System Assessments

This article explores the distinction between standard system controls and holistic controls for highly efficient process cooling systems. Examples of high performance controls features and implementations are provided, and screening questions are listed for initial investigation of existing system and potential new systems.

For the Production Support team at the expansive Quad printing plant in Sussex, Wis., there isn’t one way to manage the operation’s complex and elaborate process cooling system. Rather, the formula for success involves a three-pronged approach that includes carefully measuring and monitoring system performance, diligently and proactively maintaining equipment to ensure peak efficiencies, and investing in updated equipment based on sound decision making. 
Since its inception, MDW has seen growth in air travel. To handle the increased passenger volume and modernize the airport, a larger terminal went under construction in 2000 and was completed in 2004 as part of a terminal development program. The program also included a new Central Heating and Refrigeration Plant (CHRP), which was completed in 2000 to serve the increased cooling and heating needs of the new terminals. The CHRP was a separate contract from the terminal modernizations and was awarded using a third-party design build contract. Unicom Thermal Technologies (UTT) was awarded the project with Hill Mechanical Group (HMG) as its contractor. 
Reducing fossil fuel use is key to meeting the dual goal of carbon and energy cost reduction. A Full Heat Recovery Engagement (FHRE) approach can dramatically reduce both, through applying simple principles and using existing technology. Simple measures can help focus the design of both the buildings served and the systems used to achieve these goals.
Opened in fall 2018, the new $19.3 million school building spans 65,837 square feet with a capacity to serve 500 students. The building serves students of pre-school age through Grade Five and is also designed to host groups of various sizes during summer months. It also serves as the campus gateway to the adjacent Elkton Public Library and the Elkton Middle and High Schools.
Schoeneck Containers, Inc. (SCI) is a company that thinks a lot about its future – and how to continue to maintain a long track record of profitability and reliability while meeting a growing demand for its quality plastic containers for customers throughout North America. It’s the kind of thinking driving the decision to install a closed-loop adiabatic fluid cooler and central chiller with free-cooling capabilities at the company’s new 250,000-square-foot production facility in Delavan, Wisconsin.   
“Evaporative cooling capacity for the district system is provided by a six-cell, open-loop cooling tower capable of 6,000 tons,” said Reid Olsen, USU Central Energy Plant Manager, who has been at the university for 26 years. “This tower serves the condensers of the water-cooled chillers at the heart of the district cooling system. There are four chillers in all, two of which are rated for 1,800 tons each, and the other two are 900 tons apiece. The cooling towers reject heat from the condenser water loop via evaporative cooling, allowing the chillers to supply chilled water to the campus cooling loop.”
For U.S. Flue-Cured Tobacco Growers, Inc. (USFCTG) sustainability is a guiding practice for tobacco production from seed to delivery. So when traditional chemical water treatment had proven problematic in air washers at its plant in Timberlake, North Carolina, the company thought outside the box for solutions to address a variety of issues while also supporting its sustainability goals. 
Do water-cooled chiller plants still deliver lower utility bills? Today, many chiller plant energy analyses carefully account for energy costs, and even energy escalation rates – a factor that projects how fuel costs will increase over time, while ignoring water and wastewater costs associated with cooling towers. While highly effective at transferring heat, cooling towers consume millions of gallons of water each year through the process of evaporation, drift, and blowdown. With the rising cost of water and wastewater, this omission can result in an incomplete picture for the building owner.
The need to pay close attention to the university’s central chiller plant has always been a priority given the energy required to power the chillers, said Michael Bolien, Manager of Central Plant Operations, University of Tulsa. At TU, seven water-cooled chillers provide 7,000 tons of cooling capacity to all university facilities. “Over the past five years, TU has had a 17% increase in cooling load, based on the square footage of new buildings. Because our central chiller plant is our biggest energy user, optimizing its operations is our first line of defense,” said Bolien.
Chillers are an essential component in many building Heating, Ventilation and Air Conditioning (HVAC) systems. They provide cooling to the building by working in tandem with pumps and cooling towers in a water-cooled chiller plant. Because of the chiller’s complexity and its role in cooling facilities, it is arguably the most important piece of equipment to maintain.