Convert a solar DHW tank (or fuel oil) into a thermodynamic water heater with a small swimming pool heat pump

[Christophe]

the water arrives preheated at the moment at 26°C... but 1 month ago it was at 18°C...

Is it the water that comes in when you draw hot water? Doesn't matter if you don't draw water during a measured cycle.
Strangely, it does not change the duration of the cycle of 6 hours?

The heat pump when running consumes 650W

Wh no?

4 cycles of about 30 min...

What is the 6 hours then?

Finally?

It was you who said 6am, not me!

6 hours is between 2 starts...

[Christophe]

4 cycles of about 30 min...

What is the 6 hours then?

If I understood everything, it's about 30mn walk from the CAP, then about 6h stop, then 30mn walk, ..etc...
As for the W and Wh, you're exaggerating a little... It "consumes" 650W, but over 1/2h it would be around 325Wh.
A bit like a car that consumes 6,5l/100km but only does 50km....

Yes he exaggerates...Ah the ravages of spikes...

[izentrop]

4 cycles of about 30 min...

What is the 6 hours then?

If I understood everything, it's about 30mn walk from the CAP, then about 6h stop, then 30mn walk, ..etc...
As for the W and Wh, you're exaggerating a little... It "consumes" 650W, but over 1/2h it would be around 325Wh.
A bit like a car that consumes 6,5l/100km but only does 50km....

A yes I had forgotten that the probe was in the wind of the fan. At the same time what a funny idea.

For the half power, I didn't stay, I still know how to divide by two. We will trust that it is the average power, but the compressor does not run all the time. An energy measurement would be preferable.

I remain convinced that a measurement at the top of the balloon or better placed would make it possible to realize the real transfer of energy to the water, because there we know nothing about it since the duration of the cycle is not affected.

[Christophe]

Yes, on this model, no inverter, the compressor runs all the time "at full" (ON cycle)...

Frankly izi, it works, do we need to jerk off the flies with ultra-precise measurements?

[sicetaitsimple]

Frankly izi, it works, do we need to jerk off the flies with ultra-precise measurements?

I quite agree...However, it would still be necessary to quantify once and for all the effect of the flow rate of the circulator and to find the "best". We have both talked about it extensively on the preceding pages, I do not feel that the conclusion is given.
You stick to your idea that a minimum flow will promote "GOOD" exchanges in the coil, I am absolutely not convinced, there is an optimum to be sought.

[Christophe]

Frankly izi, it works, do we need to jerk off the flies with ultra-precise measurements?

I quite agree...However, it would still be necessary to quantify once and for all the effect of the flow rate of the circulator and to find the "best".

That I agree and the test is in progress...response in 2 days on the duration between cycles for the difference between the average and low speed!

[Christophe]

So the point after a few days of measurements with low speed of the circulator and sampling at 5 minutes :

a) the number of daily cycles is almost unchanged, but it seems that there is a slight improvement, on some days I have 8 or even 9 hours between 2 cycles...but it still depends "a little" on the ECS that we shoot too ...

Here is a day with 3 cycles on the kWh (each peak is at 0.27, 0.3, 0.3 kWh or 25 to 27 min cycle at 650W consumption of the heat pump):

Screenshot_20230309-104833_Smart Life.jpg (155.65 KiB) Viewed 121 times

b) I have a more precise measurement of the temperature indicating the duration of the cycles, PAC ON: I estimate it between 20 minutes and 30 minutes but I have to compare with another speed under the same conditions...

I put the circulator on high speed.

[izentrop]

I have a more accurate temperature measurement

Where do you take it?
Is there no housing for a thermal probe in the volume of water in the tank heated by the heat pump?

Otherwise, note the HP return temperature at the start and end of the cycle could already provide some information on the real efficiency.

[Christophe]

More accurate via 5 min sampling instead of 30 min ambient temperature measurement! Must follow a little huh!

Of course I have thimbles but they are used for thermostats...

[Christophe]

Otherwise, note the HP return temperature at the start and end of the cycle could already provide some information on the real efficiency.

Already done, see above...