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Refrigerants, lubricants and mixtures

Industry

on request

Dr. Steffen Feja

+49-351-4081-767

Determination of working fluid properties

Investigations of refrigerants, oils and its mixtures

On base of our great database and knowledge ILK offer consulting services to choose the right refrigerant-lubricant system for special purposes. Following you will find a selection of applicable determination methods to qualify working fluid.

Floc point

Standard:

DIN 51351

Instrument:

Pressure proof autoclave with elongate glasses, cooling bath

Principle:

The refrigerant-oil mixture with defined weight fraction (10 wt% oil) is cooled down in a pressure proof autoclave with elongate glasses (see picture 1), until flocs appear at a defined temperature.

The cloud point is dependent from the concentration of the refrigerant-oil mixture.

Temperature range:

 –60 °C to room temperature

Amount of sample required:

10 ml

Modifications:

Nebula Test (5 wt% oil), Cloud point of immiscible fluids ( = with oil saturated refrigerants)

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Solidification Point / Pour Point

Standard:

DIN ISO 3016

Instrument:

Freezing tube with stirrer, cooling bath

Principle:

The liquid to be tested is cooled down until the liquid is no more free-flowing at a defined temperature.

Temperature range:

–60 °C to room temperature

Amount of sample required:

250 ml

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Miscibility Gap

Standard:

DIN 51514

Instrument:

Pressure proof autoclave with elongate glasses, cooling bath

Principle:

The segregation line between one and two phase of refrigerant-oil mixtures is determined in dependency of the concentration, both at high and low temperatures.

Temperature range:

–60 °C to 140 °C

Amount of sample required:

250 ml

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Specific heat capacity

Standard:

ASTM D 3947 or E 1269

Instrument:

Differential scanning calorimeter Setaram µDSC VII or

Differential scanning calorimeter TA Instruments Q200

Principle:

Thermal effects of the sample can be detected in dependence of temperature and time by continuous heating, cooling or isothermal operation mode and comparing with a reference. For instance these effects can be freezing, melting, phase changing effects, chemical reaction and so on.

Temperature range:

-45 °C to 90 °C in the pressure range up to 20 bar

-180 °C to 750 °C at normal pressure up to 200 bar

Pressure range:

1 to 200 bar

Sensitivity:

0,2 µW

Amount of sample required:

10 ml

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Thermal conductivity

Instrument:

test cell for stationary cylinder gap method

Principle:

The coolant to be measured is placed in a gap between a heatable inner and an outer cylinder. The inner cylinder is heated with a defined rate. After the heat flow is stationary the temperature difference of the liquid in the gap is measured with Pt100 temperature sensor.

Temperature range:

-40 °C to 140 °C

Pressure range:

1 to 100 bar

Measurement range:

50 to 200 mW · m–1 · K–1

Amount of sample required:

250 ml

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Vapor pressure

Instrument:

Test cell for determination of vapor pressure (500 cm3)

Principle:

The measurement of the vapor pressure allows conclusions on the liquid solubility of the refrigerant in refrigeration oil. The refrigerant-oil mixture is made gravimetric direct in the measuring cell (picture 2). This cell is tempered and the vapor pressure is determined with direct method.

Temperature range:

-60 to 90°C

Pressure range:

 1 to 140 bar

Amount of sample required:

500 ml

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Density

Standard:

DIN 51757

Instrument:

Oscillating U-tube density meter DPR 412 Y / DMA 60 (Anton Paar)

Principle:

A defined volume of the sample is filled into a U-shaped tube which is electronically excited into undamped oscillation. The eigenfrequency of this U-tube is depending on the mass of the sample. The density is calculated from the frequency of the oscillation.

Temperature range:

-20°C to 140°C

Pressure range:

1 to 160 bar

Measurement range:

600 to 1300 kg · m–3

viscosity:

< 15000 mm2/s

Amount of sample required:

250 ml

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Dynamic / Kinematic viscosity

Standard:

ASTM D 7483

Instrument:

Oscillating piston viscometer (Cambridge Viscosity)

Principle:

Oscillating piston viscometers allow dynamic viscosity measurement of a broad range of materials including transparent, translucent and opaque liquids. The measurement principle and stainless steel construction makes the Oscillating Piston Viscometer resistant to damage and suitable for portable operations. Kinematic viscosity is calculeted from dynamic viscosity with the density.

Temperature range:

-40 to 140°C

Pressure range:

0 to 140 bar

Measurement range:

0,2 to 20000 mPa · s

Amount of sample required:

at least 10 ml

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Dielectric constant - Permittivity

Standard:

ASTM D 924 – 04; DIN IEC 247

Instrument:

Pressure proof measuring cell for measuring electrical properties (selfmade)

Principle:

The test liquid or the mixture of refrigerant and refrigeration oil is placed in an annular gap. Inner cylinder and outer cylinder are used as electrodes. The measuring cell can be tempered. The permittivity, the alternating current resistance and the dissipation factor are measured at standard conditions of 1 V and 1kHz.

Temperature range:

-20 to 100°C

Pressure range:

1 to 140 bar

Measurement range:

1 to 20

Amount of sample required:

250 ml

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Direct current of insulating liquids

Standard:

ASTM D 1169 – 02; DIN IEC 247

Instrument:

Pressure proof measuring cell for measuring electrical properties (selfmade)

Principle:

The test liquid or the mixture of refrigerant and refrigeration oil is placed in an annular gap. Inner cylinder and outer cylinder are used as electrodes. The measuring cell can be tempered. The direct current resistance can be determined with an exposure from 1 to 500 V and 3 mA to 0,1 pA (10-12 A).

Temperature range:

-20 to 100°C

Pressure range:

1 to 140 bar

Measurement range:

1 kW – 1,6 TW

Amount of sample required:

250 ml

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DSC Measurements

Standard:

several

Instrument:

 

Differential scanning calorimeter Setaram µDSC VII or Differential scanning calorimeter TA Instruments Q200

Methods:

 

Besides the measurement of heat capacity of solids and fluids following material parameter are measurable with differential scanning calorimetry at the ILK:

 

  • Melting and crystallization enthalpies and temperatures
  • Storage capacity of PCM according RAL-standard
  • Glass transition of synthetic material
  • Decomposition enthalpy and temperature
  • Reaction enthalpy (pressure dependent on request)
  • On request: absorption  enthalpy of gases in gas storage material (i.e. zeolite) 

Temperature range:

-40 °C to 750 °C

Pressure range:

1 bar (whole temperature range); 1 to 100 bar (-45 to 90 °C) higher pressures or temperatures on request

Amount of sample required:

1 ml or 1 mg
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Further measurements (for instance neutralization number (TAN, TBN),  speed of sound, surface tension) can be arranged on request.


Your Request

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Contact

Institut für Luft- und Kältetechnik - Gemeinnützige Gesellschaft mbH
Bertolt-Brecht-Allee 20, 01309 Dresden


Secretary to the Management

+49-351-4081-520

+49-351-4081-525

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