The energy capacity of seawater used for cooling indoor air


YIT Construction Ltd. wanted to install the most energy-efficient solutions and latest technology for its seven blocks of flats in the Merenkulkijanranta area in Helsinki. One of these solutions was the Chiller cooling system which utilises seawater to cool indoor air.

Energy-efficient cooling solution

The solution uses sea water to cool incoming air. The temperature of the water entering the system is 15 °C. When the free cooling capacity of the seawater does not suffice, the compressor cooling system kicks in. The temperature of the cooling water is around 7 or 8 °C. With the fan coil unit, humidity can be removed to produce pleasant indoor air even when outdoor conditions are warm and humid.

In compressor-based operation, Chiller’s system achieves a cooling capacity of 84 kW (cooled water 12/7 °C and seawater 25/30 °C). The system’s free cooling capacity is 57 kW. In free cooling use, the machine generates chilled water of 15 °C when the temperature of the incoming seawater is 10 °C, after which the compressor system is switched on.

Residents play a major role energy efficiency

Residents have a huge impact on their homes’ energy efficiency via their choices and actions. At the Merenkulkijanranta housing company, the solutions were designed to encourage individual residents to monitor their energy consumption and to make changes in their behaviour as required. This is facilitated by the property’s flat-specific water and electricity metering.

Seawater cooling system for residential properties

The chilled water system consists of the actual water chiller, cooling and condensing circuit automation, and the electrical components of the system.

Chillquick chilled water station
Box fan coil units