There's actually more to filling a swimming pool with water than you might realize.
In the next several steps we will investigate considerations associated with filling a swimming pool with water.
We have a [Swimming Pool] that holds 20,000 gallons of water. The [Drain] is closed so we're not going to lose any water. We have a [Hose] that delivers water at 50 gallons/hour. So how long will it take us to fill he pool?
If we run the model for 24 hours it's apparent that it's going to take a very long time to fill the pool.
Now when we run the model for 480 hrs (20 days) we overflow the pool because the water doesn't turn off when the pool is full.
Now we've added [Full Level] as a goal with balancing feedback and set [Hose] = ifthenelse(([Full Level]-[Swimming Pool])>50,50,[Full Level]-[Swimming Pool]). 50 being the [Hose] capacity.
Now the [Hose] shuts off when the [Swimming Pool] reaches [Full Level]. What would make this model better would be to surface the [Hose Capacity] rather than having it buried inside the [Hose] flow.
Here we've added [Hose Capacity] as a [Variable] and set [Hose] = ifthenelse(([Full Level]-[Swimming Pool])>[Hose Capacity],[Hose Capacity],[Full Level]-[Swimming Pool]). You'll see why this is a good thing in a minute.
To develop a better feel for the relationships in the model change the values of the [Drain], [Swimming Pool], [Full Level] and [Hose Capaicty] using the sliders on the right and then click [Run Simulation] on the toolbar. You can do this repeatedly if you wish.