[EnergyPlus_Support] Warning meassage in Exercise 2C of "Getting Started..."

[Álvaro Fialho <alvarofialho@xxxxxxxxx>]

Hello all,

I was playing a bit with the sample Exercises provided in the "Getting 
started with EnergyPlus" document. And Exercise 2C (the most "complete" 
one) outputs a warning message (and some consequent error messages) that 
I don't know what to do. As a "learning exercise", could you please help 
me into solving this? It is important to let you know that I'm a 
computer scientist, with no experience at all (for the moment) with the 
design of HVAC systems :-) Thanks!


Here goes the warning message:

    ** Warning ** Coil:Cooling:DX:SingleSpeed "NORTH ZONE UNITARY 
COOLING COIL" - Full load outlet air dry-bulb temperature < 2C. This 
indicates the possibility of coil frost/freeze. Outlet temperature = 1.29 C.
    **   ~~~   **  ...Occurrence info = Chicago Ohare Intl Ap IL USA 
TMY3 WMO#=725300, 04/25 14:00 - 14:15
    **   ~~~   ** ... Possible reasons for low outlet air dry-bulb 
temperatures are: This DX coil
    **   ~~~   **    1) may have a low inlet air dry-bulb temperature. 
Inlet air temperature = 21.146 C.
    **   ~~~   **    2) may have a low air flow rate per watt of cooling 
capacity. Check inputs.
    **   ~~~   **    3) is used as part of a HX assisted cooling coil 
which uses a high sensible effectiveness. Check inputs.



And the consequent error message:

    ************* ===== Recurring Error Summary =====
    ************* The following recurring error messages occurred.
    *************
    *************  ** Warning ** Coil:Cooling:DX:SingleSpeed "NORTH ZONE 
UNITARY COOLING COIL" - Full load outlet temperature indicates a 
possibility of frost/freeze error continues. Outlet air temperature 
statistics follow:
    *************  **   ~~~   **   This error occurred 46 total times;
    *************  **   ~~~   **   during Warmup 0 times;
    *************  **   ~~~   **   during Sizing 0 times.
    *************  **   ~~~   **   Max=1.986818  Min=0.362192


Thanks lot!
Álvaro.

ps: I'm sending the IDF attached, although you might all have it in the 
Examples/BasicsFiles folder of your E+ installation.


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Attachment not found:
d:\eudora\attach\Exercise2C-Solution.idf