Now, thanks to a new hybrid chiller system, this community college in California’s San Fernando Valley, northwest of Los Angeles, has campus-wide comfort year-round.
In years past, extreme temperatures often interfered with learning. Summer classes were often moved to air conditioned areas, held outdoors, or cancelled due to the heat.
“On hot days, I’d get so many calls to see if space was available for classes in air conditioned environments,” said Frank Vitone, Pierce College HVAC supervisor. “The students were all fanning themselves. It was a real uncomfortable way to learn.”
In the late 1990s, president Darroch Young headed a task force that assessed the future needs of the campus. Among the recommendations were the installation of energy-efficient lighting and air conditioned classrooms.
Consulting mechanical engineering firm Kevin A. Smola and Associates of Pasadena helped develop a comprehensive cooling plan. Only scattered buildings had A/C — generally old, inefficient room units and small packaged units. Where there were duct systems, they were typically dual-duct and constant-volume.
HYBRID CHILLER SYSTEM
“Most hybrids are half-gas, half-electricity all the time,” said Smola. “Which one the system uses is determined by time of day. During the peak period for electricity, gas is used, and vice versa. But for the Pierce College system, I developed an equation to determine which chiller to use, based on energy prices from the utilities. There are only about 20 hybrid systems in the country, but this is the only one I know of that determines which chiller to use.”Jim Lowe, systems manager with RSD/Total Control of Lake Forest, CA, which furnished the controls and programmed them according to Smola’s specifications, said, “I hadn’t written this type of program before — one that involves time-of-day usage rates and cost of utilities.”
Though the system is capable of switching between gas and electric on “an hour-by-hour or minute-by-minute basis,” Smola said, “we’re a long way from having instantaneous response to changing prices because the utilities only provide rates on a daily basis. If the utilities provided that information, we’d act on it. It’s fairly simple to make the conversion, but not if we can’t anticipate price fluctuations. Right now, all we have to work with is the current rate for the day.”
But that’s plenty enough for Vitone, who is not fazed by California’s energy crisis. “The higher the prices go,” he said, “the more money we save.”
“It’s piped in series, not in parallel,” said Smola. “By doing that, it’s much easier to know which chiller picks up the majority of the load, and we can put a minimum load on the absorption machine when both have to run simultaneously.”
Project manager Mike Hart of All Temperatures Controlled, which served as the general as well as the electrical/mechanical contractor, said, “Originally, all the piping was to be on the tops of canopies, but we decided to put it underground — almost a mile of pipe. What’s amazing is that we completed the entire project without disrupting classes by working a lot of nights and weekends.”
LIGHTING CONVERSION SAVES BIG BUCKS
Eight thousand lights — 24,000 light bulbs — were swapped out. The new low-wattage, high-efficiency lighting resulted in “tremendous savings,” says Smola.
Vitone concurs: “Last summer our electricity costs went up only $100 a month, but we added 900 tons of a/c!”
“The electrical retrofit helped pay for the a/c,” says Smola, who noted that a $57,000 gas company rebate further sweetened the deal.
All lights and a/c are set to occupancy levels. If the campus is closed, they’re off, regardless of what happens. If the campus is open, but no one is in the room, they’re on standby. And if class is in session, they’re on.
“Typically, it’s set at 74 degrees, plus or minus a degree or two,” says Smola. “When the classroom isn’t occupied, it’s given a wider tolerance — five or six extra degrees in both directions. At first Frank worked with a tolerance of plus or minus 10 degrees, but he felt that it took too long to get the room back in control. I suggested he keep moving that number until no one complains.”
“When we converted from double-duct to VAV,” said Smola, “we used the existing equipment. Typically, you take out the old and put in the new, but using what was there saved a couple million dollars.
“My firm has been doing this type of conversion since 1994. I know of only one other company in the greater Los Angeles area that does this, and they only started three years ago.”
The addition of CO2 sensors provided a good return on investment.
“With the new carbon dioxide sensors, if the air quality is good inside the building, we can reduce the amount of outside air brought inside, thereby saving energy and money,” said Smola.
“When we designed the system, we used temperatures from the on-campus weather station rather than temperatures from nearby LA. The weather at Pierce College can get to 110 degrees, while the surrounding areas are 102 degrees. Typically, Pierce is seven to 10 degrees higher than the rest of the Valley.”
But no longer does that make students and faculty hot and bothered because now when temperatures soar, they’re sitting cool.
Sidebar: Facts, Figures, And Specs For Pierce College Project
Campus specs: 25 buildings (approx. 200,000 sq ft) on almost 500 acresHvac design: Kevin Smola, Kevin A. Smola and Associates, Pasadena, CA
Hvac installation/general contractor: All Temperatures Controlled, Inc., Chatsworth, CA
Controls supplier and software program designer: RSD/Total Control, Lake Forest, CA
Overall cost: $6 million for the initial phase; additional $3 million for Phase 2
Mechanical equipment involved:
Air handlers were converted from constant volume systems (double duct and multi-zone) to variable air volume, double duct systems.
Return air quality is monitored and used to control the volume of outside air, allowing, at times, to reduce the required volume of outside air and thereby save energy. The classrooms are monitored for occupancy: when not in use, the temperature tolerance is enlarged to save energy.
— Heidi Nye
Sidebar: College Plans To Generate Its Own Power
“We’re planning an on-site generator to provide our own power,” said the HVAC supervisor for Pierce College, Frank Vitone. “Then we’ll be able to cut loose from the DWP (Department of Water and Power).”Vitone envisions fuel cells and micro-turbines allowing the “use of waste heat to heat buildings in the winter, and eventually to air condition them in the summer. As such, we’ll become one of the leaders in the community as far as energy savings are concerned.”
The college recently has hired an engineering consulting firm to “do the value engineering and lay out the cost savings in a report.”
Pierce College currently spends approximately $750,000 on electricity each year. “If we generate our own power, we anticipate a net savings of $30,000 a month — from day one!”
The estimated cost of the equipment and installation to pull this off is $4 million. The money the college is now paying to the electric company would instead be paid to the equipment manufacturer to pay off the loan. In about seven years, Vitone said, the cost of the system would be completely paid off.
“It’s really a no-brainer,” he said. “There’s so much instability with the utility companies that we don’t know where prices are going. This way, we lock in our costs, and we can sell our excess power to our sister colleges — Valley College in Van Nuys and Mission College in Sylmar.”
The means to self-sufficiency are “already in place,” Vitone said. “We have a 30,000-gallon propane tank that’s a backup at present. In case our gas supply is cut off during an earthquake, we can keep the campus open, converting the propane to natural gas, electricity, and hot water. As technology evolves, we’ll be able to convert that to A/C, too. A micro-turbine will run the excess heat through the absorption chiller to generate chilled water to air condition buildings in the summer, just as that excess heat can be used to heat buildings in the winter.”
Vitone is just as excited about the academic aspects of such a system as he is about its energy efficiency and profit potential. “The interesting part,” he said, “ is that we can incorporate this into the academics here. Students could take a look at fuel cells and the micro-turbine. It could become a course of its own. There aren’t many places you can study energy devices that are online. When this project finally comes through, it’s going to be a good one!”
— Heidi Nye
