Custom Chiller with Ambient Dew Point Control Improves Cleanup and Efficiency at Manufacturing Plant
01/29/2026
Many manufacturing plants optimize their chillers’ outputs to minimize condensation on production machinery, but in this case study, a manufacturer had a problem with too little condensation. That opportunity gave Delta T Systems a chance to create a custom solution and win over a major manufacturer.
Half the chillers Delta T Systems delivers are customized for the client’s process.
A building materials manufacturer in California had a problem with the dust produced by its manufacturing process. Dust adhered to the production machinery and hardened, and cleaning it was a time-consuming chore. Plant managers had a solution in mind, but the company’s existing chiller couldn’t support it. After researching options, the company reached out to Delta T Systems of Richfield, WI.
Most manufacturers want process chilled water temperatures set so dew won’t form on the outside of their production equipment. This plant wanted the opposite: It wanted dew to form. Then, dust would adhere to the dew, and the moist paste it formed would be easier to clean than the hard crust that built up otherwise.
Rick Holzhauer, Director of Engineering, Delta T Systems.
Jochen Naujokat, President, Delta T Systems.
Lowering the Chilled Water Temperature Makes Cleanup Faster
The plant uses a slurry cement mix to create various products, including cement board and cement siding. Finishing equipment rollers pick up heat from the cement, and then need to be cooled with chilled water. The plant’s existing chiller supplying process chilled water didn’t include an ambient dew point sensor.
“Dust built up in their finishing equipment,” said Rick Holzhauer, Director of Engineering, Delta T Systems. “By having the dust adhere to the rollers through the moisture, it was easy to clean. It saves them a lot of time.”
Running chillers above the ambient dew point is more common. In injection molding, for example, plants don’t want their molds to sweat, because that would introduce moisture into the plastic.
To get dew or condensation to form on the outside of the rollers, the temperature of the chilled water needed to be below the ambient dew point. It’s the same principle that makes beads of water form on the outside of a cold soda can. The company was able to supply a chiller with an automatic ambient dew point sensor. It monitors the ambient dew point and automatically adjusts the temperature of the chilled water so it’s below the ambient dew point. The plant set the automatic ambient dew point sensor to 5-15°F (3-8°C) below the ambient dew point, so as not to waste money by chilling water more than was needed.
“The chilled water temperature is automatically adjusted because our chiller senses not only the dry-bulb temperature, but also the humidity in the air. The set point adjusts itself based on that. It's all automatic. All the plant does is set the number of degrees below the ambient dew point they want to arrive,” Holzhauer said.
“They're making cement board, and when that cement dries on the inside of their finishing equipment, it turns to concrete,” added Bob Proudfoot, Sales Manager. “If they can keep their chilled water pipes and rollers sweating, dust doesn't harden. It stays soft. Then, when they clean after several days of production and they pressure wash the inside of their equipment, the layer of dust is soft, more like mud than cement. Cleaning the inside of a machine used to take them a full shift, but now takes about an hour.”
Around half of the chillers the company delivers are customized for the client’s process. In this case, the requested changes led to customization of the controls.
“They told us we want to be able to run far below the ambient dew point,” Holzhauer said. “They told us what they wanted for a setting window, and we changed our program and controller to allow for that. The colder the process water is, the more the process machinery is going to sweat. We experimented a little. Originally, we changed the controller so the customer could go 5 or 10°F (3-6°C) below. Now, it's set up so they can go to 25°F (14°C) below.
“Customers all have different demands. Just like your home air conditioner, you might put a window unit in because you have a lower demand in one room, versus a large central air system. It just depends on the load the customer puts on the chiller.”
Delta T Systems modified the controller on this chiller so the customer can chill water 25°F (14°C) below the ambient dew point.
Energy Savings with Variable Speed Drive Chillers
The automatic ambient dew point sensor wasn’t the only reason the plant selected its new chiller. The previous model didn’t include a variable speed drive (VSD), and that’s the only kind Delta T Systems manufactures. All of its chillers now use R-32 refrigerant, a single refrigerant (not a mixture) with high efficiency and no PFAs, meeting the EPA’s new global warming potential limits.
“Anytime you put a VSD on any kind of motor, you're going to increase the efficiency during lower speed operations,” said Holzhauer. “It's a cubic function: the horsepower is a cubic function of the speed. It's not like if you ran at half the speed, you use half the horsepower; it's actually less than that. It's beneficial to only run the motor at the speed you need it to run. Most chillers run at full speed when they don't need to run at full speed. The chillers will either cycle the refrigerant compressors on and off or incorporate what's called a hot gas bypass valve to essentially falsely load the evaporator. That’s inefficient. You're taking discharge gas from the refrigerant compressor and dumping it right back into the evaporator. At full speed, a 10 horsepower (hp) motor, you're going to have 10 hp of energy used, no matter what the load is.
“With variable speed chillers, we can vary the speed to exactly match the precise horsepower the plant needs. That's a huge energy saver because most people don't run at full speed. A study by the Air Conditioning, Heating and Refrigeration Institute (AHRI) showed how many hours at each capacity chillers run. The study mostly looked at air conditioning chillers, and found out on average they run at about 50-60% capacity.”
The plant had multiple chillers running at fixed speed, even though process demand varied. At times, the process didn’t need the full amount of chilled water produced. Switching to a VSD chiller allowed it to better meet demand.
“They were mostly concerned with controlling the chilled water temperature. A VSD refrigerant compressor is going to hone in on the exact speed it needs to run to maintain the temperature, because this particular customer – and a lot of customers – run variable loads for their process. They might run one or two or several production lines, and that changes throughout the day. They want their chiller to consistently give them a constant temperature,” Holzhauer said.
VSD Chiller Optimization“Everything on our chillers is automatic,” Holzhauer said. “Our control looks at the most efficient operating point. We're looking at not only the water temperature of the unit, but the refrigerant temperatures and pressures, as well. That adjusts the speed of the refrigerant compressor and the condenser fan to operate at the most efficient point, and also adjusts the electronic expansion valve. We have an algorithm built into the control that always looks at the most efficient operating point and makes adjustments as needed. “We monitor the ambient temperature, as well, and we can determine where the fan should operate based on the ambient temperature. We also offer, as an option, a variable speed drive on the pump, which gives additional energy savings. If they don't need full flow and pressure on the pump, we can adjust to whatever their needs are. “Customers can set a specific pressure they need for their process. With most customers, that's what they're looking for. If they're turning machines on and off, closing valves, they want to maintain a constant pressure that gives them the constant flow they need to the process, which is important because the constant flow helps with the quality of their parts. If that flow changes through their molds, you're going to get hot and cold points in the mold. Customers try to maintain flow through the mold cavities. We monitor the pressure and vary the speed of the pump to maintain that pressure.” “One customer rarely runs 24/7 at 100% load of the chiller,” Naujokat said. “That's the only example where there's probably no difference between us and a traditional on-off chiller. But the normal circumstances are that the customer runs at various loads during the day, and the chiller ramps up and down, running at different speeds and different capacities. With that comes energy savings. Customers might end up paying a little bit more at the beginning, but if you look at it over a chiller’s 10 to 15 year lifespan, the total cost of ownership for a VSD chiller is significantly lower.” |
Adding a 30-ton Chiller with a 50-micron Water Filtration System
Delta T Systems audited the plant and calculated the load required based on the amount of material flowing in the process, the temperature of the material and the temperature the plant needed to maintain. In the end, the company recommended a 30-ton chiller. The customer selected filtration options appropriate for the dusty nature of the plant: It selected a fine mesh filter to prevent dust from settling on the heat transfer coils, and a 50-micron water filtration system. The ease of access it offered for cleaning was well received by the customer.
“The plant was a very dusty environment. With our chillers, removing the air filter screens around the condenser coils is a matter of seconds,” said Jochen Naujokat, President, Delta T Systems. “You pull the release pins and you take it out, wash it off and put it back in. From a maintenance perspective, they really appreciate that simplicity.”
The plant also selected a display option that let it add the chiller to its network and see and operate the chiller remotely from a phone or tablet.
The chiller replacement has been so well received that the customer purchased VSD chillers with custom ambient dew point controls for plants in the Midwest and South, as well. When the California plant outgrew its 30-ton chiller, it transferred it to a Midwest location and purchased a 40-ton VSD chiller. In all, the company has sold the customer eight chillers for four locations.
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About Delta T Systems Delta T Systems has been in business since 1990. When the original two owners retired in 2012, Jochen Naujokat purchased the business. At the time, the company only made water and oil temperature controllers. When Rick Holzhauer joined in 2017, he designed the company’s first chiller. Since then, the company has extended its engineering capacity and product offerings with different sizes and designs. “We’re now going into larger refrigerant compressor sizes that allow us to reach higher capacities,” Naujokat said. “It's more cost-efficient because we’re reducing the number of circuits in the system. Right now, for a 60-ton cooling capacity, we need four circuits. Soon, we will be able to supply 50-ton chillers with two circuits, which is a massive price reduction for our customers.” The company offers a dry cooler with an air-to-water heat exchanger for customers that have the ambient temperature needed for free cooling, rather than using a vapor compression cycle. “It's a lot more efficient,” Holzhauer said. “You don’t have to run a refrigerant compressor at all. You only run fans across coils to cool the water. Especially in Wisconsin here, you can use it much of the year to get cold water without running a refrigerant compressor. “We're also creating a chiller-dry cooler combo unit where you can run a dry cooler most of the year and then use the chiller when you need it. It's highly energy efficient, as well.” That model should be available in the first half of 2026. |
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