Mike I would bet there are many wanting to do the same thing here but like me are not good at electronics. I had thoughts about going grid tie at one point. Its very convenient to be able to store that energy on the grid till you need/want it. In my case, the deciding factor to not go grid tie was the wording in the contract that basically gave my local government free access to my house to "inspect" when they deemed necessary. The other issue is you don't have access when power is out or even worse if the grid goes down. My goal now is low key urban partial off grid.
Storing some of that energy as heat is a good idea. I'm guessing you want it for domestic hot water and radiant heating maybe?
I'm going to be watching this thread with much interest. Perhaps one of the solar manufactures will also be reading and come up with a heat pump tied charge controller. Diverting to grow lights would also be another good source for many solar folks. There is a lack of load diversion controller options in the solar industry. Someone smart could find a good business nitch here.
I may adapt part of your idea. I like the idea of dumping some load for hot water. Resistive heating is a poor option. How about a simple charge controller that detects battery voltage and turns on a compressor/heat pump. If voltage still rises, it turns on another? Not as smooth as a variable but simpler to source parts. A large enough battery bank would smooth out the gaps in load size. Panels would be directly connected to the batteries as the controller would be purely diversion based. I would also include secondary load of LED grow lights once water temp was reached.
What are you going to do with the cold side of the heat pump? How about pulling heat from a cooler/freezer upstream from the source heat? Kill 2 birds with 1 heat pump.
How about going off the DC side? There are a few options with DC 3 phase brushless compressors. You could build a controller interface to pull power off of the batteries to control charge rate. It would be easy to make it a variable vs on/off. Thats basically what the newer inverter heat pumps are, 3 phase DC motors.
I like the idea of not having all your eggs in one basket. My systems tend to have lots of simple parts rather then one large device doing everything. That way I can move things around if there is a failure and keep things going. Its from a grid down self reliant angle. Down side is it requires more baby sitting.
Looking forward to see what you build
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