Infrared Heat Increases Comfort, Lowers Energy Costs
Put the Heat Where It’s Needed
For many industrial and institutional facilities, space heating during the cold months is a major expense. Yet many portions of these buildings do not require continuous comfort-level heating. Examples are warehouses and high overhead spaces in manufacturing areas. Other facilities need heating only during certain times of the day, or during certain operations. Yet convection heating necessarily heats the entire space, and often has to continue to operate even when the space is unoccupied. An energy-saving solution is natural gas-fired infrared heat.
Heating People, Not Air
Modern gas infrared heating units take several forms, including radiant tubes, ceramic panels, and various types of radiant reflector units. A large portion of the heat they produce does not heat the room air, but rather heats solid objects in its path – tables, work surfaces, floors, and most importantly . . . people. Thus infrared is inherently more energy efficient, and because it begins heating immediately, need only operate when the area is occupied.
Infrared is the portion of the light spectrum with a wavelength longer than visible light. Much of the heat we get from the sun is in the infrared wavelength. Think of the heat one feels from the sun outdoors on a bright February day, when air temperatures may still be quite low. That’s infrared.
Suitable for Many Environments
Jim McLellan from Schwank Group was recently a presenter at a Technology & Market Assessment Forum sponsored by the Energy Solutions Center. Schwank is one of the major suppliers of infrared heating products for industrial, institutional and commercial buildings. McLellan points out that gas-fired infrared heating units can be used in a wide range of environments, except where conditions require “explosion-proof” equipment. He notes, “Infrared heaters provide comfort based on the principle that comfort temperature is equal to the average of ambient air temperature and mean radiant temperature in the space. So by increasing the radiant temperature in a space, the ambient temperature can be reduced, yet comfort of personnel remains the same.”
McLellan adds that warm-air systems result in hot air near the ceiling that is called the ‘chimney effect.’ “The greater the temperature differential from outside, the greater the rate at which the hot air will escape from the building, and draw in cold air at lower building levels to replace it.” Because infrared systems do not heat air, temperature stratification is greatly reduced, thus dramatically reducing heat loss. He emphasizes, “Reduced heat losses equal reduced fuel consumption compared to systems that only provide comfort with warmed air.”
Improved Infrared Output
According to McLellan, the proportion of heat emitted by infrared heaters as actual infrared has significantly increased over the years. The ANSI/CSA Standards by which IR heaters are approved require a minimum of 35% radiant output to qualify as an “infrared radiant” heater. Earlier technology achieved levels of 45% to 50% radiant. McLellan notes that Schwank has invested in R&D that has allowed certain infrared appliances to reach outputs of up to 81% infrared efficiency. Tube heater technology has improved from 45% to the 60-65% range. As IR efficiency goes up, heat losses go down.
One of the principal advantages to infrared comfort heating is its adaptability to zoned heating. McLellan indicates, “Not only is zoning practical, it is the standard procedure. Storage and warehouse areas can be maintained at lower temperatures than personnel production areas to provide further reductions in operating costs . . . try that with warm air systems!” In many production facilities, certain areas are only used part of the day, or during certain times of the year. Infrared units can be switched on or output levels increased only during those occupied hours.
A widely used type of infrared heating system is indirectly-fired radiant tubes. In this system, a burner directs a long flame into the end of a specially-designed coated metal tube. The tube is surrounded by a polished metal reflector, which directs the energy down and outward, to warm people, machinery, products and the floor below. These systems can be used for wide areas, even entire buildings.
According to Bob Alcott from Schwank, in industrial facilities the best applications are buildings with ceiling heights of 14 feet or greater. It is generally recommended that the heating units be placed in greater density in areas with the greatest heat loss, such as overhead doors and perimeter walls. Because part of the heat output of an infrared is convective heating of the surrounding air, the use of these units will contribute to higher room air temperatures as well.
Range of Climate Applications
Industrial and institutional infrared space heating is an attractive primary or supplementary resource in cold climates such as the northern tier of the U.S. or Canada, but it is also very suitable for climates further south, that have a shorter heating season. Owners of facilities in these areas may not wish to invest in a forced air or hot water heating system for the entire facility, but need spot heat during the coolest months of the year. Gas-fired infrared is affordable and valuable facility floor space need not be tied up with heating equipment that is used only a few months of the year. Overhead infrared units are ideal.
According to John Vancak, President of Calcana Industries Ltd., the flexibility of infrared is one of its greatest features. Calcana offers its SR-Series of radiant tube heater for industrial, commercial and agricultural applications. This product is available with an input rating of 40,000 to 200,000 Btu/hr in lengths from 10 to 80 feet. For ease of installation, the first ten feet is pre-assembled, and can be configured for L-shaped and U-shaped installations.
Significant Savings Possible
Vancak says, “By using infrared tube heaters, one can realize significant savings over conventional boilers and forced air units in the 40% range. This is supported by ASHRAE studies.” He adds, “Infrared heaters not only offer significant fuel savings, but they offer the ability to zone and spot heat an area, thereby giving comfort to a specific spot without heating the entire space. Also, there is very little noise with our units, and the draft-free heat combined with warm, dry floors gives workers an outstanding work environment.
Manufacturers of infrared equipment such as Calcana and Schwank indicate that industrial or institutional owners can contact them directly for guidance on sizing and placement of infrared heating equipment for optimum efficiency and comfort. If your industrial or warehouse building heat plan needs an update, be sure to include the infrared option as a consideration.
Original content can be found at Oil and Gas Engineering.