Ice rink refrigeration systems are often designed as indirect systems to reduce the refrigerant charge and therefore require a secondary refrigerant. The associated pumping power typically corresponds to 10-20% of the total refrigeration system energy usage.

Aqueous solutions with ethylene glycol or salt are the most commonly used fluids but they have less favourable thermophysical properties implying higher pumping power demand.  

There is a growing interest in using aqua ammonia as secondary refrigerant in ice rinks for both new construction and retrofit. This is an environmentally friendly and very energy efficient fluid which offers low corrosivity and very low pumping power. Material compatibility and safety must be considered when designing the systems.

Aqua ammonia uses only 45% of the pumping power compared with ethylene glycol. Field measurements show that in modern systems using aqua ammonia the share of pumping power in the total energy usage is often less than 5%.