What fuel sources are available?

I would think that with your green solar system that a high eff heat pump would be the best choice. Not certain how common this type system is for your location. Have you discussed your options with a local HVAC pro?

Post back.

IMO

I would think that mini-split systems might better allow individual units to operate off of the solar power... a single central system would require a lot more energy than say one or two mini-split units at a given time.

Is cooling ever required?

"average tempature is about 75 degrees but it get chilly at night sometimes temp drop 60 to 50 degrees at night"

I sure hope you mean they drop TO 60 to 50 degrees at night."

A "temp drop 60 to 50 degrees at night" would put you down to 15 to 20 degrees.

If power is stable a heat pump would be good.

"central air" and "Split ac" are not necessarily different things.

"Central air" refers to how the duct work is run, while "Split ac" refers to a system that has separate condensers (outside with a compressor) and evaporators (inside coil) with an air handler (that may supply a central air system).

Mini splits will likely cost more in equipment but enable you to set different rooms to different temps. Most of them have inverter-driven, variable speed compressors. This helps with humidity control if you have mild temps with high humidity. You'd have to talk with an engineer or get more data than I have been able to see to be sure, but I think that the inverter-driven compressors a lower magnitude of starting surge compared to more conventional motors. This might be easier for your PV inverters to handle. It will be easier for the PV inverters if you have more than one compressor for sure.

If you decide to go mini-split, look up other posts about them in this forum.