LPG or Oil?

delfagio

Hi all,

I chatted to two different plumbers recently regarding our new build house approx 2700sq foot. We are building a timber frame house with underfloor heating both downstairs and upstairs.

One plumber said "go with an oil tank with an oil condensing boiler as it is better suited to underfloor heating"

Second plumber said "get an LPG tank burried in the garden and get a gas condensing boiler"

Can anybody help at all as to which is the better system or set up to use. The boiler will only be used for the space heating of the underfloor heating. All Domestic Hot Water (DHW) will be a completely seperate system heated by using Thermodynamic Solar Panel system which will provide 100% of all DHW needs.

If anybody could help that would be brilliant

Thanks

Delfagio

MicktheMan

What does your ber assessor advise?

delfagio

BER Assessor has said that it would be up to myself as to which system to use. Obviously the efficiency of the either the oil or gas boilers will be taken into consideration for the BER.

In terms of the BER rating, we were not going to go down the line of any ground source heat pumps or anything like that due to the costs. We were orginally just going to go with oil, but now I'm confused as to which one to use, oil or LPG.

MicktheMan

Bulk LPG will be more expensive than oil to run going forward. See here.
That said, a lot depends on the setup wrt storage/buffer tank and control system. Again, you ber assessor is best positioned to advise. (btw, imo, "leaving it up to you" is poor advice from your assessor, as he/she should be well able to lay out and explain the pro's/con's of all possibilities)

cabledude

delfagio wrote: »

All Domestic Hot Water (DHW) will be a completely seperate system heated by using Thermodynamic Solar Panel system which will provide 100% of all DHW needs

100% of your DHW needs from solar? Are you sure about this. Seems aspirational to say the least.

delfagio

cabledude wrote: »

100% of your DHW needs from solar? Are you sure about this. Seems aspirational to say the least.

Hey cabledude,

No not aspirational at all, there's been a good few threads about them for a while on and off. To be honest I have no idea why people are still going with other solar panels over the thermodynamic one. No need for back up from boiler, stoves or electric imersion. 100% DHW needs. Check it out online for yourself.

cabledude

delfagio wrote: »

Hey cabledude,

No not aspirational at all, there's been a good few threads about them for a while on and off. To be honest I have no idea why people are still going with other solar panels over the thermodynamic one. No need for back up from boiler, stoves or electric imersion. 100% DHW needs. Check it out online for yourself.

I will do. We looked at solar tubes a few years ago, but, the cost was high and the efficiency didn't impress me one bit.

P.S. are these systems much more expensive than regular solar

delfagio

Hey Cabledude,

I'll pm you as I don't think I can post company names or costs in this thread.

Anybody else got views on LPG v Oil thanks

fclauson

how are you complying with Part L if you just use these thermodynamic panels ?

daver123

delfagio wrote: »

Hi all,

I chatted to two different plumbers recently regarding our new build house approx 2700sq foot. We are building a timber frame house with underfloor heating both downstairs and upstairs.

One plumber said "go with an oil tank with an oil condensing boiler as it is better suited to underfloor heating"

Second plumber said "get an LPG tank burried in the garden and get a gas condensing boiler"

Can anybody help at all as to which is the better system or set up to use. The boiler will only be used for the space heating of the underfloor heating. All Domestic Hot Water (DHW) will be a completely seperate system heated by using Thermodynamic Solar Panel system which will provide 100% of all DHW needs.

If anybody could help that would be brilliant

Thanks

Delfagio

I have a gas condensing boiler ( Baxi ) and 20 solar tubes ( Kingspan Thermomax ) as part of the one system and it is very efficient, 3 zone hortsmann control and trv's on all the rads. It works out at about 600 - 700 euro a year to heat the house and hot water 2 bedroom 900 square feet

delfagio

fclauson wrote: »

how are you complying with Part L if you just use these thermodynamic panels ?

Hey Fclauson,

The Thermodynamic Solar Panel will be providing 100% of my DHW needs, so how would I not be complying with Part L. In fact I would be exceeding Part L in some respects as traditional solar panels will still only give you about 50% of your DHW needs as it relys on direct sunlight and still needs back up from oil/gas boiler, stove or imersion to give you the remaining 50% DHW.

fclauson

not necessary true

I built a Passive/A1 house - but it failed to comply with Part L until I added 16Sqm of solar panels :eek:

Get your BER assessor to agree that you will meet Part L with this system as I am suspicious that your will not - but would be happy to be proved wrong

delfagio

fclauson wrote: »

not necessary true

I built a Passive/A1 house - but it failed to comply with Part L until I added 16Sqm of solar panels :eek:

Get your BER assessor to agree that you will meet Part L with this system as I am suspicious that your will not - but would be happy to be proved wrong

Hi Fclauson,

I will look into this with my BER assessor, thanks for the help. Hopefully what you say will not be the case because to be honest the thermodynamic solar panel system I will be going with far outstands the traditional solar panels with either plates or tubes.

And let me just say, if just to comply with Part L, I have to go with a less superior product or less productive/achieveing product, then I think thats ridiculous and that Part L has to change .....FAST.

MOTM

delfagio wrote: »

Hey Fclauson,

The Thermodynamic Solar Panel will be providing 100% of my DHW needs, so how would I not be complying with Part L. In fact I would be exceeding Part L in some respects as traditional solar panels will still only give you about 50% of your DHW needs as it relys on direct sunlight and still needs back up from oil/gas boiler, stove or imersion to give you the remaining 50% DHW.

Nope. The solar panel does not provide 100% of your DHW needs. In these thermodynamic systems, the solar panel meets some of it and a heat pump meets the majority. The claim that they meet all of the water, rain or shine, night or day through solar heating is rubbish.

The thermodynamic solar collector is unglazed and typically only about 1.6m2 so the sun will be providing a small part of your hot water. This contributes to the part L renewables requirement.
Compare this to conventional solar thermal system providing 50-60% solar fraction. On a dwelling up to about 180m2 this would meet the part renewables requirement. The small unglazed collector on the thermodynamic system has a solar fraction well below 50%.

The remainder of the demand is met by what is effectively an A/W heat pump heating hot water. If you don't have accredited test data for that heat pump, the efficiency applied is defaulted to 250% and multiplied by 0.7 as it is heating hot water rather than say a much cooler underfloor heating system. This heat pump would not contibute anything to the Part L renewables requirement as the effective efficiency (250*.7) is far below the portion of heat pump considered renewable in Part L (any energy from a heat pump > 250% considered renewable). I'd advise you to seek test data from an accredited source to one of EN14511, 255-2, 255-3 or 16147 for the heat pump portion of the thermodynamic collector if you want to get anything toward renewable contribution from the heat pump part of the system.

delfagio

MOTM wrote: »

Nope. The solar panel does not provide 100% of your DHW needs. In these thermodynamic systems, the solar panel meets some of it and a heat pump meets the majority. The claim that they meet all of the water, rain or shine, night or day through solar heating is rubbish.

The thermodynamic solar collector is unglazed and typically only about 1.6m2 so the sun will be providing a small part of your hot water. This contributes to the part L renewables requirement.
Compare this to conventional solar thermal system providing 50-60% solar fraction. On a dwelling up to about 180m2 this would meet the part renewables requirement. The small unglazed collector on the thermodynamic system has a solar fraction well below 50%.

The remainder of the demand is met by what is effectively an A/W heat pump heating hot water. If you don't have accredited test data for that heat pump, the efficiency applied is defaulted to 250% and multiplied by 0.7 as it is heating hot water rather than say a much cooler underfloor heating system. This heat pump would not contibute anything to the Part L renewables requirement as the effective efficiency (250*.7) is far below the portion of heat pump considered renewable in Part L (any energy from a heat pump > 250% considered renewable). I'd advise you to seek test data from an accredited source to one of EN14511, 255-2, 255-3 or 16147 for the heat pump portion of the thermodynamic collector if you want to get anything toward renewable contribution from the heat pump part of the system.

Hi MOTM,

This to me seems bonkers,

On traditional solar panels with either flat plates or tubes they provide approx 50-60% of the hot water, BUT you will STILL have to provide the rest of the heat (40-50%) by either using an immersion, oil or gas back up, or stove etc. So therefore this means that you still have to pump money into heating your water tank from some form or oil,gas, wood pellet, stove etc. Which lets face it, is still going to cost a lot of money a year.

With the Thermodynamic Solar panel system, yes I agree with you that the panel itself, only provides less than 50% of the hot water and the remainder coming from essentially a small heat pump. However the cost of running this heat pump is no more 200-300euro a year.

To me this is madness that Part L will not recognise this

MOTM

delfagio wrote: »

Hi MOTM,

This to me seems bonkers,

On traditional solar panels with either flat plates or tubes they provide approx 50-60% of the hot water, BUT you will STILL have to provide the rest of the heat (40-50%) by either using an immersion, oil or gas back up, or stove etc. So therefore this means that you still have to pump money into heating your water tank from some form or oil,gas, wood pellet, stove etc. Which lets face it, is still going to cost a lot of money a year.

With the Thermodynamic Solar panel system, yes I agree with you that the panel itself, only provides less than 50% of the hot water and the remainder coming from essentially a small heat pump. However the cost of running this heat pump is no more 200-300euro a year.

To me this is madness that Part L will not recognise this

Ballpark, a 150m2 house has total hot water demand of about 3000kWh per year. Accounting for 90% efficient boiler , storage and pipework losses, this requires about 4000kWh/yr oil at the dwelling. At 9c/kWh thats €360 per year.
Add conventional solar heating system and its closer to €180 per year.

With the thermodynamic system, solar fraction unlikely to be more than 25%. It is a small collector and it is unglazed.... Meaning that the heat pump has to output 3000*0.75= 2250kWh and likely another 500kWh for storage losses. Thats 2750kWh needed from the heatpump. At 250*0.7 efficiency (due to higher temperature and seeming unavailability of accredited COP data) this requires about 1500kWh electricity costing at least 16.5c/kWh assuming day rate is about €250.

Thermodynamic system saves €110 per year over basic condensing oil system and costs €70 more than boiler +conventional solar thermal. Do the sums!!

fclauson

good reply MOTM

as I have said elsewhere - don't trust "it should" always look for it will and here is the maths to prove it

brophis

You may find also that getting an air source heat pump may be cheaper than the thermodynamic panels and boiler combined.