Heat Pumps - post here.

Once you bring the heat pump flow temperature up past anything approaching hand hot, your heatpump is little more than an immersion heater.

My hot water is set to 48c and still gives a COP of 2.6, my underfloor heating flow temp is between 25-28c and gives a cop of 3.74.

I understand you are a dead set against heat pumps for some unknown reason.

I live in the real world and these are real world numbers from my house.

A little bit of self education and knowledge goes a long way.

Peace 😁

Mine is regularly above 4, even in winter.

Total power consumption in Feb was about 230kW and delivered a little under 1000kW.

March was 300 consumed and over 1200kW delivered.

DHW is set to peak of 45C and flow temp is usually between 26 and 29 degrees, depending on the outside temperature.

Thats really good. I looked at mine for those months.

Feb22 195 consumed, generated 763 3.91 cop

March22 66 consumed, generated 252 3.82 cop

Feb23 45 consumed, generated 190 4.22 cop

March23 17 consumed, generated 70 4.12 cop

I found this winter to be warm so didnt use near what we used in 2022.

These numbers are for house set at 21.5c and doesnt include hot water.

Yes, before I took the heatpump off "standard" settings, my ufh heating cop was 2.6's 😮 and kWh were almost double what they are now. So with tweaking, my cop rose to almost 4 and consumption of electricity halved.

On the default settings my flow temp would be between 35c-45c. Just bizarre for underfloor heating.

So I can understand some of the horror stories people have about heat pumps. One just has to be proactive and educate themselves a small bit. Or read Boards 😁

The Ecodan is made by Mitsubishi Electric, who have an office and sizeable support team in Dublin, and have had for over 30 years.

Samsung do not

Are you running it constantly or on off ? Last winter, first winter in the house i ran it on off with stats with loads of zones in my bungalow. After researching im going to open all loops and run from say 5am-9pm with over night set back. I also lowered my flow temp on the weather compensation graph as regularly it was giving 40deg flow temp, had big bills so hoping this winter will be much better. Think my commissioner didn't give a **** about my bills.

29 at minus 5 is very very good, Dont think i would get near that. My original wcc was 44 at -3. Just wondering do you have a lot of short loops in your house. Was thinking maybe my loops are longer,but doubt in a highly insulated new 242sqm bungalow i would get near that flow temp. Is house heating to 21deg?

Yeah maybe the longer loops require more floe temperature so, waiting to trial my new curve when weather gets colder, think i have it 38 at -5, hope that will get house to 21.

Pipe spacing in the loops is a key factor

What are yours: not just Keno but others

Plumber definitely knew better than the person designing the system from the manufacturer…

Just making the job simpler for him. Less loops; less terminations in the manifold; less places to leak…

Did you agree to let him cut corners?

always on ,but set back at 7pm, on again at 9am. House will lose .5c overnight on a very cold night. I tried it both ways but found set back was the best method (most economical) for our house. 1st winter was trial and error until we found the right balance.

Spacing is 150mm and all loops fully open downstairs. No heating on upstairs, so 1 zone.

At the end of the day, the heating is working, im not going to be tearing up floors to add loops and not going getting into a long court battle or something over it. More important things to care about i suppose. I havent tried always on method yet with overnight setback so im going to try this my 2nd winter and see how all goes.

All this talk about COPs it got me thinking and I was a bit board so I hit up Grafana and downloaded my Heat pump power usage for the last year and a bit and see could I plot the COP of my heat pump sucessfully. Anyway this is what I came up with and if its correct its very interesting in that the COP of the unit is lower during the summer months that the winter.....🤔

My initial toughts are that the HP is during the summer its heating the DHW and it has to work harder to reach the higher temps but during the cold months most of the work id space heating (eg underfloor) which is a lot lower than the DHW.

The chart below is the average daily COP but its based of 5 min data (excel was giving out with 1min data..) i discounted any 5 min data points with power input below 3000w as this was the unit ramping up and if I didnt do this then I was getting crazy COPs. My unit is a 12kW output Samsung Joule unit.

Just a qucik check with you people, to calculate the COP its bascially the power output/power input and you assume the unit when on is outputting 12 kW in my case. Just to make sure my sums are right??

The red line is the moving 7 day average just to smooth out the up and downs.

Winter COP 3.0 to 3.4 nearly and summer around 2.9

Thoughts

What temp do you have your hot water set to?

your heat pump prob breaks down the COP by heating and DHW. The average of the two should result in the number from your calcs.