Note
Heat transfer oil has an impact on valve selection (material of O-rings and gaskets). Compatibility must be checked.
When planning and commissioning a plant or when sizing valves, the suppliers’ specifications must be observed. To make certain the right type of heat transfer oil is used, one should rely on the suppliers’ experience and know-how.
When using heat transfer oil (thermal oil), the following supplier-specific values must be taken into consideration:
Correction factor FR, if the supplier-specific kinematic viscosity ν exceeds 10 mm2/s
Density ρ
Room and operating temperature
During the heating up phase, the kinematic viscosity ν is very high. The volumetric flow is much smaller than planned and thus the available amount of energy Qheating up phase as well. This must be taken into account during the planning phase and when sizing the valve
Refer to chapter "2.8.3 Impact of fluid properties on valve sizing", page 36.
Types of heat
transfer oil
Heat transfer media on the basis of mineral oil
Synthetic heat transfer fluids
Organic heat transfer fluids as per DIN 4754
Heat transfer media of a uniform substance or mixture
Heat transfer oils on the basis of silicon
Planning
Install a strainer (dirt trap).
Installation and commissioning
The company making the installation is responsible for the quality of the media used
Before filling a hydraulic HVAC circuit with a medium, the installer must observe the supplier’s specification. If such specifications or regulations are not observed, severe damage to the plant can occur
When commissioning a plant, the company that made the installation is obliged to write a commissioning report including information about medium quality and filling (plant volume) and, if necessary, about water treatment and the additives used
Recommendation
Keep a plant record.
Maintenance and service
The installer should check hydraulic HVAC circuits at least once a year.
Before adding medium to a hydraulic HVAC circuit, the installer must observe the supplier’s specification. If such specifications or regulations are not observed, severe damage to the plant can occur.
When adding medium at a later stage, the company that made the installation is obliged to write a commissioning report including information about the quality of the medium and the filling (plant volume) and, if necessary, about treatment and additives used.
Recommendation
The quality of the medium in open or closed plants must be checked at regular intervals. The plant record must always be kept up to date.