What is the approximate amount of BTUs needed to melt or freeze 1 pound of ice/water at 32°F?

To understand the amount of BTUs required to melt or freeze 1 pound of ice or water at 32°F, we need to consider the latent heat of fusion, which is the energy required to change a substance from solid to liquid at its melting point without changing its temperature.

For water, the latent heat of fusion is approximately 144 BTUs per pound. Therefore, it takes about 144 BTUs to melt 1 pound of ice at 32°F into liquid water at the same temperature. Similarly, when freezing, the same amount of energy (144 BTUs) is released when water transforms into ice at the freezing temperature.

This value aligns perfectly with the concept of latent heat, confirming that 144 BTUs is indeed the correct answer for both melting and freezing 1 pound of ice/water at 32°F. Understanding this concept is essential for calculations related to phase changes in thermodynamics and also relates to various practical applications where heat transfer processes occur.