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E-commerce expansion is putting the spotlight on warehouse construction. Recent data from Cushman & Wakefield shows that e-commerce accounted for roughly 20 percent of new industrial leases in North America heading into 2018. That’s up from less than 5 percent in 2013. Expansion is expected to continue, with a net 655 million square feet of warehouse space absorbed between 2017 and 2019.
Although most warehouses are built near economic hubs with access to natural gas and electricity, growing distribution footprints and rapid industrial expansion mean there are opportunities beyond the gas grid. Harris Baker, president at HBH Gas Systems and former vice president of business development at Pinnacle Propane, said Pinnacle is among the suppliers seeking out such projects in high-growth markets “where industrial expansion can outpace the grid.”
For Pinnacle, that includes a large custom cabinet manufacturer and a beer distributor. “Both are simply off the natural gas grid,” he says.
In those cases, and others like them, propane is helping construction professionals deliver efficient and effective heating solutions tailored to the project’s needs.
One size doesn’t fit all
To maintain indoor air quality, the cabinet manufacturing facility and beer distributor each need continual infusions of outdoor air. But their unique functions — refrigeration in one and manufacturing that contributes VOCs to the air in the other — required different approaches to HVAC.
To maintain its controlled-environment warehouse, the beer distributor uses makeup air units (MAUs) for heating and ventilation. Refrigerated areas totaling around 40,000 square feet are kept at 38 degrees Fahrenheit (F), the warehouse at 70 degrees F, and the two-story, 20,000 square foot office space between 73 and 75 degrees F.
“Beer distributors are required to monitor and report all temperatures as product moves through the warehouse and draft cooler spaces,” Baker says. “It was therefore essential that correct temperatures be maintained in the [warehouse and cooler] as varying amounts of product move through those spaces.”
To achieve that level of zone control, variable frequency drives, variable air volume boxes, and fan terminal units are used. Because outdoor air is being pulled in and chilled, below-freezing weather can make the indoor refrigerated areas too cold, degrading product quality. The MAUs warm the air during those periods and pump it into the coolers, keeping temperatures stable.
“It sounds really simple, but an important question to consider when heating a warehouse is: How many times do the warehouse doors open and exchange air/heat loss?”
Climate-controlled warehouses must also be designed to move product quickly to avoid damage. That makes features such as level floors, high-speed automatic doors, sealed openings, and strip curtains critical. “It sounds really simple, but an important question to consider when heating a warehouse is: How many times do the warehouse doors open and exchange air/heat loss?” says Steve McCoy, regional vice president at Blossman Gas.
The cabinet maker Pinnacle services uses power-vented heating along with MAUs to keep indoor air fresh in its 30,000-square-foot space. That is particularly important because the manufacturing process contributes wood particulates and VOCs to the air, Baker says.
Getting the load right
Propane can be an efficient option for heating the large volumes of space typical for warehouses. To tailor an HVAC system to a warehouse’s needs, engineers calculate variable heating and cooling loads for products and systems such as variable speed fans, desiccant dehumidification systems, and forced-air MAUs, Baker says.
In non-refrigerated warehouses, high-intensity infrared is typically the most popular heating choice because it has a low per-unit cost and doesn’t require venting, according to McCoy. The units can be suspended from the ceiling and directed toward the source of the heat loss.
“In other words, if a warehouse has three solid walls and one wall of overhead doors, the heaters would be directed down in front of the doors to ‘wash’ the heat loss [area] with heat,” he says. Low-intensity infrared is also popular, but it requires venting.
Knowing how propane can be used to fuel application-specific heating and ventilation systems can help pros in all areas of the country take advantage of the current warehouse construction market.