In today's world, where energy efficiency and cost reduction are playing an ever greater role, contact thermostats are becoming increasingly important. Thanks to their versatility, they can be used in industrial applications as well as in heating heating, ventilation and air conditioning (HVAC), they offer an efficient means of temperature control. Contact thermostats and the associated contact sensors not only offer precise control of the temperature in various systems. They also make a significant contribution to saving energy and thus reducing operating costs.
Functionality of contact thermostats
Contact temperature sensors, also known as contact or surface sensors, are sensors that are used to measure the temperature on solid surfaces. They function by being brought into thermal contact with the surface whose temperature is to be measured. The sensor itself consists of a temperature-sensitive element, such as a thermocouplea resistance thermometer or a semiconductor, which changes its electrical properties (such as the electrical resistance or the voltage generated) depending on the temperature. This behavior allows the sensor to detect the temperature changes of the surface and convert them into an electrical signal, which is then sent to a display instrument, a controller or an automated system to monitor the measured temperature and initiate control processes if necessary. To ensure efficient heat transfer and minimize the influence of ambient temperatures, the contact temperature sensor is typically firmly attached to the surface using thermal paste or a comparable agent.
Criteria for the correct selection of contact sensors
Selecting the right contact sensor is crucial to ensure precise and reliable temperature measurements. Key criteria for selection include:
- Temperature range: The sensor must be suitable for the specific temperature range of the application. Different sensor types - e.g. thermistors, thermocouples or RTDs - have different temperature ranges and accuracy characteristics.
- Measuring medium and ambient conditions: The resistance of the sensor to environmental influences, such as moisture, chemicals or mechanical stresses, should be suitable for the intended measuring medium and operating environment.
- Accuracy and response time: Each application has its own requirements for accuracy and speed of measurement. Highly accurate sensors or those with short response times may be required, depending on the need for fast and precise temperature control.
- Mounting technique: The type of mounting influences the efficiency and accuracy of the temperature transfer. It is important that the sensor is compatible with the surface and that the installation enables optimum heat conduction.
- Output signal: Depending on the control or monitoring system, the output signal of the sensor (e.g. 0-10 V, 4-20 mA for active sensors or generation of a resistance value for passive sensors) must be compatible.
- Compatibility with control units: The contact sensor should be compatible with the existing control unit or evaluation system to ensure that the signal can be read and processed correctly.
- Design and size: The physical compatibility of the contact sensor with the application must be ensured, so factors such as size, shape and mounting accessories must be taken into account.
Careful evaluation of these criteria can ensure that the selected contact sensor is optimally suited for the respective application and reliably fulfills the desired function.
Areas of application for contact thermostats
The areas of application for contact thermostats and contact sensors are diverse and cover almost all industries that require precise temperature control. Here are some specific examples:
- Industrial production: In production plants, contact thermostats can be used to monitor the temperature of machines. Active contact sensors provide precise data to keep the machines operating at optimum levels and prevent overheating.
- Food industry: Precise adherence to certain temperatures is essential for processing food. Contact thermostats regulate the temperature in smoking ovens or brewery kettles and ensure that the quality of the products is maintained.
- HVAC systems: In building automation, contact thermostats control the temperatures in heating systems, air conditioning units and ventilation systems. Passive sensors are suitable here for increasing efficiency by adapting the operating times and intensity of the systems to the actual demand.
- Data centers: In data centers, it is essential that servers do not overheat. Contact thermostats with passive sensors monitor the cooling and increase the efficiency of the cooling system by regulating it as required.
Practical examples of increasing energy efficiency with contact sensors
Contact sensors make a significant contribution to increasing energy efficiency in industrial applications and in the heating, ventilation and air conditioning industry by enabling precise temperature monitoring and control.
A practical example from industry is the use of contact sensors in process control. In a plastics processing plant, contact sensors precisely monitor the temperature of the extruders. By precisely controlling this temperature, the energy required to heat the material can be optimized. Overheating is avoided, which not only saves energy, but also improves the quality of the end product and reduces waste.
In HVAC technology,contact sensors in a ventilation system ensure that the temperature of the supply air is adapted precisely to the room conditions. Sensor-based controls can, for example, ensure that the heating of the air flow is only activated when the outside temperature falls below a certain point or the room occupancy rate requires it, thereby reducing unnecessary energy consumption. In this way, contact sensors ensure demand-based and therefore energy-efficient air conditioning, which in turn lowers energy costs and helps to reduce the building's carbon footprint. These examples illustrate how important accurate temperature measurement and control is for the energy efficiency of heating and cooling processes, which ultimately leads to economic and ecological benefits.
In modern agriculture, greenhouses play an important role in efficient and year-round plant production. Precise control of the climate is crucial here in order to create ideal growing conditions and save energy at the same time. Contact sensors can make a significant contribution to energy efficiency in this environment.
Another practical example is in greenhouses that grow various sensitive plants that require optimum temperatures for growth and development. Contact sensors are installed on the pipes of the heating system to precisely measure the surface temperature of the heating pipes. These continuous measurements enable the climate control system to regulate the heating output in real time. If the outside temperature rises during the day, the contact sensors detect a higher temperature on the heating pipes and signal the system to reduce the heating, as the natural sunlight provides sufficient heat. This avoids excessive heating and leads to considerable energy savings. At night, when temperatures drop, the contact sensors provide feedback on the falling temperatures and the system can react by raising the heating to the required level to protect the plants from the cold.
The use of contact thermostats not only saves costs and protects the environment, but the precise operation of the contact sensors also increases comfort and functionality in residential buildings and industrial plants.
Investing in modern contact thermostats and high-quality contact sensors pays off for companies and private households alike by helping to improve energy efficiency and reduce operating costs. The innovative further development of contact sensors will further increase the precision and efficiency of these systems in the future, making them an indispensable part of building automation and industrial processes.
Typical mistakes when using contact sensors and how to avoid them
When selecting and installing contact temperature sensors, various errors can occur that can significantly affect the accuracy and reliability of the temperature measurement. Below we have summarized some typical errors that should be avoided:
- Incorrect sensor type: Selecting a sensor type that is not suitable for the specific application or the medium to be measured can lead to inaccurate results. It is important to select the sensor based on specific requirements such as temperature range, response speed and environmental conditions.
- Insufficient thermal contact: The efficiency of heat transfer between the sensor and the surface is critical. If the sensor is not mounted properly or if a suitable thermal paste is not used, this can lead to poor thermal contact and consequently to inaccurate measurements.
- Incorrect mounting position: The sensor should be mounted in an area that is representative of the entire surface to be measured and not in the vicinity of heat sources or sinks, for example, in order to avoid incorrect measurements due to local temperature gradients.
- Environmental influences: Mounting the sensor in a location that is exposed to the weather or other environmental conditions can falsify the measurement. The sensor should be mounted in a protected location to minimize external influences.
- Mechanical stresses: If sensors are damaged by over-tightening or mechanical stress, this can affect the accuracy or even cause the sensor to fail.
- Use of incorrect mounting materials: Mounting the sensor with unsuitable materials, e.g. with non-heat-resistant adhesive tape or sealant, can lead to measurement errors or damage to the sensor.
- Ignore cable and lead resistances: Particularly with passive sensors such as thermocouples, the resistance of the connecting cables can influence the measurement signal. It is essential to take this into account during measurement and installation.
- Ignoring calibration and long-term stability: Sensors age and their measurement accuracy can change over time. When selecting a sensor, it is important to choose one with known long-term stability and to calibrate it regularly.
To avoid these errors, the specifications of the contact temperature sensor should be carefully checked, the installation instructions strictly followed and specialist knowledge consulted if necessary. Correct selection, handling and installation are key to reliable temperature measurements and the long-term functionality of the system.
