Week 9: Storage and seasonal reliability

What size store, what it costs, and the month it still runs dry.

You have a supply curve and a demand curve; storage is what turns one into the other. The method is a monthly balance run with a spin-up, so the starting volume stops mattering, reporting the month the tank is emptiest, the volume imported and the volume overflowed. The point of the week is the saturation: past some volume more storage buys almost nothing, and finding that knee is the difference between a design and a shopping list. Then you break it. The same model is re-run against the synthetic dry year and you name what fails first. Darwin leads, because it is where the annual balance lies most confidently. One measured year, even a real one, does not establish drought reliability, and the dry-year dataset is labelled synthetic wherever it appears.

This week

Lecture, 3 May 2027

The month the tank runs dryWeek 9 — the monthly storage balance, why annual averages hide drought, and a synthetic dry-year dataset to test your design against

Tutorial, 6 May 2027

Running the tank balance, then breaking itWeek 9 tutorial — size storage on a monthly balance, find where the curve saturates, then re-run the whole thing against the synthetic dry year

Worked example

DarwinThe Williamss' home leads this week, because its climate makes this subsystem hard. All five homes are compared on the lecture page.

What you leave with

A sized store with its saturation point identified, re-run against the dry year with the first failure named.

You have finished the tutorial when all of this is true, and you can tell without asking anyone:

• your balance runs a three-year spin-up and reports the third year
• you report the month the tank is emptiest, the volume imported and the volume overflowed
• you have identified the storage volume beyond which your water closure stops improving materially
• the same model has been re-run against the dry-year dataset and the first failure is named
• your supply side uses your home's measured year, labelled as synthetic case data

Assignment milestone

Tutorial checkpoint 8 of 10 (2 %) due 5 pm Friday.

Where this sits

With the measured year in hand you size, cost and compare the options, then argue for the one you recommend — the cheapest arrangement that meets the household's own targets, plus an honest case for any dollar spent beyond it.

Expected effort

About 8 hours this week: 2 h lecture and notes, 2 h tutorial, 1 h preparation and quiz, 3 h assignment 2. The assignment hours go into: Storage sized, saturation found, dry year run.

A planning guide from the semester planner, not a requirement and not a measurement of anyone. Tutorial submission sits inside the tutorial hours and the quiz inside preparation; neither is counted twice.