Any thoughts on Adia thermal?

[sharpener]

 

3 hours ago, Beelbeebub said:

They could junk the pump and mixer and run directly and either

 

modulate the flow to each loop so the power is appropriate - conceptually there isn't any difference between a UFH loop and a big, high mass radiator. The only caveat would be if the flow temp for radiators is too high to safely use in the UFH loop. 

 

Another problem with this approach is that if you have to turn down the flow very low then the temperature will not be even remotely constant along the loop. It will decay exponentially along its length so may end up being very uneven across the room even if the total dissipation is correct.

 

[Beelbeebub]

12 hours ago, sharpener said:

 

 

Another problem with this approach is that if you have to turn down the flow very low then the temperature will not be even remotely constant along the loop. It will decay exponentially along its length so may end up being very uneven across the room even if the total dissipation is correct.

 

Yes, though this would very much depend on the UFH system itself. If it was a close spaced spiral in a slab, it would probably be fine. But if it was the up/down pattern in a thin overlay system it woukd be a problem. 

 

I do wonder how quick HPs can ramp temps up and down.  If the temp ramped up to rad target and the UFH loops shut down, then the temp ramps down and the ufh opens up whilst the rads remain open all the time. That would be a possible solution. 

[JohnMo]

1 hour ago, Beelbeebub said:

do wonder how quick HPs can ramp temps up

6kW heat pump into UFH system.

 

5.5 hrs of data. 6 degs outside. 4 degs rise in flow temperature.

 

 

If you have a mixed system you need the UFH on all the time, if it's on a mixer the floor temp stabilises and the hot water flow inlet to system stays low, as does the out flow, so allows radiator flow temp to increase to required level. Faffing about with on off cycles just stops that process. Floor temperature requires most the flow. Gas boiler just throws out lots of kWs to compensate, heat pump cannot do that.

 

 

[Beelbeebub]

One of the big issues with HPs is hot water. Specifically the tank needed as they cannot provide instantaneous hot water so require a cylinder.

If there isn't an existing cylinder, fitting one requires extra cost (around 1k for a 150l cylinder plus labour ), space (at least 150l!), disruption and time.

 

Say £1500 in materials plus labour.

I had a look at battery storage as an alternative though experiment. (stop me if I've corked up the maths)

A 150l cylinder stores about 10kwh of energy (4.2kj x {65-10} x 150 /3600)

 

So a 10kwh battery would have roughly the same DHW capacity.

 

A 10kwh battery is around £2500 (a fox ess home battery)

 

A 13kw stiebel eltron instantaneous water heater is around £400.  So say £3k for a battery DHW solution equivilent to a 150l cylinder.

 

A 300l equivilent woukd cost about £5,500 (vs maybe £1,500)

 

So the batteries cost more.... But you could combine it with a small inverter it could provide home electricity storage to help lower bills by time shifting cheap electricity so your HP (and house) could use more cheap rate electricity from a tariff like Octopus Cosy. 

 

Given the cheap HP rates are about half normal ie about 2x gas prices it should make being cheaper than gas very easy whilst making the install much easier and quicker

 

We just need batteries to come down a tiny bit more.

 

 

[DamonHD]

If you don't care about paying to heat your water at electricity kWh rates rather than gas, or electricity/CoP with a heat pump, there already exist some more compact (energy dense) solutions such as the Sunamp Thermino.  I now have a 150l water tank with the heat pump and an equivalent-ish Thermino 150 beside it for capturing PV diversion, and the Thermino is less than half the size of the tank, and conveniently squareish, and with about half the rated standing losses...

 

That is, where space is at a premium and DHW is a small fraction of energy footrpint then there are already solutions, including in stealth R&D that I know of!

Edited February 24 by DamonHD

[JohnMo]

When I lived in Singapore the apartment had small local storage cylinders with heating element. So one in kitchen and one in the wall for showers and sink. For showers gave the same experience as an UVC shower. Near instant heat.

 

Having a big cylinder isn't the only solution, storing small amounts of hot water and only heating what you use is a better solution, better than instant heater.

[JamesPa]

3 hours ago, JohnMo said:

Having a big cylinder isn't the only solution, storing small amounts of hot water and only heating what you use is a better solution,

... particularly if its a long run from tank to outlet.  To get hot water to flow in my kitchen I have first to drain 9l of cool water from the pipework.  If Im using less than 9l of hot water at a time, which is likely, a COP of 2 at generation stage becomes a COP of less than 1 at point of use.    

 

 

 

 

Edited February 24 by JamesPa

[Beelbeebub]

3 hours ago, DamonHD said:

If you don't care about paying to heat your water at electricity kWh rates rather than gas, or electricity/CoP with a heat pump, there already exist some more compact (energy dense) solutions such as the Sunamp Thermino.  I now have a 150l water tank with the heat pump and an equivalent-ish Thermino 150 beside it for capturing PV diversion, and the Thermino is less than half the size of the tank, and conveniently squareish, and with about half the rated standing losses...

 

That is, where space is at a premium and DHW is a small fraction of energy footrpint then there are already solutions, including in stealth R&D that I know of!

The sunamp is an option though that would have be installed inside and they are super heavy.

 

Cost wise they are about half way between a cylinder and a battery.

 

The batteries can be installed outside or anywhere really and can provide more functions than any pure thermal storage solution eg uninterrupted power supply, time shifting all electrical demand, solar input. As has been mentioned it could also get around the "cold leg" issue for large/awkward properties. It also offers the possibility of easy increace in hot water storage by simply adding another battery

 

The key thing would be to get the BUS grant to apply in cases where the HP isn't the sole hot water source and/or to reduce the price of batteries.

[sharpener]

23 hours ago, Beelbeebub said:

A 150l cylinder stores about 10kwh of energy (4.2kj x {65-10} x 150 /3600)

 

So a 10kwh battery would have roughly the same DHW capacity.

 

 

This is the bit where it goes slightly wrong. Yes the energy stored in the cyl is ~10kWh from stone cold. But the water is not useful below 30 or 35 deg so in practice the useful stored energy is a bit over half that.

 

Whereas the energy in the battery is available at any temp you want which is in its favour. The problem is with the power, most battery systems are power rated for ~ 2 hour charge/discharge so you would get ~ 5kW out (i.e. 100A at 50V), this is not enough for an instantaneous shower.

 

23 hours ago, Beelbeebub said:

So the batteries cost more.... But you could combine it with a small inverter it could provide home electricity storage to help lower bills by time shifting cheap electricity so your HP (and house) could use more cheap rate electricity from a tariff like Octopus Cosy. 

 

Yes, I installed a 5kVA inverter/10kWh battery 2 years ago. But now I have put in a 12kW HP as well, the battery is too small to bridge the 3 hr evening peak period even with tricks like having the HP in noise reduction mode then. 

 

(Would be worse still if we didn't cook on an AGA. In summer we use an electric cooker, I had to increase the battery from its original 7.1 kWh to 10.65 as it would not survive cooking supper.)

 

However the economics seem quite good as the battery makes 3 round trips every 24 hours.

Difficult though to justify doubling the battery capacity just to meet peak demand in the depths of winter. Outside the heating season and with 7kW of PV, 10kWh is more than enough to power the house from sundown to sunup. Even yesterday as it was nice and sunny we managed to export 25kWh.

 

BTW I would not like to be wholly dependent on the electricity supply. It is nice to know the AGA will keep alight come what may, we also have some oil lamps and the bedroom is over the kitchen so never gets truly cold.

 

 

Edited February 25 by sharpener

[Beelbeebub]

3 hours ago, sharpener said:

This is the bit where it goes slightly wrong. Yes the energy stored in the cyl is ~10kWh from stone cold. But the water is not useful below 30 or 35 deg so in practice the useful stored energy is a bit over half that.

Isn't the point that a UVC stays relatively well stratified when discharging so if you have 150l of 65C water you get most of that at 65C before the last little bit drops off due to mixing?

 

This was one of the arguments against thermal stores for HPs. 

 

Yes, a good chunk of batteries only output 0.5C ie a 10kwh battery only puts out 5kw, which would mean having to install (and pay for) a larger capacity. This does make the economics a bit worse. 

 

But a larger battery of 20-30kwh would give enough storage to run a HP through the peak periods meaning it would be plausible to install a 20kwh battery, 12kw HP and 10kw instant boilers.  That may be alot quicker to install and every day is £750 in labour minimum. 3 days saved coukd be £2k plus saved on the install which is a good chunk of the materials difference 

[SteamyTea]

2 hours ago, Beelbeebub said:

0.5C

Just to clarify.

A C is for coulomb, which is an amp-second, As.

 

But

2 hours ago, Beelbeebub said:

kwh

Is nonsense.

As is

2 hours ago, Beelbeebub said:

kw

Units matter.

[sharpener]

4 hours ago, Beelbeebub said:

Isn't the point that a UVC stays relatively well stratified when discharging so if you have 150l of 65C water you get most of that at 65C before the last little bit drops off due to mixing?

 

Yes I think you are right, I was confusing this scenario with my thermal store where recirculating the water through the rads ceases to be useful when the temp has dropped by about a half.

 

4 hours ago, Beelbeebub said:

Yes, a good chunk of batteries only output 0.5C ie a 10kwh battery only puts out 5kw, which would mean having to install (and pay for) a larger capacity. This does make the economics a bit worse. 

 

1 hour ago, SteamyTea said:

A C is for coulomb, which is an amp-second, As.

 

Usage of C/n to denote charge rate as a fraction of rated capactity of batteries is unfortunately long established so I fear that ship has sailed.

 

4 hours ago, Beelbeebub said:

But a larger battery of 20-30kwh would give enough storage to run a HP through the peak periods meaning it would be plausible to install a 20kwh battery, 12kw HP and 10kw instant boilers.  That may be alot quicker to install and every day is £750 in labour minimum. 3 days saved coukd be £2k plus saved on the install which is a good chunk of the materials difference 

 

20kWh of batteries would in rough terms occupy about the same space as an UVC. Also to be able to charge in the shortest (2hr) Cosy window you would have to charge at 10kW as well, this has quite big implications for mains intake capacity (no, not in Farads @SteamyTea!). I was lucky in that my DNO was OK with a 7kW EVCP, 12kW (thermal) HP, 7kW PV and an unrestricted 5kVA inverter all on an 80A fuse (which I can't increase bc of the 16mm^2 meter tails that go through a thick stone wall).

 

WPD used to have a policy of offering free uprating to 100A but I read recently that under NGED they are no longer doing this, IIRC you will have to pay for a 3-phase upgrade now.

[SteamyTea]

4 minutes ago, sharpener said:

C/n to denote charge rate as a fraction of rated capactity of batteries

From https://www.energyowned.com/battery-c-rating-explanation-and-calculation.html

 

How To Calculate The C Rating For The Battery?

A battery’s C rating is defined by the time of charge and discharge.

C-rate is an important information or data for any battery, if a rechargeable battery can be discharged at that C rating, a 100Ah battery will provide about 100A, then the battery has a discharge rate of 1C. If the battery can only provide a maximum discharge current of about 50A, then the discharge rate of the battery is 50A/100Ah=0.5C.

C-rate (C) = charge or discharge current in amperes (A) / rated capacity of the battery(Ah)

Therefore, calculating the C rating is important for any battery user and can be used to derive output current, power and energy by:

Cr = I/Er

Er = Rated energy stored in Ah

I = Charge/discharge current in A

Cr = C rate of the battery

t = Charge/discharge duration

Calculate charge and discharge time

t = Er / I

100Ah Lithium Battery C Rate Example

For same 100Ah lithium battery,

1C means 100Ah*1C=100A discharge current available.

1C means 100Ah/100A=1 hours discharge time Capable.

It means the battery can be use for 60minute (1h) with load current of 100A.

2C means 100Ah*2C=200A discharge current available.

2C means 200Ah/100A=0.5 hours discharge time Capable.

It means the battery can be use for 30minute (0.5h) with load current of 200A.

0.5C means 100Ah*0.5C=50A discharge current available.

0.5C means 100Ah/50A=2 hours discharge time Capable.

It means the battery can be use for 120minute (2h) with load current of 50A.

Sometimes analyzer capacity readings are given as a percentage of the nominal rating. For example, if a 1000mAh battery can supply this current for about 60 minutes, read 100%. However, if the battery lasts only half an hour before the cut-off point, the displayed value is 50%. Sometimes a brand new battery can provide more than 100% capacity. The battery can be discharged using an analyzer which allows you to set your favorite C rate. If the battery is discharged at a lower discharge rate it will show a higher reading and vice versa. However, you should be aware of differences in battery analyzer capacity readings for different C rates, which are related to the internal resistance of the battery.

[Beelbeebub]

3 hours ago, SteamyTea said:

Just to clarify.

A C is for coulomb, which is an amp-second, As.

 

But

Is nonsense.

As is

Units matter.

Yes they do. 

 

I reread my post and the units were correct (aside from capitalisation - which is an artifact of using a touch keyboard making capitalisation time consuming) 

[Beelbeebub]

2 hours ago, sharpener said:

 

Yes I think you are right, I was confusing this scenario with my thermal store where recirculating the water through the rads ceases to be useful when the temp has dropped by about a half.

 

 

 

Usage of C/n to denote charge rate as a fraction of rated capactity of batteries is unfortunately long established so I fear that ship has sailed.

 

 

20kWh of batteries would in rough terms occupy about the same space as an UVC. Also to be able to charge in the shortest (2hr) Cosy window you would have to charge at 10kW as well, this has quite big implications for mains intake capacity (no, not in Farads @SteamyTea!). I was lucky in that my DNO was OK with a 7kW EVCP, 12kW (thermal) HP, 7kW PV and an unrestricted 5kVA inverter all on an 80A fuse (which I can't increase bc of the 16mm^2 meter tails that go through a thick stone wall).

 

WPD used to have a policy of offering free uprating to 100A but I read recently that under NGED they are no longer doing this, IIRC you will have to pay for a 3-phase upgrade now.

The 2h window is just before midnight and then there is a 4h window just before "getup" time so most households would have 6h to charge.

 

But regarding power draw, the situation would be no different from an unvented cylinder. That can only charge at a specific rate, usually no more than 6kw (2 elements). Often only 3kw.

 

Except every bit of energy you put in can be transformed into whatever temp water you wish. Plus the standing losses are near zero, so even if you charge up your battery with 10kwh at 4pm, there will still be 10kwh to use at 10pm. Cylinder losses are typically 60w so about 1/3kwh in that same time. 

 

You also have the possibility of variable charging rates. So your system can monitor your overall draw and modulate it's charging rate to stay under your set limit. So if you put a kettle on, or the dishwasher kicks in, your battery can reduce it's draw. 

[sharpener]

13 hours ago, Beelbeebub said:

The 2h window is just before midnight and then there is a 4h window just before "getup" time so most households would have 6h to charge.

 

If you are running a HP you would probably want to fully cycle the battery in each of the 3 charging periods, on Cosy they are 0400 - 0700, 1300 - 1600, 2200-2359. Though IME the last one is the least useful for charging the battery or TS, but it does at least keep the real time cost down when the battery has run out of an evening.

In order to make full use of the idea, as well as the 20kWh/10kW battery pack you are going to need a 10kW inverter, they are neither small nor cheap.

 

[Beelbeebub]

29 minutes ago, sharpener said:

 

If you are running a HP you would probably want to fully cycle the battery in each of the 3 charging periods, on Cosy they are 0400 - 0700, 1300 - 1600, 2200-2359. Though IME the last one is the least useful for charging the battery or TS, but it does at least keep the real time cost down when the battery has run out of an evening.

In order to make full use of the idea, as well as the 20kWh/10kW battery pack you are going to need a 10kW inverter, they are neither small nor cheap.

 

The HP would be for heat, the battery for DHW (in this thought experiment) 

 

So your HP would run pretty much as is on the cosy type tariff.

 

The battery would run, pretty much as a cylinder would on the cosy tariff.

 

The major difference would be a HP charging a cylinder draws less than a battery charging (for an equiv amount of hot water delivered) so there is a downside there.

 

But the battery capacity could also be used to reduce the demand on normal and peak electricity.

 

Remember this stems from the idea of speeding up and simplifying the install by not having to fit a cylinder. If you already have an appropriate cylinder then the disruption is zero anyway.

 

But if your cylinder and piping isn't appropriate or, worse, you don't have a cylinder at all and just have a combi (say your combi breaks down and you just need a replacement ASAP). Then we get into the question of "how to replace a combi with a HP quickly and cheaply" the ultimate efficency can come later.

 

Fitting some batteries (prob nearthe HP) and a high power boiler should be quicker and less disruptive than fitting a cylinder.

 

Yes a 10kw inverter isn't cheap, but not super expensive either, under £1k is possible. Even £500.

 

Fogstar sell a 15kwh pack for £2.5kish. With a £500 inverter and a £300 boiler you are talking £3.5k for the kit to replace a combi with very little disruption inside. Add another 4k for a 6kw HP and some fancy controls to utilise the existing rads as well as possible and we have £7.5k of hardware to swap out a combi boiler without doing any work inside bar replacing the existing boiler box with an electric boiler and Adia hub. The cables and pipes exit via the flue hole to the batteries and HP outside. The only other inside work might be a chunkier cable to the "boiler" from the fuse box.

 

 

 

 

[JohnMo]

2 hours ago, Beelbeebub said:

The HP would be for heat, the battery for DHW (in this thought experiment) 

 

So your HP would run pretty much as is on the cosy type tariff.

 

The battery would run, pretty much as a cylinder would on the cosy tariff.

 

The major difference would be a HP charging a cylinder draws less than a battery charging (for an equiv amount of hot water delivered) so there is a downside there.

 

But the battery capacity could also be used to reduce the demand on normal and peak electricity.

 

Remember this stems from the idea of speeding up and simplifying the install by not having to fit a cylinder. If you already have an appropriate cylinder then the disruption is zero anyway.

 

But if your cylinder and piping isn't appropriate or, worse, you don't have a cylinder at all and just have a combi (say your combi breaks down and you just need a replacement ASAP). Then we get into the question of "how to replace a combi with a HP quickly and cheaply" the ultimate efficency can come later.

 

Fitting some batteries (prob nearthe HP) and a high power boiler should be quicker and less disruptive than fitting a cylinder.

 

Yes a 10kw inverter isn't cheap, but not super expensive either, under £1k is possible. Even £500.

 

Fogstar sell a 15kwh pack for £2.5kish. With a £500 inverter and a £300 boiler you are talking £3.5k for the kit to replace a combi with very little disruption inside. Add another 4k for a 6kw HP and some fancy controls to utilise the existing rads as well as possible and we have £7.5k of hardware to swap out a combi boiler without doing any work inside bar replacing the existing boiler box with an electric boiler and Adia hub. The cables and pipes exit via the flue hole to the batteries and HP outside. The only other inside work might be a chunkier cable to the "boiler" from the fuse box.

 

 

 

 

Or you just do a heat geek mini cylinder, install in the wall space taken up be combi. Piping is already there, for heating, cold supply and distribution of DHW. Then you comply with BUS requirements so you can get a grant. Cheaper and easier than any other options offered.

[Beelbeebub]

38 minutes ago, JohnMo said:

Or you just do a heat geek mini cylinder, install in the wall space taken up be combi. Piping is already there, for heating, cold supply and distribution of DHW. Then you comply with BUS requirements so you can get a grant. Cheaper and easier than any other options offered.

Reasonable point, but does the HG thermal store provide similar hot water volumes?  The HG mini stores that would replace a boiler are only 80l and the delivered hot water volume is less than that as the store can't deliver any useful heat once it gets below 40/45C

 

I know they say you can run the HP at the same time to extend the volume but I don't think that would work in winter with defrost etc.

 

The point abiut the bus grant is very valid though, which is why an adjustment so DHW can be via other means might be a good idea. This would make hybrid systems (which I guess this would be) and a2a systems eligible.

 

Whilst installing a full HP system with a SCoP of 5.0 in every house would be the ideal, it's unrealistic.

 

Heating is the majority of housing thermal demand. Electrifying that as much as possible would be a huge win and, as has been pointed out, a lot of boiler installs are "distress" installs where there isn't time for all the usual gubbins that goes with a "proper" HP install.

[JohnMo]

But looking at the flow rate of a 10kW electric heater, winter output at 41 degs is a pathetic 6 L/min. So on that basis an 80L equivalent would 18 mins without top up.

 

Zero outside here last night and around an hour between defrosting. So ample time for multiple showers or a bath fill.

 

Even if the a HG combi cylinder was an interim solution it's easy to do. If owner thinks it rubbish the solution is an UVC and they will need to allocate space. Electric showers were always pants, electric efficiency is still 100%, so would be no better, with an online heater instead.

25 minutes ago, Beelbeebub said:

Reasonable point, but does the HG thermal store provide similar hot water volumes?  The HG mini stores that would replace a boiler are only 80l and the delivered hot water volume is less than that as the store can't deliver any useful heat once it gets below 40/45C

 

I know they say you can run the HP at the same time to extend the volume but I don't think that would work in winter with defrost etc.

 

The point abiut the bus grant is very valid though, which is why an adjustment so DHW can be via other means might be a good idea. This would make hybrid systems (which I guess this would be) and a2a systems eligible.

 

Whilst installing a full HP system with a SCoP of 5.0 in every house would be the ideal, it's unrealistic.

 

Heating is the majority of housing thermal demand. Electrifying that as much as possible would be a huge win and, as has been pointed out, a lot of boiler installs are "distress" installs where there isn't time for all the usual gubbins that goes with a "proper" HP install.

 

Edited February 26 by JohnMo