solar hot water

[billybongo]

Hi everyone , just like to ask a couple of question re solar hot water , i am in the process of buying a new build with solar hot water and was wondering what i can expect to get in terms of hot water without boiler coming in , the second question for my own mind is how does the boiler know when to take over from the solar if the hot water needs to be raised to a certain temp or does the solar reach this , obviously you want the solar to be primary heat source but i dont know how they interact so that i can keep an eye on the system. Sorry if this seems long winded and appriciate any help.
Billybongo AKA Mark .

 

[Worcester]

Hi Billybongo, assuming the system has been installed to the correct standards the output /estimate of 'savings' will have been calculated according to the MCS rules - contact the builder and ask for the "Thermal Solar Performance Energy Calculation"

With regard to the second part, it depends upon the sophisticatoon of the controls.

The DHW cylinder should have a dedicated solar volume so that it will always provide at least some assistance, additionally the DHW cylinder should be fitted with a TMV so as to prevent the possibility of scalding (the collectors can get up to 150°C + ) what we would recommend is a controller that allows multiple temperature settings at different times of day (like programmable room stats), cheapskate way, just set the DHW heating to come on only at the end of that day that way you're guarantted to have a tankfull for baths / showers / morning showers, and then the solar system can do its job during the day.

Are you sure its solar thermal? That is an unusual, expensive way to meet the building regs, the usual way is a couple of solar PV panels, (much cheaper for the builder / developer)

 

[chris watkins]

Depending on the size & type installed & of course how much you use, the boiler should hardly have to fire during the summer months (so that June in England & one week in Scotland LOL)
for the evacuated tube types they should provide around 65-70% of your hot needs averaged out across the year.
Most use timing and a thermostat to top up the hot water cylinder during the night or first thing in the morning, only if the temperature is less than the 60-65deg in the top half of the cylinder. (taking it is a twin coil cylinder that has been installed)

 

[billybongo]

Hi Worcester, it is solar panels , did my question imply solar thermal as i dont know what that is , i know understand boiler is for top up not in conjuction with solar panels , as chris says it will only top up if reqd to make 60 -65 degrees , silly question but will there be a temprature guage on hot water so for instance if i havnt had the boiler on i can tell what i have achieved via the panels to know wether there it is hot enough for showers / baths .

 

[solutions]

Hi Worcester, it is solar panels , did my question imply solar thermal as i dont know what that is , i know understand boiler is for top up not in conjuction with solar panels , as chris says it will only top up if reqd to make 60 -65 degrees , silly question but will there be a temprature guage on hot water so for instance if i havnt had the boiler on i can tell what i have achieved via the panels to know wether there it is hot enough for showers / baths .

So billy bingo it sounds like you have solar pc (photo voltaic) panels powering 1 or possibly 2 immersion ellements capable of 3 kw each. There may be more sophisticated controls in place but typically the boiler simply uses the cylinder stat to determin if the cylinder is up to temp or not. There is not normally a manual temperature gauge fitted to the cylinder although feeling the water from the tap will tell you pretty quick whether the boiler is needed to top up the temperature to your desired setting.

 

[billybongo]

Thanks solutions , so the cylinder stat determins the hot water temp if reqd from boiler , and this only happens when boiler comes on under timer control or overide .
sorry to make this laboured but just trying to clear up which does what in terms of the water heating , billybongo .

 

[billybongo]

I am a bit confused , my question is about solar heated water and there is talk of PV which i have looked at and is for electricity , or can this be used for hot water .
sorry if i am causing confusion .
Billy.

 

[JCSPLUMBING]

Yes. The electricity produced powers your immersion heaters, therefore your hot water also.

 

[townfanjon]

Billy solar heated hot water is solar thermal mate , usualy one or two panels.

Chris wants to try living in Yorkshire lol lol, i have solar and my boiler fires plenty in summer months lol.
One thing to always remember is on a relativly cloudy day in summer , you get defuse sunlight and even though you may not actualy see the sun but it will be heating the cylinder. Ok it might not heat the cylinder up to 60 so the boiler doesnt fire , but it contributes all the time. So say its heated the cylinder to 40 degrees , the boiler will only have to lift the temp from 40 to 60 .A sunny day in winter could do the same.
The further south you live , the better your solar will work.

 

[chris watkins]

Billy solar heated hot water is solar thermal mate , usualy one or two panels.

Chris wants to try living in Yorkshire lol lol, i have solar and my boiler fires plenty in summer months lol.

Thats close enough to Scotland to feel the effects, you should have gone for that larger cylinder to store the hot water on the good days for the rest of the time! How much free space do you have?:winkiss:

 

[Worcester]

See my post get the FACTS from the builder / developer , too much speculation here that will just leave you confused. We install both Solar thermal (plates and tubes) and Solar PV, and I would be confused by the responses so far above. They are all partially correct.

Post a photo (link to photObucket or similar), get a copy of the calcs from the builder / developer they will (haha , - should) be in the handover pack.

 

[Unregistered]

Thanks to you all , I certainly have a better understanding of solar energy .
i will ask builders for information and let you know what I have .
regards billy .