Thermera use

System

Thermera is a completely dissolved solution of water and betaine. It is intended mainly for closed systems and circuits. In an open system, part of Thermera’s water content might evaporate and the concentration of the fluid change. In an open circuit, oxygen also dissolves in the solution, and corrosion prevention becomes more difficult, as with all heat transfer fluids. So technically Thermera can be used in open systems as well, but careful condition monitoring is essential. General instruction for the choice of materials: system components are selected in the same way as in the use of glycols. General instruction for the dimensioning of the components and heat transfer: dimensioning is done specifically for each system using Thermera’s physical properties (cf. also the appended CDROM).

It is usually observed that in heat recovery, and heat pump applications, the replacement of ethylene glycol with a Thermera product with corresponding freezing point does not lower the efficiency of the system.

Temperature range

The highest operating temperature recommended for Thermera products is 110°C. This is the temperature above which betaine is no longer completely stable; a certain amount of degradation may occur. In practice the temperatures of building systems are below 50°C. If Thermera is used in higher temperatures, the seller’s expert should be consulted. The name of the Thermera product refers to the lowest operating temperature. Consequently the lowest operating temperature of Thermera -20 is -20°C. It is highly important to note that the lowest operating temperature refers to such temperature of Thermera fluid in which the fluid starts to crystallize and viscosity starts to increase to a great extent. So in normal operation the lowest operating temperature does not refer to the outdoor temperature.

If a Thermera fluid is kept for a long time in a temperature which is much lower than its lowest operating temperature (Thermera -10 is used in the temperature of -20°C, for instance), the fluid crystallises heavily. This can be seen as similar partial phase transition as in conventional glycols; Thermera fluid turns into snow-like mass. However, only minor thermal expansion will occur, so pipe burst protection reaches considerably beyond the lowest operating temperature. Extreme-temperature tests have shown that use of the Thermera product has caused no damage to pipes or heat exchangers.

Materials

Thermera is completely compatible with all the used pipe and equipment materials. We have test results and operating experiences of copper, carbon steel, brass, solder, cast iron, and stainless steel. All the used elastomers and sealants have also been tested to be compatible with Thermera products. A universally applicable rule is that the system shall be implemented in the same way as in glycol use.