LVP Thermodynamic solar Panels

How many coils has the neus, was it difficult to get it into hot press or did you move services to suit it?
Sorry for all the questions but what did the unit cost?

Sounds ok, will have a closer look over weekend. Thanks

beertons wrote: »

Have a rep calling round from LVP soon. Would I be better getting a wired energy monitor? He said he would have his guys fit it for me, just so I can keep an eye on usage.

As you may know there are different methods of measuring the power being drawn. You could use a clampmeter type (which Shane is using) or a dedicated plug in unit which I am using.. Mine is a Proteam HO1569 into which the Energie unit plugs into. Either will do the job except there's no fitting on mine as you just plug it in...(costs around 15 euro).
If you are getting it one fitted it may cost more than that?

Maybe worth mentioning you do not need a south roof for solar thermal as it is pressuried you can site anywhere with unshaded south facing aspect. Pipe runs need to be as short as possible but if sized correctly you can send the hot water many meters to a remote cylinder.Putting on the ground or a pergola is perfectly acceptable.

How quickly the year has flown! and this LVP/Thermasol/Energie system has worked well. (See attached XL file)

I've used 18cent as an average per KWhr ..cost €208.

As Shane said...winter will be the test for his system .........and I'm looking forward to see how my Energie system compares to his and other new systems during the coming year.

MOTM wrote: »

< €5/wk
So < €250/yr
Would this not be near comparable to the running cost of a condensing boiler system with decent controls (I'd expect would certainly be less than €300/yr). Add conventional solar water heating with a solar fraction of 50% and the water heating costs would be a good bit less than the LVP system.

...from earlier post on thermodynamic running cost versus oil or oil+solar

shane0007 wrote: »

None of that "ish" malarchy please.

So if we were to just get a wee bit technical here, we can calculate exactly what energy it takes to heat said 250 litres from 10C to 55C as per the air to water heat pumps & then we can truly compare the two costs with the "ish" removed:

Time = (Volume x Specific Heat Capacity of Water x ΔT) / KW
Time = (250 x 4.186 x 45) / 23 (26kw oil boiler factory set to 23kw) less HE 10% + 10% System losses
Time = 47,092.5 / 18.4
Time = 2,559.38 secs = 43 minutes


So, 0.65 US Gal/Hr nozzle @ 8.5 bar pressure = 2.99 litres per 60 minutes
So, 43 minutes = 2.14 litre
So, daily cost = 2.14 x €0.90 = €1.93
Therefore, weekly cost = €1.93 x 7 = €13.51
Therefore, annual cost = €13.51 x 52 = €702.52

Now comparing Braka's €208 per annum, it seems to be exactly €494.52 cheaper!

If the boiler was a Standard Efficiency, we would be looking at 16.1kw from the 23kw output, so time would extend to 49 mins & therefore use 2.44 litres & @ €0.90 per litre, the daily cost would increase to €2.71 per day, €18.97 per week & €986.44 per annum! Difference here of €778.44!!

Hmmmm.....

OK Shane0007, point taken (I hadn't realised the spec was 250L at 55oC - so my "ish" remark is withdrawn). 250L at that temperature is more than I'd expected when previously talking about oil running costs. DEAP, for example, maxes out at 210L. SAP 2012 would never get close to 250L as far as I'm aware. PHPP2007 says 10 people would be needed in the dwelling to reach 250L at 60 degrees.

So, at 250L at 55 degrees: for a system with 20% losses, I make the boiler system running cost to be €604 rather than €702 though (although if the thermodynamic system is running at €208 for the same hot water requirement, that is still clearly a significant saving, so fair dues).

Its still cheaper than even a condensing system with solar offering 60% solar fraction (604*0.4=€242). I do note that the SEAI fuel cost comparison kWh costs for electricity are higher than the 18c mentioned earlier but the thermodynamic system is still cheaper (although SEAI figures are averages dependent on multiple suppliers I think).

kWh yr for boiler with 20% loss (or 80% efficient).
250L/d at dT=45 degrees. SEAI oil cost is 0.1013€/kWh
0.1013*[250*4.186*45*365/3600]/[80%] ~=€604.5

I think the difference in our methods is when you state 2.99L/hr:
10kWh in a litre: 2.99*10kWh in an hour.
29.9KWh in an hour from a 23kW boiler would indicate 79% efficient. But you'd already accounted for 10% losses in each of the boiler and system earlier in your post?

shane0007 wrote: »

Forget about SEAI's stats, they can be way off. I have based my calculation on 90 cent per litre for kerosene, so a boiler with 23kw output setting less 20%, (10% boiler efficiency & 10% system losses). This gives the figures I have quoted of €702 for oil.
Solar generally gives a solar fraction of 50%, not 60% as 60% would decrease the efficiency.
This would give a total saving of €351.
You should also consider also the total cost of a solar installation. Usually 40 Kingspan tubes with 250 Litre s/s cylinder would be circa €5,500 for a decent quality.
Heat pump system supplied & installed for €3,500, a €2,000 saving plus €150 per year saving on running costs.

I still don't get how the boiler with 2.99L/hr input (~29.9kW) is outputting at 18.4kW . That doesn't look like 20% loss. It looks much larger. (even if I'm right on this, the boiler only system is still not close to €208 running costs)

Also, I'm genuinly surprised at 250L usage at 55 degrees, but that's neither here nor there.

shane0007 wrote: »

23kw - 20% = 18.4kw

With 29.9kW input - it looks like ~61% system efficiency rather than ~80% if only outputting 18.4kW heat from the system.

Also, was the water quantity heated by the €208 measured at 250L/day at 55 degrees? I can't find the post stating this - Braka you might help me on this.

shane0007 wrote: »

Nobody mentioned 29.9kw! It was a 26kw which are factory set to 23kw.

You worked out the boiler running time required to heat 250L water based on 80% system efficiency:

shane0007 wrote:

23 (26kw oil boiler factory set to 23kw) less HE 10% + 10% System losses

So far so good. This is fine if there is 23kW energy input from oil fuel to the boiler. You then went on to say that the boiler burns "2.99 litres per 60 minutes".

There's ~10kWh energy in a litre of oil. Thats 2.99*10 kWh = 29.9kWh in an hour or an oil input of 29.9kW with a thermal output of 18.4kW. Thats a 61.5% efficiency you've assumed for the condensing oil heating system.

shane0007 wrote: »

Also Braka never mentioned the exact litres of usage per day. This would require a flow meter to be installed.
Ariston NUOS are tested to heat 250litres in 5 hours & 200litres in 4 hours with an air temperature of 15C. This gives the full COP of 3.7. At 7C, the COP drops to 3.1.
So no matter what usage the figures will adjust on both the oil side & the HP respectively & accordingly.

I know a flow meter is needed to measure the water usage.

shane0007 wrote:

we can calculate exactly what energy it takes to heat said 250 litres from 10C to 55C as per the air to water heat pumps & then we can truly compare the two costs with the "ish" removed

I'm afraid you've put the "ish" back into it;)
The point is that you've assumed Brakas system is heating 250L to 55oC for the cost he has stated as €208 Euro and then checked to see how much it would cost an oil system at 61.5% efficiency to heat the same.

The oil system has come out at a whopping €702 cost per year for water heating. The oil is almost 3.4 (702/208) times more expensive than Brakas systems according to your calculations.

However:
1) You have not accounted for how much water is actually being heated and to what temperature by Brakas system, so it is wrong to compare the oil heating costs for 250L at 55 degrees given that we've no idea how much water and what temperature Brakas system was providing.
2) The oil system efficiency is overly pessimistic.

shane0007 wrote: »

No, 10.8 is gross.
A 23kw output on HE boiler will have a 0.65USGal/Hr nozzle. This gives 0.65USGal/Hr at 7.0bar pressure. Check your MI's & to give 23kw output you will find it will require an increased pump pressure of 8.5 bar.
Convert 0.65USGal to litres & this is 2.46 litres.
Divide this by 7 & multiply by 8.5 = 2.99 litres per hour.
I have not tested this in a controlled laboratory environment & I have assumed that Danfoss are correct with their testings & boiler manufacturers are correct with their published test results.
What I have not accounted for is the coil of a cylinder cannot transfer 23kw of energy at any given time so there is will significant wastage every time the boiler fires.

With regard to water volumes, I can only assume the cylinder is sized according to usage. It is with mine anyhow.

Yes, the kWh/L I've used is based on GCV, but so is the 10% reduction for boiler efficiency (condensing boiler being 90% gross efficient on HARP). Net efficiency would be higher. I've worked entirely based on GCV for energy content and efficiency.

I've assumed no more than the 10% system efficiency including the coil. So thats 20% total losses.

Would be great to have a better handle on what is actually heated for the €208 so a fair comparison could be made.

shane0007 wrote: »

So are you still an "ish" man or are we over that now? Lol

Looks like we'll have to agree to disagree- ish on that one. ;b