Techno-economic investigation of the potential for energy efficiency measures of multi-story apartment buildings at cluster level using different district heating tariffs

The paper presents a systematic approach to study energy renovation of a larger building stock at cluster level using categorization, classification into modules, life cycle cost (LCC) optimization, and bottom-up modeling. Seven-story clusters of slab and tower blocks were analyzed to investigate the techno-economic potential for energy efficiency measures (EEMs) of 401 multi-story apartment buildings constructed during the 1960s and ’70s located in two Swedish municipalities. Energy renovation with intention of lowest LCC and projected energy savings concerned the purchased energy for space heating and domestic hot water use allocated by different district heating (DH) tariffs. Different conditions for DH and performance indicators demonstrated code compliance. The LCC analysis revealed a rather small potential for cost-optimal EEMs on building envelopes. Incentives to gain LCC savings during energy renovation increased with a DH tariff with constant price rate throughout the year. A starting point for cost-effective energy renovations arguably would be clusters with 94 two-story and 160 three-story slab blocks, also requiring fewer EEMs to achieve thermal performance requirements. DH systems using industrial excess heat can improve buildings’ energy performance and reduce required EEM investment costs. The DH price level is shown to be a vital issue for cost-effective energy renovations