In This Article
- 1.District Heating Service Conditions
- 2.Key Standards for DHC Valves
- 3.Recommended Valve Types for DHC Networks
- 4.Actuator Requirements for DHC
District heating and cooling (DHC) networks distribute thermal energy from centralised generation plants (cogeneration, heat pumps, waste heat recovery, biomass boilers) to industrial and residential consumers through insulated pipe networks. DHC is a major infrastructure sector in Northern Europe (Scandinavia, Germany, Poland, Finland), Russia, China (Beijing's 8,000 km network), and South Korea (Seoul). Valve procurement for DHC is characterised by large quantities of medium-to-large-diameter valves (DN100–DN1200), moderate pressures (typically 6–25 bar), and extended service life requirements (30–50 years).
District Heating Service Conditions
| System Type | Supply Temperature | Return Temperature | Max Pressure | Typical Pipe Range |
|---|---|---|---|---|
| 1st generation steam DH | 200°C steam | N/A condensate | 10–16 bar | DN100–DN600 |
| 2nd generation HW (≥ 100°C) | 120–150°C hot water | 70–90°C | 10–16 bar | DN150–DN1200 |
| 3rd generation HW (< 100°C) | 70–90°C | 40–50°C | 10–16 bar | DN100–DN900 |
| 4th generation ultra-low temp | 55–70°C | 25–40°C | 6–10 bar | DN80–DN600 |
| District cooling (chilled water) | 6–8°C supply | 12–16°C return | 10–16 bar | DN100–DN900 |
Key Standards for DHC Valves
- EN 1074 (Parts 1–6) — European standard for valves for water supply: general (Pt 1), gate valves (Pt 2), check valves (Pt 3), air release valves (Pt 4), pressure control (Pt 5), fire hydrants (Pt 6)
- EN 13831 — Sealed expansion vessels for hot water systems (not valve standard, but specifies the operating pressure context)
- AWWA C504 — Rubber-Seated Butterfly Valves (DN76–DN1800, Class 25–250) for water and cooling systems
- AWWA C509 / C515 — Gate valves for water and wastewater
- EN 12266 — Pressure testing of industrial valves (applicable to DHC valves in EU)
- ASME B16.34 Class 150 (PN 20) — Used for North American and export DHC projects as baseline pressure rating
- PED 2014/68/EU — CE marking required for valves in EU DHC systems (Category II and above)
Recommended Valve Types for DHC Networks
The primary valve types for DHC systems by application: Isolation valves in substations and heat exchanger stations — DN150–DN600 butterfly valves with EPDM seats (suitable to 130°C), cast iron body, PN 16 or ASME Class 150, with either gear operator or electric actuator. Main network isolation (scour valves, sectionalising valves) — DN200–DN1200 double-eccentric (high-performance) butterfly valves, ductile iron or carbon steel body, EPDM seats to 130°C or metal seat for temperatures > 130°C. Flow control in heat exchanger substations — DN15–DN100 globe control valves (SS 316 body) with pneumatic or electric actuator, equal-percentage characteristic for flow regulation. Non-return check valves — DN150–DN600 dual-plate check valves (API 594 / EN 12334) for secondary network substation backflow prevention.
Actuator Requirements for DHC
DHC network valves are increasingly automated for remote operation, leakage management, and demand response. Key actuator requirements: Electric actuators (AUMA SA/SAR series or Rotork IQ3) rated for −30°C to +60°C ambient (Scandinavian networks require arctic-rated actuators); Fail-safe spring return for ESD-designated isolation points (fail-closed for heat supply isolation, fail-open for cooling water make-up); Position feedback (4–20 mA or HART) to SCADA system; IP67 or IP68 enclosure rating for outdoor installation; CE marking per Machinery Directive 2006/42/EC.
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