Optimized Operations

Nov. 1, 2010

Fresh produce at the grocery store is something that consumers commonly take for granted. When one thinks of the amount of energy consumption required to bring these commodities to market, transportation is the focus. What it takes to maintain an environment that ensures freshness at the point of sale probably is not the first thing that comes to mind.

The management at Mission Produce, Oxnard, CA, knows well what it takes to get produce into ready-to-eat condition for the grocery store. The global packer, importer, processor, and distributor of avocados and asparagus operates seven regional US ripening and distribution centers that allow just-in-time delivery. Using this network, Mission Produce—which also has operations in Mexico, Peru, Chile, and New Zealand—innovated the practice of supplying ripe avocados to retail, wholesale, and foodservice customers throughout the United States.

“It was probably seven years ago that ripening facilities started to pop up and helped increase per-capita consumption,” says Jake Nixon, process improvement project manager for Mission Produce. “When the person at the store picks up a rock-hard avocado, they might put it back because it’s not ready to eat that night. When stores were able to provide ready-to-eat product, the consumption went up. The business model changed slightly where, at the source, we try to maintain a really solid cold chain and keep as much shelf life as we can on that product, and then we try to ship it out to the distribution centers. They keep it in that suspended state of animation, and then, when it’s ready for an order, they ripen it to order—that’s how the business model changed.”

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These capabilities come at a cost, though. Several years ago, management became increasingly aware that energy costs were among the company’s highest. To keep up with dynamic cooling requirements at its Oxnard and Uruapan, Mexico, facilities, the company incorporated a Powerit Solutions Spara energy management system (EMS). Mission Produce’s experience is one example of how organizations are reducing energy consumption and improving their profitability through the use of intelligent, scalable EMS.

Nixon explains that the varying temperature of fruit that enters the Oxnard facility necessitates dynamic cooling environments in each of its 11 ripening rooms. The facility receives fruit from as far south as Temecula near San Diego, as well as from areas such as Oxnard, Ventura, and San Luis Obispo along the California coast. Nixon explains that incoming product can have widely varying temperatures, and some needs to be cooled more rapidly to sustain freshness.

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“The demand changes so much; we might have hot product coming in from the field that we might need to cool it really quickly, which takes a lot of energy, but then storage might not take so much,” says Nixon. “So we have to have a system that’s capable of ripening and then cooling it back down so that we can store product. We had to design a system for worst-case scenarios because we can’t afford to have the product to go bad, but then we don’t want to use the full capability all the time.” Nixon explains that the ripening rooms act like forced-air coolers that rapidly cool product, in contrast to more energy-intensive refrigerated rooms.

When the time came to act on the high energy costs, Mission Produce approached the Oxnard facility’s power provider, Southern California Edison (SCE), about participating in a demand-response program. But implementation proved difficult without an EMS tying together the company’s numerous disparate systems, according to Nixon. When the company was alerted to a demand-response event, trying to manually shut down system components took too long to be effective and the staff lacked the ability to fine-tune the entire system for ramp-up.

The company’s SCE representative recommended that SCE conduct an energy audit, and a representative from an energy management solutions company, EnerNOC, explained the benefits of automating demand responses. Ultimately, the Spara system was recommended as the intelligence in Mission Produce’s demand-response system, and it was implemented in Oxnard at the end of 2008 and at Uruapan in late 2009.

Spara is a Web-based EMS characterized by a graphical user interface (GUI) with industry-specific icons. The GUI is designed to enhance a facility’s existing HVAC decision-making system, i.e., its programmable logic controllers. The EMS is configured—initially by the vendor’s staff, subsequently by the customer’s staff—with decision thresholds such as outside temperature and relative humidity. When the preprogrammed thresholds are exceeded, the customer is alerted to adjust the operation of HVAC components such as compressors and condensers. In some situations, according to the manufacturer, some rules actually prevent some adjustments to be made. Under this scenario, alerts are sent indicating the need to adjust the rules. It is also possible to store system operating data in a database for future access and adjustment of the rules.

For Mission Produce, the system is configured to take advantage of energy efficiency, peak demand control, and demand response. Compressor staging and sequencing were implemented at the Oxnard facility and variable frequency drives (VFDs) were installed on condensers and evaporators. Additional temperature sensors were also installed on the walls opposite evaporators in the ripening rooms so that the system can more accurately gauge temperature throughout the rooms.

For demand control, the EMS facilitates the Mission Produce staff’s process of understanding where and when energy spikes occur and taking precisely timed measures to reduce them or shift them to nonpeak-rate hours. The EMS technology rapidly tracks dynamic operating conditions and adjusts power loads, sometimes for just minutes. This capability allows companies to participate in real-time pricing arrangements offered by some utilities that change their energy rates frequently, based on the market price of electricity. For demand response, Mission Produce is paid to reduce electricity consumption upon demand at times to be determined in the future. The Mission Produce staff occasionally receives a message of a demand-response event, such as an unusually hot day, and power usage must be reduced according to the terms of a contract with SCE.

The EMS at Mission Produce’s facility allows peak shaving, i.e., minimizing peak demand charges every month, according to Bob Zak, general manager and president of Powerit Solutions North America. Rules are established for the HVAC system, such as ensuring that defrosting occurs when rates are high and that the system is coming off of a defrost when rates are low. The key to successful peak shaving, Zak says, is blending and balancing controls capabilities with energy management curtailments.

The EMS’ ability to store historical data has led Mission Produce to adjust rules using the data. “Just having the system brings a whole new level of visibility within the operation,” says Nixon. “With that visibility comes the ability to get to know your equipment better and your process. So over the time that we’ve gotten to know that stuff better, we’ve been able to make minor changes.” A phase-two upgrade is planned for the facility that is intended to optimize some HVAC system components.

Most importantly, Nixon and Mission Produce have been able to quantify energy and financial savings through the use of the EMS. Since system implementation, the company has reduced its peak-load energy use by and monthly energy bills by about one-third. The average billed kilowatts have been reduced by 279 kilowatts (kW) and use has been reduced by an average of 141,112 kW. The EMS was said to pay for itself in 20 months, which is typical.

“I look at [return on investment] a little differently with this system because we got rebates [a $177,750 SCE rebate that paid for 52% of the system] and financed the balance,” says Nixon. “We put very little money down, and we’re paying approximately $4,000 to $5,000 on our financing and saving approximately $10,000 a month on energy. So from day one we were saving money. We went through the process in Oxnard and, we were happy enough with the results that we decided that we were going to do this with our facility in Mexico. Also, we’re currently looking at doing this with our other US operations.”

Photo: Powerit Solutions
Mission Produce’s EMS allows the operations staff to continually track total power consumption.

Dairy Producer Goes Enterprise-Wide
Gaining HVAC system performance visibility was how a leading US dairy producer set out to achieve a goal of reducing carbon emissions—and thus energy consumption—by 20% in five years starting in 2008 with the help of energy management solutions provider EPS Corp. Simply tracking monthly utility bills would not be enough. So the company and EPS implemented a four-plant pilot program using EPS’ xChange Point EMS, and the impact of increasing HVAC intelligence was immediate.

The system began to collect “near-time” electric, water, fuel, and weather data at each site and provided insight into the performance of subsystems such as refrigeration, compressed air, wastewater, and steam boilers within 90 days. Buried in the data were several remedies for optimizing system performance. For example, it was determined that boiler overutilization on weekends was leading to gas overconsumption. Correlating natural gas use with boiler feed water use helped save 20% on natural gas. Also, by shutting down noncritical loads, the system helped identify 200–300 kW in electrical savings, yielding savings of $3,000 per month at one facility.

In a January 2010 “Analyst Insight” white paper titled “Energy Intelligence: Creating Data Driven Efficiency,” EPS identified two main Key Performance Indicators (KPIs). Real Change in Energy Use means year-over-year change in energy consumption. Operating Margin versus Corporate Plan provides a more strategic operating context for energy consumption. EPS surveyed companies to determine which were reducing energy consumption the most, and why.

The survey identified three groups of companies. Best in Class (top 20% of the industry) achieved 15% real reduction in energy use and a 14% higher operating margin than planned. The Average group (50% of industry) saw gains of 7% and 2%, respectively, and Laggards (bottom 30%), experienced changes of 6% and -9%, respectively. Then, two major strategies were identified among the Best in Class companies. Under optimization, these companies improve system performance and, thus, energy efficiency. They also establish visibility into energy efficiency across the enterprise.

The provider’s xChange Point EMS is designed to provide a real-time energy management by taking enterprise-wide energy usage data and converting it into targeted, actionable information for managers and employees. The system tracks energy usage of subsystems by unit of production at plants across an entire enterprise. EPS also continually monitors a customer’s facilities and report conclusions and recommendations.

According to Julie Moran, executive vice president for xChange Point, the most energy-intensive subsystems at the dairy company were steam boilers, refrigeration, and compressed air. Some of the more common opportunities for improvement in these three subsystems are setting the right discharge pressure in steam boilers, discharge pressure for refrigeration, and overall pressure settings in the compressed air system. Often, it is not abnormal to find that setpoints are higher than what’s needed for optimal production, she adds. As a general rule of thumb, just by optimizing those set points, companies can cut overall energy consumption by 2% to 3%, according to Moran. Other areas for improvement in this type of facility typically include normalizing for weather, reducing overall water volume used in processes and for cleaning pipes—which reduces steam usage—and identifying and fixing water and compressed air leaks.

Once a baseline is established for a standard production cycle, e.g., over a week, minimum and maximum rules are set up. An e-mail message is sent directly to a manager alerting him when operating data fall outside of these parameters. Moran reports that, within the first month of monitoring, a customer achieves a 3% energy-consumption reduction using no-cost or low-cost measures. For an entire typical project, she adds, the improvement is commonly more than 20%. In some cases, achieving the 20% savings requires some capital investment, Moran notes.

Access to real-time HVAC operating data can completely transform the way that management views energy consumption, Moran argues. “A change in behavior comes from knowing that someone can actually monitor whether the staff did what it was supposed to do, whether or not they’re actually applying the best practices or the standard operating procedures,” she says. “The other thing we’re finding is that companies are integrating this information into their continuous improvement processes so that the daily tracking and daily measurement is more automated. Today, a lot of this information is captured manually—it’s slow or way after the fact that they have the information. The third benefit is the ability to prioritize capital spending more effectively as it relates to carbon emissions.

“One of the things we’ve incorporated is tracking of all the savings opportunities that have been identified that may require capital investment,” continues Moran. “Those are all measured consistently; in other words, the energy savings calculations are done consistently whereas, typically, if you don’t have this type of system in place, you may be getting those calculations from manufacturers or from other sources; they may not help you as far as measuring capital requirements.” It is also possible for a customer with multiple facilities to actually create a sense of competition among the plants using a Web-based information-sharing system that allows management to view dollar savings or emissions reduction across the enterprise, Moran adds.

“Industrial operations are definitely a ‘show-me’ environment, and the ability to visualize the data—actually see it in front of you, actually log on and watch it in real time—has an impact on people’s beliefs,” says Moran. “Also, the more facilities with similar operations that you monitor, the faster it is for us to establish the best practices and the baselines to immediately identify the key variables. I would say that speed is really key. In the past, this would have been done with computer models or projections, and this all would have been theoretical.” Based on the success of the pilot program, the system was eventually implemented at 50 of the firm’s largest plants in 2009.

Mall Prepares for Demand Response
A good candidate for participating in a demand-response program is a regional shopping mall such as The Mall at Robinson, a two-level, 880,000-square-foot enclosed regional shopping center with more than 120 specialty shops and eateries located in Pittsburgh, PA. Dave McGaffin, operations manager, explains why. “Peak demand is normally from four to eight o’clock [p.m.], when people are getting home from work, which is typically a slower time for us,” he says. “So demand response is a really good fit for us. We might be able to compromise our lighting or temperature at that time because our occupancy is low.”

Photos: Powerit Solutions
Using an industry-specific graphical user interface, Mission Produce’s EMS indicates to operations staff how HVAC system components such as compressors are performing versus preprogrammed rules.

With this in mind, the mall signed up for the PJM ILR Summer Capacity Program offered by demand-response solutions provider North American Power Partners LLC in 2009. As of late summer 2010, the mall had not had the opportunity to participate in two years, but the capability is there. The mall already had an Andover EMS set up when it opened in 2001; the Andover system has since been acquired by Schneider Electric. When demand response is activated on the EMS, electricity would be cut to individual heating and cooling system components and some lighting circuits. McGaffin reports that automatic demand response was recently incorporated to manage peak loads; since enrolling in the program, the mall has been able to stay within 10% of its automatic demand-response targets. The system does have temperature sensors to override response measures if necessary, to keep the temperature at a comfortable level, although it does not adjust to the environment outside of the mall to any appreciable degree, according to McGaffin.

McGaffin says that the mall staff would also shut down many components and circuits manually. After the decision was made to get involved in demand response, the staff went through the facility’s electric distribution rooms and put pink demand-response stickers on the outside of the panels that have equipment that has to be manually disconnected. Some circuits inside the panels are also marked with pink stickers, according to McGaffin. “The stuff that’s under our control, like our HVAC units or ventilation fans or lighting, we’re controlling through the EMS,” says McGaffin. “But we’ve also found that, for example, we have a dishwasher in our food court that draws a 50-amp load at 480 volts, and we would manually shut that down so it’s not used. Sometimes we would shut down a couple of our service elevators, too.”

Beth Edwards, the mall’s general manager, explains that The Mall at Robinson’s involvement in the demand-response program is a pilot for other properties in owner Forest City Enterprises, Inc.’s portfolio of properties. The mall also signed up for another program with North American Power Partners. Under the voluntary Energy program, the PJM regional transmission network asks aggregators such as North American Power Partners to have companies either generate power for the grid or request that they curtail use, if possible. In contrast to the PJM ILR Summer Capacity Program, which involves mandatory participation in demand-response events, companies can determine how long to curtail energy use under the Energy Program. Participants can earn financial incentives under both programs.

A recent development in EMS for lighting is Schneider Electric’s release of the Powerlink EM system, an addition to the Powerlink G3 intelligent lighting control portfolio. The Powerlink G3 systems automatically switch loads off during non-occupied periods and are often used to reduce peak demand by switching unnecessary lights off, in response to an automated demand response signal or when high time-of-day energy tariffs occur. The Powerlink EM system is configured with individual branch circuit remote control and metering functions in a lighting panelboard enclosure. The enclosure is designed to allow users to monitor the performance of the control system by energy savings by circuit, zone, space, panel, or entire lighting system. The system captures historical trend data that can be used to determine additional energy savings and generates reports on actual energy used. It has an integral scheduling functionality for operating individual brand circuit according to a daily schedule, connectivity to building automation systems via BACnet and Modbus communications, and an embedded Web server that allows access to the system operation and configuration. The system can be used in conjunction with the PowerLogic Branch Circuit Power Meter, a multi-branch circuit power meter designed for low-current monitoring.
About the Author

Don Talend

Don Talend specializes in covering sustainability, technology, and innovation.

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