Innovative Process Heating Technologies
Heat plays an essential role in a wide spectrum of manufacturing processes: cooking, softening, melting, drying, curing, fusing. For the manufacturing sector as a whole, process heating represents the largest share of all energy used for heating, cooling, lighting, and power.

Historically, firms have relied on fossil- and by-product fuels to meet process energy needs. Today, however, new high-efficiency electric technologies for process heating applications are commercially available.

Electric process heating offers two significant advantages. It can be delivered in exact amounts, at precise temperatures, and at any specific point. Another electric process heating advantage is the comparatively low capital investment required to use it.

The cost of maintaining electric process heating systems also tends to be far lower than that associated with fossil-fuel fired systems. Electric process heating also can realize extraordinary labor savings due to its automation capabilities.

The innovative electrotechnologies include:

• Process heat pumps
• Infrared drying/curing
• Dielectric heating/drying/curing
• Ultraviolet curing
• Electron beam heating/curing
• Induction heating/melting

Industrial Process Heat Pumps
Industrial process heat pumps absorb heat given off by an evaporation or drying process. Through compression, the waste heat's temperature is raised and then recycled back into the process.

Process heat pumps are commonly applied in a broad spectrum of industries that require large quantities of hot water. These include food processing, textiles, lumber and wood products, pulp and paper, and chemicals.

Competitive benefits of industrial process heat pumps include a low initial cost; lower operating costs due to high energy-efficiency ratings; the recovery and use of waste heat; and low maintenance costs. Since most conventional industrial processes dispose of 80 percent or more of the heat energy they consume, process heat pumps greatly lower operating costs by decreasing primary energy requirements for the process. And since industrial process heat pumps recycle waste heat, they provide an on-site environmental benefit.

Infrared Heating, Drying, And Curing
Infrared heating is used in the food industry for mass production baking of breads, cakes, and cookies. TV dinners, chicken, and hamburgers often are precooked prior to freezing. The plastics industry uses infrared heating for pre-heating and softening of adhesives.

Infrared drying and curing is used for both water- and solvent-based surface coatings (paints and inks) in the automotive, container, electric equipment, home appliance, steel galvanizing, textile, and wood product industries. Infrared radiation also is used to cure polymer coatings in the textile and metal decorating industries.

The competitive benefits of infrared technologies include low space requirements and costs; a rapid rate of heating (3 to 5 seconds from "off" to full power); selective drying of localized areas is possible; and there is a uniform drying of paint, without the threat of blisters.

Because paint solvents can be eliminated, and overall energy is saved, these technologies also benefit the environment.

Dielectric Heating, Drying, And Curing
Dielectric heating, drying, and curing uses electromagnetic waves (microwaves and radio frequency waves) to vibrate molecules in electrically nonconducting materials. The vibration causes friction, which in turn causes heat.

Microwaves are used in the food industry for thawing deep-frozen foods, pre-cooking chicken and bacon, and for drying pasta, onions, and tomato paste. In the rubber industry, microwaves are used for curing and vulcanizing and to heat rubber before forming. In foundries, they are used for rapid drying and curing of molds.

Radio frequency waves can be used to dry paper, preheat plastic, and cure glue in the manufacturing of furniture, particle board, or plywood. In addition, they have proven useful in pasteurizing processes associated with food canning and packaging.

The competitive benefits of these technologies include accelerated drying time; increased production rates; reduced scrappage; uniform heating; enhanced product quality; reduced energy costs; floor space savings; a more comfortable work environment, and reduced labor costs. They also benefit the environment because they emit no end-use pollution.

Ultraviolet Curing
Light energy in the ultraviolet range chemically transforms a liquid to a solid on a material's surface. This is called ultraviolet curing.

Ultraviolet curing is used to decorate metal, produce wood particle board panels, harden polymer coatings on non-wax floor tiles, and to cure the printing on record jackets.

The competitive benefits this technology provides include a reduced need for floor space and operating labor; high productivity levels; uniform heating that ensures product quality; and reduction of curing time from a matter of minutes to a second or less.

This technology helps the environment because solvents are eliminated; little energy is used overall; and the amount of radiant heat produced is insignificant.

Electron Beam Heating And Curing
In electron beam heating, metals are heated at intense temperatures when a directed beam of electrons is focused against the work surface. In electron beam curing, a liquid is chemically transformed to a solid on the work surface by a stream of directed electrons.

Electron beam heating is used extensively in many high-production-volume applications for welding, especially in the automotive industry. Using electron beams for heat treating applications is relatively new, with the primary application being in the automotive industry for local surface hardening of high-wear components.

Electron beam curing generally is used to cure a thicker, more heavily pigmented coating than ultraviolet curing. It is used widely in film lamination and magnetic tape manufacture, with limited use in the wood finishing and automotive industries.

Electron beam welding is five to fifteen times as fast as conventional welding systems. Cost savings over other systems range from 20 to 80 percent per inch of weld. Other competitive benefits include minimal thermal distortions because the power density and energy input can be controlled; substantially reduced set-up and post cleaning time; lower labor costs; and the ability to achieve complex and precise heating patterns.

Electron beam curing systems require much less floor space and operating labor; have higher productivity levels; and reduce curing time from a matter of minutes to a second or less.

Electron beam systems provide environmental benefits because they eliminate solvents; use little energy; and the amount of indoor heat produced is insignificant.

Induction Heating
Induction heating occurs when metal is heated from the inside out after being placed within a wire coil with alternating current flowing through it. Both ferrous (iron, steel) and nonferrous (aluminum, brass, copper, and zinc) industries use induction heating for forging, forming, heat treatment, and joining.

Induction heating is ideal for repetitive operations, as part after part can be heated with identical results. It also offers a precise application of heat; the advantage of locating hardening operations directly in production lines instead of remote areas; no pre-heating of heaters; and less product waste due to scaling.

In addition, no harmful emissions or radiated heat are released in the plant.

Induction Melting
In this electric-driven technology, the material to be melted (or kept molten) is held in a crucible, which contains a coil with alternating current flowing through it.

Coreless induction furnaces are used primarily for remelting in foundry operations and for vacuum refining of high-alloy steels and specialty metals. Channel induction furnaces are commonly used as holding furnaces for nonferrous metals (aluminum, brass, copper, and zinc) that are melted in a cupola, arc, or coreless induction furnace.

The use of induction melting eliminates oxidation, deoxidation, and sulfur contamination. In addition, lower-cost refractory can be used and maintenance reduced; the loss of material due to oxidation is very low; and the high efficiency of induction melting can, in many cases, actually result in lower energy costs. It also greatly reduces plant air pollution.

Electric Arc Furnaces
In an electric arc furnace, a power electric current leaps from an electrode to scrap steel and then back to another electrode to complete its circuit. In the narrow gap between electrodes and steel, air resistance creates searing heat.

Electric arc furnaces are used primarily in the production of steel in large integrated operations and in newly emerging "minimills" -- small- to medium-sized decentralized steel mills that use scrap as raw material and produce those products in greatest local demand.

The competitive benefits of electric arc furnaces include fast melting (cold scrap to liquid steel in 60 to 90 minutes); ease of temperature control; repetitive heats of high quality; ease of start-up and shut-down; and lower capital and operating costs.

They also help the environment. Making a pound of steel electrically from scrap saves roughly four pounds of coal compared with making a pound of steel from ore.