In article ,
writes:

Does anyone know of a good paper showing the luminosity of the
universe as a function of age of the universe? ie, a plot showing
total L per unit co moving volume, for each Gyr time back to early
universe.

Look up "Madau diagram". This isn't exactly what you want, but might
point you in the right direction.

It also depends on what you mean by "luminosity". To a first
approximation, all photons are CMB photons. Hoyle pointed out that the
total amount of energy emitted by stars in the last few billion years is
about the same as that of the CMB. (He thought that this might indicate
that the CMB is recycled starlight---of course, he didn't believe in the
Big Bang---and was looking for an alternative explanation for the CMB.)

Check out papers from the late 1970s by the late Paul Wesson and (still
alive, as far as I know---saw him last year) Rolf Stabell on
extragalactic background light.

Also, I'm trying to figure out how to account for the change in
energy per m^3 of space, for the cosmic background radiation, as a
function of age of the universe. As we go back in time, the CBR
would have been at higher energy, so, the CBR energy per m^3 would
have been higher in the early universe than it is today.

This is easy: radiation density is proportional to the fourth power of
(1+z), where z is the redshift. Three powers of (1+z) come from the
expansion, and the fourth comes from the fact that the wavelength
stretches with the expansion of the universe. Black-body radiation
remains black-body radiation when stretched this way, the temperature
being proportional to (1+z).