Marstal District Heating and Alfa Laval

When the district solar heating plant in Marstal was started, there were some initial problems getting the system to run according to plan.

"At first we didn't get the delta T right - that is, the cooling of the water in the district heating network," says Leo Holm, plant manager, Marstal Fjernvarme (Marstal District Heating). "These are problems that are inherent in district solar heating, and Alfa Laval solved them to our satisfaction."
 

"The problems," says Alfa Laval service engineer Henrik Juul, "are caused by the low temperatures used. There is usually only a two-degree [Celsius] difference between the primary and the secondary sides of the heat exchanger, which puts great demands on the unit. Alfa Laval's heat exchanger plates feature the high heattransfer efficiency needed to extract energy from the solar energy."

At the moment Marstal Fjernvarme has installed 10 Alfa Laval plate heat exchangers to transform the solar
energy from the solar panels into heating that can be distributed through the district heating network's 32 kilometres of pipes to the 1,450 end users in the town of Marstal.

The heat exchangers also separate the solar system from the district heating system, one important aspect being to keep the solar system glycol from the district heating system. There are three brazed heat exchangers and seven gasketed plate heat exchangers in various sizes.

Plate heat exchangers are the perfect choice in heating applications that must balance high demands for comfort, reliability and safety, such as encountered in district heating networks. Alfa Laval plate heat exchangers feature high heat-transfer efficiency and are able to handle the pressure differences very well.