BEST SOLAR SYSTEM ADVICE FOR NEW BUILD

gooseygander wrote: »

I have heard no good reports for pv systems to work in this country, don't know a whole lot about it but I am led to believe that the cost outlay does not reap the required benefits

You "heard" this where exactly and from whom?

gooseygander wrote: »

one should only heat water with solar in this country,

By "solar" I assume you mean "solar thermal" here. If designed properly, you are already installing an excellent water heater. I don't understand why people spend on 2 separate water heating plants when in fact all they need is one. That is why solar pv, imo, might be a better choice.

gooseygander wrote: »

but as I say I am fairly ignorant on the issue and my knowledge and opinions are just going from a bit of web research

Well then, why not go out into the real world and seek the advice of an independent professional who can do the calcs and tell you exactly what is best value for you. By independent I mean someone who is not selling you something other than their experience & expertise.

gooseygander wrote: »

Thanks Mick, can I take that you have one of these pv systems in your house and are very happy with the workings and cost benefits of same ?

I don't know why you "take it" that I have solar pv installed.
Also, it is of no relevance what I have installed.

You made a broad statement regarding solar pv and I questioned it. Perhaps the reason you've heard "no good reports" on pv is because relative to solar thermal, far fewer systems are installed. It used to be cost prohibitive to install pv but not now.
Just curious, what do you mean by "cost outlay does not reap the required benefits"?


Btw, I don't have any solar installed in my home nor do I have anything to do with solar technology. I am, however, seriously considering covering my unshaded south facing roof with pv. I do not consider solar thermal a good investment for several reasons.

gooseygander wrote: »

Thanks Mick, any main reasons why in your opinion solar thermal is not a good investment on a new build, I did not mean to make any "broad statements" on this issue and I did say in my initial post that I did not have much knowledge of same. Thanks again for your views

In your case where you are already installing an oil condensing boiler and a back boiler stove:


You already have 2 water heating devices, with associated service and maintenance costs. Why unnecessarily introduce a third with more associated running and maintenance costs, which only works for a portion of the year ?

Contrary to a lot of opinion (mainly solar thermal salesmen) using a properly designed oil boiler system to heat dhw is quite efficient and as the plant is already in place for space heating & dhw, this hot water is produced for no extra capital outlay. Many people do not know or work out what their dhw needs are or are going to be. If you "do the math" you might be surprised to learn how little dhw costs actually are or could be given a well designed system.

If the harvested solar energy is not used, it gets dumped. That, to me, seems crazy.

I understand that the pressures and temperatures in solar thermal systems can get very high during summer and personally I'm not sure if I could relax on my summer holidays with such a system on the roof of my house. I know that there are heat dumps etc but still if something was to go wrong...

gooseygander wrote: »

Hi all, looking for independent advice/info/suggestions for a solar system best suited to our new build is south east. house is 2700 sq foot story and a half. I am told that our roofs are located perfectly for solar design. I don't know much about it but we are going with oil, stove with back boiler for just a few rads and solar for the water. Plumber has suggested a 40 tube evac system and a 300 ltr 3 coil cylinder. Anybody with any suggestions on the above, we are looking at best possible design to make full use of our "sunny" south east location (the house will not be overlooked or shaded from trees). Thanks in advance for all opinions/suggestions.

Hi GooseyGander
(1) I sell & install solar among other renewable energy sources

The first thing you need to consider with your new build is Insulation, It's the most important thing on a new build.

If you are fitting a Back Boiler Stove do you have a cheap supply of solid fuel ???
Some of the stoves on the market require a lot of solid fuel which can get expensive if you have to buy...

I would recommend a 500 litre Multifuel tank which will combine all heating sources into 1 supplying your domestic hot water and heating but if you were to fit this size tank you would need a 60 tube solar collector.
The solar combined with a stove would practically leave your oil boiler redundant but would only be feasible if you have cheap solid fuel otherwise its a non runner.

If the harvested solar energy is not used, it gets dumped. That, to me, seems crazy.
If the solar system is sized correctly it would only dump heat on the very hot summer days.

I understand that the pressures and temperatures in solar thermal systems can get very high during summer and personally I'm not sure if I could relax on my summer holidays with such a system on the roof of my house. I know that there are heat dumps etc but still if something was to go wrong...

A thermostat on an oil boiler can malfunction very easily and cause a fire, If a solar system malfunctions in any way the computer shuts everything down.

Do you leave your car in the garage because you might get a Tyre blow out while driving it....

By "solar" I assume you mean "solar thermal" here. If designed properly, you are already installing an excellent water heater. I don't understand why people spend on 2 separate water heating plants when in fact all they need is one.
Because oil prices keep rising and you need a back up to boost the solar in winter,
A solar system if fitted correctly will last for 20+ years and should only need a service every 5 years.
You need to install a reasonably priced renewable energy to meet part L of planning.
Carbon Tax down the road.

Well then, why not go out into the real world and seek the advice of an independent professional who can do the calcs and tell you exactly what is best value for you. By independent I mean someone who is not selling you something other than their experience & expertise

Ya, Great Idea
But I think you are already in the real world that's why you are asking the questions on boards.

If only looking to heat water, would thermodynamic panels be the best option?
No renewable energy contribution to meet part L


If you are seriously considering solar then get the contact details from your supplier of a minimum of 5 people who have it installed a minimum of 18mts and phone them up and ask them are they happy..are they saving money...


Best of luck
CC

For a large house, solar PV is a very cost effective way to meet Part L. Because the energy requirement is based on the area of your house (and not on how much water you actually need) a house of 2700 Sq Ft is going to have a large and rather wasteful solar thermal system which may produce far too much hot water for its inhabitants to usefully use.

Because electricity is a premium form of energy, the amount of energy required from PVs is only 40% of that for solar thermal, so the Part L requirement is quite modest. I would consider having a solar thermal system designed to meet your needs, and topping up the Part L requirement with PVs. Or just go for PVs.

The reason there is so little PV in Ireland is that when you export electricity from PVs, you only get paid 9c for the export. Your neighbor buys your power then for about twice that amount. In the UK you get more than double this payment.

The advantage to PVs is that they are absolutely maintenance free and trouble free. If you are using electricity during the day, it will come from your panels, but your surplus is exported. A house of 2700 Sq Ft with a south facing roof will need 4 or five panels and an inverter, total hardware cost will probably be less than €2K. If you use 1/4 of the power from this yourself, the average electricity value is €110 per year.

If you go for a hybrid of solar thermal, you may only need one or two panels to top up your Part L needs. The PV industry is one that is reaching maturity now thanks to incentives in other countries (but defo not in Ireland).