Incorporating Solar panels into UFH system

highdef

I am about to install the heating system in my new build. I will have UFH heating downstairs and rads upstairs, powered by an external Grant or Firebird condensing boiler. I will be installing solar panels onto the roof. I know they're good for the hot water but would it be easy to incorporate them into the UFH? I plan to have a 300l twin coil stainless steel hot tank. There will only be 2 people living in the house so that should be more than enough.
The running temperatures of the UFH are very low so I would imagine the solar panels could provide enough heating for the UFH during the transitional spring and autumn seasons when the sun is quite strong but the nights are generally cool. I will also have a wood burning stove in the main living area, which is very large. This will provide additional space heating to much of the ground floor, if needed. The house is very well insulated so in theory, I would often get away with the stove and UFH only for the downstairs and just a little bit of rad heating upstairs......well that's plan anyway.

I've a feeling I'm missing something here and am hoping someone can point me in the right direction. From what I've been reading, I may need a buffer tank. And from what I can tell, a buffer tank is a big oversized hot water tank??? The problem there is that I may not have room for a massive 800l buffer tank in my hot press, located off the hallway.

If anyone can help, I would be most obliged. I did a search first but could not find the answer there......maybe there's a reason for that!!!

Thank You

items

What you propose to do I cant see working based on what you've mentioned. I doubt your solar system will have some spare heat to go around. The solar system your planning to have installed is more than likely going to be sized up only to suit hot water cylinder solar requirements. Solar in Ireland doesn't perform as well as people imagine. Its almost a fine art, results depend on type of collector, location / position of house, slope of roof and a few others. Their seems to be no base standard temp that can be obtained, some say their solar can bring cylinder to 90 degree while others struggle to reach temperatures above 60.

Last solar job I was on had top spec thermomax solar vacuum tubes, fitted by thermomax solar installers. I don't remember cylinder temp ever passing 50 degree the whole time I was their, right in height of summer.

If your solar set up is only sized for cylinder best leave be, adding additions could result in loss of efficient % meaning pointless to even install solar when it struggles to provide enough energy to supply hwc along with ufh.

Best thing to do is allow for provisions to be made depending on how well solar performs, If you do happen to have left over energy should be no problem linking up the two solar & ufh once provisions are left to connect at a later date.

Buffer tanks take up any heat left over, most cases solar is over sized to allow for inclusion of buffer tank, like I've mentioned above if your solar system has only been sized to supply cylinder then buffer to feed ufh system might not work.

To go about things the right way, meaning your sure of results you'll have to size solar collector enough to supply hwc along with buffer tank, might not take too much, depending on size of ufh you might only have to add a few more tubes / fit slightly bigger panel.

You say two people in house at moment indicating less demand on hot water, thats now but things do change so best look more into future.

highdef

Thanks very much for your indepth reply, items. I guess it was too good to be true to get hot water AND UFH supplied by the sun without a lot of trouble and a lot more money that first envisaged.

For the record, I was planning to go with a company called Solar Focus....I think they're Austrian. Their panels are a new (so I was told) hybrid system which are a kind of parabolic system.....not quite flat panel but not quite evacuated tube either. They seem good on paper anyway. Have you heard of this system?
My panels will facing more or less bang on south westerly which is not too bad and the angle is a little under 40 degrees which is also fine.

It's a big area of UFH to be covered....approx 1600/1700 sq ft so I think I'll just have the solar provide the hot water. I reckon I'll be asking for trouble (and an empty wallet) if i try to incorporate UFH heating into it. I'll leave the condensing oil boiler to do all the heating! Depending on cost, I will leave provisions for the ability to add solar UFH heating at a later date.

Many thanks again, for your help. Oh, and rest assured, there will never be any unexpected kids arriving

items

No bother, I've never heard about those panels or the company, their is so many different types of company's / panels its hard to keep track. From the bits I know, panels have come to a stage where they cant be developed much more. The development moved up to vacuum tubes, if I was installing solar myself I'd go for vacuum tubes, main reason being the negative pressure inside the tube gives more of less the best chances of light to heat transfer.

Another plus is should something happen as in damage or some kind of problem with internal workings all I'd have to do is replace a tube or a few tubes. With panels if something was to go wrong, entire panel might require replacing.

At the end of the day, all types and makes of panels will and do work, a manufacturer would'nt be allowed sell on the market unless their product was capable of achieving results.

It's up to you really, don't be afraid to ask the solar company questions. Ask company can they provided contact details of a previous customer, if company feel confidant on their works they'll have no problem providing contact details. Ask about guaranteed min hot water temp that can be achieved, ask what kind of standard's the panels they fit have been obtained.

How well the company answers those questions will give you prob the best idea on how good they are. The price difference for a standard solar fit out is close enough through out all solar company's, some company's make profits by having plenty of work and their jobs are good while others might have less work so they try to cut costs leading to not such a good job.

Best of luck with it.