It's how every engineer would like to design things, in a carefully controlled environment. You pretty much need to start with a virgin system and design the house around it. Funny how he wants to heat with MPPT, but regards it as useless when charging batteries. If you can't get through the lit, MPPT is achieved switching in and out resistive elements of a central heated core. The old 1, 2, 4, 8, 16 binary way. In this example you get 32 possible currents. The heating elements need to be pretty close tolerance to do that. Suspect that 16 is really the practical upper limit and that is probably sufficient anyway. Not sure what mixing the MPPT and PWM do to the overall efficiency.
The nice thing about this is the heaters are on or off and no storage in capacitors are needed to store energy like in a typical MPPT controller. I'll be the first to admit that can be a long term problem if not well designed. Those of you that have followed my posts know I like to PWM heaters. The reason is many things only have a single element, like a water tank, and the only way to control current is with PWM. That also allows you to do zone heating quite easily if you wish to concentrate heat in just a few areas. Want everyone to be aware that if you have a mish mash of heating elements it will be difficult to configure without using multiple boards.
Hey, it's all in the software. This new product is nothing more than a relay board. If you buy a few SSR and a NANO, you can have the same system short of fancy screens, data logging and wifi. I think a lot of PV energy is wasted and all for improvements. I haven't seen much interest here in PV heating. He has some interesting ideas and a lot of energy. What he has is only a part of a heating system from what I can tell. I don't think he has a full understanding of the industry. I wish him luck. It is going to be a hard sell. He has trouble getting across the main talking points.