaper than using electricity.

As regards my solar panels, I used a company in Macroom, Co. Cork - Solaris Energy. 6SQ metres of German made Flat panels built into roof with a 300 litre tank. On average water drops about 1 degree an hour during the night etc - so it's often 60 degrees at 10pm and 50 degrees at 8am the following morning - more than enough for several showers
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If I were to build a house tomorrow I would not fit solar panels. However I would make allowances for them to be fitted in the future I.E run pipe work and fit a cylinder with extra coil.

I have been to a few courses on the subject and with all honesty the technology used in the actual solar panel coulld have been something you would have seen in De Vinci's handbook

. I feel since they have become more popular, companies will spend more and more money on them. It's a bit like buying a PC five years ago, the same PC is now nearly obsolete.

In the next five to ten years we will have solar panels good enough to heat the entire home, hot water and heating (by way of buffer tanks) and they will work with any amount of light as opposed to direct sunlight.
 
Thanks for all the responses so far - great stuff.

With respect to those on both sides of the argument, I am more convinced than ever that now is not the time to commit to solar in Ireland.

I am going to focus my efforts and cash on other measures.

Keep the opinions coming!
 
DavyJones said:
In the next five to ten years we will have solar panels good enough to heat the entire home, hot water and heating (by way of buffer tanks) and they will work with any amount of light as opposed to direct sunlight.
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A quick glance at the wikipedia article about the sun tells us that the amount of sunlight hitting the earth per square meter on a clear day when the sun is high in the sky is about 1000 watts.

In Ireland there are clouds quite a lot of the time.

The solar panels today can only capture about 1/5 of the sunlight which the sun has to offer. In the future it might be more.

Even if solar panels are 100% efficient, it will be a big challenge for them to meet all the heating and hot water requirements.
 
LouisCribben said:
A quick glance at the wikipedia article about the sun tells us that the amount of sunlight hitting the earth per square meter on a clear day when the sun is high in the sky is about 1000 watts.

In Ireland there are clouds quite a lot of the time.

The solar panels today can only capture about 1/5 of the sunlight which the sun has to offer. In the future it might be more.

Even if solar panels are 100% efficient, it will be a big challenge for them to meet all the heating and hot water requirements.
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Broaden your scope of research.
15 years ago they said the internet was impossible. they said you needed a computer the size of a house to do the things laptops do now. Google it, topping up heating systems by means of buffer tanks has already started. In the near furture clouds will have nothing to do with harvesting solar energy.
 
ubiquitous said:
The internet is still impossible if you rely on the equipment that was on the market 15 years ago.
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Yes, but that equipment was good enough for the internet of 15 years ago.

Content tends to expand to fill the capacity of the channel. So the "speed" of the internet tends to stay the same, it's just that the content becomes richer.

To apply the analogy to the world of solar heating, the technology will indeed improve. It can still only produce hot water, but the water will be hotter, or there'll be more of it.

And next year's technology will always be better!
 
Without wanting to extend the analogy too much, unfortunately Moore's Law

http://en.wikipedia.org/wiki/Moore's_law

does not apply to solar energy systems.

The rate of improvement in the technology is clearly much much slower, given how little it seems to have improved in the last 10 or 20 years.

So, assuming, as I now do, that it is not worth doing just yet, then at this rate of improvement, it will be a long time before it becomes clearly and convincingly worthwhile from an economic point of view.
 
eamonn123456 said:
Without wanting to extend the analogy too much, unfortunately Moore's Law

http://en.wikipedia.org/wiki/Moore's_law

does not apply to solar energy systems.

The rate of improvement in the technology is clearly much much slower, given how little it seems to have improved in the last 10 or 20 years.

So, assuming, as I now do, that it is not worth doing just yet, then at this rate of improvement, it will be a long time before it becomes clearly and convincingly worthwhile from an economic point of view.
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if you are willing to develop this thecnology yourself, it would be a lot less costly.....

http://www.diydata.com/projects/solarpanel/solar_collector.php
 
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