Convolution in frequency space with fft and ifft -> num output samples?
What you do is called circular convolution but you want "linear" convolution: Say you have two signals of length $N$ and $M$. Append zeros to both time-domain signals, so that their length is $L=N+M-1$, then calculate the $L$-DFT of both signals, multiply them in frequency-domain and convert the result back to time-domain.

In your case, you should append 44099 zeros to each signal before transforming it to the frequency domain. The result will then be 88199 samples long.

If the available FFT is shorter than 88199 you have to divide the signal into shorter blocks and apply the overlap add method.