Laboratory Thermodynamics

facilities

The laboratory Thermodynamics consists of the machines, test rigs and measuring devices, listed below.

  • Fuel cell: The operational behaviour of fuel cells (PEMFC) can be analyzed with a fuel cell test rig. Hydrogen is used as fuel; air or oxygen is used as oxidator. The test rig is dimensioned for specimens with an electric power of about 1 kW; the stack used is built up of 24 fuel cells with an electric power of about 500 W at 55 °C.
  • Stirling engine: The test rig enables the calculation of the operational behaviour of a Stirling engine with different engine-settings. The engine is powered by a temperature-regulated filament heating with a maximal electric power of 10.8 kW. The generator, which is incorporated in the output side, produces an electrical power up to 1 kW. To plot the cycle and to determine the characteristic dimensions the engine is additionally fitted with a variety of measuring equipment.
  • Solar Stirling engine: A Stirling engine is driven by a concentrating solar collector with a system to guide the slats according to the position of the sun and provide a maximum of 350 W of electric power.
  • Solar cooker: In the framework of several seminar papers the solar cooker was calculated and developed. The solar cooker consists of a Scheffler reflector used as a parabolic dish, which guides the slats according to the position of the sun, as well as a cooking box, in which the solar radiation is concentrated. Based on the constructed system properties should be tested in practice.
  • Wind power plant: The wind power plant, which is positioned on the site of the University of Applied Sciences, has been dimensioned, constructed and finally built in a framework of a project thesis. The plant has about three 1.75 metres long rotor blades (profile: NACA 4412), which are provided by the OTH Regensburg. The power generated is fed into the grid of the university.
  • Otto engine: A stationary single cylinder four-stroke Otto engine is fired with gas. The compression of the engine can be variably adjusted; furthermore the engine can be operated as Diesel cycle too after several modifications.
  • Refrigerating machine: The two refrigeration machines in the laboratory are working with the refrigerants R134a and R22. The performance of both machines is 11 kW (refrigerant R134a) and 14 kW (refrigerant R22).
  • Philips gas refrigerating machine: The gas refrigerating machine, which is driven with Helium and is working like the reversal of a Stirling cycle, achieves in two stages temperatures of 80 K or 30 K. To measure the refrigerating capacity both stages are equipped with electrical heating; alternatively the refrigeration capacity can be used for producing vacuum.
  • Liquefaction of nitrogen: The cryogenic system produces liquid nitrogen by rectification of the ambient air at a very low temperature and atmospheric pressure. The lower temperatures are reached with a gas refrigeration machine, which is powered by helium. The machine produces about 6 litres of liquid nitrogen per hour with a purity of 99.5 %.
  • Vortex tube: The vortex tube consists of a cylindrical tube, in which airflow is blowing tangentially with high speed through a nozzle. In the tube a faceplate is built-in close to the nozzle; at the other side of the tube there is a ventile, which forces a part of the air to flow through the faceplate. This airflow is cooled down, the part of the airflow, which is streaming through the ventile, is heated up. Depending on the pressure in front of the nozzle the temperatures of the cold and warm airflow are measured.
  • Calorific value of gases: The calorific value of gaseous fuels can be fixed by means of 5 Junkers-calorimeters.
  • Viscosity of fluids: There are 5 falling-ball viscometers, 2 visco-scales, a capillary viscometer, a hand visco-tester as well as a rotation-viscometer to measure the viscosity.
  • Friction coefficient of solids: The friction coefficient of solids (with and without lubricating film) can be measured dependent on stress (normal force) and rotational speed.
  • Thermal conductivity of insulation materials: A special test rig enables the measurement of the thermal conductivity of insulation materials according to DIN 52612.
  • Critical point: The behaviour of fluids at the critical point can be demonstrated with SF6 (critical temperature: 45.5 °C; critical pressure: 37.6 bar).
  • Measurement of thermal parameters: In the laboratory measuring instruments are available for determining temperature, pressure, flow velocity, radiation intensity of the solar radiation as well as meteorological data like barometer reading, wind velocity and wind direction.

The equipment of the laboratory Thermodynamics is primarily used for the education of students. Beyond that a part of the equipment can be used for research and development. By internal diploma theses available test rigs are renewed as well as new test equipment is built up.

Photovoltaic solar power: On the roof of the laboratory building solar cells are located with a size of approximately 35 m² and an electric power of 4.5 kWp. The modules are orientated to the south and pivoted. The global solar radiation as well as the electric power of the system is measured.

solar cells

Calorimeter

Thermography system: A portable thermography camera enables accurate measures in a wide temperature range for applications in the range of the construction physics, materials engineering, electronics and a lot of other tasks.

Friction factor