Abstract: . . .  [kWh/a] 83 83 83 83 PRIMARY ENERGY SAVED Primary Energy Demand of the Reference System Q conv,tot [kWh/a] 16557 16557 16557 16557 Auxiliary Heating Demand Q aux,tot [kWh/a] 12584 12915 14074 11921 Primary Energy Saved PEA sub [kWh/a] 3973 3642 2483 4636 ENERGY PAYBACK TIME AZ [a] 2.6 3.1 3.9 2.2 Without Integrated Burner With Integrated Burner Symbol Unit  . . .
. . .  83 83 83 PRIMARY ENERGY SAVED Primary Energy Demand of the Reference System Q conv,tot [kWh/a] 16557 16557 16557 16557 Auxiliary Heating Demand Q aux,tot [kWh/a] 12584 12915 14074 11921 Primary Energy Saved PEA sub [kWh/a] 3973 3642 2483 4636 ENERGY PAYBACK TIME AZ [a] 2.6 3.1 3.9 2.2 Without Integrated Burner With Integrated Burner Symbol Unit  . . .
. . .  PRIMARY ENERGY SAVED Primary Energy Demand of the Reference System Q conv,tot [kWh/a] 16557 16557 16557 16557 Auxiliary Heating Demand Q aux,tot [kWh/a] 12584 12915 14074 11921 Primary Energy Saved PEA sub [kWh/a] 3973 3642 2483 4636 ENERGY PAYBACK TIME AZ [a] 2.6 3.1 3.9 2.2 Without Integrated Burner With Integrated Burner Symbol Unit  . . .
. . .  Energy Payback Time A Key Number for the Assessment of Thermal Solar Systems Page 1 Proceedings of EuroSun2004, 20 - 23 June 2004, Freiburg, Germany Page 1 of 10 t KEA t KEA KEA (t) PEA m o p in · + · + = (t) PEA (t) PEA sub in = Energy Payback Time – A Key Number for the Assessment of Thermal Solar Systems E. Streicher, W. Heidemann, H. Müller-Steinhagen University of Stuttgart, Institute for Thermodynamics and Thermal Engineering (ITW) Pfaffenwaldring 6, D-70550 Stuttgart Tel.: 0711 / 685-3536, Fax: . . .
. . .  reduced by using a thermal solar system. Therefore both systems are credited with the cumulative energy demand of a conventional hot water store of 135 litres (store credit in Table 2). The collector of system 1 is integrated in the roof, saving a large number of rooftiles. The cumulative energy demand for the saved rooftiles is therefore also credited to the thermal solar system. Table 2: Determination of the cumulative energy demand for production In addition the cumulative energy demand of the transport . . .
. . .  times between 1.3 to 2.3 years. For solar combisystems typical energy payback times are slightly higher, from 2.0 to 4.3 years. Taking into consideration that thermal solar systems have a minimum lifetime of 20 years or more, the substantial potential for saving of primary energy has hence been demonstrated. System 3 System 4 System 5 System 6 PRIMARY ENERGY EMBODIED IN THE SYSTEM Production KEAp [kWh] 9448 9420 7596 9531 Operation KEAo [kWh/a] 282 542 443 207 Maintenance KEAm [kWh/a] 83 83 83 83 PRIMARY . . .
--3000,6,250,2978,22681