Temperature Sensor Types: A Beginner’s Guide

A temperature sensor is a device that measures the degree of hotness or coldness in an environment and converts this measurement into a readable electrical signal. Think of it as your thermal watchdog, constantly monitoring critical equipment to prevent failures and maintain optimal performance.

Consider a local brewery that recently installed temperature sensors on their fermentation tanks. Before implementing these sensors, they lost an entire batch of craft beer due to an undetected temperature spike during fermentation. Now, their sensors provide continuous monitoring and instant alerts if temperatures drift outside the ideal range, protecting thousands of dollars worth of product. The sensors save them from potential losses and help maintain consistent quality across all their batches.

These essential devices come in contact and non-contact varieties, serving as the foundation of modern preventive maintenance plans by providing real-time data about equipment health and performance.

The Importance of Temperature Sensors

Sensors are vital in modern maintenance management, serving as critical components for equipment protection and operational efficiency. Whether wireless or hardwired, these devices perform three essential functions: tracking ambient temperatures, conducting temperature probe readings and recording temperature data over time.

These devices help businesses avoid equipment failure and optimize performance in industrial and commercial environments. In data centers, these sensors prevent computers from overheating, while in factories, they monitor machinery bearings for potential breakdowns. Temperature monitoring optimizes heating and cooling systems, saving energy and money. 

Beyond equipment protection, digital temperature sensors are also essential for health and safety compliance. In cold storage facilities, they ensure products remain at safe temperatures, while in working environments, they help maintain comfortable conditions for employees. 

These sensors can send real-time alerts and historical data to current computerized maintenance management system (CMMS) software solutions, helping maintenance managers determine the necessary maintenance and equipment replacements for their most valuable assets. They’re typically used as part of an overall predictive maintenance strategy that requires IoT devices and other predictive maintenance tools to better understand asset needs.

6 Common Temperature Sensor Types

Sensors come in several varieties, each with unique characteristics and applications. Here’s a detailed look at the six main types:

1. Thermometer

Digital and electronic thermometers are among the most basic and widely used temperature sensors. 

Used for: These devices use electronic heat sensors to measure temperature through direct contact with solids, liquids or gases. Thermometers are commonly used in HVAC systems, refrigeration units and general-purpose temperature monitoring applications. 

Also, thermometers are essential in medical settings for measuring body temperature as well as in laboratory environments for monitoring experiments.

Pros: Thermometers excel at providing quick, basic temperature readings in various settings, from industrial applications to everyday use. Their main advantages are simplicity, ease of use, affordability and reliability. Thermometers are ideal for general use cases and don’t require complex signal conditioning or calibration.

2. Thermocouple

Thermocouples consist of two different metal wires joined at one end, generating a small voltage when exposed to temperature changes. 

Used for: Thermocouples frequently appear in industrial settings to monitor machinery temperatures, exhaust gases and other high-temperature applications. These sensors are also commonly found in ovens, furnaces, heating systems and aerospace applications. The versatility of thermocouples makes them particularly useful in harsh environments where other sensors may not survive.

Pros: The impressive temperature range of thermocouples spans from -200° Celsius to 1750° Celsius, making these sensors incredibly versatile. Their durability, cost-effectiveness and ability to function in harsh environments have made thermocouples popular in industrial settings. 

The key advantages of thermocouples include a wide temperature range, robust construction, fast response times and self-powered operation, requiring no external power source.

3. Infrared Sensors

Infrared sensors measure temperature without physical contact by detecting thermal radiation from an object’s surface.

Used for: Infrared sensors prove particularly valuable when direct contact is impractical or unsafe, like measuring moving objects, extremely hot surfaces or hard-to-reach areas. These sensors excel in applications requiring rapid response times and maintaining product integrity. Think food processing and electronics manufacturing. Infrared sensors are also used in non-contact fever screening and thermal imaging cameras.

Pros: A significant advantage of infrared sensors is their ability to take surface temperatures from a safe distance. Infrared sensors provide noninvasive temperature monitoring, can cover large areas quickly and offer fast response times. 

Additionally, they are relatively low-cost and require little maintenance. Infrared sensor accuracy is affected by surface emissivity, ambient temperature, environmental variables and object distance. 

4. Silicon Diode

A silicon diode is a semiconductor-based temperature measurement device that allows current to flow in one direction only, acting essentially as a one-way valve. 

Used for: Silicon diode sensors are particularly valuable in electronic and integrated circuit applications, where precise temperature control is critical. These sensors are also used in cryogenic and aerospace applications because of their ability to measure extremely low temperatures. They’re often integrated directly into microprocessors, FPGAs and other electronic devices for on-chip temperature monitoring.

Pros: These sensors offer excellent linearity and accuracy over a wide temperature range, typically from -50° Celsius to 150° Celsius. The key advantages of silicon diode sensors include compatibility with modern electronic systems, compact size, low cost and the ability to provide accurate measurements in space-constrained applications. They also have fast response times and low power consumption.

5. Negative Temperature Coefficient (NTC) Sensors

This type of thermistor sensor operates on the principle that its electrical resistance decreases as temperature increases.

Used for: NTC sensors find use in precision temperature measurement applications, industrial process control, HVAC systems and automotive temperature sensing. These sensors are well-suited for applications requiring high sensitivity to small temperature changes. NTC sensors, like temperature compensation circuits and battery management systems, are also commonly found in consumer electronics.

Pros: NTC sensors excel in their applications because of their high sensitivity, fast response times and high accuracy within their operating range, typically -50° Celsius to 250° Celsius. They are particularly effective in applications requiring quick response times and precise temperature control. NTC sensors are relatively inexpensive, small and easy to integrate into electronic circuits.

6. Resistance Temperature Detector (RTD)

RTDs measure temperature by correlating the resistance of pure metals, typically platinum, with temperature changes.

Used for: RTDs are commonly used in industrial applications, like pharmaceutical manufacturing, food processing, and oil and gas industries, where high accuracy and stability are essential. These sensors are also used on laboratory equipment, precision instruments and environmental monitoring systems.

Pros: They are renowned for their exceptional accuracy and stability over time. Available in both wire-wound and thin-film constructions, the former offers higher accuracy up to 650° Celsius and better vibration resistance. The primary advantage is their unmatched precision and repeatability.

Equipment That Benefits From Temperature Sensors

A temperature sensor can play a vital role in various industrial and commercial equipment. Here’s a detailed look at a few critical applications:

Refrigerators & Freezers

Temperature sensors are essential in refrigeration systems, where they continuously monitor and maintain precise temperature control. In commercial freezers and refrigerators, these sensors help prevent food spoilage and ensure compliance with safety regulations by monitoring real-time temperature. 

They enable quick detection of temperature fluctuations that could compromise stored products, triggering alerts when temperatures drift outside acceptable ranges. It’s especially important in situations where maintaining precise temperature zones is critical for product integrity and safety compliance.

Boilers

In boiler systems, temperature sensors serve as critical safety and efficiency components. They monitor water temperature throughout the system, ensuring optimal heating performance while preventing dangerous overheating conditions. 

These sensors enable precise water temperature control for distribution throughout facilities, which is especially important during peak demand periods. Accurate temperature readings increase boiler efficiency, reduce energy usage and prevent thermal stress, extending equipment lifespan. 

HVAC Systems

HVAC applications rely heavily on thermostats to maintain comfortable indoor environments and ensure system efficiency. These sensors monitor temperatures across different zones within a building, allowing for targeted heating and cooling based on specific area requirements. 

They enable sophisticated climate control by providing real-time data to building automation systems, helping to optimize energy usage while maintaining consistent comfort levels. In modern HVAC systems, sensors also contribute to predictive maintenance by detecting unusual temperature patterns that might indicate potential system issues.

Electrical Equipment

Temperature sensors are critical in electrical systems, where they help prevent overheating and potential failures. They monitor critical components like transformers, switchgear and motor control centers, providing early warning of possible problems. 

These sensors enable continuous monitoring of electrical connections and joints, where increased temperatures often indicate deteriorating conditions or loose connections that could lead to equipment failure or fire hazards.

Bearings

In industrial machinery, bearing temperature sensors prevent catastrophic equipment failures. They continuously monitor bearing temperatures to detect early signs of wear, inadequate lubrication or misalignment. Sensors monitor real-time temperature variations that may signal stress or impending failure, helping maintenance crews avoid costly breakdowns.

IT Equipment & Data Centers

Temperature monitoring is essential in IT environments where precise climate control directly impacts equipment performance and lifespan. Servers and network equipment generate significant heat during operation and must be maintained within specific temperature ranges to prevent system crashes or hardware damage. Temperature sensors help optimize cooling systems and ensure proper airflow management, contributing to equipment reliability and energy efficiency.

Solar Energy Systems

Temperature sensors help optimize system performance in solar installations by monitoring panel temperatures. Since solar panel efficiency decreases as temperature rises, these sensors provide crucial data that helps maintain optimal operating conditions. 

They can trigger cooling systems or adjustments to panel positioning when temperatures exceed desired thresholds, helping to maintain maximum energy production efficiency.

How a CMMS Can Help Track Temperature Sensors

A CMMS software like Coast can transform how maintenance managers monitor and analyze temperature sensor data. The platform centralizes temperature readings from multiple sensors across different equipment and locations, providing real-time monitoring and instant alerts when readings fall outside acceptable ranges. Maintenance teams can track historical temperature data, identify patterns and schedule preventive maintenance based on temperature trends.

Through Coast’s mobile app, maintenance technicians can access temperature sensor data on the go, respond quickly to alerts and document their maintenance actions directly in the system. Simply ensuring that significant temperature-related problems are resolved rapidly, this integrated strategy helps to prolong asset life and prevent equipment breakdowns.

Ready to see how Coast can help you manage your temperature sensors and maintenance operations? Book a demo today to learn more about our all-in-one CMMS solution.