Agenda Background and purpose with study Data collection - - PowerPoint PPT Presentation

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Agenda Background and purpose with study Data collection - - PowerPoint PPT Presentation

Oct 09, 2022 364 likes •516 views

Agenda Background and purpose with study Data collection Results radiator temperatures Results factors affecting the temperatures Conclusion 3 Background Future Expectations Situation Today 3 rd generation

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SLIDE 1
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SLIDE 2
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SLIDE 3
  • Background and purpose with study
  • Data collection
  • Results radiator temperatures
  • Results factors affecting the temperatures
  • Conclusion

3

Agenda

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SLIDE 4

4

Background

Low temperature district heating (LTDH)

50-55°C Supply 20-30°C Return

Situation Today

  • 3rd generation
  • 90-75°C Supply / 40-50°C Return
  • Customer temperature demand:

20°C space heating / 50-60°C DHW

Future Expectations

  • Decrease of building heat demand
  • New heat sources to be integrated
  • Improve environmental

performance

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SLIDE 5

5

Background

What are the temperatures

  • f radiator systems in

existing buildings? Radiators in Buildings

  • Design before 1980: typ. 80°C supply
  • Design after 1982: max 60°C supply
  • Control, monitoring and balancing of

radiator systems important

Previous Work

  • Focus on temperatures on the district

heating side

  • Lack of documentation of

temperatures on secondary side

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SLIDE 6

10/19/2016 Chalmers Teknologkonsulter AB 6

The Actors Involved in This Project

District Heating Provider

  • Major DH customer
  • 330 Substations
  • 26 900 Apartments
  • Hourly data

measurements available from SCADA system Public Housing Company Research Institution

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SLIDE 7

Temperature data from:

  • 5 different geographical areas within

Gothenburg district heating system

  • Multi-family buildings only
  • February 1st 2015 to January 31st 2016
  • 109 radiator systems in total
  • Recorded automatically in the substation of

each radiator system

  • Each radiator system serves
  • approx. 100 apartments

10/19/2016 Chalmers Teknologkonsulter AB 7

Data Collection

District Heating Substation

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SLIDE 8

10/19/2016 Chalmers Teknologkonsulter AB 8

Radiator Supply Temperatures

10 20 30 40 50 60 70 80 90

  • 16°C
  • 10°C
  • 5°C

0°C 5°C 10°C 15°C Radiator Supply Temperature [°C] Outdoor Temperature

For DOT = -16˚C

  • Avg: 64°C

Max: 81°C Min: 53°C

  • Outliers (circled)

almost 4˚C higher than control curve set points

  • 9 radiator systems

(8%) have supply temperatures of 55˚C or less Design Outdoor Temperature (DOT) Building Balance Temperature

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SLIDE 9

10/19/2016 Chalmers Teknologkonsulter AB 9

Radiator Return Temperatures

10 20 30 40 50 60 70 80 90

  • 16°C
  • 10°C
  • 5°C

0°C 5°C 10°C 15°C Radiator Return Temperature [°C] Outdoor Temperature

For DOT = -16˚C

  • Avg: 42°C

Max: 57°C Min: 28°C

  • Minimum value for

each outdoor temperature belongs to same radiator system

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SLIDE 10
  • Any renovation

done to buildings not accounted for

  • Majority of

buildings constructed between 1950 and 1965, also have the highest supply temperatures 10/19/2016 Chalmers Teknologkonsulter AB 10

Building Construction Year

50 55 60 65 70 75 80 85 1930 1940 1950 1960 1970 1980 1990 2000 Radiator Supply Temperature at DOT = -16°C [°C] Year

  • 1. Angered
  • 2. Guldheden
  • 3. North Hisingen
  • 4. South Hisingen
  • 5. Frölunda
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SLIDE 11

10/19/2016 Chalmers Teknologkonsulter AB 11

Building Specific Heating Demand

50 55 60 65 70 75 80 85 50 100 150 200 Radiator Supply Temperature at DOT = -16°C [°C] Space Heating Demand (DHW not included) [kWh/m2,yr]

  • 1. Angered
  • 2. Guldheden
  • 3. North

Hisingen

  • 4. South

Hisingen

  • 5. Frölunda
  • Low space

heating demand does not mean low supply temperatures

  • For the lowest

supply temperatures, same space heating demand as for radiator systems where supply temperatures are the highest

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SLIDE 12

10/19/2016 Chalmers Teknologkonsulter AB 12

Radiator Size and Space Heating Demand

0,0 2,0 4,0 6,0 8,0 10,0 12,0 50 55 60 65 70 75 80 Krad/QSH [W∙103,yr/ KnkWh] Supply Temperature [˚C]

  • Radiator systems

with the higher supply temperatures had a low heat transfer area to heating demand ratio

  • Majority of

radiator systems need heat transfer area to be increased or building heating demand to be lowered, or maybe a combination

  • f both

Relation between Radiator Size and Yearly Specific Heating Demand

  • vs. Radiator Supply Temperature
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SLIDE 13
  • Reduce tempertures to some extent
  • Reduce tempertures during parts of the year
  • 8% of radiator systems with supply temperatures less than 55°C for DOT
  • Renovation needed and heat transfer surfaces to be increased
  • 64/42°C for DOT = -16°C
  • Large range of values

13 Chalmers Teknologkonsulter AB

Radiator Temperatures 4th Generation District Heatting Potential actions today

Conclusion

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SLIDE 14

Thank you!

Questions?