I'm starting this new topic for my neighbor Craig, as he hates computers. But I persuaded him to allow me to post his new ZP build to share with others.
A quick history...I've known Craig's wife for 15 years, and she introduced me to Craig about a year and a half ago, even though we live less than a block away. Since he retired, he spends pretty much all his time either fishing or tinkering in his 600sf workshop. He has a propane furnace in the workshop so he spent a lot of money keeping it warm and comfortable throughout the long winter months. So his wife thought it would be a good idea for us to meet. Once I explained the concept of solar heating he was intrigued, but later told me that he thought I was also full of crap about solar heating. Not anymore…
He proceeded to build this beauty without ever seeing a solar heater in action to verify the concept even works!
He was thrilled with the results and is now a firm believer in solar heat and loves showing off his collector to anyone that will listen. He has not needed to use the gas furnace the past two winters. He can work in the shop in a tee shirt, even when it is below zero outside as long as the sun is out. Like many of us, his head started spinning with ideas for his "next" solar heater for the house. His first ZP build was essentially a copy of my ZP design, as I assisted him with this build. But Craig has his own way of doing things as you can tell by the beautiful cedar sides and industrial strength hinged stand.
Craig’s new ZP build uses 1” aluminum square tubes with ⅛” thick walls, covered with an aluminum skin on all sides. He originally wanted to use my self-tensioning frameless screen idea, but has switched to using aluminum screen frames from the store after several frustrating attempts. The frameless screens idea works, but not if you need to be able to adjust the screen gaps too. He may still attempt frameless screens at a later time. So for now this new ZP will be testing to find if a 1” screen gap is the optimal gap, or if a slightly larger gap will improve performance while allowing better air flow. At some point the heated screens won’t be close enough to the main flow of air for effective heat transfer. We devised an easy way to change the screen gap in ¼” increments to find out.
As it is now, we both have had trouble occasionally keeping our output temps down below 125˚F even with 400+ CFM pushing through our collectors. Actually, his current ZP often outperforms mine, partially due to having a clear view of the sun as opposed to my usual peaks at the sun through tree branches. His current and new ZP both have a 6” deep box, as opposed to my ZP’s 3.5” deep box. It’s these differences between our two collectors that has us wondering how further opening the screen gap, along with larger 8” ducts, and other possible tweaks and changes will further improve ZP output performance. We hope to start testing in couple of weeks. So stay tuned…
Greg, posting for Kraut Man Craig, in MN
Below are some pics from Craig’s new ZP build:
Adjustable tension, self-closing hinges, were going to be used to pull the screens tight. But they will not be used at this time, instead Craig will be using standard aluminum screen frames.
1” polyiso fit between the aluminum frame. A layer of ½” polyiso will cover this before the screens are placed.
The collector is incredibly light. You can lift the entire 4’ x 16’ unit quite easily.