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

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phil59
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## Re: Transform a solar DHW tank (or fuel oil) into a thermodynamic water heater with a small swimming pool heat pump

Christophe wrote:
Those who are not happy can find new friends on facebook or twitter...

I do not have !
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hmmmmm, hmmmmmmmmmmmmm, hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhmmmmmmmmm, huh, hmmmmmmmmmmmmm.

Christophe
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## Re: Transform a solar DHW tank (or fuel oil) into a thermodynamic water heater with a small swimming pool heat pump

Christophe wrote:I put the circulator on high speed.

After 1 week, I notice some changes on the kWh but the inter cycle duration remains the same (still 3 to 4 cycles per day)...

In effect; I now cycle at 0.23-0.25 kWh instead of 0.28-0.30 kWh (despite higher circulator power) and the duration, from ambient temperature readings, seems to be closer to 20 min (22 min if 0.24 kWh) than 30 min (28 min if 0.30 kWh)...

If we make the correction by taking into account the power of the circulator (at least 15 W more because the power displayed is, I believe, the hydraulic power, we must add +30% to have the power consumed but I will do the reasoning on the one displayed) we have:

a) Low speed 30 min cycle, circulator consumption = 7 * 0.5 =3.5 Wh i.e. 3.5/290 = 1.2% of the total consumption of a cycle
b) High speed 20 min cycle, circulator consumption = 22 * ​​1/3 = 7.3 Wh i.e. 7.3 / 240 = 3% of the total consumption of a cycle

In all cases, the consumption of the circulator is quite negligible (even if +30%)... and even if in % it more than doubles at high speed.

In short, contrary to what I presented (yes yes I know how to recognize my mistakes ), high speed makes it possible to run shorter cycles and save a few hundred Wh (2 to 3) per day and therefore a few tens of kWh per year (less than 50 kWh but it's still good to take!) .
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sicetaitsimple
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## Re: Transform a solar DHW tank (or fuel oil) into a thermodynamic water heater with a small swimming pool heat pump

This is a solved question.
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izentrop
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## Re: Transform a solar DHW tank (or fuel oil) into a thermodynamic water heater with a small swimming pool heat pump

sicetaitsimple wrote:This is a solved question.
Are we sure that the final temperature of the heated volume follows the same logic?
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Christophe
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## Re: Transform a solar DHW tank (or fuel oil) into a thermodynamic water heater with a small swimming pool heat pump

Explain to us how the triggering of the (“immersed”) thermostat is impacted by the speed of the circulator?
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sicetaitsimple
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## Re: Transform a solar DHW tank (or fuel oil) into a thermodynamic water heater with a small swimming pool heat pump

izentrop wrote:
sicetaitsimple wrote:This is a solved question.
Are we sure that the final temperature of the heated volume follows the same logic?

I don't often take a shower at Christophe's, it's up to him to ask the question....
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Christophe
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## Re: Transform a solar DHW tank (or fuel oil) into a thermodynamic water heater with a small swimming pool heat pump

Quite infrequently!

Well, I don't understand the question...

Now I feel like the hot water is slightly warmer with the high speed…
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sicetaitsimple
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## Re: Transform a solar DHW tank (or fuel oil) into a thermodynamic water heater with a small swimming pool heat pump

Christophe wrote:Now I feel like the hot water is slightly warmer with the high speed…

I didn't dare say it, but I thought so... When the circulation at maximum flow stops at the end of the cycle, your coil is full of water "on average" warmer than when it circulates at flow reduced. Heat which will then be transferred to the balloon even without circulation. It will of course not work miracles, but that you notice a slight increase in temperature does not surprise me.
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Christophe
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## Re: Transform a solar DHW tank (or fuel oil) into a thermodynamic water heater with a small swimming pool heat pump

Possible…the rise is small…a few tenths…
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izentrop
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## Re: Transform a solar DHW tank (or fuel oil) into a thermodynamic water heater with a small swimming pool heat pump

Christophe wrote:Explain to us how the triggering of the (“immersed”) thermostat is impacted by the speed of the circulator?

It's me who doesn't understand.

The submerged thermostat, I thought it was in the lower volume and was not affected. and that the heat pump cycle was stopped by reaching the setpoint temperature, return temperature?
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