Boiler Room Components Addition Nearly Complete

The solar capacity tank (which as my existing DHW tank) is now installed, filled and opened to the boiler system. It is shown on the left in the photo below. The new pump that will carry the heat from the collectors to the existing header that supplies my radiant heat system has also been ran. It is in the photos and is one of the two purple Grundfos pumps that are placed between the tanks.

The other two new pumps, one in the Solar Divicon and the other one below the Divicon, are ready to be test ran once the tubing runs to the roof are done and the Vacuum Tube collector header and support frame for the tubes is installed. The tubes cannot be installed until the system is filled and circulation is established.

If you examine the picture closely, you will see a vertical line with a temp gauge and a flow meter in the line just to the right and above of the left hand tank.




These were installed to augment the temp gauge and flow meters in the Divicon, which monitor the flow and temp of the fluid on it's way to the collector from the DHW tank, and the temp of the fluid coming back from the collector. The added flow and temperature metering is to monitor the fluid from the solar capacity tank used for radiant heat going back to the collector, that ties in down stream of the Divicon, and would otherwise not be monitored. Each flow comes from a separate pump. Referring to the schematic would make this a little less confusing. Clicking on it should expand it to a readable size.



This is why I must be able to monitor both flows:
The correct flow rate for a single 30 tube collector is .8 gpm, and will be controlled by using one of the three speeds available on the pumps. The Vitosolic controller will only run one pump at a time, so a flow meter on each pump discharge is necessary to determine what speed setting will give the correct .8 gpm flow on each pump.

2nd reason for monitoring and maintaining equal and correct flows:
In addition to controlling the solar heating system, that neat little Vitosolic controller can also compute and generate a "heat statement" hopefully in the form of how many BTU's you have collected and distributed to your DHW and radiant heat. It does it by measuring temperatures (differential temperatures across the collector to be precise), and calculating the BTU's using a set flow rate programmed in. So, you must have equal and known flow rates for what goes across the collector for the calculated BTU's to be accurate.

Why do you need BTU's? Simple! This is all about saving money. In my case, I have to buy propane which has 91K BTU's per gallon. I am expecting to pay $2.50 to $3.50 a gallon this winter.

I've spent $12,500 on equipment (should get $2000 back with the Federal tax credit), so if propane averages $2.50 per gallon that is 4000 gallons that is required to be saved to pay back on my solar investment. Even with burning almost 2 cords of wood a winter, I still have to buy around 1400 gallons of propane a year. Even if my solar conversion only saves me from buying 1000 gallons a year (I still have to dry my clothes with propane), that is a 4 year payback! I would be thrilled if the payback is any less than 5 years! Time will tell.