nogard

Have a look at this site and these Batteries.
Nickel Iron NiFe Batteries

www.bimblesolar.com/nifebatteries

Cossieg

macliam

I'm certainly no technical expert, but, in researching these things always consider whether the best technical solution is the best practical solution. In Portugal, the abundance of sunlight means you do not need a system to be as efficient as in Northern Europe - but, given costs and other influences, a robust system requiring less maintenance is an advantage. Is it better to have a system that is 75% efficient 95% of the time, or one that is 100% efficient 20% of the time? It's a bit like the Armalite Vs the AK47 - there is no doubt which is technically the better weapon ..... but in Vietnam it was more useful to have one that worked reliably (you can also use the Russian pencil Vs the US "Space Pen" example).

Many people get confused and are misled by "experts" - a perfect example is the way Solar thermal panels are mounted ...... inordinate effort is made to get them facing due South, but almost always at a default c30 degrees (rather than the recommended latitude +/-) ...... so the extra efficiency of direction is lost due to the inclination providing poor efficiency in Winter and overheating in Summer.

Jonny22

macliam

I think I remember the "loss" from facing 90 degrees from due South being about 20% (I stand to be corrected, it's not my field), so it seems to me that a larger panel size could compensate for the loss in efficiency. For the inclination, if I remember correctly, you start at latitude and allow a variance of +/- 15% for Summer/Winter variance. As sun in a Portuguese summer is not a problem, it was suggested that a fixed panel at the Winter optimum would be a good compromise as the "drop" in summer efficiency would reduce the likelihood of overheating and the optimised Winter efficiency would reduce the need for supplemental energy. For me in the Alentejo, I think it gave an angle of about 52-53 degrees - a lot different to the "standard" 30-35 degrees set by cheap supporting frames. IIRC, the angle of 30-35% was fine for photovoltaic panels, but I wasn't considering them and I can't for the life of me remember why. But it's all out there on t'Web if you look for it.

Does that make sense?

nogard

Due East is 20% loss. The efficiency drop is 1.1% for every five degrees from South. Your best option is the Winter angle, quoted angles are from the vertical. Yes, put panels on both the East and West aspects of your roof. You will need more panels; to give you the same output, than if your panels were South facing.
I can highly recommend this; Solar Electricity Handbook by Michael Boxwell. £12, from Amazon. All one needs to know, in lay mans terms.

macliam

Thanks for the confirmation ..... good to know the memory is still functional. HOWEVER, I had soooooooo many arguments about this, particularly with a civil engineer, Sr.Engenheiro insisted that 30 degrees was fine and anything other than due South was a disaster. So, when you look for "professional" advice, be warned!

Fredbargate

Attached is a photo of a very recent commercial installation for the Gibraltar government,and their solutions to the geographical directions.

If on Google Earth you go to the location 36 07 37.17N 5 21 09.28W you will see the various directions these building face coupled with the fact they are in the shadow of the Rock for a few hours in the morning.
Also on the photo but difficult to see the next building to the west has elevated panels similar to it's neighbour.

Jonny22

macliam

The panels in the picture look photovoltaic and they are set at quite a shallow angle. The info I've given is for water - BUT, you have 2 possible issues, firstly the panel (what size?) will be working inefficiently - so when you say "heat up a 200 litre tank", how quickly? When do you need the hot water? I would suggest an oversize panel. Secondly any fixed inclination will either make collection slightly less efficient in the Summer in order to collect more energy in winter, or, if optimised for Summer (or left at 30-35 degrees) the panels are likely to overheat in Summer - which can be an issue if you are not there unless you have a good dump system. I have heard of people advised to cover their panels in the summer to avoid this!! The last thing you want is a system that doesn't supply enough water when you want it and still requires use of the electric supplementary coil...... So, ask a lot of questions up-front, based on what has been said here..... if you don't get a good answer or a "standard" kit is suggested, you might want to look elsewhere.

EMR

We had the system blow one summer when we were not there.
We now cover if away for any extended period..

BillBullock

Say please!

Ana waters

Hi. I am building a house from scratch in Lisbon and i want to make it as green as possible. I want to install solar power and i wondered if anyone can advise me as to the best solution. I will work from home and so use a lot of energy. Thanks.

calman014

Take a look at the YouTube Channel, "Fully Charged", which is not only about electric cars but also Green developments in general. It's presented by Robert Llwellyn, previously known for his role as "Kryten" in Red Dwarf or Scrapheap Challenge. There are couple of episodes about his personal house setup and integration of a Tesla Powerwall battery package. Things are moving in the direction of home battery packs (now many more options available besides Tesla) as well as panels on the roof so I would consider this seriously as part of your home setup.

In addition to Solar (PV) a heat pump setup (either an airco system that cools and heats internal air, or a PV/Vacuum tube setup to heat a storage tank) is beneficial.

AndyPT

For this climate, I'd strongly recommend a heating pump combined with underfloor heating. There is plenty of free heat in this country, your job is to collect it and direct into the house.

Even if you aren't ready to buy a heating pump just yet, the underfloor heating in a modern house is a "must have" thing. There is no easy or economical way of fixing this mistake in the future (if at all).