merge ice tank model

[YangyangFu]

@mwetter can you please create a new branch so that I can make a pull request?

Or you can get the model here: https://github.com/BE-HVACR/modelica-ice-tank/tree/release_for_mbl.

The current implementation is validated against onsite measurement data, which contain three discharging experiments (with various discharging rate) and one charging experiment (with fixed charging rate). The data and descriptions are also documented in the implementation. More details can be found in the following reference.

Li, G., Fu, Y., Pertzborn, A., Wen, J., & O’neill, Z. (2021, September). 
An Ice Storage Tank Modelica Model: Implementation and Validation. 
In Modelica Conferences (pp. 177-185).

[mwetter]

@YangyangFu : Thanks, I created the branch issue2820_iceTank. Can you please make a PR against that branch. Note that this branch is based on MSL 3.2.3 which is the same version as your ice tank model. I think it will be easier for you to integrate it into that version. I therefore suggest we integrate it into that branch, and then I can upgrade that branch to MSL 4.0.0 which is what the master is currently at. See also #2812

[mwetter]

The current tank model contains built-in control for the outlet temperature during discharging. This makes it hard to use model for configurations such as this (unless cascading control where used, which is not needed and adds complexity):

(Image from https://www.evapco.eu/sites/evapco.eu/files/2017-03/Thermal%20Ice%20Storage%20Application%20%26%20Design%20Guide.pdf)
or the one in http://www.calmac.com/stuff/contentmgr/files/0/c0e62901daa3ddb1722d04aaeaf31997/files/ice_storage_how_and_why_lessons_learned_17_garcia_coulard4.pdf

Therefore, the model should be edited to move the control out of the component.

Todo:

• Make a model 'Tank' and 'ControlledTank'.
• Revise documentation.