Archive for oktober, 2011

TAP installed

By the end of September the installation of the TAP was completed. The flue gas heat exchanger is inserted into the STEG exhaust ( cross-section 3 x 3 m) and  connected by an isolated water/steam circuit down to the intermediate heat exchanger located near the TAP.


From the intermediate heat exchanger a thermal oil circuit is used to transfer heat to the high temperature heat exchangers in the engines stages of the TAP.  The use of an intermediate hex for separation of both the thermal oil and water circuits was required here for concession reasons. In future systems this intermediate heat exchanger and pump has to be avoided because of the additional temperature drop which is harmful at low operating temperatures.

Installation SKSB(4)The low temperature heat exchangers in the TAP are connected to an existing  cold water storage tank in a stand about 80 meters away. All fluid circuits are equipped with pumps,   flow sensors and thermocouples for measuring thermal powers. Piezo resistive pressure sensors on the TAP are used for measuring mean pressure, pressure amplitude frequency, phase and acoustic power.

Testing the periphery was done by running the TAP, without alternators and with pressurized air (up to 750 kPa) to generate maximum heat flow trough all heat exchangers. At maximum heat flow the temperatures at the various sections are measured.

Conclusion from this test was that the effective temperature for the TAP to run at is limited mainly, but not only, by the heat transfer in the thermal oil circuit. Also the air sided temperature drop in the flue gas heat exchanger is higher than expected. As a result the effective input temperature of the TAP is not more than 100°C  which means that about 60 °C is lost in the periphery.

This observation stresses again the conclusion that at low and medium temperatures the design and performance of external circuits, to supply and reject heat to the TAP, are as important as the performance of the TAP itself.