Digging for Water
When a company develops a new product the “beta” version is an early version of the product generally used to gather real information about how the product performs, how people use it and what kind of failure modes to expect. My storage system for holding the summer heat to use in the winter is really a beta product, even though it wasn’t called that when I bought it.
The adage that we learn more from our failures than our successes holds true for many endeavors – from classes we take in school to entrepreneurial efforts we might undertake later on in life. The mistakes and failures teach us invaluable lessons which, in the case of a new product introduction, can make that product more reliable, easier to use, more efficient, or better in many ways.
Foaming the storage tank
I can now fully appreciate the benefit and even the necessity of a backup heating system in New England. In 2011 alone there were 3 or 4 storms that caused power outages, but I have been very lucky that they only caused minutes or a few hours of interruptions for me. Many others experienced days without power. On the other hand my solar heating system is in its first year of life and needs some serious debugging, so my back up systems are needed – often!
In this part of the world multiple days without heat in the winter can be life threatening. This, and the potential for frozen pipes, provide ample reason why insurance companies want to know the details of a home’s heating system, and it’s backup, before providing insurance.
The solar collector we are building at my future house, 78 Main St, has been in place for a couple of weeks now, and we have been collecting temperature data. I’m hoping to have some “live” data at the website at some point in the future, but for now I have downloaded 8 days of data and created some graphs to help understand how the system is working.
The charts below show the rise and fall of various temperatures in my solar heating system. Each chart represents readings taken for one day, from midnight to midnight of the next day.
Out of the 8 days of graphs below, there were 3 days that were bright and sunny: March 10, March 16 and March 17. You can see a nice rise of the solar collector temperature (blue line) above 100 degrees. For these sunny days, the temperature stays there for all the daylight hours and then falls as the sun sets. Once the collector temperature rises above 130 degrees, the pumps start moving water through the heat exchanger.
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.
Solar Thermal Storage
It took a while to get this going but we finally have a time-lapsed video of the building of the solar storage tank. This tank was designed by TSS (Thermal Storage Solutions) with installation help from Murphy Cell-Tech and Greenworks Solar.
I set up a webcam to get the time-lapsed photography of this tank being built. Unfortunately I had a problem on the second day of the build and missed some important parts. Fortunately, Paolo from Murphy Cell-Tech also set up a time-lapsed camera and his movie came out really well. Here is the link:
Youtube video: Building the Solar Thermal Storage Tank
For more information on the building of the tank, click here: Thermal Storage Tank, part 1 and here: Thermal Storage Tank, part 2. For more information on the entire renovation, click here: 78 Main – Renovation
Solar Storage tank
Unfortunately we had a problem with the webcam and didn’t get any time-lapse pictures of the second day of building the solar storage tank (see Thermal storage tank
, part 1 from the first day). We did get some video footage and a few stills, see below.
The first day was the construction of the tank itself with foamboard and spay foam and the beginning of fill, which is mostly sand. The second day included the addition of temperature sensor conduits, as well as the heat exchanger hardware for both the solar heating loop and the house extraction loop. Also the domestic hot water heat exchanger was added.
For our zero-energy building
we are using the sun to provide ALL of the heat we will need throughout the winter. After months of discussion, engineering models of heat requirements, heat losses, heat storage and solar heat generation… the team came up with a system. There are three major ingredients:
- Solar collector
- Thermal storage tank
- Super insulated house