Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Apparatus Dew Point #1

Open
ThibaultMarzullo opened this issue Feb 6, 2021 · 2 comments
Open

Apparatus Dew Point #1

ThibaultMarzullo opened this issue Feb 6, 2021 · 2 comments
Assignees

Comments

@ThibaultMarzullo
Copy link

See related issue in MODRLC:
henze-research-group/MODRLC#5 (comment)

@ThibaultMarzullo ThibaultMarzullo self-assigned this Feb 6, 2021
@ThibaultMarzullo
Copy link
Author

The issue could be related to another problem when setting the nominal parameters and performance curves for the CC. This is what happens in Dymola when it is set to replicate the .idf file's CC:

Warning: The following was detected at time: 0
  *** Warning: In DX coil model, gamma is too large for these coil conditions.
    Instead of gamma = 1.5, a value of -0.892027, which
    corresponds to a mass transfer effectiveness of 0.8, will be used.
    Coil nominal performance data are:
    nomVal.m_flow_nominal = 0.55
    dX_nominal = XEvaOut_nominal-XEvaWetBulOut_nominal = 0.0124652 - 0.0109999 = 0.0014653
    QLat_flow_nominal  = -1807.66
  Failed condition: mod.HVAC.sinSpeDX.eva.nomVal.gamma <= mod.HVAC.sinSpeDX.eva.gammaMax

@ThibaultMarzullo
Copy link
Author

ThibaultMarzullo commented Feb 6, 2021

Gamma is constrained by gammaMax with:
gammaMax = 0.8 * nomVal.m_flow_nominal * dX_nominal * h_fg / QLat_flow_nominal;
and
0 < gamma <= gammaMax
If we look at the rest of the equation and parameter declarations: dX_nominal must be positive; h_fg is positive; QLat_flow_nominal must be negative; m_flow_nominal is not constrained but crashes the simulation if it is set to a negative; gammaMax must be positive.
There is a sign problem.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
None yet
Projects
None yet
Development

No branches or pull requests

1 participant