We are finally making progress again on the solar heating system at 78 Main St. After building the tank (Solar Storage), building the collector rack and trench to the basement, and building the heat exchanger (see pictures below), the next step was to get the two main loops pumping (see Solar Storage Tank, part 1 and part 2).
The first loop is the solar heating loop. This is a loop of copper pipe that takes the hot water/glycol mix from the top of the collector to a heat exchanger in the basement and then returns the colder water to the other side of the solar collector. This is one continuous loop under a small amount of pressure so the pump needed to move this water is small and only requires a 5-10Watts. You can see from the pictures below that we have a 20W solar electric panel mounted on top of the solar thermal collector (evacuated tubes). This solar panel should provide enough power to circulate the water in this loop.
The second loop draws water from the bottom of the storage tank into the heat exhanger (to be heated by the solar loop) and then back to the top of the storage tank. This loop is not pressurized so it requires a heftier pump, which can be run off 120V AC (standard house power).
When setting up a complex system like this it is always good to plan some testing and debug time in order to get the bugs worked out. The Thermal Storage Solutions team was on site putting all the evacuated tubes in place, priming and charging the two loops, and needless to say it was late and dark out when the work was complete. So we couldn’t know exactly what would happen when the sun came out the next day.
Before opening the Energy Emporium I spent 25 years running quality control, testing, and customer support departments for various hardware and software products. In my experience the quickest way to learn how a systems works (or how it is supposed to work) is when it is broken and you have to debug it. Well, that is true for my collector as well.
The next morning when the sun came out and started heating the collector, the solar pump was not able to circulate the water. What that meant was the pressure was building up as the temperature rose and if there was going to be a leak in the system, the extra pressure would force the leak to show itself… and it did. In the picture on the right you can see steam coming out from a small leak in the collector. Kent took a video, which is actually much more impressive: Solar collector steaming video.
Future blogs will provide more info on what all the plumbing is for and what the brain (controller) does.