One of the most unwanted guests in a cold storage facility is air infiltration, often let in by improper sealing of roofing, walls, and doors. The result is increased fluctuations in climate control and increased energy costs.
Refrigerated dock areas, for example, present an opportunity for warm, moist air to infiltrate a climate-controlled facility. This can be attributed to the number of dock doors, the duration of time dock doors are open, and the quality of the dock seal or shelter.
“The result is fogging, resulting in low visibility for employees and slippery floor conditions for forklifts and staff walking on these surfaces,” says Brad Barke, President/Founder, ESI Group USA.
Fortunately, improvements to roofing, refrigeration, metal panels, and doors, are making it easier to control temperature and, ultimately, lower utility costs.
Refrigerated Dock, photo credit to NM.Photos
TPO Roofing
The standard in today’s temperature-controlled buildings is a white thermoplastic polyolefin (TPO) mechanically fastened or a fully adhered roofing system. Unlike the ethylene propylene diene terpolymer (EPDM), the “go-to” roof membrane for years, a single-ply TPO is more resistant to weather, ozone rays, heat, and oxidation. Other advantages include:
- A 45-60-mill thick membrane and reinforced with a fiber scrim to provide additional strength;
- Heat-welded seams in the membrane;
- Higher vapor resistance compared to EPDM;
- Better wind uplift rating and less chance for leaks compared to ballasted roof systems; and
- A reduction in the size of certain steel members due to the reduced weight of the system.
Thicker Panels
Factory-insulated metal panels have been the standard for decades. Manufacturers have been improving the technology, specifically the joint details and the formulas of the foam core and insulation blowing agents, to reduce the amount of ozone reducing minimize greenhouse gases.
“Today’s temperature-controlled facilities use thicker panels to increase R-values, depending on the room temperature,” says Barke. “The thicker panels also have the ability to achieve longer spans that can increase horizontal girt spacing.”
Faster Doors
The tighter the building envelop the better. But we still need doors to enter and exit cooled spaces. The challenge is to open and close doors as quickly as possible and maintain the insulation value of the walls. The most common door is the high-speed rollup, which provides a quick open and close, minimizes air infiltration, and can even self-repair if hit by a fork truck. The downside is the R-value is minimal compared to the wall panel. Air doors are another good option for minimal impact from fork trucks and minimized infiltration, however the R-value is almost nonexistent. Often, air doors can be paired with a high-speed rollup. “This is a great solution but is expensive to operate and comes with a very high up-front cost,” says Barke.
Low-Charge Refrigeration
Modular low-charge refrigeration systems use ammonia or CO2, along with a secondary refrigerant, to maintain temperature control while using less refrigerant. Advantages include:
- Eliminating the need for a compressor room;
- Shorter construction duration;
- Reducing field piping and wiring; and
- Compressor vessels and pumps are assembled under controlled conditions with lower labor costs.
Today’s facility owners understand that utility costs are one of the largest operational expenses. When considering a new facility or an expansion, an early point of discussion should focus on how to minimize those costs by controlling temperature within the building. “We can show owners energy models, discuss energy-saving technologies, and present them with the options discussed above,” says Barke. “These are solutions that are well worth the cost and will ensure a return on investment.”
Quick Facts
40% of construction costs stem from rework of faulty or incorrect builds
Low-charge refrigeration requires 1-lb. of refrigerant/ton
High-speed roll-up doors open and close in 1-2 seconds
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