Hello everyone. I have installed a 90 evacuated tube system that has a 80 gal tank. I live near Chicago, IL and would like to know what size should I have for 90 tubes. In the summer, it overheats and in the winter, I do not get enough heat. Any help will be greatly appreciated. There is only one person, me, living in the house, but I have hydronic heating so all the heat I can get would be great. Thank you.
Quite coincidentally, I recently installed a 60 evac-tube water heater too. I live nowhere near Chicago (I'm 36 deg south, 147 deg east). I have two hot-water tanks, each of about 500 gallons. They're usually coupled to act as a 1000 gallon combined DHW & hydronics source tanks.
It's now winter and I'm getting enough hot water for the domestic hot water for two people, dishwashing, clothes washing etc, but its not enough to make any worthwhile contribution to the heating situation more than once every few days.
The only things I can suggest (and you may not be able to do anything about some of them anyway) is to check your tubes are at the correct angle to maximise your energy collection and to check your flow rate and pump times.
Obviously if the tubes are too shallow (or too steep) you won't get the maximum energy, same if they're not facing the right direction.
If your water tank is small enough, you can get *hotter* water by running the pump slower (or as I do) increasing the thermostat setpoint so you only pump water when it's hot enough to be immediately useful.