The truth about solar water heating
(source www.ecologicsolutions.ie)
Today is the 14th of October, we are in the west coast of Ireland and our six metre square flat panel are reaching temperatures in to the high fifties (Celsius) supplying almost all of our small family needs. In fact our panels have supplied enough heat for most of September and October so far with the exception of just two or three days when we had to rely on our wood pellet boiler to meet the shortfall. That was possibly for just one half of an hour as it was required to just heat the already tepid water.
Now here’s the thing! If you live in Ireland then you know about Irish weather. If you don’t, please let me explain. In Ireland when you least expect to get fine weather you can have a glorious day like today. Unfortunately the converse is also even more true. Our summers can often feel more like winter at times, cold, wet and windy. This is something that the literature about solar panels from most suppliers doesn’t tell you.
Before we installed panels in 2006, there were very few panels already installed. All of a sudden courtesy of generous grants from Sustainable Energy Ireland, there were suppliers everywhere.
Most suppliers suggested that panels would supply 70% of our needs. Not sure where they get that figure from but I suppose it’s near enough the mark. However it was the suggestion that from March until October the panels would supply 100% of out hot water needs. NOT BY A LONG SHOT! Not in Ireland in any case. For the past few summers, during June, July and August, we have had substantially less hot water than in months like March and October.
If you get an “Irish Summer”, you may not see the sun for weeks. It is true to say that the panels are working but at nowhere near the capacity even to fill a sink to wash dishes.
The other argument that swings over and back is the superiority of flat plate collectors over evacuated tubes or vice versa. There has been several independent pieces of research carried out on this and the reality is that there is no significant difference in performance.
It is interesting to visit many of the trade shows that have sprung up over the past few years and listen to salesmen spending more time berating their competitors’ products but having very little to say about their own.
The best advice when talking to potential suppliers is ask them for sources of independent verification, If they can do this, then they may well know what they are talking about.
Talk to people who have panels already and ask their advice but do be wary that some people who have made dreadful mistakes, might not readily admit it.
Try and use a locally-based company who have some track record in this or other businesses. Local businesses are easier to chase if there is a problem and they are often less likely to risk getting a bad name in their home town – especially in Ireland.
I chose a local family-run (mum, dad, son & daughter) business to supply both wood pellet boiler and solar panels and I’ll have to say the product and service was pretty good. What I found with the small business, they were pretty keen to get feedback. There were a free initial teething problems but they were pretty keen to sort out these problems early on.
One of the difficulties is that many renewable energy products are manufactured (albeit to a very high standard) in countries such as Austria and Germany. In some cases the literature is not always translated to a good technical standard and also the appliances themselves may not take into consideration conditions in their host country such as water quality e.g. high iron and manganese content
