Have you ever wondered how the MMCC Staff gets the Curling Ice out?

March 18th was the last night of curling for the 2021 season. While it was a challenging and short year, we now move onto the next job of getting ice out and the curling rink ready for mass vaccination clinics. So, we’re going to show you the process of taking ice out here at the MMCC. Just like installing ice, it isn’t as easy as flicking a switch and takes planning and expertise to do it safely and economically.

Some rinks have a floor drain, and their ice out is much easier. Turn off the plant, wait for it to melt, then hose all of the paint down the drain. We’re not so lucky – out facility does not have drains, and because of all of the piping underneath the pad, it would be too costly to get them installed now. So, we have to find the right balance between softening the ice so it can break, but not having it melt to the point where it makes a huge mess and floods. This is where some science comes in, specifically a property of ice (and matter) called the latent heat of fusion.

The latent heat of fusion is the point at which ice melts to water. Normally, the curling ice is set to 24F (-4.5C), and of course stays frozen throughout the year. As we remove cooling, the temperature rises to 32F (0C) and the ice begins to melt. But, because of the latent heat of fusion, the temperature will not go above 32f (0C) until all of the ice is melted. It needs to absorb more energy to change its state from a solid to a liquid. Check out the graph for a visualization of this.

Because we have to remove ice, we must make sure that the bond between the ice and the pad is broken before we can effectively take it out. If you remember our ice installation posts, you will know that we put down thin layers to create a strong bond and a cohesive surface. We need these thin layers to melt first before we can get under the ice and scrape the rest off in chunks. Normally we do this by circulating glycol to melt the bottom before the top, but for this year we have to change our approach.

So, for us to remove the ice, we have to find that sweet spot where it is starting to melt, and get our timing right so we remove the ice before it finishes melting. We cannot control this directly with the thermostat, as there will be no temperature difference during the change of state, only an energy difference that we cannot measure with our equipment.

This involves a ton of variables including outside temperature, glycol temperature, ambient heating, but also things like staff scheduling, building schedule, etc. It wouldn’t be much use if it started melting overnight and we aren’t around!

This year, we are going to use a technique called throttling. We are changing the temperature settings in the ice plant to make sure that we can better control the timing of these variables to match up with the right time, when everything lines up, drop the cooling to start removing ice. Some nicer weather this weekend will surely help!

Stay tuned as we do some work to get ready for the removal, as well as do some tests to see what the ice is doing and how it reacts.

SOURCE: MMCC Staff