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Electric Heater Selection for an Existing Problem

By:  - February 02, 2022  


Heating applications vary greatly in the industrial sector. From agricultural needs to cooking, from sterilization to drying, from killing to chemical processing, heating requirements are as diverse as the industries that require thermal solutions.

But what happens when you are faced with finding the right heater for an existing challenge, or you need to replace a heater that was not an optimal fit for your current system?

The first step when considering a heater for an existing problem is a step back. Assess the big picture regarding your application and system needs, then you can begin to focus on a few crucial elements that will lead you to the ideal heating solution.

What is the heater’s application?

Start by considering the heat transfer application. Does the heater come into direct contact with what is being heated? Is heat being transferred through another material, such as a pipe or the air, etc.? Is what is being heated flowing or stationary? What is the desired temperature for the application? Answering questions like this will determine what type and what size of heater is needed to meet the demand? 

Immersion heaters are typically used for heating flowing gasses and liquids, such as water or oil. They are a fast and economical method for heating applications that require some level of protection from surrounding conditions such as exposure to outdoor weather.o protect a product by maintaining a consistent temperature. Watlow immersion heaters come in a variety of sizes with NPT screw-plug, ANSI flange, square flange or plate-flange adapters.

Radiant heaters are known for evenly radiating heat to dry materials or to mold pieces of dissimilar plastic together. Watlow radiant heaters are either ceramic or panel assembly heaters, both of which provide even heat distribution and energy efficiency.

Heaters used in flowing systems raise the temperature of a liquid or gas as it passes the heater. For example, petroleum tank farms consist of several vertical tanks holding 10,000 gallons or more of petroleum in various stages of refinement. Heavy petroleum requires low watt-density heaters to move the material.

What material will be heated?

Understanding the material being heated is critical to selecting the right heater. Is it gas, liquid or solid? Will the heater need to be immersed or operate in a vacuum? Does the material require direct or indirect heating?

Also consider the thermal properties of the media itself. What is the heat response time for the material and the maximum heat transfer? What is the life expectancy of the media?

Different materials heat at different rates, and knowing the specific heat capacity of the media being heated is crucial in determining the correct KW required to bring the process up to target temperature in the correct time. This will also help determine the wattage necessary to heat and maintain the operating temperature for the specified material.

As such, the material is one of the factors that influences the watt density of the heater. The heater needs to be able to warm the media without burning the material or other system components. Oils or liquids containing glucose may need a lower watt density heater to avoid burning. Likewise, gas applications typically need lower watt density heaters compared to applications heating water.

When the general temperature range and heater style have been determined, other attributes can be altered to adjust the watt density. These attributes include wattage, heater length, element diameter and element shape.

What are the temperature needs and power requirements of the system?

The material to be heated informs the necessary temperature and power requirements to achieve the desired results, but the size of the application is also a factor. A small heating application has different needs and power demands compared with a large project that necessitates significant wattage.

A University of Rome study about the potential for solar heat in industrial processes found that approximately 43% of industrial heating applications require temperatures above 750 degrees Fahrenheit, while about 27% require temperatures of 212-750 degrees and about 30% require temperatures of 212 degrees or less. Knowing your temperature needs will help narrow down the field of eligible heaters.

Another vital consideration is the time it takes the material to reach its final temperature. Not all materials or systems can or should be heated as quickly as possible. Some require a ramp-and-soak approach, which gradually increases the system’s temperature over a predetermined time or maintains a set temperature over a specific period of time.

Other factors related to the operating temperature include the start-up power needs and the maintenance power requirements.

What is the operating environment of the heater?

The space available for the heater as well as its operating conditions will also affect the heater choice.

Some applications, such as semiconductor production, call for tiny heaters that can be placed in compact spaces within a cleanroom environment. Other applications demand large heaters that may need to function in an explosion-resistant environment or even in a vacuum.

Depending on the environment, the heater may further require an enclosure or housing to protect it. Some applications require a heater that can withstand exposure to significant moisture or caustic chemicals.

In some circumstances, a customized option may be needed to meet the unique demands of space, operating temperature and wattage.

Watlow® can Help Find the Right Heater for Your Application

Watlow® creates heaters for a broad range of industries and applications. When you are exploring a new or different heater for an existing problem or system, our “Digital Product Assistant” can help you hone in on the best options.

Our team of experts is also ready to answer your questions and guide you through the selection process. Connect with Watlow today to speak with one of our representatives or locate a knowledgeable distributor near you.