[Bldg-sim] How to model a district ice-storage system using option2?

[Esmireta]

Dear modelers,
I'm simulating several buildings using district cooling for LEED certificate. The district cooling plants are ice-storage plants.
The "Treatment of District or Campus Thermal Energy in LEED V2 and LEED 2009 – Design & Construction" specify that a virtual plant should be used to represent the district cooling plants performance. However, general virtual plant operate in day time, which cannot reflect the advantage of ice-storage system. 
I have two questions about it.
1 If the default efficiency of chiller is used in the virtual cooling plant, shall I also construct an ice-storage system in the proposed case? I did this in the first submission, and the reviewer did not reject it. I wonder if it is acceptable, because no guidance is given in the "Treatment V2" of this condition.
2 Appendix C of the "Treatment V2" said that if the efficiency of the district plant would like to be input as it is, the efficiency of the district cooling plants should be modeled or monitored. If modeling method is used, I really question how this should be carried out. How the load is determined or modeled? How the ice-storage performance of the virtual plant be identical with the district plants?
Thanks for your suggestions!
Esmi
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