Annex 60 : subtask 2.2 - Connection methods in district heating networks

Connection methods in district heating networks

Kevin Sartor

Substation

 Link between (group of) buildings and heating

plant(s)

 Could be composed of

• Piping and insulation • Isolation valves

• Heat exchangers

• Tank (domestic hot water) • Heat metering

Connection methods

 Open connection method

 Direct connection method

 Indirect connection method

• Hydraulic separation

Open connection method

 Simple

• No heat exchanger, no pump

• No extra investment

 Same water in primary and “secondary”

network

 No hydraulic separation

Open connection method

 Temperature between 70 and 135°C

 Disadvantages

• Could be dangerous for inhabitants

• DH water could be too high due to pressure and temperature ranges

• Difficult to control the temperature network

• Higher return temperature (higher heat losses)

• No hydraulic separation (

• Consumption of water

• Extra money for water treatment

Direct connection method

 Simple

• No heat exchanger,

• No pump

• if buildings is not too tall

 Same water in primary and secondary network

When using them?

 Direct connection method

• Water temperature < 90°C

• Water pressure < 6 bar

• No loss of temperature (

)

 Disadvantages

Indirect connection method

 Heat exchanger in each (group of) buildings

When using them?

 Indirect connection method

• Water temperature over 110°C

• Water pressure up to 16 bar

• Hilly locations

 But

• Extra cost (HX, pumps)

• Extra pumping cost (in the secondary side)

• Loss of temperature (HX operation)

Control strategy

 DH Supply temperature

• Determined by weather conditions

 DH water flow rate

Conclusions

Each method has its (dis)advantages

Proposal: Indirect connection method

• More complete

HX DH Supply

Thank you for your attention

Questions?

Remarks?

Sources

 [1] Guidelines for district heating substations, Europower, 2008  [2] Background Report on EU-27 District Heating and Cooling Potentials, Barriers, Best Practice and Measures of Promotion, JRC scientific and policy reports, 2012

 [3] Evaluation of systems and products – Chapter 4, Danfoss  [4] District heating systems in Finland and Russia, Kirill Eliseev