Discussion ... ASHP(Air/Air) with Solar pv ....

1961Nick

mmmmikey wrote: »

Just wondering - what are batteries made of and when does it run out........?

Lithium, nickel, copper & cobalt. Nickel & cobalt seem to to the primary concern at the moment. More than half of the cobalt comes from the DRC which is clearly not the most stable part of the world.

Martyn1981

JKenH wrote: »

Even if domestic battery prices remain static they will make more financial sense both for home consumption and trading if TOU prices become more volatile.

Yep, they will make much more sense, but ...... if one large batt is then installed in your area by a smart investor, an energy supplier, or the DNO, and "all the best laid plans of mice and men often go awry."

joefizz

Martyn1981 wrote: »

Yep, they will make much more sense, but ...... if one large batt is then installed in your area by a smart investor, an energy supplier, or the DNO, and "all the best laid plans of mice and men often go awry."

All of the above.
I mentioned, over on the battery thread, going to an electricity generators conference last year where distributed storage was all the talk and presentations on trials and small scale implementations.
There was also a few presentations on brexit and network security and I came home and ordered the battery but thats a side issue!


TOU was a bit hazy as theres no requirement for smart meters here in NI but in side discussions it did seem that eventually that would be the way forward, if billing was capable (its the billing bit that slows everything down - ever notice why some telcos offer free calls over long weekends when they are upgrading their systems - because they cant do that and log calls at the same time). If billing does become capable then its down to how granular they want to go. Its definitely bye bye to E7 in the long run, when you will be billed according to what it actual costs to produce at that particular time. There will probably also be a carbon tax tie in as well which will be over and above the TOU tariff (or just display as a surcharge).


Will make it interesting if they have to kick in gas/coal (yes coal hasnt been ruled out in the future if nuclear needs to ramp down suddenly - a la germany) overnight whilst all those EVs are charging, or ashps running during winter with no wind....
...it might also be regional, so overall grid may not count in billing but rather your local mix...
The EVs TOU will be a given for anyone who installs a connected fast charger (why one of my mates with an EV put in a 3kw dumb charger). Easier to bill that directly and separately. The fuel tax extras will have to come from somewhere, although may just be different VAT for electricity used as car fuel to home use.



As I mentioned over on the battery thread, its no coincidence the pylontechs come in a standard equipment rack form factor.... ...easy to co-locate at your local substation.

JKenH

JKenH wrote: »

The wife has been away helping with grandchildren Monday to Friday so I managed without any central heating and a 20/21C room temperature. Result was 11.1kwh used over 27.7 hours equals exactly 400 watts/hour. I was quite surprised at that but with less usage per day it spends a greater proportion of its time getting up to temperature and less time at a steady temp. Now the wife is back we have to have the oil C/H on for 1 hour in the morning on to dry towels etc. I also have had the kitchen ASHP at the other end of the house on for half an hour at breakfast and the occasional half hour at tea time. I only have one power meter so can’t monitor usage on both.

I can’t do it all on solar but at least I have the satisfaction this time of year of using all the solar I can generate with the ASHP, IBoost and cooking. I would love a battery but I could only use about 4kwh /day use of stored solar PV in summer and winter would be entirely from E7. I need to do the sums on TOU tariffs but how long will they stay cheap if BEVs take off?

Update 14 October: I ran the 3.5kw ASHP for heating continuously for 12.5 hrs today achieving/maintaining a temperature of 21/22C from a 19C start in a 38 sqm room.Outside temperature 6-12C. Used 3.4 kWh which works out an average of 272 watts/hour. This evening with the door closed consumption was 500 watts over 2h40m - 187 watts/hour average or about 3p an hour.
I also ran the kitchen ASHP for about 10 hours today and a few hours yesterday. I don’t have the facility to monitor power on both but despite two miserable days have avoided putting the CH on even though the wife is at home.
Update 15 September: I ran the 3.5 kw ASHP for 17.1 hours today to see if longer running would reduce the average consumption but it didn’t. Used 6.1 kw average 357w/hr. I was surprised at that as the outside temperature was similar to yesterday and although the door to the hall stayed open all day and evening that wouldn’t account for difference. The last 10 hours averaged 295w and the extra was all used in the first 7 hours.

Just an update. W/C 4 November produced a poor result for our lounge ASHP of 41.2 kwh used over 80 hours- an average of 512 watts/hour. We had some colder weather that week and so the ASHP was less efficient. Consequently we used it less so when it was heating it was having to work harder.

This week it has averaged 337 watts.

Last night I forgot to turn the ASHP off and it has now been running continuously for 35 hours over which time it has used 9.4 kWh - an average of 269 watts/hour, with the door open for all but a couple of hours sustaining a temperature of 23C.This has worked well at heating the hall up (20C) and we have had no central heating on for the period the ASHP has been running. (The kitchen ASHP was on early morning and tea time). This has cost us 4.1p per hour daytime and 2.3p per hour on E7, about 86p per day, which seems pretty reasonable for a larger than average house. I am now inclined to just leave it running continuously (day and night) for the winter.

ASavvyBuyer

Been a while since anyone posted on this thread, but thought I would use it to ask those that have installed ASHP what makes & models they have had installed.

We are looking to get another ASHP installed at the other end (kitchen) of our bungalow, once the lockdown is over.

I have been looking at the specs for various models and although very happy with the Toshiba unit we have in the lounge, there now appears to be a few other makes & models with similar efficiency (Midea, Panasonic, etc) at a lower cost.

What sort of COP are people getting from the units they have installed?

JKenH

ASavvyBuyer said:

Been a while since anyone posted on this thread, but thought I would use it to ask those that have installed ASHP what makes & models they have had installed.

We are looking to get another ASHP installed at the other end (kitchen) of our bungalow, once the lockdown is over.

I have been looking at the specs for various models and although very happy with the Toshiba unit we have in the lounge, there now appears to be a few other makes & models with similar efficiency (Midea, Panasonic, etc) at a lower cost.

What sort of COP are people getting from the units they have installed?

 I have Mitsubishi Heavy Industries SRK20ZS and SRK35ZS wall mounted ASHPs.

Below is a link to the technical manual if you are interested.
https://condex.bg/wp-content/uploads/2016/manuals/SRKxxZS.pdf
Page 91 gives the COP figures at various external temperatures with a maximum of 7.8 at 12C outside and 20C inside (if I have understood that correctly).

 

joefizz

Ive a cheap chinese electriq eIQ-9WMINV. Cost less than 500 quid IIRC.

I dont put much store in COP figures but its rated at 4 for a band of temperatures and produces good output in that range. Where it does fall down (why its cheap) is that its min operating range is effectively around 5C, so below this its no more effective than an infra red heater used in one room as it seems to spend half as much energy heating the outside unit as it does inside, coupled with air flow etc. Ive also had to install it on a north west facing wall which isnt ideal either, so unlike last year with the lower overnight temperatures so far this year its only really been on overnight this past week.
The spec sheet says its rated down to -7C but
As an example I used around 60% of 9.6kw battery one day last week running it overnight with temperatures in mid single figures outside, this time last year with low double figures outside it was around 15-20% drop overnight, which is what you would expect really.
The air con function this week has been more useful!

gabitzul

I have a Midea one, cheap as chips (£399 I believe), self fitted and just called a local company to leak test and certrify (another £90).

Really happy with it, supposed to be A++. Have solar panels so it was a no brainer really.

JKenH

Just an update, actually a bump, to keep the thread alive for anyone considering air to air heat pumps. Last Friday I plugged our living room ASHP into the Engenie meter again (now we are on the Octopus Go tariff) to check the cost of running the heater. 

I have been using the ASHP during the day between the CH switching off after breakfast and coming on before tea to soak up any spare solar in preference to it being diverted to heat water (which is now done overnight at 5p/KWh). I don’t know just how much of the usage has been covered by solar but over 60 hours the Engenie (set to the daytime tariff of 13p/hr) has recorded consumption at the plug of  £1.79 or 3p/hr which equates to 230 watts per hour maintaining a room temperature of 23*C. It has been quite a mild week here so the COP will have been quite high.

mickyduck55

Whenever I enquire about Air/Air HP no one seems interested in installing.. plenty happy to quote for Air/ Water.  Farnham Surrey area