Aha! An excellent idea. In order to exceed the limit which I mentioned (the total human metabolic energy mustn’t be greater than the quantity of incident sunlight which is not reflected in normal circumstances), we could actively cool the Earth.
By linking the earth to a series of dynamic orbital rings, the effective surface area of the Earth could be extended almost indefinitely, allowing us to cram even more hundreds of trillions of humans on the planet. We would never run out of carbon, hydrogen, oxygen or nitrogen, since these elements are abundant on the planet. If we run out of some trace element it could be imported from the asteroid belt.