TECMED electronic temperature controller for Dometic TCX 14 / 21 / 35 transport coolers

The TECMED temperature controller is an electronic control module designed for upgrading Dometic TropiCool TCX 14 / TCX 21 / TCX 35 transport coolers. The solution has been developed for transporting medicines, vaccines, insulin, laboratory samples and other temperature-sensitive materials.

The controller is supplied programmed according to previously agreed operating parameters. This allows the cooler to maintain the required temperature without manual adjustment by the user.

Application:

TECMED is intended for transport coolers where stable and controlled transport temperature is important. It can be used in pharmacies, laboratories, sample collection points, medical offices, medical transport, veterinary applications, service vehicles and companies distributing products with defined temperature requirements.

The controller is suitable for transporting:
- medicines,
- vaccines,
- insulin,
- biological samples,
- laboratory samples,
- reagents,
- veterinary preparations,
- medical materials,
- products requiring protection against overheating,
- products requiring protection against excessive cooling or freezing.

The solution can be prepared to maintain temperatures typical for refrigerated transport, room-temperature transport or an elevated chamber temperature. The exact temperature, hysteresis and operating logic are agreed before ordering.

Main advantages:

The TECMED controller turns a standard Dometic TCX thermoelectric cooler into a more controlled transport device. It enables automatic maintenance of the set temperature by controlling both cooling and heating.

As a result, the cooler can protect the transported contents not only from overheating in summer, but also from excessive cooling in winter. This is especially important for medicines, vaccines, insulin and samples, which may lose their properties at both too high and too low temperatures.

Main features:
- programmed operating temperature according to arrangements made before ordering,
- operation with one or several temperatures possible,
- chamber operation configurable in the range of 2–8°C, 20–25°C or up to approx. 40°C at an ambient temperature of approx. 20–25°C,
- automatic cooling and heating,
- compatibility with the cooler’s original NTC sensor,
- possibility to connect additional digital temperature sensors,
- built-in temperature sensor near the heatsink on the warm side,
- input for an external NO/NC switch,
- possibility to use a key switch,
- possibility to connect a digital display via I²C,
- input supply voltage 9–15 V DC,
- possibility to use the built-in power supply of the TCX cooler, typically approx. 13.8 V DC,
- typical installation without an additional power supply,
- in standard configuration, connection by soldering 6 wires,
- configuration for a specific transport application.

Compatibility:

The controller is intended for upgrading selected Dometic TropiCool TCX thermoelectric coolers, in particular:

- Dometic TropiCool TCX 14
- Dometic TropiCool TCX 21
- Dometic TropiCool TCX 35

Before purchase, the device version, wiring layout, connector type, control method and sensor configuration should be confirmed. In case of design differences, installation adaptation or service configuration may be required.

Chamber operating ranges:

Depending on the programmed configuration, the controller can maintain different temperature ranges in the chamber. At an ambient temperature of approx. 20–25°C, the upgraded cooler can operate, among others, in the following ranges:

- 2–8°C — for medicines, vaccines, insulin and products requiring refrigerated transport,
- 20–25°C — for materials requiring room temperature or protection against excessive cooling,
- up to approx. 40°C — for applications requiring elevated chamber temperature, depending on configuration and operating conditions.

Actual temperature stability depends on the cooler model, load arrangement, ambient temperature, operating time, heatsink ventilation, power supply and configured hysteresis. The exact operating range and setpoints are agreed before ordering.

How the TECMED controller works:

The controller reads temperature from the sensor used as the main measurement source and compares it with the programmed setpoint. Based on this, it automatically decides whether the cooler should cool, heat or remain in holding mode.

Dometic TCX coolers use a thermoelectric Peltier module. The TECMED controller uses its bidirectional operation — it can control both heat removal from the chamber and chamber heating when the ambient temperature is too low.

In practice, this provides better control over transport conditions. In summer, the controller can activate cooling to reduce the risk of overheating medicines or samples. In winter, it can activate heating to prevent excessive cooling or freezing of transported products.

Temperature measurement system:

The controller works with the original NTC sensor built into the Dometic TCX cooler. In a typical configuration, the NTC sensor can be used as the main chamber temperature measurement. This allows the existing cooler sensor to be used without always adding a new main sensor.

Depending on the configuration, the controller can also work with digital temperature sensors. They can be used as the main, additional, control or comparison measurement. Digital sensors can be connected on wires and installed in the transport chamber, near the transported load or at another point requiring temperature control.

The controller also has a built-in temperature sensor measuring temperature near the heatsink on the warm side, outside the cooler chamber. This measurement supports diagnostics and monitoring of the operating conditions of the thermoelectric system.

Temperature settings:

The TECMED controller is programmed according to previously agreed operating parameters. Before ordering, the following are defined, among others:
- operating temperature or temperatures,
- allowed hysteresis,
- temperature measurement method,
- method of switching operating modes,
- NO/NC input logic,
- cooling and heating control method,
- scope of diagnostic and protection functions.

The controller can be prepared to operate with one fixed temperature or with several programmed modes. This makes it possible to adapt the cooler to a specific application, such as refrigerated transport of medicines, protection against freezing in winter or maintaining an elevated chamber temperature.

Settings may be unavailable to the user, reducing the risk of accidental temperature changes. This is important in applications where the transport temperature should be defined and repeatable.

External NO/NC switch:

The controller has an input for connecting an external NO/NC switch. It can be used to select an operating mode or one of the previously programmed temperatures.

Depending on the ordered configuration, a standard mechanical switch, panel switch, toggle switch or key switch can be used. The key switch version allows mode changes to be limited to an authorised person only.

This is a practical solution for transport coolers used by staff, drivers, pharmacies, laboratories or medical teams, where operation should be simple and access to parameter changes should be limited.

Digital I²C display:

The controller allows connection of an external digital display communicating via the I²C bus. The display can show basic information about the cooler’s operation, such as current temperature, selected mode, set temperature, cooling or heating status and diagnostic messages.

The range of information shown on the display depends on the controller configuration and arrangements made before ordering. The display can be useful for daily operation, work monitoring and service activities.

Power supply and installation in Dometic TCX:

The controller is designed for an input supply voltage of 9–15 V DC. This range allows use in typical 12 V systems, DC power supplies and power systems used in transport coolers.

In Dometic TCX coolers, the controller can use the cooler’s built-in power supply. The typical operating voltage available in the device is approx. 13.8 V DC, so in standard configuration there is no need to install an additional power supply or make major changes to the power circuit.

In a typical version, installation consists of connecting the controller to the existing cooler wiring by soldering 6 wires. The wires are responsible for power supply and control of the basic system elements.

This allows the upgrade to be carried out without significant mechanical changes to the cooler. Before installation, however, the device version, wiring layout and available voltage should be confirmed. In case of design differences, the connection method may require individual adaptation.

Protection and diagnostics:

The controller can be equipped with diagnostic and protection functions adapted to the specific configuration. Their purpose is to protect the cooler, Peltier module, electronics and transported load against operation under incorrect conditions.

Possible functions include, among others:
- supply voltage monitoring,
- monitoring of heatsink temperature on the warm side,
- temperature measurement correctness control,
- delay when changing the operating direction of the Peltier module,
- error signalling,
- operation lockout in selected fault states.

The scope of diagnostics and controller reactions are agreed before ordering.

Technical data:

- Product type: electronic temperature controller for transport cooler
- Series / module name: TECMED
- Application: transport of medicines, vaccines, insulin, samples and temperature-sensitive materials
- Compatibility: selected Dometic TropiCool TCX 14 / TCX 21 / TCX 35 coolers
- Chamber operating ranges: 2–8°C, 20–25°C or up to approx. 40°C, depending on configuration
- Reference conditions: ambient temperature approx. 20–25°C
- Controller input supply voltage: 9–15 V DC
- Typical supply in TCX cooler: from the built-in cooler power supply, approx. 13.8 V DC
- Additional power supply: usually not required in TCX coolers with built-in power supply
- Typical installation: connection to existing cooler wiring, usually 6 wires
- Main temperature measurement: compatibility with the cooler’s original NTC sensor
- Additional sensors: possibility to connect digital temperature sensors on wires
- Built-in sensor: temperature measurement near the heatsink on the warm side
- Temperature control: cooling, heating, holding
- Actuator: cooler’s thermoelectric Peltier module
- Fan control: depending on version and configuration
- Operating mode input: external NO/NC switch
- Switch type: mechanical, panel, toggle or key switch
- Switch function: selection of programmed mode or operating temperature
- Display interface: I²C
- Display connection: yes, external digital display
- Settings configuration: programmed before ordering / installation
- User adjustment: unavailable or limited, depending on version
- Diagnostics: depending on controller configuration
- Installation: service installation or by a person experienced in 12/24 V electronics

Installation and commissioning:

Installation requires access to the cooler electronics and connection to the power supply, Peltier module, fans, sensors and optional external mode switch. In a typical Dometic TCX configuration, no additional power supply is required because the controller can use the cooler’s built-in power supply.

In the standard version, the upgrade is limited to connecting the controller to the existing wiring, usually by soldering 6 wires. Depending on the cooler version, removal of the original control panel or adaptation of the existing wiring may be required.

After installation, temperature measurement, cooling operation, heating operation, response to the NO/NC switch and chamber temperature stabilisation should be checked.

The controller can be supplied as a component for service installation or as part of a transport cooler upgrade service.

Temperature logging and transport validation:

The TECMED controller helps prepare a transport cooler for applications requiring temperature control. However, when transporting medicines, vaccines, insulin, biological samples or laboratory materials, the use of an independent temperature data logger is recommended.

A data logger placed in the cooler chamber or directly near the transported load makes it possible to confirm actual transport conditions and prepare a temperature report. This is especially important where documentation of the transport process is required.

The controller itself does not replace validation of the entire transport process. The suitability of the cooler for a specific application depends on the complete configuration, installation, testing, packaging method, transport duration, ambient temperature and user procedures.

Important information:

The controller is programmed for a specific application. Before ordering, the required operating temperature or temperatures, allowed hysteresis, measurement method, mode switch type and expected cooler operation should be defined.

The product is not an original Dometic control panel, a standalone medical device or a complete validated medicine transport system. It is an electronic control module intended for upgrading a transport cooler.

Best results are achieved after correct installation, temperature tests and adjustment of the controller configuration to the actual way the cooler is used.