25 MB of wavs strung together creates 512 MB file. Why?

I have 24 low-quality wav files from an emergency-dispatch system. They each have a sample rate of 8,000 Hz and show up in Audition as 32-bit floating. All of the files together amount to 25.4 MB.  That's the size of the folder housing them. That tells you how low the original quality is.

I need to simply string them together into a single file. No problem. There's a bunch of ways to do it. But every method I use creates a wav file that is 513 MB, which is 20 times the size folder containing the individual clips. No filters applied, no overlaps, no multitracking... just 24 wav files back-to-back-to-back. Couldn't be easier.

My question is, why does this create a single file that is 20 times larger than the sum of the original files individually? What is the technicality involved there and is there a way to create a single wav file that is closer to the sum of the individual files?

It's worth mentioning, any conversion to mp3 immediately exploits how low the original quality is to begin with, so I'm hoping to avoid that conversion.