Sunamp heat battery

[AndyT]

10 hours ago, Pete said:

Trying to get my head round all this. Now that Sunamp make a unit that will do DHW and UFH is there a need for an ASHP? I realise that the ASHP could provide a means of cooling a near Passive/Passive house and charging the Sunamp. I think I can cool my house quite considerably using the chimney effect and for when the sun is not shining how much will it cost to buy/install and maintain an ASHP and how much electricity could you buy with that amount to top up the Sunamp when the sun is not shining? I think as some are doing on here it may be a case of living in the house for a year and then deciding if we need an ASHP to supplement the Sunamp.  I am waiting for a quote from Sunamp so hopefully it may become clearer then.?

@Pete do you already have solar PV? If so then i can do a monthly off-set analysis

 

As I showed @Nickfromwales today one client was hell bent (with a PH build) on having 14.3kWp of PV on his roof.

I worked out his DHW and space heating loads and realised he was short by 18.3kWh per day in Jan and Dec, and 3.6kWh per day in Feb.

The rest of the year there was a surfeit of generation.

 

My 1st question back to the consultant was "do you really think the client needs an ASHP?" thinking an electric towel rail or two would be able to make up the difference if really needed.

18kWh a day for 60 days = 1080kWh at 7.7pkWh off-peak = £81

With an ASHP typically costing £9k fitted, £9000 /£81 = 111 years!!

 

Consultant replied saying client would be informed of my observations, but might still want to have the ASHP installed. ? 

[Pete]

1 hour ago, AndyT said:

@Pete do you already have solar PV? If so then i can do a monthly off-set analysis

 

As I showed @Nickfromwales today one client was hell bent (with a PH build) on having 14.3kWp of PV on his roof.

I worked out his DHW and space heating loads and realised he was short by 18.3kWh per day in Jan and Dec, and 3.6kWh per day in Feb.

The rest of the year there was a surfeit of generation.

 

My 1st question back to the consultant was "do you really think the client needs an ASHP?" thinking an electric towel rail or two would be able to make up the difference if really needed.

18kWh a day for 60 days = 1080kWh at 7.7pkWh off-peak = £81

With an ASHP typically costing £9k fitted, £9000 /£81 = 111 years!!

 

Consultant replied saying client would be informed of my observations, but might still want to have the ASHP installed. ? 

No PV installed at the moment. All to be decided when we choose Sunamp, Sunamp/ASHP or Sunamp/Genvex as has been thrown in the mix!!

[Triassic]

19 hours ago, Pete said:

I  realise that the ASHP could provide a means of cooling a near Passive/Passive house and charging the Sunamp. I think I can cool my house quite considerably using the chimney effect 

We live in a well insulated cabin and when it’s never been too hot inside, it’s warm in winter and cool n summer. If we want ventilation we open a door or a window. A Sunamp doing both the DHW and UFH would be the simplest approach, couple these with a PV array and a pre heat buffer vessel fitted with immersion heaters using excess PV and your done!

[Gone West]

14 hours ago, Russdl said:

Can the Genvex hot water temperature be dialled down to make it more suitable for UFH and as a pre-heat to a Sunamp and if so what are the reasons why such a set up would be ridiculous (price alone? I bet there are more) 

 

I guess the Genvex would have to go to a higher temperature every so often to prevent Legionella?

 

Standing by...

 

 

The Genvex Combi hot water temperature can be set to between 0C and 55C using the EASHP and increased to 65C by use of the immersion if required.

[Nickfromwales]

33 minutes ago, PeterStarck said:

The Genvex Combi hot water temperature can be set to between 0C and 55C using the EASHP and increased to 65C by use of the immersion if required.

Does the space heating suffer whilst the hot water is regenerating?

[Russdl]

Thanks for that information @PeterStarck. Good question @Nickfromwales. 

 

If a Genvex Combi feeding a Sunamp isn't a ludicrous suggestion it seems to me that it would be quiet an elegant solution to all the DHW and ventilation needs of a home.

 

 

[PeterW]

5 minutes ago, Russdl said:

Thanks for that information @PeterStarck. Good question @Nickfromwales. 

 

If a Genvex Combi feeding a Sunamp isn't a ludicrous suggestion it seems to me that it would be quiet an elegant solution to all the DHW and ventilation needs of a home.

 

 

 

I doubt it could cope - the heat output isn't massive on them and you would be quicker with a small mono backed up with immersions

[Russdl]

Sorry @PeterW, 'small mono' what is that?

[Nickfromwales]

1 minute ago, Russdl said:

Sorry @PeterW, 'small mono' what is that?

Monoblock ASHP

[Russdl]

@Nickfromwales Doh!  Thanks. 

 

@PeterW 

17 minutes ago, PeterW said:

I doubt it could cope - the heat output isn't massive

 

But would it need a massive heat output as the Sunamp (in my theoretical set up) would be boosting the DHW temperature?

[PeterW]

Sorry !!

 

For those that don't need the eRp rating stuff, there are loads of brand new 5kw and 9kw Heat pumps on ebay at the moment for less than £1k delivered.

[PeterW]

Just now, Russdl said:

@Nickfromwales Doh!  Thanks. 

 

@PeterW 

 

But would it need a massive heat output as the Sunamp (in my theoretical set up) would be boosting the DHW temperature?

 

To "melt" the PCM58 you need to output a temperature higher than the phase change temp - that is the limiting factor

[Triassic]

6 minutes ago, PeterW said:

Sorry !!

 

For those that don't need the eRp rating stuff, there are loads of brand new 5kw and 9kw Heat pumps on ebay at the moment for less than £1k delivered.

Less than £1k delivered! But which make would you recommend?

[Russdl]

1 minute ago, PeterW said:

To "melt" the PCM58 you need to output a temperature higher than the phase change temp - that is the limiting factor

 

Ah, I think I've spotted where we are diverging here. My theoretical system is a:

 

Genvex Combi producing hot water at a suitable temperature for the UFH whilst also dealing with the MHRV requirements of the house.

 

Sunamp being charged by Solar PV and off peak electricity.

 

The Genevex providing pre heated water to the Sunamp (instead of a cold supply) so that the Sunamp has less to do to get the temperature up to that required for DHW.

 

Is that what you understood by my original question?

[PeterW]

4 minutes ago, Russdl said:

Genvex Combi producing hot water at a suitable temperature for the UFH

 

That won't work..... You need a constant flow at 34-36c and I doubt a Genvex can do that

[PeterW]

7 minutes ago, Triassic said:

Less than £1k delivered! But which make would you recommend?

 

Pick one.... for less than the price of a cheap combi, you can pick any of them in reality as most are chinese made. Something with an inverter driven fan would be preferable along with some sort of controller but essentially you can run them pretty constantly anyway and there is not a lot in them to go wrong.

[PeterW]

Fairland Orilux 8.2Kw

 

Change of £800 and takes offers... CoP figures don't look too bad either, comes with its own controller too

[Onoff]

19 minutes ago, PeterW said:

Fairland Orilux 8.2Kw

 

Change of £800 and takes offers... CoP figures don't look too bad either, comes with its own controller too

 

At that money is it worth ditching an oil boiler even in a draughty old house?

[Nickfromwales]

2 hours ago, Nickfromwales said:

Does the space heating suffer whilst the hot water is regenerating?

I suppose I should have added : IF the combi is being used for space heating and there's no UFH. That's typically what the 185 is aimed at. 

[PeterW]

12 minutes ago, Nickfromwales said:

I suppose I should have added : IF the combi is being used for space heating and there's no UFH. That's typically what the 185 is aimed at. 

 

So it prioritizes hot water... And its heat input into the air is quite low - shade over 2kw at 160 m3/h so that isn't going to warm a place quickly, this is aimed at low energy houses.

 

Combi 185 BP is suitable for dwellings, where a high heat recovery rate and a low energy consumption are requested, while energy of the extract air is used to heat the supply air and the domestic hot water. The energy is recovered in the counterflow heat exchanger first and then the heat pump uses the residual energy. Combi 185 BP can deliver an air volume of up to appr. 325 m3/h at an external pressure of 100 Pa.

 

http://www.genvex.dk/en/wp-content/uploads/2017/07/COMBI_185-BP_UK_print-1.pdf

 

 

[ProDave]

36 minutes ago, Onoff said:

 

At that money is it worth ditching an oil boiler even in a draughty old house?

Only if your whole house can be heated in the depths of winter with less than 8KW and at low temprature (UFH or low temperature rads)  I suspect in the middle of winter your oil boiler is working a lot harder than that.

[AndyT]

Sunamp PCM34 is now back on and I am advised that Andrew Bissell will be releasing a letter as a follow up to the previous letter later in July once he returns from his holiday.

This is all I know for now.

Kind regards

For and on behalf of Sunamp Ltd.

AndyT.

[newhome]

1 hour ago, Onoff said:

 

At that money is it worth ditching an oil boiler even in a draughty old house?

 

I've toyed with getting one TBH as I'm on all electric here at the mo but I'm not sure whether the cost vs performance would add up. Mind you after all the effort it took to get my heating working I may be better leaving things be . 

 

[PeterW]

15 minutes ago, newhome said:

 

I've toyed with getting one TBH as I'm on all electric here at the mo but I'm not sure whether the cost vs performance would add up. Mind you after all the effort it took to get my heating working I may be better leaving things be . 

 

 

 

ASHP ..?? I’d consider it ..! Set it to 42 and put it into the bottom of the tank and then let the boiler just do the top up ... 

[le-cerveau]

12 hours ago, Russdl said:

The Genevex providing pre heated water to the Sunamp (instead of a cold supply) so that the Sunamp has less to do to get the temperature up to that required for DHW

Use a PCM34 UniQ fed from Genvex as a buffer for UFH and DHW pre heat, the cells take water at 45C.  (This is what my ASHP does).

The PCM58 cells do the hot water top up.