ECODAN , can I run just the heating without DHW?

Swizz

Thank you for your helpful suggestions. Thankyou for the concern regarding extra jumpers, and the advice to get stuck in. I will stop lounging about and make more of an effort .
I have a 12kw ecodan system. The EPC for the property is C. We live in south Devon, with a lot of sun. We have  solar panels producing around 4kw. We do not have a smart meter by choice, and are happy with that for various reasons that are beneficial to us.

I have upped the WC curve by plus 2, and am monitoring that. On a sunny day, our solar gain upstairs in our living area means it is often too hot with that WC, like today...but sunny hours not much, so don't want to fiddle with it. Last 24 hours consumption a big better, but COP still only around 2

I watched the freeze stat video, but in this cold spell will leave, as anti freeze low..

I have a feeling things could be better, and I can assure you I'm engaging as best as I can and really do appreciate the helpful advice. Bearing in mind that we didn't appreciate exactly how ASHP works, as the installer didn't really tell us., I have learnt a lot recently. 

Right, off to remove the 4th jumper I put on this morning

Reed_Richards

Do you not have a room thermostat that will reign-in your Weather Compensation when solar gain makes it too hot?  Of course that could make it too cold in other parts of the house that don't get the sun but maybe you can live with that.  Some heat pump enthusiasts favour a hard core approach where you rely entirely on Weather Compensation to give you the right temperature but this approach ignores the possibility of solar gain so it doesn't work for everyone.   

MultiFuelBurner

Swizz said:

Thank you for your helpful suggestions. Thankyou for the concern regarding extra jumpers, and the advice to get stuck in. I will stop lounging about and make more of an effort .
I have a 12kw ecodan system. The EPC for the property is C. We live in south Devon, with a lot of sun. We have  solar panels producing around 4kw. We do not have a smart meter by choice, and are happy with that for various reasons that are beneficial to us.

I have upped the WC curve by plus 2, and am monitoring that. On a sunny day, our solar gain upstairs in our living area means it is often too hot with that WC, like today...but sunny hours not much, so don't want to fiddle with it. Last 24 hours consumption a big better, but COP still only around 2

I watched the freeze stat video, but in this cold spell will leave, as anti freeze low..

I have a feeling things could be better, and I can assure you I'm engaging as best as I can and really do appreciate the helpful advice. Bearing in mind that we didn't appreciate exactly how ASHP works, as the installer didn't really tell us., I have learnt a lot recently. 

Right, off to remove the 4th jumper I put on this morning

If your solar was put in and your EPC was only a C after that then it's likely you are loosing a lot of heat. What age is the house and what extra insulation have you performed?

What does the EPC say about kwh to heat the house? And square m of the property?

As asked before what did the MCS certificate state?

Reed_Richards

Yes, @Swizz, you really should have access to more information than you have given us so far and those of us following this thread are experiencing varying degrees of frustration about this.  Without the context of this information it's difficult to know what to advise.  I also have a 12 kW heat pump.  It was a requirement when installed that the heat pump had a dedicated electricity meter so I can tell you exactly how much electricity it has used for the last 3 years but would that help without knowing how your expected heat loss compares to mine?

Swizz

Good morning
Re using the room stat for overriding the WC when very sunny , yes, we've been doing that, although I thought it was supposed to be less efficient.

So, I've dug out stats. According to our ofgem account, we have an estimated 1109.36 kWh heat use, with a seasonal performance factor of 3.28

We have an area of 122sqm
EPC says 13,004kwh heating requirement
129kwh/SQM

After I raised WC by plus 4, energy consumption even worse.52kw for last 24 hours.

Again, I'm sorry if I've frustrated some of you

Reed_Richards

Swizz said:

Re using the room stat for overriding the WC when very sunny , yes, we've been doing that, although I thought it was supposed to be less efficient.

In my opinion there is a lot of dubious "information" around this.  The idea that you can do everything purely with Weather Compensation only works if you have a very well draught-proofed house that doesn't let cold air in when you go out - don't even think about ever opening a window.  And you must have a well-shaded house that doesn't get any significant solar gain - which would be a pity, because solar gain saves you money on heating.  If you allow your heat pump to be off when your house gets too hot that is not less efficient.  If you have your room stat about one degree higher than you want your room to be and if your Weather Compensation is well-tuned then the room stat just acts as a backstop and will only intervene when the room starts to become uncomfortably hot.    

Reed_Richards

Swizz said:

According to our ofgem account, we have an estimated 1109.36 kWh heat use, with a seasonal performance factor of 3.28

I think you have either lost a numeral or shifted the decimal point there.  The correct figure must be in the vicinity of 11000, not 1100.  It should be somewhere near your EPC figure which is 13000 kWh.

    

matelodave

The only way to improve your COP is to reduce the flow temperatures and possibly running the system longer so its no cycling. Raising the WC by 4 degrees could easily increase the energy consumption by around 10%

Perhaps if you gave us some info on your settings - flow temp, weather compensation slope and running times. By lowering the flow temp, tweaking the slope and running the system for longer but at a lower temperature you could probably improve the system efficiency.

Dont get hung up on COP figures, they are a snapshot of the performance at defined input and flow temperatures so when its cold and the flow temp is higher then the COP will be a lot worse than when its not so cold and the flow temp is lower.

Measuring stuff or randomly adjusting things when you dont really understand what is going on wont help you optimise the system but will upset you when you cant get the figures that you expect.

Your indoor temp, running times, outdoor temps, weather compensation slope and flow temps all have an effect on your system efficiency, cost, COP and comfort levels and so all need to be taken into account when tweaking or optimising your system.

So you should only adjust one thing at a time, leave the system a couple of days to settle down, record what you are doing, what effect it has and then do it again until you feel that the system is running at the lowest temp you can get away with without being cold or having extended reheat times.(As we are at home all day we dont have that problem) . The lower you can get the flow temp the better your efficiency will be  but it takes time to optimise.

We have our heating system running 24/7 with weather compensation controlling the house temperature. There is a set back on the w/c of 4 degrees overnight (21:30 to 06:00). The thermostats only shut the system off it if gets over warm, like in the lounge when the sun shines on it. Our max flow temp is 40 degrees when it -5 outside (and TBH the house temp does drop a bit when its that cold, but then we just up the W/C by a couple of degrees but it then resets itself the next day) Most of the time the flow temp is between 30-35 degrees.

I dont know what our COP is but I reckon we get through around 3500-4000kwh a year for heating plus a bit for hot water (our total leccy annual consumption is around 7500kwh).

My EPC comes out at a D for our 140m2 detached bungalow. And reckons we need 12500kwh a year for heating and 2750kwh for hot water.

If I did the sums on that basis allowing 4500kwh for heating and hot water against an EPC guess of 15250kwh we'd have a SCOP of 3.38 (SCOP is the annualised average COP rather than the instantaneous COP which I'm sure is pretty poor when its very cold).

We can easily end up chewing through over 60kwh in a day when its really cold but that's not everso often and I don't lose sleep over it. Last week our average leccy consumption (thats everything) was 39kwh a day, with the highest on Monday 49kwh (washing and tumble drying and the seagulls were skating on the frozen pond in the field behind our house)) and the lowest was 32kwh on Friday when it wasn't everso cold

Reed_Richards

Looks like this thread is fading away now.  But the last comment from @matelodave was excellent.

All I can say to help is that I also have a 12 kW heat pump but my property is bigger in area and my EPC predicts a higher heating requirement.  In the last two years my heat pump used about 5100 kWh in each year for heating and hot water in winter.  You should be able to achieve better than that.