MuDoCo: Multi-domain comfort models

People living and working in buildings are exposed to a large variety of indoor-environmental conditions. These conditions, which influence people`s health, comfort, well-being, and productivity, differ both in terms of type and intensity. When discussing indoor-environmental conditions, we usually distinguish between different domains, including thermal, visual, acoustic, and air quality domains. In the past, many researchers have investigated the impact of these conditions on people`s perception and comfort. However, both research efforts and related standards and guidelines often treat these domains separately. There are very few cases where the complex multi-domain indoor-environmental conditions are studied in a holistic and integrated way. The main reason for this is the lack of deep knowledge about interdependencies of different environmental factors (e.g., temperature, light intensity, sound level) and how they collectively influence buildings` occupants. In our project, we target scientific advances in this area. As such, we aim toward a better understanding of how people react to a combination of different environmental parameters. To achieve this, we conduct systematic laboratory experiments involving human participants who provide feedback regarding their perception and evaluation of multi-domain indoor- environmental conditions. Moreover, we intend to prepare the foundations for the development of multi-domain comfort models. In future, such models are expected to aid professionals involved in building design and operation. To summarize, our project intends to i) create an up-to-date knowledge base about the impact of interdependent multi-domain indoor-environmental factors on people`s perception; ii) develop a systematic theoretical framework for experimental multi-domain studies; iii) explore the potential for the development of a general multi-domain comfort model; and iv) apply and evaluate different modelling approaches by exploiting objective and subjective (perception) data collected in various experimental settings. These objectives are sought through the collaborative effort by all three partner universities in Austria (TU Graz) and Germany (KIT Karlsruhe, RWTH Aachen). Whereas each partner will have a distinct methodological and thematic focus, together they explore the influence of multiple simultaneously existing indoor-environmental factors influencing people`s comfort perception and evaluation in working environments.

Good indoor-environmental conditions are essential for guaranteeing occupants' health, comfort, and productivity within indoor spaces such as homes, offices, schools, and hospitals. Indoor-environmental quality (IEQ) is influenced by factors in multiple domains, typically categorized into the thermal, visual, acoustic, and air-quality. Scientific literature, standards and guidelines mainly focus on these domains in isolation. However, recently researchers have started to address possible cross-domain effects. Nonetheless, findings remain fragmented and inconclusive. In this context, the MuDoCo project aimed at advancing the theoretical and methodological foundations of multi-domain comfort research by systematically investigating interactions between factors in thermal, visual, aural and olfactory domains and how such interactions are reflected in people's perception of indoor-environmental conditions. The main objective was to improve understanding of the underlying mechanisms, strengthen experimental design approaches, and advance modelling strategies. In line with these objectives, this project was structured in three parts: 1) Theoretical and methodological frameworks, including concepts, constructs, and scales used in multi-domain research; 2) Three sets of experimental studies conducted under controlled and semi-controlled conditions at three locations. These studies addressed distinct domain pairings, namely visual - acoustic, led by TU Graz; visual - thermal, led by KIT, Karlsruhe; and thermal - olfactory, led by RTWH Aachen; 3) surveys complemented controlled studies and examined evaluative trades-offs across domains. The study at TU Graz explored the influence of acoustic stimuli on visual discomfort in an office environment. The objective was to see if when people are exposed to a higher degree of acoustic strain, they would adopt a less favorable evaluation of the same visual exposure setting. The results of this study suggest that the acoustic environment can influence, albeit to a small degree, the perception of visual discomfort caused by experiencing glare in the visual field. The study also explored further related questions, including participants' reporting of their sensation and satisfaction levels across other domains (i.e., thermal comfort, indoor air quality, and the perceived overall quality of the environment). The project results could effectively contribute to the body of research on the combined effects of indoor-environmental stimuli. The cumulative findings of such studies could not only inform IEQ standards and guidelines but also increase awareness and understanding of key stakeholders in the building design and operation field. In the course of the project, scientific dissemination and collaboration activities were conducted to actively engage with the research community. A series of workshops were organized and facilitated to structure expert dialogue around key project outcomes and multiple scientific papers were presented at international scientific conferences and published in scientific journals ensuring continuous visibility and peer recognition. Lastly, engagement in international research networks, including IEA EBC Annex 79 and 95, supported collaboration and alignment with broader research agendas.