i have this exercise that i dont know how to solve, i know how to solve it when the density and specific heat is given but without it i dont is there any other way to solve this ?

The data obtained in a pin heat exchanger is shown in the following table:

Calculate the efficiency of the pinned heat exchanger

\begin{tabular}{|l|l|l|l|} \hline ST-1 & ST-7 & SC-1(L/min) & SW-1(W) \\ \hline 21.705 & 20.02 & 158.6385 & 4.76 \\ \hline \end{tabular}