My CHP process doesn't work

[huichenpku]

Dear all,

    I designed a CHP process referring to existed cases, but I found my CHP process doesn't produce heat at all, and I hope someone can answer me. Thank you!

~FI_T

TechName

Comm-IN

Comm-OUT

STOCK

EFF

AFA

INVCOST

FIXOM

CHPR~FX

VDA_CEH

CEH

LIFE

PRC_CAPACT

*Technology Name

Input Commodity

Output Commodity

Existing Installed Capacity

Efficiency

Utilisation Factor

Invesctment Cost

Fixed O&M Cost

Lifetime

*Units

PJa

Years

ELC-COA00

COA1

250

0.40

1.00

10

1.00

2.00

31

ELC

HET

[AKanudia]

Can you post your model?

[huichenpku]

Attached is my model,

uploads/271/CHP.zip

[Antti-L]

The CHP attributes work only if one of the primary outputs is known to be electricity (Ctype=ELC).

Perhaps a warning should be added to the QA check log, if there is no electricity involved.

[huichenpku]

Thank you for you useful answer! I have a new question now.

In my opinion, with the absence of the thermal efficiency, the usage of EFF and CHPR can't conclude the amount of coal needed to produce heat. For example, EFF is 0.4, CHPR is 2, electricity demand is 100 J, so heat demand is 200 J, and 250 J coal is needed to product ELC, but  the amount of coal needed to produce heat is unknown when the thermal efficiency is not defined. 

What I concluded is in consistent with the computed result of my model, because EFF and CHPR seems are enough for model operation.

[Antti-L]

The thermal efficiency of a conversion process refers to the conversion efficiency, in other words it is the output/input ratio. See https://en.wikipedia.org/wiki/Thermal_efficiency 

For a CHP technology with flexible outputs, in condensing mode the thermal efficiency 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.

For modeling a CHP technology with flexible outputs of electricity and heat, you will 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

However, in your example you had fixed outputs of ELC and HET. In that case the thermal efficiency is not necessary as an input parameter. You can model the technology only on the basis of the electrical efficiency in the fixed CHP mode, because the thermal efficiency will then be also known. If the electrical efficiency is 0.4 and CHPR is 2, the thermal efficiency (ratio of electricity+heat produced to fuel consumed) will be :

    Thermal efficiency = (1+CHPR)/(1/EFF) =1.2 

The thermal efficiency in your example is thus over 100%, which seems over-optimistic even with the best flue gas condensing systems.