system was installed on the roof of Keyawa’s
new drying building. The system measures 9300 ft2
), and provides 65,000 cfm of solar heated air to
the air intake of the walnut dryer using traditional ducting.
If the dryer is running at full capacity and more airflow is
required, the bypass dampers can be used to supply additional
air. Conversely, if the air from the panels is too hot,
the bypass dampers will open automatically to cool the air
to the desired temperature.
The SolarWall system is equivalent to a 500 kW heater.
It displaces 1431 MMBTU of fuel and 92 tons of CO2
emissions each drying season. In terms of cost savings, at
the time of the installation—using 2003 natural gas
prices—the projected fuel savings were $13,832 each fall
when drying occurs.
Commenting on the success of the system, Keyawa said:
“I’m currently designing the new building with one directional
slope towards the south so that I can add SolarWall
if I want, and grab more of the sun. I’m gearing up for the
Ron Keyawa is the founder and operator of a large walnut production & processing facility in Ordbend, California. He had previously seen another SolarWall® system operating at Carriere, a neighboring walnut producer, and with the success of that installation, Keyawa decided to incorporate a larger solar system into his processing facility during an expansion.
Walnut drying is ideally suited for the SolarWall technology. Walnuts require large volumes of heated air to reduce the moisture content to less than 8%. However, in order to maintain the proper flavor and texture, it is essential that the nuts are dried slowly using low level temperatures. Ron Keyawa explains: “To dry the nuts, I need air that’s at 110°F, so if ambient is 80°F, then I need a 30° heat gain. At night, when things cool down here, I use a lot of natural gas! That’s expensive—really expensive—so I looked for ways to reduce my energy costs and found SolarWall. Now there are times when I don’t need to run natural gas at all because I’m getting enough heat from the SolarWall panels on the roof to shut off the burners.”KeyawaOrchards_Y03_SolarWallCaseCropDryingV2(PDF)