Warming a Tank With PV

This seems like an incredibly inefficient way to heat water....I believe a thermal system would work much better....You need something like this...

http://www.sidite-solar.com/product.html

? What? Water? Who said "water"?

The OP is heating a "tank". Could be empty, for all we know.

OP gives no useful information. I think OP is 15 years old.

I already have something like this and the PV panels too.I want to utilize the extra energy from the panels.Thank you for your reply.

Make some hydrogen...

What's that, Capt Moosie's house?

Good answer, put it in the sunshine and cut out the middleman!

Some water heater elements in parallel would perhaps be most economical.

This makes no sense to me. The tiny amount of information and choices given to us just makes no sense to me. Why do you want a linear regulator to run resistive heaters, to keep the voltage constant. Why in the world would you want to lose 25% of your available power to heating this linear regulator when you're trying to heat something else. Then there's the uncertainty of how much mass of whatever will be heated. I really do not understand the idea of adding an aluminum heatsink somewhere. Is this heatsink supposed to transfer regulator heat to air or resistance heat to this tank?

The OP reminds me of our member hydrogenhead. No offense to either one.

I think OP has solar heat and just wants to use those unused PV panels. I'd use the power generated by the PV panels to run the circ. pump on the heat system.

What do I know? I'm just an old grouch.

To transfer regulator heat to the tank.

This 25% is no lost.

"I have an 8KW-240V DC PV system. I'd like to connect it with resistors to heat a tank, so I need a series linear regulator with heat loss of 2KW."

By your definition it's a 25% loss.

Forget regulation, just use a heating element (i.e. resistor) which will handle the maximum power the panel can generate, and things'll take care of themselves.

Use 2 or more electric hot water heater elements in parallel. They are 240v ac or dc and available in wattages of 1,500 to 5,500 watts apiece. McMaster (not a commercial endorsement) sells them from $10.26 to $20.35 each depending upon the wattage. They are available with a 1" npt male thread or a square flange with a 2-1/2" square bolt configuration. Mount them on the bottom, or better yet mount them on the lower side. Suggest cutting a small section of the side out and use a piece of 8 ga stainless steel to mount the elements on and mount this on the tank. The temperature can be regulated with hot water heater thermostats if necessary or some sophisticated temperature control with extreme accuracy if needed.

Good Luck, Old Salt

If the tank is a liquid tank there is nothing more efficient than a solar hot water panel.

Converting PV to resistive heat is going to be much less efficient, more costly, and more maintenance prone.

Since we have no idea what to go on, I might as well put in the equlivelent of $0.02 USD in the currency of your choice,

I was involved in doing an experiment of using an unregulated solar array for an element of a water heater. It proved somewhat useful. It was just a place to dump unused solar power. Using excess power to run the house fan was probably better. I forget the results of the published paper.