Cogeneration for Dummies
#7

For modeling a CHP technology with flexible outputs of electricity and heat, you need the following parameters:

  • Thermal efficiency (either in condensing mode or full CHP mode): ACT_EFF
  • Heat-to-power ratio in full CHP mode: NCAP_CHPR
  • Coefficient of electricity to heat: NCAP_CEH

The thermal efficiency of a conversion process refers to the conversion efficiency, in other words it is the output/input ratio. In the condensing mode it is thus the ratio of electricity produced to fuel consumed, and in the CHP mode it is the ratio of electricity+heat produced to fuel consumed.

The heat-to-power ratio is simply the ratio of heat output to electricity output in the full CHP mode ("backpressure mode”).  The coefficient of electricity to heat is needed for defining the ratio of electricity lost to heat gained when moving from the condensing mode towards the full CHP mode.

If I understand correctly, your technology has a thermal efficiency of 77% in the full CHP mode, and it has a heat-to-power ratio of 0.696. However, your data appears to be missing the information needed for NCAP_CEH.  Nevertheless, as the technology is apparently a combined-cycle gas turbine plant with a waste heat boiler, we can assume that NCAP_CEH is relatively small, i.e. in the condensing mode the gain in electricity output is not too large. Assuming e.g. that NCAP_CEH = 0.114, we can derive the condensing efficiency:

EFF(con) = EFF(chp) * (CHPR*CEH + 1) / (1+CHPR) = 0.49

That looks reasonable, and so you could use the following data for modeling the technology on the basis of the condensing mode efficiency:

  • ACT_EFF = 0.49
  • NCAP_CHPR = 0.696
  • NCAP_CEH = 0.114

In ANSWER, they could be specified like shown below (the other parameters shown are based on your data file):


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Messages In This Thread
Cogeneration for Dummies - by sld - 22-02-2012, 12:07 AM
Cogeneration for Dummies - by Antti-L - 22-02-2012, 08:27 AM
Cogeneration for Dummies - by sld - 23-02-2012, 09:11 AM
Cogeneration for Dummies - by Antti-L - 23-02-2012, 01:16 PM
Cogeneration for Dummies - by sld - 23-02-2012, 11:46 PM
Cogeneration for Dummies - by sld - 10-03-2014, 08:31 PM
Cogeneration for Dummies - by Antti-L - 11-03-2014, 06:38 AM
Cogeneration for Dummies - by sld - 11-03-2014, 08:05 AM
Cogeneration for Dummies - by sld - 12-03-2014, 02:00 AM
Cogeneration for Dummies - by Antti-L - 12-03-2014, 07:17 AM
Cogeneration for Dummies - by sld - 12-03-2014, 07:58 AM
Cogeneration for Dummies - by Antti-L - 12-03-2014, 08:20 AM
Cogeneration for Dummies - by sld - 12-03-2014, 08:52 AM
Cogeneration for Dummies - by sld - 12-03-2014, 08:58 AM
Cogeneration for Dummies - by Antti-L - 12-03-2014, 10:47 AM
Cogeneration for Dummies - by sld - 12-03-2014, 11:09 AM
Cogeneration for Dummies - by sld - 30-03-2014, 10:01 AM
Cogeneration for Dummies - by Antti-L - 31-03-2014, 06:54 AM

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