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Thermal storage in district heating
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Thermal Storage
in District Heating Systems
AGENDA
• Setting the scene
• Operation considerations
• Design considerations
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THERMAL STORAGE
A thermal store makes it possible to create a
time delay between heat or cooling
consumption and its production.
Having heating/cooling at a time where the
production price is low and then utilize this low
cost heat/cooling at a time, where the
production cost would be high.
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SO WHAT ARE WE TALKING ABOUT
• Thermal Store
• Thermal Energy Store
• Thermal Heat Store
• Heat Accumulator
• Chilled Water Store
• Seasonal storage of heat
USE OF HEAT ACCUMULATORS
• A heat accumulator is an
important component in a
modern CHP system
• Or when using renewable fuels
such as sun or biomass
• Practically all CHP plants in
Denmark are equipped with
heat accumulator(s)
• The heat accumulator is used
for short-term storage of
water-based energy (1-3 days)
• A heat accumulator is a big water tank
utilizing that water at different temperature
stratifies in a hot an cold volume.
• The design of the heat accumulator tank
depends on supply temperature, static
network pressure and combinations of
temperature and pressure.
• Below a 100◦ C supply temperature, the heat accumulator tank can be designed as an
atmospheric tank – non-pressurized.
• Above 100◦ C the heat accumulator tank must be designed as a pressure vessel.
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HEAT ACCUMULATOR
• Technology considerations:
• Back pressure production.
• Extraction production.
• Time difference - production & demand
• CHP plants producing electricity when they get a high price
• Low heat demand – low efficiency of CHP plant
• Solar heating plants
• Reduce peak demand of production
• Fit with fuel deliveries (biomass)
HEAT ACCUMULATORS - CONSIDERATIONS
HEAT ACCUMULATOR INTEGRATED IN A DISTRICT HEATING SYSTEM
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HEAT ACCUMULATOR WITH HYDRAULIC SEPARATION FROM A DH SYSTEM
TYPICAL CONFIGURATION
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Design considerations:
• Temperature and static network pressure. • Diffuser. • Network Connection. • Sizing.
SOME PICTURES
CHARGING – COOLING STORE
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ADVEDØRE POWER STATION
MARSTAL – SOLAR THERMAL – SEASONAL STORAGE
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