A Kendall-Jackson winery in California
is benefiting from both the heat and power provided by the sun through
a solar cogen system developed by Cogenra Solar.
By Tony Kryzanowski
"With solar cogeneration and
the Cogenra system, the payback was much more attractive than
photovoltaics alone, and the incentives on solar thermal are quite
strong," says Robert Boller (left), vice-president of sustainability at
The sun provides both light and heat energy, and California wine
producer Kendall-Jackson, the second largest vineyard owner in the
state, is working with renewable energy provider Cogenra Solar to take
advantage of both forms of energy, while showcasing some breakthrough
technology in the process.
The company has installed the largest rooftop solar cogeneration array
in the U.S. at its Kittyhawk winery in Windsor, California. It provides
the winery with both solar power and hot water.
The Kittyhawk installation was a test case for Kendall-Jackson, and
given its success, the company decided to proceed with two additional,
similarly-sized rooftop installations at its Vinwood estate in Sonoma
County and another winery in Monterey County. The goal is to eventually
install the technology at all 10 of its domestic and international
wineries. There is also potential for project expansion at Kittyhawk,
beyond its blending and bottling facilities.
The 96-module, 241 kilowatt hybrid solar photovoltaic and thermal array
supplied by Cogenra and installed by SunWater Solar will provide the
Kittyhawk winery with 15 percent of its power needs and 60 percent of
its hot water needs. The installation covers about 9,000 square feet on
the winery's blending and bottling facility roof.
"With solar cogeneration and the Cogenra system, the payback was much
more attractive than photovoltaics alone, and the incentives on solar
thermal are quite strong," says Robert Boller, vice-president of
sustainability at Kendall-Jackson.
The winemaker has a long history of supporting, investigating, and
implementing energy conservation and renewable energy opportunities. It
has a three-step energy conservation program that first looks at how it
can reduce energy demand from its processes, how it can re-commission
or replace equipment with high efficiency equipment, and how it can
invest in renewable energy either onsite or offsite. The company has
conducted case studies for installing solar and wind projects at all
its facilities. The Cogenra solar cogen technology was a good fit for
Kendall-Jackson because of the nature of its manufacturing process.
"We essentially are a food processor so sanitization is a key component
of food safety in the quality of our product," says Boller. "Therefore,
we use a lot of hot water. Being able to pre-heat that water with a
solar cogen system and provide electricity as a bonus is a natural fit
Finding ways to increase the energy efficiency of solar power systems
so that they can better compete with conventional power generation
systems has been a major focus of the industry for decades. What is
exciting about this combined solar power and heat recovery installation
from a technological advancement point of view is that the system
increases the energy conversion ratio of the solar system from 15
percent to 75 percent, says Dr. GiladAlmogy, CogenraSolar's CEO.
Finding ways to increase the
energy efficiency of solar power systems so that they can better
compete with conventional power generation systems has been a major
focus of the industry for decades. The combined solar power and heat
recovery installation at Kendall-Jackson has been able to do exactly
that, increasing the energy conversion ratio of the solar system from
15 percent to 75 percent.
He adds that the technology has numerous potential applications in
areas of the world that receive a significant amount of sun, for
industries that need both power and large amounts of hot water in their
processes. In addition to the wine industry, some examples are the milk
and dairy products industry, meat processors, makers of personal care
products, hotels, large apartments, laundries, and the processed foods
The company has completed a number of installations, including a
project for another winemaker, a dorm building at the University of
Arizona, projects for the U.S. Army and Navy, and the Facebook fitness
center where the installation provides power and hot water for people
to use for showering.
"What makes a site a good fit for this technology is power production
as well as the ongoing and continuous demand for heat," says Almogy.
In addition to generating its own projects, he says that Cogenra would
like to supply the equipment and guides and train other companies to
market and install the system themselves.
Cogenra is marketing concentrating photovoltaic thermal technology. The
sun's rays reflect off mirrors that track the sun's movement and
project the light energy onto downward facing photovoltaic (PV) cells.
Each cell generates solar power while reflecting and concentrating the
light to one location. The cells that capture the solar energy and
convert it into electricity are black, silicon-based cells that emit a
lot of heat energy.
"What we do is flow a water/glycol solution behind these cells, which
takes the heat away," says Almogy. "In the process, the cells are
cooled down and the captured heat is used to heat the water for the
He says that improving the performance of the silicon-based cells from
concentrated solar energy and developing the cogeneration array (which
allows for both solar power generation and heating water) were the
significant breakthroughs that Cogenra has developed and commercialized.
"Mounting of these cells to a
channel that flows water is very different than a traditional solar
job," says Almogy. "What we invented was the system architecture. The
economical coupling of the silicon cells to the heat collection
element—that's the breakthrough that has enabled us to go from 15
percent to 75 percent efficiency."
The water/glycol solution flows to the solar cells at 60 degrees
Fahrenheit, and after capturing the heat energy from the sun, it is
heated to 160 degrees Fahrenheit. The hot solution flows to a boiler
where it heats water through the use of heat exchangers.
Kendall-Jackson uses this hot water in its extensive tank and bottle
washing operations. The system will produce about 1.4 million gallons
of hot water annually for Kendall-Jackson.
Boller describes the Cogenra technology as a brilliantly simple
approach to solving an age-old problem of how to get the most out of
the sun's energy. "They've put all the brain power into the thermal
exchange between the PV and the water passing through the back of the
PV. That's where all the intellectual property is really quite visible.
The rest of the system is off the shelf."
An important lesson Cogenra learned on the Kittyhawk project, which
Almogy described as a huge improvement in the overall system, was how
to draw a small amount of the generated solar power for operating the
system that controls water temperature and flow and to run the pumps
that circulate the solution through the heating system.
Kendall-Jackson expects to save $30,000 annually in energy costs with
installation of the Cogenra rooftop array and earn a payback on its
investment within five years. It anticipates the same amount of savings
from the Sonoma and Monterey installations.
It took three months from the signing of the contract to commissioning
of the system in December 2011. Almogy says the quick installation of
the project is a reflection of Kendall-Jackson's previous experience
working to improve energy efficiency and reduce water consumption at
the winery as well as SunWaterSolar's experience as an installer.
SunWater developed the design of how the hardware would be installed on
the roof, installed the equipment, and also performed the work required
to connect the solar power and water/glycol solution circulation system
to Kendall-Jackson's facility.
The system was installed and commissioned without any interruption to
Kendall-Jackson's production schedule.