Do Italian plumbers understand thermal stores?

08/24/2010 - 13:53

I'm very worried about how our excellent plumbers are going to react to my request to install a Thermal Store with a wood stove incorporating boiler plus solar panels. I've been skimming through information online and it seems that most British plumbers haven't really understood this tecnology.So are Italian plumbers any more informed? Basically if you need to heat a house with a pellet/wood stufe you need to store masses of hot water - in our case 1,200 litres which then goes to the rads all over the house.If you just need dhw then 500 litres is more like it. I'm worried that they won't know enough about it but will bluff and I'll end up with a great big expensive store that's not working.



I guess the sensible response it to suggest you ask the plumber - assuming he is qualified to install heating systems, of course. If he is a heating engineer he should know more about them that you might tink, as they are pretty common items in Italy as they are normally supplied with 'real' solar heating systems, with quite a few companies making them up to some very large sizes (look at the ones from La Nordica, for example). I think they are a good idea, but remember that the ones with electric water heaters in them are going to cost you an absolute fortune if they should ever turn on. Some (non-advertising!) links are below.|R-IT-PL-0002049|- OK, enough. There are loads more if you want to look - just search with Italian words and it will all become easy - even in English!

yes,of course a good plumber knows about and installs such systems we are doing exactly that and indeed not informing the plumber but following his advice on the subject including the hot water resovoir of which we have already had one for ten years anyway.The main difference is that not everything in the country is "driven by the web"...

If I may chip in a bit on tank sizes. The main issues revolve around recovery times (increase hugely with bigger tanks unless they are top down heated and extract from the top down too which mitigates this effect)   Energy stored to make domestic hot water... you need a bigger tank than you are used to as the water tends to mix before you can extract it all.. 500 litres odd is good for a family home and works well with a modest array of solar panels... you have to get the balance right with all the components involved. A wood furnace tends to demand a bigger tank because the burn time will load a bigger tank but 800 - 1,000 works well without breaking the bank. Actually the burn time on a 30kW furnace, say, needs a much much bigger tank but most of the time the heating will be on so half the energy is diverted. The trick with heat stores is to change your thermostats for programmable ones to get timed shots into the floors or rads so that the tank does not get overwhelmed by the unregulated heat source. A quick comment on buying Italian stoves because you can get them repaired here... the cheap European stoves have cast in boilers so yes they do need repairing eventually but actually you have to chuck them away and start again. One expensive British stove on the other hand has a clip in boiler that can be replaced and the stove is in modern welded steel plate which is not prone to cracking and leaking. Re a comment on how expensive electrical heating is - as we move away from gas in our systems we have used short bursts from immersion heaters to great effect and the cost is minimal if not better than gas as all the energy goes into the water and not up the chimney.

As you will know very well already, sagraisolar, precise tank sizes are dependant absolutely on the individual circumstance and existing equipment on site, rather than the hypothetical 'clean sheet' situation - although from the point of view of an installer/agent it is the most desired one. So, tell me, what do you think of multi-tank soluutions where one heat source is pointed to one tank and a lower temperature source is pointed to the other, with suitable connections between the tanks, of course. I must say that I find your comment regarding "cheap European stoves" to be a bit beneath you though. I might understand your saying that cheap stoves are pretty crappy but not to try to fly the "British is best" flag in Italy. Might I just remind you of the problems that Hunter had with poor quality boilers in the past? Just to name one cheaper British brand. I appreciate that you sell Clearview products, but that doesn't give you any rights to diss the engineering products from an entire continent, including Germany, Sweden, Italy, France and Switzerland. It makes your sales pitch look a bit thin.

Beery - Yes twin tanks are a great part of the many solutions and I have a pair running now to test my 'stripper circuit' which enables the solar pump to run practically every day of the year... I would say though that although it works really well the cost to benefit ratio is usually beaten by just adding more panel. As for slagging off the cheap Euro stoves... sorry if that was a bit offensive and some of the less cheap ones are very good... I was taking great care not to advertise and never mentioned any specific aim on this forum is to try to steer the debate towards the real opportunities available to everyone to practically eliminate their heating costs. Everyone can then choose their favoured stove/tank/panel and do their own thing. 

Interesting thread, obviously any heating system has to be tailored to the individual property and indeed inhabitants. Sagraisolar was only trying to be helpful.  From my point of view the first thing to consider is insulation and draught proofing-in our property this should save around 50% on energy needs. A 3kw Solar FV set-up is a no brainer and this will enable an electric immerser to be employed to keep the thermal store topped up. OK no swimming pool or such-like but with solar thermal , a wood burner and an electric back-up I reckon our energy bills will be minimal ...oooh perhaps ENEL will be paying us!!! I fully intend to do most of the work myself and it will be a steep learning curve, but there are some lovely people about who provide free and detailed advice.

Bunterboy - I note your aim to have a 3kW PV array and I hope this may be useful to you and anyone thinking of doing something similar. The nominal output of the panels is not what you get!!! In the winter you get about one third of the rating and believe it or not in the summer you get about two thirds even at mid day with no cloud. To get the rated output you need a cool day with sun breaking through a lot of cloud. There are loads of appliances in the house that use 2 - 3kW - washing machine, kettle, immersion heater etc so for a winter match with probably minimal use of the immersion (re wood) and pool pump off you ideally need something like 5 - 6kW nominal. My 4.6kW is so because the Commune would only allow me that size for a car port with a tidy 20 panels. It does scrape home with Zero electricity bills and has allowed the gas boiler to be turned right off (well it was on once for 15mins last month). Apart from zapping the electricity bills the separate production meter produces almost 8 Euros a day on average.  e.g.  this month (with a spare day left) 675kW.hrs at .451 Eur gives 304 Euros and also a tiny bit of surplus on the two way electricity meter.

Good points Sagraiasolar, I understand that a 3Kw set up will not produce 3kw very often, but hopefully we'll have a hot fill washing machine and dishwasher from the solar thermal set up , perhaps a 1.2kw immerser for the heat store backing up the solar thermal and wood burner. Obviously it's important to have  good insulation and draught proofing.No swimming pool is planned-not very green really..hopefully an outside shower will be adequate or cooling off. However, I do not speak from experience like yourself so I may be hopelessly  optimistic. Still, I reckon that a 3kw FV rig will allow us an almost zero ENEL bill- I expect we shall be using timers to maximise the use of the cheaper night time tarrifs. Shame our houses are so far apart , limited opportunity for a chinwag, but i'd love to know more about your FV array. My main concern is their life time, 25 years seems a lot when you consider just how damaging UV can be. Fingers crossed.....

Can't say I'm often coherent at this time of the evening but I'll have a go..  First hot fill washing machines are rare these days... the mfrs finally twigged that the hot water takes a while to come through so hot fill machines were really cold fill with a redundant extra pipe... doooooh .. you'd think they'd have seen that sooner.  Any way you sound as though you are well on the way to having a sensible set up with costs approaching ZERO...  If you are an Excel man let me know and I can send you a model to map your returns from the panels; not that it matters really as you don't have to match them to consumption - it is just more elegant that way. I expect you'll spend nothing on gas or electricity and 1,000 on wood which will be met from the PV panels income so Robert's your father's brother - ZERO COST on all energy.

The missus is already trained up to run the hot tap before she puts the appliances on, but this could be an issue when  we use the them on the timer over night, as regards wood we have 110 olive trees badly in need of a prune so hopefully that should get us started. The current conundrum if you excuse the pun, is do we have a Stufa or a Termocamino (Eg as our primary heat source -the latter would fit nicely into the fireplace in the kitchen but be more difficult to integrate with the thermal store, a stufa in the large lounge, (I quite like the Lilyking 677) would be easier to plumb in..decisions , decisions

Bunterboy - Unless your house is really huge a stufa will have enough oomph to heat it and the water and it has benefits of cosy flames and some cookability too. I usually only turn to a ground floor forno when there is an upstairs salone with tricky log lugging. If you can get either to be close to your heat bank you can save a lot of money by using a gravity circuit. I have examples of both the Termorossi and 14kW stoves running very well so whatever you do will work. The termorossi works with a vented tank so keep it all unpressurised. The stufa will be less than half the price of the forno and you can use a smaller tank so the benefits swing to the stufa if it fits in with your layout.

Thanks for that Sagraiasolar, I note the forno has a 10 year guarantee whilst the Lillyking only 5, are cast iron stufe inherently shorter lived? Gravity circuit? You mean no pumps? I note the Pandora thermal store comes with several  pumps already fitted are you suggesting a different sort of store? I need an idiot proof system and an unpressurised system sounds safer to boot!

Bunterboy Gravity circuit? You mean no pumps? I note the Pandora thermal store comes with several  pumps already fitted are you suggesting a different sort of store? I need an idiot proof system and an unpressurised system sounds safer to boot! A gravity circuit is dead simple - just 2 pipes directly to a thermal store for example. The heat source MUST be lower than the target so you may see the thermal store on a small plinth on some installations. The water will circulate on its own accord without a pump. The DPS thermal store comes with various pumps attached but thats for other things like radiator circuits and underfloor heating. An unpressurised system is essential with unregulated heat sources. You can connect the stufa straight onto the tank without any fiurther expansion tanks or heat dump radiators. It's all very neat and cheap when you go for a gravity circuit.

Having been researching different solutions to heating a 230 square metre house for a while now, we have found a wood burning cooker that has the capacity of providing domestic hot water and central heating for up to 580 cubic metre capacity.  It has its own coil heating system built-in.  One pipe come out for the hot water and the other for the central heating.  It seems as though they might have thought this through...

This is just a thought about the amount of space thermal stores (of water) take up. It's not relevant if you have loads of cantina space, but if you are in appartamento mode, consider how much you are paying (per square metre) for potential residential accommodation - and if it is financally sensible to devote about the same space as a small bathroom would require to a water store?

Sounds Just the thing Sangraiasolar. Presently trying to organise some Kingspan insulated plasterboard (92mm thick)to be delivered to Italy as I've not been able to find it locally, unless someone else knows different!

Just back from the "heel" and been to see about the insulated plaster board-unbelievable as it may seem it is still cheaper to buy kingspan K17 board in Holland and ship it out at a cost of over 1000 euros.I can't believe it really. the Italian stuff (made by gyproc) is of lesser quality and more expensive. Anybody fancy ordering up a load too and reduce the delivery charge!

Just back from the "heel" and been to see about the insulated plaster board-unbelievable as it may seem it is still cheaper to buy kingspan K17 board in Holland and ship it out at a cost of over 1000 euros.I can't believe it really. The Italian stuff (made by gyproc) is of lesser quality and more expensive. Anybody fancy ordering up a load too and reduce the delivery charge!

 Hi for those wondering what a gravity system is, it's actually a convection system. Using the fact that the density of a liquid (water) changes with temperature, it gets less dense so therefore lighter with temperature increase. This means that colder water in the system is more dense (farthest away from the boiler) and therefore heavier will pushh the water back to the boiler. I've just put a 6 rad system in my house in Palombaro. The top connection comes out of the top of the boiler and goes vertically upwards to upstairs to the highest point (rising gently all the way if poss) then back down to return to the boiler via the rooms you need to heat. The beauty of it is you can put the wood on go out and not c**p yourself worrying about a power cut. If the power is cut, you come home to a lovely warm house your neighbours are shivering cos there gas systems have shut down. The one with a wood fired pumped system are frantically throwing hot fire out of their stufa's or the their overflow pipe is 'blowing off steam' like the Flying Scotsman ready to leave kings cross with the ten o clock non stop! Invite them round for a warm, a glass of vino and get to know some more friends.

Hi everyone I'm sure all of you who are familiar with the heatbank/woodburning  heating, hot water systems will think this is a silly question but I would be grateful for an answer all the same! If you have a woodburner with a back boiler connected to a heat bank which will provide hot water for radiators & washing etc., I assume this will be on a timer the same as with a gas fired system. If  the woodburner goes out, for  how long does the heatbank keep the water & radiators hot? Having read through all the posts both old & new I am sure that woodburner/heatbank/solar is the way to go, just trying to understand as much as I can before finally deciding on a system. thanks for all the information so far

That depends on the size of the heat bank, the temperature of the water therein and the number of radiators you intend to feed, however, I reckon if you put a few logs in the burner before you retire for the evening you should be OK for a bit of heating and hot water in the morning, but  not much more than that. Then again if you have 2000 litre thermal store...

yes valerie after many months of research it all seems to come down to the size of the store and how insulated it is. If you think about the potential a fully blazing woodburner has to heat water as well as the room then its really a matter of how you store that hot water for long enough.Of course a small wood burner cannot heat 2000 litres of water many times over each day so you do need to do a few calculations on the back of an envelope!