Where does solar energy go....

[Obx_guy]

Good day all... I am new to this forum and new to using solar...
Don't want to get into to much of my project but I am looking at using a solar panel with a submersible pump.
The inverter is built into the pump so only panel and pump.
My questions is... when the pump is shutoff because the tank is full or the well is low what happens to the solar panel energy.
The sun continues to shine and produce energy... does it become an open circuit or what... just trying to understand this because I an very new to doing this.

[Mike90250]

If the pump is not using any power, then everything else is idle, unlike a windmill which needs active loads or braking . Solar is real easy that way.

[foo1bar]

The sun continues to shine and produce energy... does it become an open circuit or what... just trying to understand this because I an very new to doing this.

It will likely be like an open circuit.
The sun shines, voltage is there at the wires coming off the panel, but there is no path for the current to flow, so no power is consumed.
Which means that 100% of the sun's energy hitting the panel is re-radiated as heat, rather than 90% of the sun's energy being re-radiated as heat and 10% turned into electric power)
(Ok - if you want to nitpick, some gets re-radiated as light as well in both cases - but you hopefully get the main point)

[J.P.M.]

It will likely be like an open circuit.
The sun shines, voltage is there at the wires coming off the panel, but there is no path for the current to flow, so no power is consumed.
Which means that 100% of the sun's energy hitting the panel is re-radiated as heat, rather than 90% of the sun's energy being re-radiated as heat and 10% turned into electric power)
(Ok - if you want to nitpick, some gets re-radiated as light as well in both cases - but you hopefully get the main point)

Not to mention the portion of the irradiance that gets converted to heat and subsequently gets carried off by natural (buoyant) convection and forced (wind) convection.

[Mike90250]

If you have nothing plugged into an outlet in your house - nothing happens.

[bcroe]

. My questions is... when the pump is shutoff because the tank is full or the well is low what happens to the solar panel energy.
The sun continues to shine and produce energy... does it become an open circuit or what... just trying to understand this because I am very new to doing this.

Your solar cells each, and collectively, follow the attached voltage, current,
and power curves. With no load current, solar voltage rises to Vopen circuit.
As increasing current is drawn, the solar voltage decreases. The Maximum
Power Point (product of V and I is max) occurs at around 80% of Voc and 80%
of Ishort circuit. The maximum available current Isc occurs at a short, zero
voltage.

When your load disconnects, the solar output just goes to Voc and zero
current. All energy received from the sun is radiated as heat, instead of
partially being delivered as electrical power. Bruce Roe

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[J.P.M.]

All energy received from the sun is radiated as heat, instead of
partially being delivered as electrical power. Bruce Roe

Bruce: Your explanation is correct until you get to the above sentence about how the energy gets dissipated.
At Voc or Isc all the irradiance will be dissipated via all three of the heat transfer modes, not simply radiation heat transfer.

At those two conditions a panel or array will dissipate irradiance just like a flat plate or block of any dark colored material sitting in the sun getting hot and distributing the irradiance it receives mostly by approx. equal amounts due to radiation to the surroundings (including the sky), and both natural and forced convection as heat to the surrounding air as well as a relatively small amount as heat via conduction to the panel frames and thus to the supports.

[bcroe]

Bruce: Your explanation is correct until you get to the above sentence about how the energy gets dissipated.
At Voc or Isc all the irradiance will be dissipated via all three of the heat transfer modes, not simply radiation heat transfer.

At those two conditions a panel or array will dissipate irradiance just like a flat plate or block of any dark colored material sitting in the sun getting hot and distributing the irradiance it receives mostly by approx. equal amounts due to radiation to the surroundings (including the sky), and both natural and forced convection as heat to the surrounding air as well as a relatively small amount as heat via conduction to the panel frames and thus to the supports.

. Yea, the word radiate is not entirely correct, need a word that covers all ways of heat leaving.

[J.P.M.]

. Yea, the word radiate is not entirely correct, need a word that covers all ways of heat leaving.

As it applies to this situation, two words: Heat Transfer. For calculations just watch the sign - negative is leaving, positive is incoming.

[Obx_guy]

Thanks for all the replies and the great explanations....