Aalborg CSP investigated the potential to use solar heating to reduce the Danish district heating plant Solrød Fjernvarme's natural gas dependency as well as to stabilize the energy prices towards the consumers. 


Client:       Solrød Fjernvarme a.m.b.a.
Location:    Havdrup, Denmark
Status:    Operational
Technology:     Solar-thermal plant
Capacity:    1.9MWth
Contract type:    EPC

Harvesting energy from the sun in the most efficient way

To match the client’s energy requirements at the lowest possible cost, the system is designed as a 2,569m2 flat panel system combined with a 1,250m3 heat storage accumulation tank. With a capacity of 1.9MWt, the solar heating system is capable of producing 1,226 MWh annually covering approx. 28% of the town's heat demand. The solar field consists of both single- and double-glazed collectors. The single-glazed solar collectors are placed in the beginning of the rows, followed by the double-glazed collectors. The purpose of using single-glazed collectors in the beginning of the rows is to get as much energy into the collectors as possible and thus harvest more energy. Single-glazed collectors absorb more energy than double-glazed collectors, but have a greater heat loss. When changing from one to two layers of glass, less energy is absorbed. However, double-glazed collectors have a lower heat loss.

Low pressure drop and precise temperature control

The system has a low pressure drop and thus lower power consumption than other similar systems. Furthermore, it is easy to control the desired temperature in the collectors, as they are built according to the meander principle, which provides a natural water distribution. Operating data from the plant's first solar season confirmed the high performance as well as the precise temperature control, which resulted in a perfect operation of the accumulation tank with a stable delivery of hot water directly to the district heating network.


  • Design and delivery of complete solar collector system (flat panels)
  • Design and delivery of pipping (valves, drain, headers etc.) 
  • Design and delivery of civil works
  •  Mechanical and electrical installation
  • P&I diagrams and control system
  • 3D model
  • Strength and flex calculations
  • Documentation
  • Supervision of installation and commissioning
  • Legalization of the plant


Andreas Zourellis
VP Sales - International
District heating / industrial solar technologies
Phone: +45 50 30 00 25 
E-mail: azo@aalborgcsp.com