u/HElGHTS

Suppose I've got 2 boxes of water in my yard. Both boxes have a large footprint but are very short, for example 10' long x 10' wide x 1' tall, so that only the top gets meaningful sun exposure and we can ignore the other sides.

Box A is painted black, using the most absorptive paint known to man. Or whatever other non-PV surface that will maximize the collection of heat.

Box B is perfectly covered with a solar panel. The solar panel is directly connected to a resistive heating element submerged in the water.

How much of a difference is there in the amount of water heating that occurs? Is it fair to say that if box B's solar panel is rated for 20% efficiency, then the water in box B will gain 20% as much energy as box A (plus whatever heat travels from the solar panel directly into the box, if they are thermally coupled enough rather than spaced out and casting a shadow on the box)?

Here's the situation:

• April 1: AF posts: $150
• April 20: billing cycle ends, statement is issued with a balance of $171 (AF plus a few other small charges) and a minimum payment of $40, due May 17. I make no further purchases, so my account balance remains at $171.
• April 24: I make a $21 payment, which is $150 short of the balance and $19 short of the minimum payment due on the April 20 statement. Now my account balance shows as $150.
• April 27: I request that the card be closed.
• April 28: The $150 AF refund posts, due to closing the card, so now my account balance shows $0.00.

Does the $0.00 balance mean it's ok that I won't be making the $40 minimum payment despite the April 20 statement saying that I must?

Note: I keep autopay on at all times (set to pay the entire statement balance), and I haven't turned it off, but I made the $21 payment separately from that, in hopes of avoiding the whole "your $150 refund will be via check in the mail" or whatever. I think I achieved that, unless they expect me to pay another $19 or something which would just cause them to send it right back to me as a check.