A combined differential pressure controller and flow controller (PQ) consists of two independent differential pressure controllers and a flow restrictor (manual balancing valve) integrated in one valve body.
This device has two functions:
1) A differential pressure controller maintains fixed differential pressure over the flow restrictor (flow control). This ensures automatic flow limitation, independent of pressure variations in the system.
2) A differential pressure controller maintains constant differential pressure over motorized control valves or over the entire loop.
This is the best solution for the district heating utility as it enables both variables (maximum flow and differential pressure) to be set independently of the consumer’s heating control system. Especially when the subscriber station is owned by the consumer, the utility has no influence over flow limitation at the consumer’s end of the system.
This enables the district heating utility to control the flow available for each consumer as well as the differential pressure control at the substation. This allows efficient network balancing.
Another solution is the PB controller, which consists of one pressure controller and a flow restrictor (manual balancing valve). The PB is used in systems where independent flow and differential pressure are not required.
Differential pressure and flow controllers in district heating or cooling systems (variable flow)
Balance your network, save energy and improve end user comfort by hydronic balancing and control of district energy networks.
Features and benefits
Eliminates pressure variations and provide optimum operating conditions with improved temperature control quality
Made for demanding systems, resistant to corrosion, cavitation and dirt
Connected system is protected against pressure surges, fluctuations, cavitation and noise
Tools and apps
Heat Selector
Danfoss Heat Selector is the best-in-class online selection tool that optimizes planning process for heating application experts.
Application guide
District heating application guide
We share experience, application expertise and make recommendations on optimum performing DH applications and key applied control components
FAQ
Case studies
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Energy efficiency was a major consideration in the design of Copenhagen’s district cooling project, where VLT® drives contribute to reducing CO2 emissions by more than 3000 t annually.
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The world’s largest solar heating plant in Silkeborg, Denmark harnesses energy to heat the homes and workplaces of 40,000 citizens. It supplies 18-20% of the annual heat consumption in the city of Silkeborg, Denmark, which has an ambitious target of CO2 neutrality in heat production by the year 2030.
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Building: Office
Application: Production of heating, cooling and domestic hot water
Challenge: Design and construct customized district energy solutions for all buildings on the park
Solution: Danfoss designed and constructed 3 pre-assembled DSE substations containing control valves for the heating, cooling and domestic hot water, heat meters, self-acting controllers and electronic controllers connected to a central Building Management System. -
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600 residents in the town of Soma in Western Turkey now enjoy the comforts of a reliable and cheap heat supply from the town’s brand new district heating system.
In the coming years, more than 8,000 households will be joining the system that exploits the excess heat from the municipal power plant – a great improvement from the charcoal boilers of the past, and much less expensive.
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The district heating supply in the new Hamburg city quarter "HafenCity" is a costeffective and sustainable solution amongst other supplied by Danfoss.
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So far, 70% of all buildings in the city have been connected to the district heating system and the network is gradually being optimized. In the near future, two hospitals, one of them a big regional center, will be connected as well.
