Collector Comparison Fixture
Evaluating a solar collector is a difficult process since sunlight intensity and climatic conditions vary from day and depend on: location, pitch and orientation. What works great in Toronto may not be so good in Orlando. A sunlight simulator may be used to do an evaluation under controlled conditions OR a solar collector comparison fixture may be used to collect data under a variety of conditions. I was given a grant by the New York State Energy and Research Authority (NYSERTDA) to build a solar collector test fixture that could be used by students at the Solar Energy Center at SUNY Farmingdale so I have taken this opportunity to build a comparison test fixture. This is the manual for the test fixture I've been working on. If you have any comments or suggestions I would appreciate them before I slep the 250 ? lb. monstrosity across the Nassau/Suffolk border.
The SRCC rates solar collectors on durability, safety and performance under a variety of controlled climatic conditions. This fixture will mainly be used as a training device, but it may also be used to compare the collector efficiencies. Efficiency, as you know is the fraction of heat collected divided by radiant energy available. It is normally expressed as a percentage. Although we will not be using the sophisticated measuring tools available to the SRCC we should still be able to evaluate and compare the performance of a Serpentine Collector with a Trickle Down Collector. The differences between these collectors will be explained later but let�s first assemble the fixture, mount our collectors and connect our pumps.
Here are the four main sub assemblies for the
1. Leg Support
2. Level 1
3. Level 2
4. Level 3
50 Watt PV panel
Two 12 VDC pumps
Two 5-gallon storage pails
Rubber tubes and wirers
Electronics Platform containing:
1. PV Controller
2. BDC Controller
3. Six position monitor
4. Five LM34 temp probes
5. Four 10K NTC thermistor probes
6. One light flux monitor
Step 1 LEG SUPPORTS
The collector-mounting fixture is modular. In other words it consists of sun assemblies that may be bolted together and reinforced with braces.
Lean the left leg support against a wall or have someone hold it while you drop the LEVEL 1 platform over the locking cross support. The front edge of the left leg support has one small hole drilled toward the bottom of the leg. This hole is just used as a marker. You will find a corresponding hole on the left front side of the LEVEL 1 platform.
Step 2. LEVEL 1 PLATFORM
After the left side of the LEVEL 1 platform is locked in place over the locking cross support of the left leg assembly the right side is dropped over the locking support of the right leg assembly.
Step 3. LEVEL 2 PLATFORM
Once the LEVEL 1 platform is locked in place it will hold the leg assemblies in place while the LEVEL 2 platform is positioned on top of the leg assemblies. There is a single hole drilled on the left front side of the leg assembly and also on the left front side of the LEVEL 2 platform. Two holes have been drilled on the right side of the second platform.
Once the LEVEL 2 platform is in the correct position as illustrated above the two front support brackets and the two back support brackets join the leg supports with the LEVEL 2 platform. Line up the predrilled holes of the and use 4� lag bolts to hold the LEVEL 2 platform to the legs.
Last but not least secure the top of the platform to the top leg cross support with 2� lag bolts. All of these supports are needed to prevent the platform from swaying. Once all the supports are in place you may connect the LEVEL 3 platform to the hinges. Some experience with installing a door on hinges may be helpful for this step.
Step 4. LEVEL 3 Platform installations.
Simply line the top platform up with the hinges and slide the hinge pins into position. Do not force the pins. They will slid in easily if the top platform is properly aligned.
Notice the wheels and the support brackets are not shown in these two illustrations.
Collector and PV mounting The two collectors and the PV panel may be placed on top of 2x2 mounts. It should not be necessary to screw the support tabs to the mounts, but this is an option. The electronics board contains two different differential controllers, a 6 position monitoring station, a sky eye and a row of switches. The angle of the LEVEL 3 platform may be adjusted between 200 and 500. For safety reasons the 500 limit should not be exceeded. At least 2 people should be available for the tilt angle adjustment.
Electronic connections: to be continued...