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Low-Pressure Lowdown: The Rise in Steam-Heat Applications

Sept. 13, 2017
The industries spurring the increase in demand.

For more than a century, steam heat has been a staple of homes and commercial buildings. Steam has proven extremely effective at providing controlled, consistent heat throughout a building without the need for pumps, requiring only a durable boiler. Over the last 50 years,
however, the use of steam for regular comfort (space) heating has declined, as newer technologies have gained traction.

Yet specific industries and applications, such as breweries, distilleries, and scientific laboratories, are increasing the demand for steam heating and enjoying myriad benefits as a result.

Why Steam?

Many applications require precise levels of heat for desired outcomes to be achieved. For example, in food production, quality must remain consistent. That can be difficult with some heating technologies, such as direct-fired heating. Direct-fired heating requires management of extremely high temperatures that can fluctuate and scorch products, yielding varying results.

Steam heating generates large heat loads, but in a more controlled way for greater consistency and higher product quality. Steam heating is available from high- and low-pressure boilers, which allows owners to match equipment to their unique needs. Many who traditionally have opted for high-pressure steam are realizing the benefits that can be had with low-pressure steam.

Use of Low-Pressure Steam on the Rise

The operating pressure of a steam boiler should match the temperature required for the application. Nevertheless, it is commonly believed low-pressure-steam boilers are not suited for process heating. In fact, many businesses running high-pressure-steam boilers likely could satisfy their heating needs with low-pressure-steam boilers, achieving the same results while saving on both equipment and operating costs.

With high-pressure steam come complex and costly regulations. With high-pressure-steam systems, operators may need specialized training and certification and be required around the clock. Additionally, with high-pressure steam, owners are required to purchase specialized insurance. Opting for low-pressure steam when it satisfies process requirements, then, reduces regulatory burden, increases staffing flexibility, and reduces overall insurance costs.

With high-pressure-steam systems often calling for specialized welding, low-pressure-steam systems can be less expensive to purchase, install, and repair. While many steam heating applications can be served easily with either a low- or a high-pressure system, some processes are better suited for high-pressure technology. For example, high-pressure steam is ideal for extremely large facilities with high heat demands, such as hospitals with sterilization requirements. These applications need much higher pressure: 60 psi and above, compared with the 15-psi limit of low-pressure steam.

Modern-Day Low-Pressure-Steam Applications

In the United States, a number of growing industries are embracing low-pressure-steam heat for its cost efficiency and versatility.

Food and beverage. Pasteurization involves heating a food or beverage product to a very specific temperature to eliminate harmful pathogens without impacting taste.

An increasing number of small craft brewers, micropubs, and microdistilleries are enjoying the low costs associated with low-pressure-steam heat while achieving consistent batches and reducing waste. Additionally, they are using their steam boilers to create hot water through a steam-to-water heat exchanger for cleaning and other sanitization needs.

Laboratories. Laboratories on college campuses utilize a tremendous amount of exhaust air when experiments and tests are being conducted. To make up for the large amount of exhaust air, the laboratories bring in an equal amount of outside air, which can be extremely cold during winter and require a significant amount of heat to warm to neutral conditions. When the air is below freezing, other forms of heating, such as hot-water coils, may be more susceptible to freezing and damage. Low-pressure steam is much less vulnerable to this risk and provides large heat capacities.

Lumber kilns. Lumber mills often house a variety of specialty hardwoods that require drying in a kiln. Using a low-pressure-steam boiler enables mills to perform this function safely and effectively for standardized results, increasing the quality of wood.

Manageability and consistency make low-pressure-steam heat ideal for these and other growing industries.

As food and beverage manufacturers adopt low-pressure-steam heat at an increasing rate, other industries are starting to familiarize themselves with the application opportunities and benefits of the technology. Chemical and cosmetics manufacturers, for example, are discovering they can swap a high-pressure system for a low-pressure-steam application to obtain the same results at a reduced installed cost and lower operating costs.

Factors to Consider

Before selecting a low-pressure-steam boiler, take inventory of your business’ needs and facility amenities. Most low-pressure-steam boilers are highly configurable to match the unique needs of an application. Furthermore, many low-pressure-steam boilers can be built into existing systems or designed for new installations, ensuring consistency and efficiency.

Further underscoring their versatility, commercial low-pressure-steam boilers come in a variety of sizes and run on several fuel sources. High-quality options can operate on natural gas, propane, oil, or a dual-fuel option, while ranging in size from 48 lb per hour to 8,800 lb per hour in a single boiler.

When evaluating boiler options, determine what is required for optimal production first and then build a system to match to avoid unnecessary costs. For businesses with limited demands, simple atmospheric burners are available at low costs. For higher-demand operations, power-burner models allow for greater capacity and flexibility.

Controls for burners are customizable to enable varying levels of precision in temperature regulation throughout a system. Burner control ranges from:

• Simple on/off functionality (good).

• Low/high/low—offers low stage to more closely match lighter loads and reduce energy consumption (better).

• Full modulation—offers precision heating and variable control (best).

Owners with complex heating requirements may opt for a multiple-boiler control system to run larger operations more efficiently.

Lastly, before choosing a low-pressure-steam boiler, owners should consult with an industry professional with expert knowledge on specifying the best boiler to meet steam-system operational needs. An industry expert can explain the different steam-piping designs available to ensure the product fits the application seamlessly and achieves optimal performance.

About the Author

Dave Burggren | Director of commercial sales

Dave Burggren is director of commercial sales for Weil-McLain, designer and manufacturer of hydronic comfort-heating systems for residential, commercial and institutional buildings. Founded in 1881, Weil-McLain is based in Burr Ridge, Ill., with manufacturing facilities in Michigan City, Ind., and Eden, N.C., and regional sales offices throughout the United States and Canada.