#1 Feb. 12, 2012 15:02:00

avalanche
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Solar Thermal


Hi to everyone,


I'm currently looking into Solar Thermal (as well as Air Source Heat Pumps).  I see there are a few people who have both solar PV and Solar Thermal installations.  


What is your overall experience of Solar thermal?  Have you found them to be efficient and are there any downsides, such as maintenance or reliability? How sensitive have you found them to orientation etc. Have they worked well in combination?


Would be interesting to see what people think of them.


Best regards


Chris


 














Edited avalanche (Feb. 12, 2012 15:02:00)

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#2 Feb. 12, 2012 17:53:00

Kerrin
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Solar Thermal


Hi


An alternative is to consider using your PV to power your hot water tank immersion heater. There is a firm in the Exeter area(Chris Rudge Renewables) who are starting to install a control unit that switches on the immersion everytime you are generating above 1kv. There is a discussion about this subject in the YouGen blog with details of the costs system requirements. The big plus is that you still get paid for your deemed 50% export even if you`ve used every last watt to heat your water. I`ve no personal experience but my impression is that it`s an idea  worth considering.


Kerrin 





Edited Kerrin (Feb. 12, 2012 17:53:00)

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#3 Feb. 12, 2012 19:29:00

avalanche
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Solar Thermal


Hi,


That's a good idea isn't it?  Had thought about it but had no information to research the feasibility or cost.  I'll have a look at your recommendations.  Thanks for that.


Chris











Edited avalanche (Feb. 12, 2012 19:29:00)

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#4 Feb. 13, 2012 09:42:00

kwakefield
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Solar Thermal


I have a solar thermal panel. You can see it on my gallery photos - My PVFIT panels.


It was on the house from new 4 years ago. It was a condition for the builder (Redrow) that they had to install them on at least 10% of properties.


I do not know how to compare it as I did not have a before and after. What I can tell you is that it looks after itself. Normally from April to Oct I do not use any additional water heating. In the winter I have my boiler on for 30mins in the morning and that is usually enough. Sometimes I need a manual boost if we have high usage during the day. Winter water temp is between 20 and 25 so not hot enough by itself. Summer is no problem, 40plus. I have a large 300L dual coil tank.


I do not know what else to tell you. Ask me a specific question and I will try to answer.


Re. using the immersion heater. Mine is 3KW so using it from my solar would need too much power normally. I would only have that much unused in summer and if it is that sunny my thermal panel is enough. I had thought about swapping it for a small 1KW unit. Then the idea is good.


Ken





Edited kwakefield (Feb. 13, 2012 09:42:00)

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#5 Feb. 13, 2012 10:42:00

avalanche
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Solar Thermal


Ken,


That's useful, thanks.  


If it's only 4 years old it's unlikely you'll have seen any problems (I hope you don't anyway!).  Do you happen to know if it is of the flat plate type or the evacuated tubes type?  I can't really tell from the photo.  


Some specific questions:


1. Does the pump self switch off at night? 


2. Can you manually regulate the water temp, if you wanted to, up to the peak output temp.? 


2. Is there any recommended maintenance required? For example, a scheduled flush?


3. Do you know what the required tempertaure is for pasturisation? Is this pertinent for a Solar Thermal installation?


4. As a Rough Order of Magnitude, how does the cost of a Solar Thermal system compare with that of a Solar PV system?


Thanks for the input.


Regards


Chris














Edited avalanche (Feb. 13, 2012 10:42:00)

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#6 Feb. 13, 2012 11:37:00

kwakefield
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Solar Thermal


Chris


It is a flat plate by Kingspan.


Pump switches on/off according to temp. It comes on f the panel is 7deg hotter than the tank and stays on until the difference is 3deg.


Water temp. No easy regulation. Due to auto operation it is always as hot as the sun can make it. There is a compulsory mixing valve that is fitted to make sure you never get max temp water at your tap. In summer you could easily get water at 60deg plus which is dangerous but hey, I live in the north west so no problem.


Recommended maintenance is to check fluid/glycol mix and pressure. As with all things an annual service is recommended.


Pasturisation? It is a sealed system?


Cost. I have no idea. It was on from new as part of the house but there are many installers who could tell you.


Ken





Edited kwakefield (Feb. 13, 2012 11:37:00)

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#7 Feb. 14, 2012 11:16:00

avalanche
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Solar Thermal


Ken,


Fantastic.  Thanks for the info.  Re pasturisation.  Yes, aware it's a closed system but if the solar didn't heat the water sufficiently I was curious to know whether any “topping up” was required.  However, if the water temp can reach 60 deg plus, clearly no problem.  That's good to know.  


Have a graet day.


Chris











Edited avalanche (Feb. 14, 2012 11:16:00)

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#8 March 1, 2012 12:08:00

bhommels
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Solar Thermal


There is the EMMA device that will do this for you. It is rather pricey at £1500,-.


If you are not afraid of soldering irons, microcontrollers and transistors then have a look at this:


www.openenergymonitor.org


I can't resist to say that the only way heating water using solar PV power makes sense is through the government subsidies being skewed heavily towards solar PV.





Edited bhommels (March 1, 2012 12:08:00)

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#9 March 1, 2012 14:09:00

avalanche
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Solar Thermal


Thanks for the info.  The site looks very interesting, but not something that I'd wish to spend the time on.  The benefits of high levels of efficiency from Solar Thermal make it an attractive option for retrospective application.  As you suggest, use of Solar PV for heating water is a much less attractive option.


Thanks for the recommendations, I'll bear the possibility of constructing a monitor in mind.


 





Edited avalanche (March 1, 2012 14:09:00)

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#10 July 17, 2013 18:02:00

ranger
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Solar Thermal


Has any one had dealings with Solar Thermal  for hot water / heating?


My understanding is simple  and would like any guidance from any one who has had any dealing with it.


 


My understanding is that the solar collector is filled with micro bore copper tubing (Not the Glass tube type) filled with a gas under pressure that has a boiling point of -10deg the outside air raises the temp of the gas to over the -10deg the high pressure gas is then passed through a heat exchanger and on to the hot water cylinder or via a valve to the heating system. I am told that as it takes the heat from the air as long as the air temp is above the -10 deg it produces heat to the exchanger the hotter the air temp the hotter the gas gets and so produces more heat.


The government has today released the figure for the solar thermal Fit tariff of at least 19.2 p/kWh but how will they measure this, as there is no meter on any systems I have looked at?








Edited ranger (July 17, 2013 18:02:00)

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