Here’s an interesting idea I heard about this week – ice based cooling. One of the big problems as a solar PV homeowner is what to do with your surplus power output. Certainly in the UK what used to be called “spillover” to the grid gets such a low export tariff that its much better to use yourself. The question is how? Many people use it to heat their water using immersion heaters, but there is only so much you can do. Battery storage is definitely coming. A company in California has had an another idea- ice based cooling.
The homeowner or even the utility (if loads of solar electricity is going to the grid) directs the home unit to freeze water. The ice is then used to cool central air conditioning coolant and can cool the house for up to 4 hours. Apparently in some buildings over half the energy use is down to air con. This would help reduce the costs of that once the unit has paid for itself. One advantage is it is said to have a 20 life span which is much better than batteries. The other advantage is that peak solar output in hot countries often correlates with air con use and air con use is a huge and growing user of energy. The final advantage is that the system could be modular and used in commercial buildings. In the UK this is less useful (although air con use is growing), but if I lived somewhere hot I would certainly think about it.