Heating Solutions and Advice

by **Geotherm** Sun Sep 29, 2013 5:49 pm

First topic message reminder :

One of the most important questions, that seem to appear on most forums in Italy, are the type of winter heating, costs, for different living styles. As we are coming up to that time of year, then this is a dedicated thread for questions and answers.

For new readers, then perhaps we can help and advise on solutions. Sagraiasolar, knows so much about woodburners, heat stores, and more, My knowledge is in heat pumps. I am sure there are many more who can also contribute to the thread and hope that they do in the near future.

I do hope that we do not confuse Ghiro and Flip too much, so their wine consumption will stay low Exclamation

by Vicino Sat Jan 25, 2014 7:48 am

Hi Steve, as an aside, does your house insurance cover for your house being allowed to get down to 9c whilst being 'empty'? I seem to recall ours has a clause in it which says it must be at least 12c whilst empty in Jan/Feb.

V

by stevegwmonkseaton Sat Jan 25, 2014 9:18 am

Vicino wrote:Hi Steve, as an aside, does your house insurance cover for your house being allowed to get down to 9c whilst being 'empty'? I seem to recall ours has a clause in it which says it must be at least 12c whilst empty in Jan/Feb.V

What insurance Laughing

by **Geotherm** Sat Jan 25, 2014 12:53 pm

Steve.
On the initial post you asked if a ASHP may solve the issue. It may not in the first instance and if the steps/suggestions earlier work, then you may have hopefully solved the problem.
Just as a aside on the units that we install, they have what is called a "holiday setting" which is at 15C and can be timed up to 30 days. So if you go away for 14 days, you set it for 13 days and the when you return, the unit has reset back to its original operating temperature, so you arrive at a warm house!!

by stevegwmonkseaton Sat Jan 25, 2014 1:31 pm

Thanks Geo. Do you have experience or know anything about these ventilation heat exchange units Article LINK ?

by **Geotherm** Sat Jan 25, 2014 1:53 pm

stevegwmonkseaton wrote:Thanks Geo. Do you have experience or know anything about these ventilation heat exchange units Article LINK ?

Hi Steve
The link will not open for some reason

Edit: Have just seen the link and no I do not know it. There is one that we use to recharge the heat in compact ground loop collectors, but that is not purely for ventilation. Looking at the info on it though, you need to have trunking everywhere and a lot of maintenance.

by Vicino Sun Jan 26, 2014 7:46 am

That article is really good ! I think anybody undertaking a major refurb should consider it along with other options, not sure what the costs would be though ?!

Unfortunately for us, we have a fully working gas central heating and stufe combination of heating and water so it would not be cost effective to start all over again. For ventilation, we do open windows a few mm(s) for an hour or so a day, which sort of does us.

V

by Sagraiasolar Sun Jan 26, 2014 11:39 am

... This topic - heat recovery - should, in my view, remain firmly in Geotherm's territory. By that I mean related to and achieved by a standard air source heat pump. I expect we all know by now that the ASHP works more efficiently if it is chewing on warmer air - the COP thing. So if you put the ASHP in a solar shed then piped the air extraction from kitchen and bathrooms to the shed then the ASHP would be recycling the extracted energy. The ASHP would be fitted to extract air from the shed and in turn would extract from the house with no fans needed.

For a new build this achieves a lot for very little money and the ASHP would be a proper bit of kit which does a serious job of heating production. Energy recovery heat pumps are a bit of a red herring and not a useful part of a complete solution IMHO.

by Bartholomew Mon Jan 27, 2014 12:32 am

Sagraiasolar - please explain to the uninitiated - what is a solar shed?
Geotherm - I have an ASHP connected to underfloor heating that I run at 18 - 20C when at home. Is there any saving in power consumption if I turn it down to 15 when out of the house during the day or does raising the temperature back to 18 - 20 when I return cancel out any saving?

by **Geotherm** Mon Jan 27, 2014 9:10 am

Bartholomew.
With UFH and a heat pump, it is recommended to not reduce the temperature on the flow setting of the pump by more than 1.5C, as you do not want to cool the floor slab too much. Please note this is not the room temp thermostat!!!
HTH

by Sagraiasolar Mon Jan 27, 2014 10:11 am

Bartholomew wrote:Sagraiasolar - please explain to the uninitiated - what is a solar shed?

With regard to an ASHP it's a concept of mine to raise the temperature of the air being chewed by the ASHP and therefor raise the COP. Imagine some corrugated plastic clear roofing sheet curved round a quadrant section shed - like a chunk of Edam cheese - with the sun shining in on some black painted plastic barrels (to store and smooth the heat delivery). The floor is of wooden slats and covers the buried posseto which has tubes entering from domestic heat recovery but also from under the ground where the air can pick up some heat. So it is all very simple cheap and passive and apart from raising the COP significantly it could eliminate the defrosting cycles. There are a few variations on this theme including proper solar panels and tanks etc... the point being to retain any high grade heat and not require the ASHP to make it inefficiently At the other end of the complexity scale just putting a poly-tunnel round your ASHP would be worth a try.

by stevegwmonkseaton Mon Jan 27, 2014 10:33 am

Mmmm I know little or nothing about heating, but reading what's here is fascinating. It seems to me that most houses have a problem that there is always part of the house facing the wrong way. from what I've read it seems to make sense to be able to move excessive heat from one side of the building to another. Is there some simple system to do so (I'm sure there will be an expensive all dancing way of doing it!)

by **Gala Placidia** Mon Jan 27, 2014 11:21 am

Steve, basically, the problem is that wall that faces north, because it will be cold most of the time and the clash between its temperature and the warmer temperature inside the house will cause condensation. We had a similar problem in a lower cantinawhich is also, literally, on the river and we managed to sort it out through cross ventilation (permanent, but done through small vents)and efficient heating. Perhaps you do not need to set the temperature at 20° C ( say 18°C) and instead of ventilating the room for 15 minutes, 10 or less will do the same without throwing away calories. In our case, it took a lot of patience and experimentation; however, as it was only a cantina, hardly used, we persevered and managed to find the perfect balance. Good luck!

by **Geotherm** Mon Jan 27, 2014 2:43 pm

The Solar shed!
I can see where Sagraiasolar, is coming from, but there can be some issues.
The outside ASHP is normally directly connected to the technical room where the rest of the system is connected. so not a long underground system. In fact that would not be normal install, and even then, the heat recovery would be minimal from the ground. 10 mtrs extra of ground source pipe length will only increase the input temperature by approx half a degree.
The solar shed, in my opinion, would help in some respects, but with a caveat that the sun does not always shine in the winter.
You must also remember that with a ASHP that it can move up to maybe 5500m3 of air in a hour, depending on the size (if your house has a floor area of 200m2 x 3 mtrs high, then it is 600m3 ).
I am not going to dispute the theory in principle, but would rather see a working example in practice and results.

by **Geotherm** Mon Jan 27, 2014 2:52 pm

stevegwmonkseaton wrote:Mmmm I know little or nothing about heating, but reading what's here is fascinating. It seems to me that most houses have a problem that there is always part of the house facing the wrong way. from what I've read it seems to make sense to be able to move excessive heat from one side of the building to another. Is there some simple system to do so (I'm sure there will be an expensive all dancing way of doing it!)

Steve:
The only way you are going to be able to do that in one sense is ducting, without changing the heating settings on the thermostats in the cooler rooms.
Try a experiment and open some doors to the cooler rooms and put a fan in the doorway of the hotter room blowing out towards them and see if there is any noticeable difference!!

by stevegwmonkseaton Mon Jan 27, 2014 11:24 pm

Ok Geo, but I'll wait until the wood burner is installed .... Oh dear what are we doing...

by Vicino Tue Jan 28, 2014 5:39 am

Steve,

Our two woodburners are GREAT ! BUT.............is it too late for you to put in a 'Volcano' wood fire? These are linked up with your radiators around the house and spread the heat better.

We have high ceilings and the heat travels upwards before seeping into other rooms through doorways, so heating the other rooms this way is a slow process.

V

by stevegwmonkseaton Tue Jan 28, 2014 10:04 am

Thanks V, but the wood burner is more because we miss Italy than to do with the heating..... Being in the UK, gas is still probably the best/easiest fuel, apart from which we had a lovely new gas boiler installed just last winter. To be honest our fuel costs here are not too bad, which I put down to the superb insulation in a small bungalow.

by Sagraiasolar Tue Jan 28, 2014 5:25 pm

... just to clarify. The underground pipes are for air and not ground source as in a GSHP although the air is ground heated of course. This is an idea in current use and you can buy big silver coated pipes - anti-bacteria - to do the job. Heat pick up is not too bad and typically 5c can be picked up. Add to that any solar input and there will certainly be a beneficial effect on the COP. You might say that picking up free solar and house air recovery is cheating but so what. Geo is right to say he'd like to see one running - me too. Anyone want us to do one for you?
I might add that this has a lot of new stuff in it but the winter solar gathering system is tried and tested in my house and is particularly suited to the lower temperatures of an ASHP installation.

by **Geotherm** Tue Jan 28, 2014 7:25 pm

Sagraiasolar wrote:... just to clarify. The underground pipes are for air and not ground source as in a GSHP although the air is ground heated of course. This is an idea in current use and you can buy big silver coated pipes - anti-bacteria - to do the job. Heat pick up is not too bad and typically 5c can be picked up. Add to that any solar input and there will certainly be a beneficial effect on the COP. You might say that picking up free solar and house air recovery is cheating but so what. Geo is right to say he'd like to see one running - me too. Anyone want us to do one for you? I might add that this has a lot of new stuff in it but the winter solar gathering system is tried and tested in my house and is particularly suited to the lower temperatures of an ASHP installation.

Sorry, I must have misread the earlier post, re using the heat recovery part via the underground ducts.
I can see a number of problems though.
I will base these on a lower flow rate ASHP of 2200m3/h.
The air temp coming out of the ducts is 5C and the volume is quite low, so if the fan is running for say 15mins, it is going to move approx 550m3 of air. There would need to be rather large heat extraction from the property to cover the 5C heat increase in the "solar shed", for a period of extensive cold weather.
The solar shed will probably cool quite quickly in periods of heavy snow, low temps. Although you have the adavantage of a enclosed area, which will help reduce heat loss, but this probably will not change the pump running times by a great amount.
I think and this is only my opinion, that the extra expense would far outweigh a normal install of a ASHP.

by Bartholomew Wed Jan 29, 2014 2:22 am

Geotherm wrote:Bartholomew.With UFH and a heat pump, it is recommended to not reduce the temperature on the flow setting of the pump by more than 1.5C, as you do not want to cool the floor slab too much. Please note this is not the room temp thermostat!!!HTH

Thanks, Geotherm. I don't usually move the flow temp from its setting of 40C but have been wondering whether to lower the room thermostat a few degrees when leaving the house (ignoring protests from the feline population who positively adore underfloor heating)

by Sagraiasolar Wed Jan 29, 2014 11:27 am

Geotherm wrote:
The air temp coming out of the ducts is 5C and the volume is quite low, so if the fan is running for say 15mins, it is going to move approx 550m3 of air. There would need to be rather large heat extraction from the property to cover the 5C heat increase in the "solar shed", for a period of extensive cold weather.
The solar shed will probably cool quite quickly in periods of heavy snow, low temps. Although you have the adavantage of a enclosed area, which will help reduce heat loss, but this probably will not change the pump running times by a great amount.
I think and this is only my opinion, that the extra expense would far outweigh a normal install of a ASHP.

... we're at cross purposes still ... yes the house air extraction would come up through an underground duct into the posso under the shed and as you say it would have a fairly trivial effect.... no more trivial than the purpose made heat recovery systems though. The main air heating comes from other much bigger buried air ducts which are often buried in a grid pattern. The surface area of these pipes is huge and can be compared with the water pipes of a GSHP set up. As the 5c delivery temperature would be enough to make the de-icer cycle uneccessary especially when the house air and solar heated water barrels are adding to the mix. This system has the benefit of being able to use the higher daytime temperatures that often come on winter days - bigger tanks help here too - so the COP will be exceptionally high for any heat pump system. To take a real Aermec ASHP - the COP at 0c ambient and delivering 40c is 2.5 ... at 5c it would be 3.22 which is 28.8% better.... That's a potential saving of €500 odd on a typical bill and may well justify the cost.

by **Geotherm** Wed Jan 29, 2014 1:39 pm

Sagraiasolar.
Now I think I fully understand what you are trying to say, as it was not very clear in the earlier post.
If I get this wrong, then please correct me.
You say that the client should have a large grid network of pipes underground to create the warm air, which is now virtually the excavation costs of a GSHP. At what depth is this grid? 1.2 mtrs is about the minimum usually for a ground heat source.
Have just run a manual test on the input temps of mine and it is not really that cold outside (7C) and they are about 5.5C input and 1.0C out of the pump. Remember this is a water/coolant based system so heat loss is less. They have been as low as 0C input and -4C out, but as the refrigerant boils at -10C that is not a problem.
How will you move the warm air into the solar shed from the ground and control the flow rate, so it has enough time to recover the energy it has lost?
I will not comment on the Airmec site, as the only heat output figures that I can see are for a external temp of +7C for UFH @30-35C, or fan coils @40-45C.
To be quite honest for all that setup, it would probably be cheaper to put in a GSHP which is far more efficient, reliable and needs less maintenance.

by **Geotherm** Wed Jan 29, 2014 2:33 pm

Bartholomew wrote:
Geotherm wrote:Bartholomew.With UFH and a heat pump, it is recommended to not reduce the temperature on the flow setting of the pump by more than 1.5C, as you do not want to cool the floor slab too much. Please note this is not the room temp thermostat!!!HTH
Thanks, Geotherm. I don't usually move the flow temp from its setting of 40C but have been wondering whether to lower the room thermostat a few degrees when leaving the house (ignoring protests from the feline population who positively adore underfloor heating)

As I do not know which make of ASHP that you have, then just a few points.
The pump should normally run, based on a external sensor for air temp, plus a internal unit. There are variations, but for the moment we will exclude the internal unit. As the outside temperature drops or increases the sensor detects this and either increases or decreases the flow temp to the UHF. Flow @40C seems quite high as a normal setting, considering temps at the moment are still quite mild.
Is there a buffer tank installed?
If you let me know the make and model, will see if I can find out more on how it operates

by Sagraiasolar Thu Jan 30, 2014 10:38 am

Geotherm wrote:Have just run a manual test on the input temps of mine and it is not really that cold outside (7C) and they are about 5.5C input and 1.0C out of the pump. Remember this is a water/coolant based system so heat loss is less. They have been as low as 0C input and -4C out, but as the refrigerant boils at -10C that is not a problem.
How will you move the warm air into the solar shed from the ground and control the flow rate, so it has enough time to recover the energy it has lost?
I will not comment on the Airmec site, as the only heat output figures that I can see are for a external temp of +7C for UFH @30-35C, or fan coils @40-45C.
To be quite honest for all that setup, it would probably be cheaper to put in a GSHP which is far more efficient, reliable and needs less maintenance.

Geo, It would need an essay to discuss all of this and the variables would er, vary a lot depending on the installation. I accept that a GSHP would be much neater but given enough solar via a poly tunnel or two and some cheap drainage pipes one could run very high day time COPs and, looking at the local temperature highs graph, the average COP over the season should be better. This bearing in mind that the GSHP COP declines over the winter as the ground freezes up.
As for the air recovery issue - ground cooling would be similar to that generated by GSHP pipes but regeneration would come from the ground AND from warm air being drawn through on sunny days. The path for air flow would be best if the ground pipes inlet was high in the roof of a poly-tunnel and after going underground it enters the smaller and neater solar shed via a posseto under the duckboard floor. Cost? depends whether one already has or wants a shed, poly-tunnel and big tanks I suppose and how much use the system is going to get. If you had wood assisted heating then any paid for efficiency gains on the heat pump side would produce trivial savings and take years to make up.

by **Geotherm** Thu Jan 30, 2014 4:19 pm

Sagraiasolar.
My brain hurts affraid

We have gone from a heat recovery house system, to a large matrix of underground pipes and now we have polytunnels as well included with ducting all over them Shocked

.
I appreciate what you are trying to put over, but as always the simple solution is probably the most straightforward and still perfectly cost effective in the long run. That is unless you want to grow exotic plants in the polytunnel!! Smile

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