Thermodynamic efficiency measurements
The procedure for such a measurement is described in detail within the IEC (International Electrotechnical Commission) standard 60041 "field acceptance tests to determine the hydraulic performance of hydraulic turbines, storage pumps and pump turbines". This standard is used worldwide for highly accurate measurements of efficiency of hydraulic machines. For measurements in small hydropower plants the IEC standard 62006 "hydraulic machines - acceptance tests of small hydroelectric installations" is appropriate.
Acceptance tests, i.e. checking the guaranteed efficiencies specified by the manufacturer, are an important field of application for such measurements. On the basis of efficiency measurement and calculation of profitability the "return of investment" can be evaluated. Further, the potential for improvement by revisions can be estimated via a current inventory of the plant and the hydraulic machines.
The thermodynamic method is suited for efficiency measurements of absolute hydraulic efficiency of pumps and turbines for heads above 100m. etaeval has also experience with measurements at 80 m head. Flow rate measurement is not required for the thermodynamic method. Discharge can be iteratively determined from hydraulic efficiency and power measurements.
Features of thermodynamic efficiency measurements:
- absolute hydraulic efficiency
- used for pumps and turbines
- used for heads higher 100m head
- measurement of flow rate not needed