Boiler, buffer, thermal store or UVC? UFH with PV

[oranjeboom]

Okay, so if I go with the UVC option, I have three areas for the UVC and the buffer tank (4 if I include the loft):

 

Locations

Cloakroom: u-shaped area: 820x760 (actual room is 820x 2000, but doorway at 760 - but door will open outwards so that will help. Incidentally, this will also has the UFH manifold in there)

Hallway cupboard (u-shaped area: 930x640)

Electric cupboard: 800x350. Bit small for even a small buffer tank and I don't like the idea of the MCB and cylinders in the same restricted space.

 

Ceiling heights are 2.4 although I could go higher if needed.

 

Sizing

So looking at Joule and Telford as example UVC sizing: 

Telford:  300L 2150mmx660 (slimfast version:  250L: 1800x510, presume they can do a custom one that is larger but longer in height?)

Joule: 300L 2000x540

 

Best UVC location would probably be in hallway cupboard if I can get one that squeezes in. Heat loss will help to heat up the hallway and adjacent rooms/spaces. This will also minimise distance to boiler.

Buffer tank is probably best to have in the cloakroom, right next to the manifold.

 

@Nickfromwales Not sure whether my earlier posting made sense to you, but I think I have made up my mind with the UVC option (though I need to chase sunamp on their pricing today still). Any BH group discount plans with Telford on the horizon??? Not a clue which UVC to get, but looks like they will loosen my wallet by a bit. Just found out the plumber I had in mind is not VAT registered so will be slugged for full 20% VAT instead of 5% (VAT notice 708).

[Dreadnaught]

3 minutes ago, oranjeboom said:

though I need to chase sunamp on their pricing today

 

I would be interested in your SunAmp quote. Andrew Bissell said on Twitter yesterday that prices had dropped recently, to about £1,000 for their most common model with average capacity, and excluding installation (which I imagine is DIY-able).

[vfrdave]

@oranjeboom which of the sunamps are you looking pricing on.  I have pricing I got last week that I can share with you.

[le-cerveau]

@oranjeboom If you go Buffer-UVC, how are you heating the buffer?  If it is all Gas then a TS makes more sense.  The Buffer would be more applicable to an ASHP install.  I am sure @Nickfromwales will come back when he can.

[oranjeboom]

1 hour ago, Dreadnaught said:

 

I would be interested in your SunAmp quote. Andrew Bissell said on Twitter yesterday that prices had dropped recently, to about £1,000 for their most common model with average capacity, and excluding installation (which I imagine is DIY-able).

 

1 hour ago, vfrdave said:

@oranjeboom which of the sunamps are you looking pricing on.  I have pricing I got last week that I can share with you.

 

 

Thanks for the headsup on pricing coming down. Was not sure what SA unit Nick was referring to costwise earlier:

On 10/04/2018 at 15:10, Nickfromwales said:

To add, if the combi / SA option was chosen, you could go for a 12kw SA or a pair of 9kw ( so 18kw total ) and offset some of the space heating too. 6 hours of sunshine would charge that lot up and provide a LOT of storage. The gas boiler would then become a standby device for a good 60% of the year. 

 

 

On 20/04/2018 at 18:32, oranjeboom said:

How much would that setup cost? So a SA PV (5Kw) unit is circa £1700 IIRC so is it fair to say 18Kw worth of Sunamp magic is going to cost circa £7k plus the ' good high flow storage combi' cost [insert bargain figure here] will probably leave me with little left over to actually pay for shower and baths units! Very little demand for gas however (only need would be for cooking in the summer).

 

On 21/04/2018 at 00:32, Nickfromwales said:

Not approx, but circa £4k + ( reclaimable ) VAT iirc. 

Ill add more tomorrow.

 

So I was looking to get two Sunamp PV units @9kw each as the plumber mentioned above,which with I guessed would cost 4 x £1700 (per 5Kw PV unit - I found that price online somewhere, probably dated) to give me a figure of £7k. So if they have come down to £1k then that will really push my decision towards SA rather than UVC.

 

 

1 hour ago, le-cerveau said:

@oranjeboom If you go Buffer-UVC, how are you heating the buffer?  If it is all Gas then a TS makes more sense.  The Buffer would be more applicable to an ASHP install.  I am sure @Nickfromwales will come back when he can.

 

Yes, been there and considered that also. I have gas (boiler not bought yet) but liked Nick's pros and cons that were mentioned earlier. Not looking for ASHP in this setup.

[vfrdave]

@oranjeboom I have sent you a PM with the pricing

[Nickfromwales]

On 21/04/2018 at 12:42, oranjeboom said:

 

On 21/04/2018 at 09:23, Nickfromwales said:

Just consider the satisfaction of sliding on your favourite pair of brown and cream Y-fronts when they're toasty warm........

And then to prance around in them in a nice warm house. Neighbours are going to love that!

Was this your debut video?

 

 

[oranjeboom]

40 minutes ago, Nickfromwales said:

Was this your debut video?

 

No, not mine that. Mine got deleted from youtube.

[Nickfromwales]

8 hours ago, oranjeboom said:

 

@Nickfromwales Not sure whether my earlier posting made sense to you, but I think I have made up my mind with the UVC option (though I need to chase sunamp on their pricing today still). Any BH group discount plans with Telford on the horizon??? Not a clue which UVC to get, but looks like they will loosen my wallet by a bit. Just found out the plumber I had in mind is not VAT registered so will be slugged for full 20% VAT instead of 5% (VAT notice 708).

First question is are you going SA and what size / qty? That will determine what size UVC you need. I only got the info off @AndyT literally today about increased capacity of the uniq units when fed by pre-heated water. Makes a huge difference. 

All the cards need to be on the table for a conclusion, so for every component you consider / add / discount changes all of the peripheral decisions in the same heartbeat.

eg add sunamps = reduce UVC size

remove boiler = increase SA size 

Each has a direct effect on the other. 

What is it you we're thinking of doing with the sunamps?

9 hours ago, oranjeboom said:

Any BH group discount plans with Telford on the horizon???

We kinda did something along these lines once lol. Just mention Buildhub and you'll be sorted as Trevor at Cylinders2go has agreed to keep us sweet.  

[oranjeboom]

7 hours ago, Nickfromwales said:

First question is are you going SA and what size / qty? That will determine what size UVC you need. I only got the info off @AndyT literally today about increased capacity of the uniq units when fed by pre-heated water. Makes a huge difference. 

Well I wish I knew what I was doing also - believe me! Been pondering all day about this. 350L UVC with an additional buffer is probably going to cost at least £1500. But bigger losses obviously heat-wise.

 

Space heating and DHW requirements (paste job from earlier):

 

DHW requirement:

• 2 adults and two soon to be teenagers (so they will hardly wash reducing the DHW figures a bit)
• 2 morning showers
• 2 evening baths
• Hot water for washing up (though may get a boiler-type tap for most hot water needs in the kitchen)

Occupancy: Wife and kids out and I although I work from home, my office will be one of the sheds out the back so main house can either be set to off or very low temps during the day.

 

UFH demands:

Groundfloor: Water volume: 129L; Estimated loading: 9.45Kw
Upstairs: Water volume: 25L; Estimated loading: 2.03Kw

 

The price reduction in the SA has confused my thinking even more, especially all of their variants now of UniQ range. I think that may confuse others also especially since their site is woeful with explaining their new generation/range of options. But I hear they will be sorting that out soon. I have a feeling they are a bit under-resourced/overwhelmed with enquiries. Until I hear back from them, I will post qs here.

 

Someone kindly sent me some info on their latest UniQ rangeUFH and With a 12KWh system, that appears to cater for 2baths 2showers.

So if the SA is fully charged that should be sufficient heat for 2baths 2showers, right?

During summer months when my solar PV is producing 15Kw, that should replenish the sunamp for the evening baths and showers, correct?

 

Any surplus PV goes to the grid (I'm only on 4.85p export tariff so worth putting everything into sunamps). Winter is different of course and I didn't collect any stats from my PV setup yet to see what I generate, but assuming I make 2.5KWh, I would rely on the gas boiler to supply the majority of the heat energy for the 12KWh SA unit - best to have the boiler feed the sunamp in one hit at it's optimal condensing settings? 2baths 2showers/day would be the max for 95% of the time. Taking into account the UFH demand of a further 12Kw that would be met by the gas boiler also, but at least the heat loss from the Sunamp unit is minimal.

 

But can the UniQ range be rigged up direct with the boiler or does that still need a buffer tank?

 

And with the boiler in the mix here, do I need a UniQ Heat unit or can I plug the boiler into the UniQ ePV unit also?

 

So @Nickfromwales, as the wife wants gas for her cooking I am thinking of using a gas boiler with SA unit(s) and do away with UVC/TS completely (Saving £1500ish). Ideally get rid of the gas too, but she's made up her mind...and being Welsh, that's it!   Sunamp UniQ ePV 12KWh will be double in cost at  £3100ish, but probably a false economy in my sitaution to wait for prices to fall as I have no heat source at all now (no point installing UVC now only to rip it out in 2yrs time when SAs will be cheaper again!). 

 

My understanding of how these sunamp units work are probably a bit off the mark still, but hoping they give me call back soon.

[Nickfromwales]

On 25/04/2018 at 15:51, oranjeboom said:

Well I wish I knew what I was doing also - believe me! Been pondering all day about this. 350L UVC with an additional buffer is probably going to cost at least £1500. But bigger losses obviously heat-wise.

 

Space heating and DHW requirements (paste job from earlier):

 

DHW requirement:

• 2 adults and two soon to be teenagers (so they will hardly wash reducing the DHW figures a bit)
• 2 morning showers
• 2 evening baths
• Hot water for washing up (though may get a boiler-type tap for most hot water needs in the kitchen)

Occupancy: Wife and kids out and I although I work from home, my office will be one of the sheds out the back so main house can either be set to off or very low temps during the day.

 

UFH demands:

Groundfloor: Water volume: 129L; Estimated loading: 9.45Kw
Upstairs: Water volume: 25L; Estimated loading: 2.03Kw

 

The price reduction in the SA has confused my thinking even more, especially all of their variants now of UniQ range. I think that may confuse others also especially since their site is woeful with explaining their new generation/range of options. But I hear they will be sorting that out soon. I have a feeling they are a bit under-resourced/overwhelmed with enquiries. Until I hear back from them, I will post qs here.

 

Someone kindly sent me some info on their latest UniQ rangeUFH and With a 12KWh system, that appears to cater for 2baths 2showers.

So if the SA is fully charged that should be sufficient heat for 2baths 2showers, right?

During summer months when my solar PV is producing 15Kw, that should replenish the sunamp for the evening baths and showers, correct?

 

Any surplus PV goes to the grid (I'm only on 4.85p export tariff so worth putting everything into sunamps). Winter is different of course and I didn't collect any stats from my PV setup yet to see what I generate, but assuming I make 2.5KWh, I would rely on the gas boiler to supply the majority of the heat energy for the 12KWh SA unit - best to have the boiler feed the sunamp in one hit at it's optimal condensing settings? 2baths 2showers/day would be the max for 95% of the time. Taking into account the UFH demand of a further 12Kw that would be met by the gas boiler also, but at least the heat loss from the Sunamp unit is minimal.

 

But can the UniQ range be rigged up direct with the boiler or does that still need a buffer tank?

 

And with the boiler in the mix here, do I need a UniQ Heat unit or can I plug the boiler into the UniQ ePV unit also?

 

So @Nickfromwales, as the wife wants gas for her cooking I am thinking of using a gas boiler with SA unit(s) and do away with UVC/TS completely (Saving £1500ish). Ideally get rid of the gas too, but she's made up her mind...and being Welsh, that's it!   Sunamp UniQ ePV 12KWh will be double in cost at  £3100ish, but probably a false economy in my sitaution to wait for prices to fall as I have no heat source at all now (no point installing UVC now only to rip it out in 2yrs time when SAs will be cheaper again!). 

 

My understanding of how these sunamp units work are probably a bit off the mark still, but hoping they give me call back soon.

Ok I'll try and summarise...

 

SA ( for PV storage ?

Sound like you've got a decent chunk of that, so that's down to sizing the SA units accordingly. 

 

Gas:

Cooking. 

Boiler.

 

You can squeeze the SA's nearly dry, and then lean on the gas boiler as a last resort.  It shouldn't come on at all during the 'sunny months' so sized properly this should be a nice solution. 

With a combi you may want a thermostatic hydronic diverter which, at a certain temp, divert DHW from the SA away from the combi and send it directly to the outlets.