Does freezing water release free energy?
When water freezes into ice it expands. Freezing involves REMOVING energy from the water yet it could be conceivably possible to extract mechanical work from the expanding ice (to burst a pipe for example). The best answer that my brain can come up with is that the expansion is a result of latent energy stored within the water molecules from the last time it was heated above freezing. For example; Ice was thawed during the spring by the sun and therefore added potential energy. When winter rolls around that potential energy is released when the ice expands.
