Student Members: Ben Almeida, Caleb Engst, McKale Hill, Wesley Olson
Acknowledgments: Dr. Getu Hailu, Dr. Jifeng Peng, SaltWater Inc., Regeneration North
Abstract: The kelp industry in Alaska is one that is growing rapidly and has garnered increased
attention throughout the state. Alaska’s cold and clean waters make great conditions
for kelp growth, so that it can be harvested and sold as an edible product. A large
issue with the kelp harvesting process is the efficiency of drying of the kelp. This
design project was tasked with helping Saltwater Inc. and Regeneration North find the
most effective, affordable, and environmentally friendly way to dry kelp in Homer, AK
as well as other coastal communities in the future.
Project Statement: Determine optimal high tunnel design to process sugar and ribbon kelp to less than
10% moisture content for food grade utilization. When determining the optimal high
tunnel design, utilization of simple installation methods and low energy consumption
are both desired by the client. These should be prioritized, as the installation locations
will be within remote locations throughout Kachemak Bay, where energy sources can
be costly and materials difficult to procure.
Conclusions:
●One of the high tunnels used this summer should have three HAF fans, exhaust fans
with shutters, and a dehumidifier sized appropriately for the air space. When it
warms up during the day, the exhaust fans can be shut to trap in the heat. The
dehumidifier will pull the moisture from the tunnel and help the drying process
significantly. One possible option to retain heat as well would be to line the walls of
the tunnel with a material like bubble wrap. From the CFD analysis, the humidity
decreased by 50% and the temperature increased by 33%.
● The second high tunnel should include a Heat Recovery Ventilator option to recycle
wasted heat, which is appropriately sized for the space per ASHRAE Standard
requirements. (3)
● The second high tunnel should also include a dehumidification unit appropriately
sized for the air space. ASHRAE Standard 62.1 recommends relative humidity be
controlled to less than 65% to control microbial growth. (4)
● After building a refrigeration cycle, it was found that the coefficient of performance
was 3. Refrigeration units should have a COP value between 2 and 4 so this is an
acceptable value. The cycle was then used to find the heat rejected, which came
out to be 1.08 kW. This is a relatively small value for heat rejection. The heat
rejection capture feasibility was further investigated by seeking input from a heat
recovery vendor, stating the unit was too small to viably recover heat from utilizing
their available technology.
● We recommend humidity and temperature sensors be purchased and installed
both inside and outside the high tunnels to log data throughout the kelp harvesting
season. Affordable options are available and have been provided to the client. This
information will be valuable for future analysis.
● Important data such as dry times and energy consumption should be recorded and
studied both throughout and at the end of harvesting season to determine which
method is best moving forward
Comments are closed