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

[Christophe]

Ps: super happy with the delay too… on November 8th when I created this subject I didn't even know if it was possible to find a compatible cap !!

[Christophe]

The 1st COP optimization would be to gradually lower the pac max setpoint ... and see how far it is bearable in the shower

I think that under 37 ° it will be "hot" ..

[Christophe]

Installation invoice, excluding heat pump: € 252 including tax with an electronic circulator at € 166 ...

I could have reduced the costs to 200-210 € by doing everything in black or galvanized, by removing the vessel and the trap (see idea above) for example, I took 2 brass union fittings to make a cleaner assembly and avoid the efforts on the PVC fittings of the heat pump ... also I put brass sleeves to have a nice plan at the joints of the hoses ...

In short, despite all this, the whole cost me 500 € ... compared to 2000-3000 € excluding transport / installation of a thermodynamic balloon from 150 to 300L ...

Good now that the performances in COP follow! To be continued ... subscribe and put a blue thumb

[izentrop]

At the consumer level I have been at 2.7 kWh since Saturday evening (almost 48 hours) including the Sunday tests, 3 showers, 1 dishwasher connected to the DHW ...

Bravo Great , me only for the normal use to wash the hands and the dishes of the big utensils, no shower 2.5 kWh / 24 h.

I drained my 200 l cumulus and replaced the safety group (it was indeed the one that caused water hammers every time we closed a tap).
I took the opportunity to insert a polyurethane plate between it and the wall. For the rest of the insulation, I am waiting to make more measurements.
It took 18 kWh to bring it back to temperature.
Normally, raising the temperature from 15 to 65 °, it would have taken 9.3 kWh (40 x 200 x 1.162) https://www.ista.com/fr/ista/blog/combi ... 0Wattheure.
Super poor performance?

You say that the coil is intended for fuel oil (70 °) at 37 ° it would have made double in size.
I also wonder if a 100 l balloon would have been more than enough, see 50 l if the showers are taken at different times.

[Christophe]

Yes that's good but I'm still far from 5 of the promised COP eh (good not at 40 ° C okay but the hot spring is around 20 ° C ...) ... as said to see over time.

Do you have the ECS config exactly? Pure resistive? If so, there is no "return" normally except for the losses of the ball ...

[izentrop]

resistive at night, energy meter only on the balloon circuit.
Half the loss in the coupling of the soapstone resistance and the water, it's huge, I think

See also the end of my previous message

[Christophe]

Yes it's not normal ... have you calibrated your energy meter on a device for which you are on the power?

I have old ones who mess around seriously with the years ... in + or - sometimes it exceeds 50% error ... (old stock of PM230 from the site shop ... recall...)

Otherwise, are you sure about the volume of your balloon?

And depending on where the resistance is placed your calculation can be even worse ... in the balloon presented above it is at about 50% of the height and the thermowell of the thermostat 10 to 20 cm higher offset by about 30 ° on the shelf so it does not heat the bottom of the ball or only slightly ...

[Christophe]

You say that the coil is intended for fuel oil (70 °) at 37 ° it would have made double in size.
I also wonder if a 100 l balloon would have been more than enough, see 50 l if the showers are taken at different times.

Yes and no, the circulator will simply have to run longer to trigger the shutdown thermostat ... the exchanges are done all the same but it takes longer ...

Next week, when I have the consumption of the current config, I will set the CAP to 39 ° C without touching anything else.

For the volume of the balloon I only use half of it in the end, or even less, since the exchanger is in the upper part (and I think it goes down, I am even sure of it since I have no air pocket inside, checked when filling, see the position of the high point: the bleeder on yesterday's photos)

[Christophe]

Here I think it's this kind of config (from memory when I opened the hatch to check the resistance during installation ... in 2008 or 2009 ...) there are 2 interchange that overlap ( maybe not as much as in this diagram but that's the idea) ... with the additional resistance in the middle ...

From memory too, I have a perforated horizontal plate which intrigued me towards mid-height... a little lower than the electrical resistance I would say ... maybe to limit the stratification by increasing the speed of convection of the hot water from the bottom which would pass through the holes ???

5c5593d0c3ddd34c9de5fe85_ballon-150-500-ecs- dimensions.jpg (71.07 KiB) Viewed 851 times

A ball of this kind is still € 1500 new!

In short, it's tough, it was at the time when we didn't do shit that leaks after 15 years or less ...

[izentrop]

Yes it's not normal ... have you calibrated your energy meter on a device for which you are on the power? Yes

I have old ones who mess around seriously with the years ... in + or - sometimes it exceeds 50% error ... (old stock of PM230 from the site shop ... recall...)I have one and I posted about its big cos phi flaw. .. Sorry they stayed on your arms

Otherwise, are you sure about the volume of your balloon? Yes

And depending on where the resistance is placed your calculation can be even worse ... in the balloon presented above it is at about 50% of the height and the thermowell of the thermostat 10 to 20 cm higher offset by about 30 ° on the shelf so it does not heat the bottom of the ball or only slightly ...

The thermowell is at the bottom and is a good 80 cm. It is true that the rod of the probe is long.
If it does not heat up the whole volume, all the more reason for poor performance?

In addition, with the CAP, it is less justified the 200 L. We kept it because sometimes there are people who sleep at home, but now instantaneous water heaters are becoming more democratic. If over-insulation doesn't work, maybe this is the solution I would go for. or second-hand thermodynamics like you.