Heat Pumps - post here.

sheff the ref

How is this experiment going for you now?

MENACE2010 wrote: »

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We have a heat pump with underfloor and have now disabled the stats.. and I have disabled "set-back" , so the pump only now in theory has to "top up " the heat of the floor . ( this is an experiment , if my usage is going to skyrocket i'm back at setback settings)

youcancallmeal

I've just gone sale agreed on a new build which has an IVT air to water heat pump system. I've read through this thread now so have a good idea what it's all about. The house is ready to move in now but will be a few weeks before we sort out all the contracts and stuff. I've viewed it twice and from what I can tell there is no UFH, just alu rads and thermostats in every room. Also no HRV but the windows downstairs have those little vents which I'm assuming can be used to help regulate temperature/airflow without having to open it fully. Would it be a big job to retrofit HRV in future, I'm guessing it would be if you have to run vents to every room in the house?

I probably need to talk to the builder about this but if the ASHP doesn't have the wifi enabled remote control feature installed(I believe it is called IVT Anywhere) is it possible to upgrade my unit later to include it? I had a look at their app on the google play store and it isn't even available in Ireland so doesn't look promising https://play.google.com/store/apps/details?id=com.bosch.tt.IVT&hl=en

When doing a survey/snaglist is there anything in particular to check for with this system?

soundskin

IVT are very good heat pump. The app connection won'r offer you anything you don't have on the heat pump controls. You won't be turning up and down heating and changing settings remotely anyway. Remote connectivity to heat pumps is only handy for holiday homes & trouble shooting for tech support.

I wouldn't loose any sleep if you can't get it. 95% of heat pumps in ireland don't have it.

I'd focus on making sure your unit is set up and installed right.

youcancallmeal

soundskin wrote: »

IVT are very good heat pump. The app connection won'r offer you anything you don't have on the heat pump controls. You won't be turning up and down heating and changing settings remotely anyway. Remote connectivity to heat pumps is only handy for holiday homes & trouble shooting for tech support.

I wouldn't loose any sleep if you can't get it. 95% of heat pumps in ireland don't have it.

I'd focus on making sure your unit is set up and installed right.

Yes absolutely, just a nice to have. I'm big into my gadgets and idea of being able to change thermostat for rooms and monitor the system remotely appeals to me. As you say though the main thing is it all works well, won't know for sure until we move in and test it out I suppose.

kilkenny31

Does anyone have any of the grant hybrid boilers installed? And if so how do they find them? Can't find much information about them except from the grant website.

http://grantengineering.ie/high-efficiency-heating_products/grant-vortexair-hybrid-range/

Dr4gul4

kilkenny31 wrote: »

Does anyone have any of the grant hybrid boilers installed? And if so how do they find them? Can't find much information about them except from the grant website.

http://grantengineering.ie/high-efficiency-heating_products/grant-vortexair-hybrid-range/

Just had the very system mentioned to me. But i cant say I have any experience with them .. would be interested to hear from others however.

gooner99

Hi. Just scratching the surface on heat pumps and have a few general questions. House will be 150sqm, airtight and have mhvr, so suitable for this type of heating.

1. A2w - My site is right on the Altlantic coast, a few yards from the water. So salt in the air all the time and everything rusts. My thinking is that even a2w heat pumps that are treated for coastal use will corrode, break and need replacing long before the payback period. Would you guys concur with this.

2. Air to air - Again part of the unit is outside, so a also at risk of rusting. But the units are cheaper so replacement wouldn't be as costly. From searching it seems that this type of heat pump seems to be very rare in Ireland. But is there a place for them in a smalker highly insulated and airtight house?

3. Geothermal - it seems like this is the top solution, no outdoor units and the best heat source is the earth. More expensive to install, but they "may" also be more reliable. My soil is sandy, in general is sandy soil suitable for horizontal and vertical geo?

Please post any thoughts and suggestions. I guess recommendations for manufacturers and systems can be posted, but please pm me any installer suggestions or experiences. Thanks.

antoinolachtnai

Air-to-air heat pumps are pretty common in Ireland in commercial applications like restaurants or offices. These are the air conditioners which you see in lots of places. They cool in the summer and heat in the winter.

The problem is that they are great for a small number of big rooms, but if you have a large number of smaller rooms (like bedrooms), the problem is how you spread the heat throughout the rooms. Otherwise you need to install a large number of separate units.

You really need to take advice from the manufacturers about how best to shelter equipment of any kind from the salty air and what the actual lifetime will be.

You are comparing payback to something like an oil burner, I imagine, but the salt air problem would also effect an oil burner to a large degree. So I don't think your point about payback period is quite that simple.

Talking about geothermal / ground source heat pump: Another option could be a seawater heat pump. I do not know if this would be really viable for a small project, but it is in principle possible. https://www.kensaheatpumps.com/the-technology/heat-sources-collectors/sea-water/

gooner99

The only thing with an oil boiler outside is that the unit is a lot cheaper to replace, so I guess that's why no one has really raised the issue of salt air corrosion before. I could be wrong but I'd imagine the outdoor unit in an air to water setup is quite expensive?

exaisle

I've seen geothermal systems use rivers as heat source, just wondering if it would be feasible to use seawater? Minimum temperature of around 8-10 degrees...

antoinolachtnai

gooner99 wrote: »

The only thing with an oil boiler outside is that the unit is a lot cheaper to replace, so I guess that's why no one has really raised the issue of salt air corrosion before. I could be wrong but I'd imagine the outdoor unit in an air to water setup is quite expensive?

Yes. The whole unit is outdoors really. The unit cost really depends on your heat requirement. If you only had a small heat requirement it might not be much more expensive than an oil boiler. I would be inclined to think an oil boiler would suffer more from salty weather because of higher temperatures but this could definitely be argued both ways.

If there were part of your land where you could dig a hole and place a coul so the coil were under the high water mark it would seem to me like you might be able to get good performance out of the ground water heat pump. But it is a pretty specialised situation.

gooner99

Hmmm. Wouldn't the a2w unit be sucking in air, so in theory I'd say it might be more affected by salty air?

House is quite compact, only 150sqm stoey and half and will be highly insulated and airtight. I guess the smallest a2w may well do the job. What price do the the decent low output units (outdoor part) normally go for?

Yeah reading the geo is the best, but a bit more expensive and that vertical bore works better than horizontal.

antoinolachtnai

The boiler will also be sucking in air, and quite a lot of it!It needs air for the combustion.

You can see prices for the units on www.rvr.ie, they start at around 3300 ex VAT. There may be some discount to be had on that.

https://www.rvr.ie/products/ecodan-5kw?variant=26096149767

There is really no indoor part with these units. Well, you need a buffer tank, but that's a different thing.

murphaph

How big is your site? What's the geology like?

A sandy soil is fine for a collector buried a metre under the surface. This will be cheaper than a borehole assuming you have the space for it (they don't work under driveways or areas where rainwater doesn't percolate down - this is not really geothermal energy by the way. It works by the sun energising the upper layers of soil in the summer and extracting the energy mostly in winter. The borehole is true geothermal, with the energy coming from the earth's core)

A borehole has to go down about 100 metres. If you hit bedrock it gets expensive.

If it was me and I had the room I'd go for the sub surface collector. Reliable and relatively inexpensive. You can do a lot of the work yourself even. This will not be the case for most other options.

antoinolachtnai

I think he has a special case because he is beside the sea. He could well be able to get better than typical temperatures because the sea may well be warmer than the ground (at least where a sub-surface collector would go). Of course, he would need to go deeper to get under the level of the sea water, but his collector wouldn't necessarily need to be as spread out as it would need to be for a sub-surface collector.

murphaph

It's possible but I'd say unlikely that the OP will be able to make economic use of the seawater by modifying a typical system. That's just my gut feeling though. Would be happy to be proved wrong and for this energy to be harvested economically.

As we have almost no information about the geology it's hard to say much more.

gooner99

Colector on the beach would be a leap of faith and as it is tidal the temps would probably fluctuate. I'd also imagine your not allowed to go digging the beach!

gooner99

On a modest sized house that is properly insulated and airtight I would guess the heat demand will be low. I need to get this calculated.

But lets say it is low, I would imagine that whatever you choose to heat such a house will not cost much. Are oil burners mostly dispelled on the assumption that it's wrong to have a carbon heat source in a low energy house rathar than having high running costs?

Anyone use oil to heat a low energy house?

murphaph

You are heading the right direction and yeah, actually digging the beach is not going to be an option. First get the demand as low as possible then choose the heat source. It's still quite common in Germany to build very energy efficient houses and heat them with gas boilers. An energy efficient house that needs a tiny bit of gas is preferable to an inefficient house that needs lots of electricity (mostly produced in dirty power stations) to run a heat pump!

The thing is you will have to satisfy building regs (Part L), so an oil boiler will have to be "offset" by "good deeds" elsewhere in your build.

gooner99

Thanks. Yeah aware of part L. But I still have the option of extending rathar than new build. I don't think part L is as strict on renovations.

antoinolachtnai

murphaph wrote: »

You are heading the right direction and yeah, actually digging the beach is not going to be an option. First get the demand as low as possible then choose the heat source. It's still quite common in Germany to build very energy efficient houses and heat them with gas boilers. An energy efficient house that needs a tiny bit of gas is preferable to an inefficient house that needs lots of electricity (mostly produced in dirty power stations) to run a heat pump!

The thing is you will have to satisfy building regs (Part L), so an oil boiler will have to be "offset" by "good deeds" elsewhere in your build.

A lot of electricity in Ireland is renewable, especially off the 5pm peak. It is a rather technical point but there is actually more wind energy on the grid on the Atlantic seaboard than elsewhere (this has to do with grid constraints).

The advantage of the heat pump is really that you'd require one less service to your house. You wouldn't need an oil or gas supply. And you wouldn't need such frequent services as gas and oil require. That's the theory anyway. The Capital cost of these services is significant enough. It will cost the guts of 1500 euros to provide a well secured oil tank with access for instance.

You cannot dig a hole on the beach without a foreshore licence. But you might be able to dig a deep hole on your own land adjacent to the shore. How deep it needs to be to be under the water level most of the time would depend on the site. It obviously needs expert advice.

What the performance is going to be like is mainly a factor of the water temperature or ground temperature. Warmer water is going to perform considerably better than colder ground from my understanding. But it needs expert advice for sure.

A regular ground source heat pump should do this job handy enough. It is just a coil with fluid going through it at the end of the day and a compressor at the end. The water should be warmer than the soil during winter so the pump should have to work less hard.

murphaph

I'm the happy owner of an A2W heat pump and agree with all the above. One of the reasons we avoided gas was the fact we'd have to pay €2000 for the connection and it's another utility to fail (if the electricity goes you have no central heating anyway). I just don't think the coastal location is going to provide any extra benefits and will essentially prevent A2W being deployed as the unit will essentially be sacrificial in that environment.

I had a google around to see if any Germans are doing this (renewable energy is far more mainstream here-water/water heat pumps are not at all exotic) and I only found 1 commercial example on the Baltic and it said it's because it's not tidal that it works. So it seems the tide alone is likely enough to kill any real opportunity for the OP.

I'd go for the ground collector loop still if I was in the OP's shoes. Oil can run out at the most inopportune times (childhood memories!) and a heat pump is essentially a fridge and requires no specialist servicing. You just have to clean filters and stuff like that.

antoinolachtnai

There are plenty locations where this is done including tidal locations. Not many in Germany though, because they just don't have a lot of coastline.

Therre is an interesting discussion at http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=2718&Focus=35365

If you can get access to a reliable supply of seawater or can put a coil or heat exchanger in the sea this is definitely feasible. The question is how much work this would involve to do to a sufficient standard. If there was already a jetty or something in place or maybe if there were some sort of inlet it might not be too difficult. Building from scratch could be pretty tricky. This would be great if you were heating a swimming pool or a stately home but probably not worth it for one house.

I had a root around and I did read about an anti corrosion coating that is available for air water coils: http://www.blygold.com/international-do-it-yourself

One other thing is that any heat pump should work better on the coast than inland because the temperature by and large is more moderate there because of the thermal mass of the sea.

gooner99

Maybe a2w with anti corrosion treatment might be worth exploring. Anyone know of models that are working well in seaside areas?

antoinolachtnai

You are really going to have to talk to installers who have experience installing heat pumps in these areas. There are plenty of companies in the country who install air conditioners, and they will know what sorts of problems arise with sea and salt.

gooner99

Yes good point. I guess they are a air conditioner in reverse and I'd imagine loads have been unstalled on the west coast.

tvisdead

I have gone with a Nibe geothermal pump, placed order only last week.
My parents have a Nibe geo installed for 12years now and it has operated hassle free without a days bother.
we are not in a coastal region
Dont get me wrong, A2W could easily be as reliable.

With the heat system in the 12 years the only issue was an electrical surge which blew out a board.
So a reminder I guess that whatever you go for to have proper surge protection on such equipment.

gooner99

Reading that some are using condensing oil and gas boilers to run their underfloor system. If you insulate and have air-tightness to near passive standards then is there an argument that it wouldn't cost too much to run such as system in a 1500sqm house,Thoughts?

murphaph

You mean 1500ft² I presume? Yes, the most important thing is to get the primary heat demand down and then choosing an actual heat source is a secondary issue. Just make sure your installation can operate at low temps in the future (with UFH this means narrower spacing of the pipework in the floor), should you wish to move from oil/gas to a heat pump.

gooner99

murphaph wrote: »

You mean 1500ft² I presume? Yes, the most important thing is to get the primary heat demand down and then choosing an actual heat source is a secondary issue. Just make sure your installation can operate at low temps in the future (with UFH this means narrower spacing of the pipework in the floor), should you wish to move from oil/gas to a heat pump.

Thanks for the reply. Yes if we go this route we will ensure the underfloor is set up so as it can take a heatpump. I'd imagine that once the underfloor is set up the correct way, then you can simply add in a different heat source in the future.