Syfte: Studiens syfte är att belysa utmaningarna som uppstår när byggnader blir alltmer välisolerade för att uppfylla ställda energikrav blir köldbryggornas andel av värmeförlusterna allt större. Köldbryggorna består oftast av svårisolerade anslutningar mellan olika byggnadsdelar och studien undersöker hur det hanteras under projekteringsskedet. Därutöver studeras hur köldbryggornas inverkan för det termiska klimatet förmedlas vidare till en VVS-konstruktör som räknar värmebehovet för att täcka alla förluster som sker genom klimatskalet. Metod: Insamling av data är baserat på att kunskapsinhämtningen görs utifrån den nuvarande kunskapen kring köldbryggor där teorin samt det som i folkmun brukar kallas ”verkligheten” i symbios studerats. För att göra detta har empirin baserats på tre insamlingsmetoder där litteraturen samt dokumentanalys om regler och krav kring arbetsgången för köldbryggor har studerats. Intervjuer i sin tur har varit den metod som tillämpats för att få insyn i hur det går till i ”verkligheten” när man beräknar köldbryggorna.  Resultat: Byggnadskonstruktörer beräknar inte köldbryggor. VVS-konstruktörerna tar liten eller ingen hänsyn till köldbryggorna i värmebehovsberäkningen. Detta innebär att vi har en ansenlig andel värmeförluster som saknas i värmebehovsberäkningar då flera studier påvisar att köldbryggornas inverkan kan spela så stor roll som 20 – 70 % av värmeförlusterna (om de underskattas enligt Building Envelope Thermal Bridging Guide från 2019). Konsekvenser: Då byggnadskonstruktörer inte beräknar köldbryggorna och VVS-konstruktören inte alltid tar hänsyn till köldbryggornas inverkan vid beräkning av värmebehovet så har vi utmaningar som behöver hanteras för att uppfylla förväntade energikrav från beställare och kravställare i form av regler. Följande rekommenderas för att få en förändring i processerna som berör köldbryggorna: ·         Att i regelförsamlingen ”Boverkets byggregler” påtalar vilka psi (Ψk)– och chi (Χ j) -värden som ska eftersträvas likt de enskilda byggnadsdelarnas U-värden (BFS 2020:4, BBR 29). Köldbryggorna ska även verifieras av tredje part. Begränsningar: I studien har inte energikonsulternas roll med att beräkna köldbryggorna undersökt vilket vore ett sätt att öka omfånget och perspektivet på fokusområdet. Nyckelord: Energiprestanda, Hållbarhet, Köldbryggor, Värmebehov. / Purpose: The purpose of the study is to illustrate the challenges that arise when buildings become increasingly well-insulated, to meet the energy requirements, and the share of thermal bridges on heat losses becomes ever greater. Underestimation of the impact of thermal bridges can create problems when e.g., energy goals and operating economy are not met, and it affects the user in the form of poor thermal comfort. The thermal bridges usually consist of connections difficult-to-insulate between different building parts and here the study will investigate how it is handled during the design phase and how the thermal bridges' impact is passed on to an HVAC designer who in turn calculates the number of heats demands to cover all losses through the climate shell. Method: Data collection is based on the acquisition of knowledge based on the current knowledge about cold bridges where the theory and what is usually popularly called "reality" in symbiosis have been studied. To do this, the empirical data has been based on three collection methods where the literature in the form of rules and requirements regarding the workflow for thermal bridges has been studied. Document analyses to study the workflow according to standards are evaluated. Interviews, in turn, have been the method used to gain insight into how things go in "reality" when calculating the thermal bridges. Findings: Building designers do not calculate the thermal bridges at all, and the HVAC designers take little or no account of the impact of thermal bridges in the heat demand calculation. This means that we have a significant proportion of heat losses that are missing in heat demand calculations as several studies show that the impact of thermal bridges can play such a large role in 20-70 % of heat losses if they are underestimated according to the building envelope thermal bridging guide from 2019. Implications: As building designers do not calculate the cold bridges and the HVAC designer does not always consider the impact of the cold bridges when calculating the heat demand, we have challenges that need to be addressed to meet expected energy requirements for customers and requirements. The following are some of recommended for getting a change in the processes that affect the thermal bridges: §  That the National Board of Housing, Building and Planning's building regulations state which psi (Ψk) and chi values are to be sought, like the U-values of individual building components (BFS 2020: 4, BBR 29), and that they should be verified by a third party. Limitations: The limitations that exist are that the study has focused only on building designers and HVAC designers and the role of energy consultants with thermal bridges would be a way to increase the scope and perspective in the focus area. Keywords: Heat demands, Sustainability Energy performance, Thermal bridges.

Energy is the core component for all industries. Most of the energy demand is met by fossil fuels, which is one of the main reasons for the high level of carbon emissions from industries. To decrease emissions or even become carbon neutral by 2050, many companies have made sustainability goals to implement renewablesin their production processes. Industries consume 74% of the energy in the form of heat, of which 30% of energy is consumed in low-temperature applications. Substituting fossil fuels in low-temperature applications with renewable energy sources such as solar-thermal technology (STT) can significantly reduce emissions. This study explores how can focus on sustainability by companies facilitate the diffusion of STT in low-temperature applications in brewery and mining industries. The study comprises a comprehensive literature review on sustainable development, drivers, and barriers of STT. The theoretical framework of the studyis based on diffusion of innovation by Rogers (2003). Empirical data is collected using semi-structured interviews to gain insights from multi-national companies about their focus on sustainability, transition towards renewable energy sources in meeting heat demand and aspects considered by companies. The study results show that companies focusing on sustainability goals are incorporating new renewable energy technologies such as STT in their processes. Companies are also making heat purchase agreements and are collaborating with neighbouring companies to incorporate STT. This form of integration of new solutions can increase the adoption rate of STT. Further, it is found that brewery companies have a better scope of implementing STT compared to mining companies.