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Book cover


Low Temperature District Heating: Consequences for Existing Buildings

Translated title

Lavtemperaturfjernvarme: Konsekvenser for eksisterende bygninger

Author

Term

7. term

Publication year

2015

Submitted on

Pages

34

Abstract

Denne bacheloropgave undersøger, hvilke konsekvenser overgangen til lavtemperatur-fjernvarme kan få for eksisterende bygninger. Op til 40 % af de eksisterende enfamiliehuse er opført i perioden 1960–1979, og derfor er fokus lagt på denne bygningstype. Fjernvarme leverer varmt vand i rør til opvarmning af bygninger, og lavtemperatur-fjernvarme betyder lavere fremløbs- og returløbstemperaturer end i traditionelle systemer. I opgaven vises, at hvis temperatursættet ændres fra 70/40 °C (fremløb/retur) til 55/30 °C, reduceres radiatorernes varmeafgivelse til omkring 55 % af den oprindelige. Opgaven vurderer, hvilke forbedringer af bygningens klimaskærm (vægge, tag, vinduer) der kan kompensere for den lavere varmeeffekt, og hvilke konsekvenser det har for opvarmningen, hvis klimaskærmen ikke forbedres. På baggrund af de opstillede modeller og antagelser konkluderes, at bygningens varmebehov kun i en begrænset periode ikke kan dækkes. Der er derfor grundlag for, at fjernvarmesektoren kan påbegynde overgangen til lavtemperatur-fjernvarme, da det kun vil medføre begrænset gene for forbrugerne.

This bachelor thesis examines what happens to existing homes if the district heating network shifts to low-temperature operation. Because up to 40% of existing single-family houses were built in 1960–1979, the study focuses on that group. District heating supplies hot water through pipes to heat buildings, and low-temperature district heating uses lower supply and return temperatures than traditional systems. The analysis shows that changing the temperature set from 70/40 °C (supply/return) to 55/30 °C reduces radiator heat output to about 55% of its original level. The thesis evaluates which improvements to the building envelope—such as better insulation of walls, roof, and windows—could compensate for this loss, and what happens if no envelope upgrades are made. Based on the models and assumptions used, the building’s heating demand is unmet only during a limited period. This provides a basis for starting the transition to low-temperature district heating, with only limited inconvenience to consumers.

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