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Dynamic simulation of district heating and cooling networks has an increased importance in the transition towards renewable energy sources and lower temperature district heating grids, as both temporal and spatial behavior need to be considered. Even though a lot and research and development has been performed in the field, there are several pitfalls and challenges towards dynamic district heating and cooling simulation for everyday use. This article presents the experiences from working with district heating and cooling projects, along with relevant research, corresponding research gaps and proposed research directions.

Dynamic simulation of district energy systems has an increased importance in the transition towards renewable energy sources, lower temperature district heating grids and waste heat recovery from industrial plants and data centers. However, a city-scale, automatically generated and updated simulator that can be used for the whole lifecycle of the plant remains a distant vision. Physics based models are often used for planning and validation, but the complexity is too high to use the models for optimization and automatic control, or for longer time spans. In this thesis, the experiences and challenges from previous district heating simulation projects using a co-simulation approach are summarized, with corresponding research gaps and proposed research directions. Two of the identified shortcomings are investigated in more detail in the thesis: First, a robust and computationally efficient method for prediction of the heat load for buildings is proposed. A deterministic dynamic model is used to predict the space heating load, and a latent variable model using Fourier basis functions predicts the heat load used for e.g. hot tap water and ventilation. The prediction model validity is shown on a multi-dwelling building located in Luleå, Sweden. Second, a probabilistic model based on Gaussian Processes is used to simulate the temperature dynamics of a district heating pipe. The model is trained and validated against a state-of-the-art physics based pipe model. It is shown that the model both replicates the behavior of the reference model, and that it can account for uncertainty of the inputs. By employing a kernel exploiting the underlying physics, many shortcomings of Gaussian Process models can be mitigated. The results suggest that a mix of physics based and probabilistic methods can be one way forward towards a digital twin of a city-scale district energy system. Natural extensions to the published papers would be to research how the methods can be applied to a larger scale district energy system.

This thesis is positioned at the intersection of product and service development and enabling digital technologies in the context of incumbent manufacturing firms. When these concepts are blended together into digital product-service systems, value growth and business model innovation may be achieved. However, incumbents may face a number of technical, managerial, and organizational challenges, which they must deal with in order to reap the full benefits of such a digital transformation. This research area has received an increasing amount of attention in recent years, but many research gaps still exist. Research addressing these gaps may support incumbent firms in their transformation towards fruitful digital product-service systems. This thesis explores three research questions: “How does the development of digital product-service systems take place in incumbent manufacturing firms?”, “What managerial and organizational challenges and opportunities are encountered in the digitalization of product-service systems?”, and “How does the use of a platform approach influence the innovation of digital product-service systems in incumbent manufacturing firms?”. The results build on the findings of five studies, all of which included at least one incumbent manufacturing firm. These firms were selected based on their histories as successful suppliers of physical goods and on the basis of their recent strategies to develop product-service systems facilitated by different digital technologies. The empirical findings suggest that digital transformation evolves in clear stages: an entrepreneurial phase, a platform-establishment phase, and an acceleration phase. The entrepreneurial spirit of a few individuals is important for initiating the first phase and for building the internal competences needed for continuous movement through the subsequent phases. The transition also includes a shift from integrated digital product-service systems to the use of a platform across several digital product-service offerings as a means to, for example, manage complexity and scale business-model portfolios. An additional finding is that the transformation into digital product-service systems involves the addition of new business models rather than the transformation of existing models. The transformation into digital product-service systems is associated with a number of managerial challenges and opportunities. The empirical findings presented here underline the importance of a holistic customer-value approach for the evaluation of the opportunities offered by a digital transformation. However, they also reveal that developing an understanding of the value dimensions of a new digital service offering may be difficult. While a platform stands out as a fruitful way to manage a number of challenges in the design of digital product-service offerings and to avoid a service paradox with underperforming business models, it may be difficult to govern and manage across firm structures. More specifically, the challenges relate to: (1) platform governance, (2) ownership of various activities, (3) deriving an overview of related product and service development, and (4) the budgeting of product-service bundles. A platform approach to digital servitization may positively affect the digital transformation of incumbent manufacturing firms by serving as a resource that can allow for business-model portfolios based on shared resources and capabilities. A platform is also a suitable resource for innovation and the prototyping of new potential offerings, as it can facilitate new combinations of existing modules and resources, which can be developed more rapidly than if they had to be developed from scratch for each proof of concept. Platforms can also be used for scaling fruitful product-service offerings. Två tydliga trender inom tillverkningsindustrin är ett ökat fokus på att erbjuda tjänster och en tilltagande digitalisering av erbjudanden. Denna utveckling kan generera flera fördelar för etablerade, tillverkande företag. Exempelvis kan både attraktiva kunderbjudanden och nya affärsmodeller skapas. Samtidigt medför en produkt-tjänstestrategi, baserad på digitalisering, ett antal nya tekniska och organisatoriska utmaningar. Denna avhandling syftar till att undersöka tre forskningsfrågor. Den första frågan undersöker hur utvecklingen av produkt-tjänstesystem, baserade på digitalisering, sker i etablerade tillverkande företag. Den andra frågan formuleras som vilka ledningsmässiga och organisatoriska utmaningar, samt vilka möjligheter företag möter i en sådan omställning? Den tredje frågan handlar om hur användningen av en plattformsstrategi påverkar innovation av digitala produkt-tjänstesystem? Slutsatserna bygger på resultat från fem olika empiriska studier, alla inkluderande ett eller flera etablerade industriföretag. De empiriska resultaten tyder på att digital transformation tenderar att utvecklas i tydliga steg – en entreprenöriell fas, en etableringsfas och en accelerationsfas. Entreprenörskap hos ett fåtal individer är viktig för initieringen av den första fasen och för att etablera intern kompetens nödvändig för en fortsatt förändring i kommande faser. Övergången innefattar också ett skifte från distinkta integrerade system, till användning av gemensamma plattformar, vilka utgör ett sätt att hantera komplexitet, men också en strategi för att hantera en portfölj av affärsmodeller. Ytterligare resultat visar att omvandlingen till digitala produkt-tjänstesystem snarare innebär ett tillägg av nya affärsmodeller, än att de befintliga modellerna förändras. Med digital transformation, och nya produkt-tjänsteerbjudanden baserade på etableringen av digitala produkt-tjänstesystem, följer ett antal utmaningar och möjligheter. De empiriska resultaten understryker vikten av att förstå olika kundutmaningar för att kunna ta tillvara på de mest intressanta möjligheterna med en digital transformation, men avslöjar också att det är en svår utmaning att förstå alla värdedimensioner i ett nytt digitalt erbjudande. En plattform framstår som en intressant strategi för att hantera ett antal utmaningar i utformningen av nya erbjudanden, men medför också nya utmaningar. Mer specifikt relaterar dessa utmaningar till (1) styrning av plattformen, (2) tydligt ägande av olika aktiviteter, (3) översikt över relaterad produkt- och tjänsteutveckling och (4) budgetering av produkt-tjänstepaket. En plattformsstrategi kan positivt påverka den digitala omvandlingen av etablerade tillverkningsföretag genom att vara en resurs som kan delas av flera olika affärsmodeller. Plattformen är också en resurs lämplig för innovation och prototypframställning av nya potentiella erbjudanden då nya kombinationer kan skapas av redan befintliga byggstenar och dessutom underlättar effektiv uppskalning av produkt-tjänsteerbjudanden.

Validerat; 20150327 (global_studentproject_submitter)