I suggest reading extensively over on probrewer.com forums
but to address a few of your questions...
Can anybody provide me with information on generic ingredients cost for each brew, What is the normal number of brews per week on a 15bbl system and how many litres each brew will produce
a "15bbl brewery" (meaning fifteen "barrels"; 1bbl = 117.35 liters; ~31 gallons) is generally referring to the amount of beer you can brew in one single production run on the equipment. Obviously costs are extremely variable based on scale. A "20bbl" materials-cost would be less than simply 20x that of a "1bbl" system, for example (but not including capitol equipment costs).
however, for estimate purposes (ignoring exact flavor profile for now; only considering recipe ingredients/materials), brewing 15bbls requires almost exactly
15x the amount of ingredients that a 1bbl recipe would call for, so you can just scale a 1bbl recipe by 15x to get a good estimate of the amount of the hops grain and yeast that you would put into a 15bbl batch, and thus, cost of a 15bbl batch.
having said that- the cost of a batch varies incredibly, recipe to recipe. an IPA that calls for 500lbs of hops is going to be way more expensive than a lite pilsner that only uses 50lbs of hops, for example.
I am confused due to the different measurements I have found while researching (BBl, litres, hectolitres etc).
those units all measure volume, just in a different scale. hopefully, being a university-level project, you should already know how liters