EKA - Energy & Kylanalys has conducted a study in a number of ice rinks, where ice resurfacing energy usage was evaluated. The aim was to measure the amount of flood water and temperature used in practice when resurfacing the ice.
The results show that most water fillings are between 300-500 litres and within a temperature range of 30-70°C. More specifically the average volume was 450 litres and the corresponding average temperature was 45°C. Larger volumes and higher temperatures increase the thermal load on the ice, which implies that controlling these parameters does matter!
About 11% of the total refrigeration load comes from resurfacing which corresponds to approximately 90 000 kWh "cooling energy" per season. This in turn leads to about 21 000 kWh of energy used by the compressors for cooling and freezing the water. Heating of resurfacing water will add about 25 000 kWh per season unless reclaimed heat is used.
Ice resurfacing machines use between 2.4 to 5.5 kWh of electricity per resurfacing, which on a seasonal basis means 3 600 kWh to 6 600 kWh for the studied machines.
An interesting observation was made regarding the flood water temperature with respect to what was charged in the machines and eventually being used. As reported above the charged water was generally about 45°C, but the temperature that eventually hit the ice was only 30°C! This is because the machines are generally filled long before they are used, which makes you lose the temperature before the water is used.
Another reason being that cold "residual water" remains in the tank which mixes with the charge water and thereby lower the temperature. This represents a heat loss costing the rinks 10 000 - 15 000 kWh per season. A further loss is that the flood water is heated to an unnecessarily high temperature which is also a waste.
From an energy perspective, you should always strive for the lowest possible water quantity and temperature, however, at the end of the day we need to produce best possible ice quality. The latter is part of the ice technician’s craftsmanship and the discussion about what "good" ice is and the way to get there will last long after this study!
Read this report and more in our Reports section.