99 research outputs found
A Multi-Domain Approach to Explanatory and Predictive Thermal Comfort Modelling in Offices
No full textIt is well known that physical variables, such as temperature, exert a significant influence on occupants' thermal comfort in office buildings. Despite this knowledge, models that are currently used to predict thermal comfort fail to do so accurately, resulting in a mismatch between design conditions and actual thermal comfort conditions. The assumption is that exclusive attention to physical variables is insufficient for understanding or predicting thermal comfort. Contextual, social and personal variables may also affect thermal comfort in office buildings and interact with each other. The question arises as to how a multi-domain approach can aid in explaining and predicting thermal comfort in offices. In this study, a unique dataset containing indoor environment, demographic, occupancy and personality related variables is used to construct two types of thermal comfort models. The dataset contains 524 observations, collected during summertime in two office buildings in the Netherlands. Firstly, structural equation modelling (SEM) is used to construct an explanatory model, with the aim to identify significant variables affecting thermal comfort, as well as the interactions between them. Secondly, machine learning is used to train four binary classification models to predict thermal discomfort. For the investigated cases, SEM suggests that thermal discomfort is significantly affected by (i) temperature, (ii) sound pressure level, (iii) the interaction between temperature, sound pressure level and illuminance, and (iv) the interaction between gregariousness and occupancy count. The four predictive models are subsequently trained using only the significant variables. Nevertheless, the weighted F1-score for all four models ranges between 0.55 and 0.59, indicating weak predictive performance. The results show that significant influencers are not necessarily good predictors of thermal discomfort. Future researchers are encouraged to combine explanatory and predictive modelling techniques, in order to test whether variables that are relevant to the domain are useful for prediction
Percieved control over indoor climate and its impact on Dutch office workers
No full textA field study was conducted in nine modern office buildings in the Netherlands. The study focused on perceived control over indoor climate and its impact on satisfaction of building occupants, the incidence of building related (SBS) symptoms and self-assessed performance.
The study involved a questionnaire amongst 236 office workers. Statistical analyses were conducted to investigate correlations between combined perceived control over temperature and ventilation on the one hand and satisfaction-, SBS- and productivity-indices on the other.
Individual perceived control over indoor climate scores were perfectly normally distributed (using a 7 point scale coded from 1 = no control at all to 7 = full control) with as mean value 3.1 (SD 1.4). Respondents that perceived to have a high amount of control over their indoor climate were considerably more satisfied with their indoor environment. High control respondents also had significant less building related symptoms (BSI(5) 0.94 vs. 0.61). And productivity scores were significantly higher (6.3 %point) in comparison with the low control respondents
Response of low-cost environmental monitors to typical emission events in daycare centers
No full textDaycare centers (DCCs), the first program for the social development of young children (0-5 years old), are the most important place for young children besides their homes. Continuous indoor air quality (IAQ) monitoring in DCCs is a means to assess the IAQ and assure a healthy and comfortable environment for infants and toddlers. To date, an extensive array of low-cost air quality monitors (LCMs) is available on the commercial market. Still, only a limited number of these LCMs have been subjected to any research-based evaluation. Furthermore, performance evaluations of low-cost sensors in previous literature are mainly focused on residential emission activities. To the best of our knowledge, there is no research into simulating emission sources related to DCCs scenarios yet. Therefore, this study is aimed to evaluate the response of one type of LCM (2 units) to typical emissions events related to DCCs in detecting the IAQ parameters, that is, particulate matter (PM2.5, PM10), carbon dioxide (CO2), total volatile organic compounds (TVOC), temperature (T), and relative humidity (RH). The LCMs were compared to outcomes from research-grade instruments (RGIs). All the experiments were performed in a climate chamber, where 3 kinds of typical activities (Background test; Arts-and-crafts events; Cleaning events; in a total of 20 events) were simulated by recruited subjects in an indoor climate condition (cool and dry [20±1 ℃ & 40±5% ℃]). The IAQ parameters sensed by the LCM detected the majority of events, despite a difference in the magnitude of responses. Intra-sensor consistency was significantly strong for all IAQ parameters, with a mean coefficient of variation of 4.14%. The LCM particle sensor underestimated the reference concentrations, with a mean RMSE of 12.8 μg/m³ for PM2.5 and 36.5 μg/m³ for PM10. Although TVOC and CO2 sensors reported a weak quantitative response, both had a close correlation with RGIs’ data, with R2 values in the range of 0.8-1.0 and 0.5-1.0, respectively. A good qualitative and quantitative agreement was observed in both T (within 1.1°C) and RH sensor (within 1%). In summary, this study reveals that the LCMs investigated are useful in providing IAQ-based monitoring in the specific application scenarios of daycare centers
Practical experiences from the implementation of extensive sensoring in a modern building
No full textThe extensive use of sensors is quickly becoming a standard feature of modern new buildings. Apart from the use of regular Building Management System (BMS) data, we see the addition of sensors that monitor in more detail the indoor environmental quality and the use and performance of innovative (and local) system solutions. This is also combined with integrated energy solutions at supra-building level. The assumption is that all these data are valuable to arrive at buildings that can optimize their operation towards indoor environmental and other sustainable performance indicators. In this research, data from a large modern building that combines office and educational rooms, features an innovative façade design and is connected to an aquifer thermal energy storage are considered. In order to perform detailed analyses, several sensor and data related issues had to be resolved first. In this paper we provide a procedure for structuring the data as was available for this specific building, originating from different sources. The outcomes provide a practical basis for other buildings to assess the correctness and quality of the sensor data and the analysis potential. An example of an analysis is presented. In addition, the paper demonstrates how the obtained measurement data can be used to calibrate a simulation model that is employed to analyse the ventilative cooling potential of the innovative façade in comparison to shading
A detailed investigation of the impact of an innovative dynamic façade system on indoor environmental quality in offices
No full textIn recent years, naturally ventilated glass façades have become a common feature in the design and retrofit of large-scale non-residential buildings, integrating architectural aesthetics and energy efficiency. These façade systems are complex and multifaceted. Thus, introducing them in buildings poses many challenges from economic, engineering, health and behavioural perspectives that can reduce optimal building performance. Building occupant behaviour and preferences are important contributors to the gap between the predicted and actual building energy performance. With people spending on average 90% of their lives indoors, the impact of indoor environmental quality (IEQ) on health, comfort, wellbeing and productivity of building occupants is vital. The use of engineering simulation, validated with data collected from operating buildings, can enable engineers, architects and facility managers to ensure optimal building design, efficient operation and improved IEQ. This paper presents the results of a detailed investigation of the impact of an innovative adaptive façade system on IEQ in an office case study. This includes the impact of façade operation on the health, comfort and wellbeing of building occupants. The study focuses on the measurement campaign carried out in an operating office environment in the Atlas building at Eindhoven University of Technology (TU/e). This measurement campaign included physical measurements of thermal comfort and indoor air quality parameters and occupant surveys. The surveys aimed to capture the occupants’ perception of the indoor environment and the effects of the dynamic façade operation on their comfort and wellbeing. The paper presents the research objectives, measurement protocol and results of the physical measurements and occupant surveys. In general, there was a good alignment between the surveyed and measured data. Furthermore, a high-resolution measurement network allowed for identification of locations where occupants’ comfort may be compromised, such as beside the window where higher air temperatures occurred.The authors would like to acknowledge the financial support of the European Commission
Horizon MSCA 2021 FaceINQ project (101066362). The authors would like to thank the
technical staff in the Department of the Built Environment at Eindhoven University of
Technology for their support in carrying out the experiments, as well as the occupants of the
Atlas Living Lab for their participation in this research.non-peer-reviewe
Assessment of the performance of the AirTulip headboard prototype
No full textThis report describes the outcomes from experimental research into the performance of the prototype headboard as developed by AirTulip. Through measurements in a laboratory set‐up the Local Air Quality Index at the head level of a sleeping person, the air cleaning potential to support the general ventilation in- the sleeping room and the potential for draught complaints has been investigated
Assessment of the performance of the AirTulip headboard prototype
No full textThis report describes the outcomes from experimental research into the performance of the prototype headboard as developed by AirTulip. Through measurements in a laboratory set‐up the Local Air Quality Index at the head level of a sleeping person, the air cleaning potential to support the general ventilation in- the sleeping room and the potential for draught complaints has been investigated
Humidification in healthcare facilities - knowledge base and practice
No full textHumidification is not a common procedure in many buildings in the Netherlands. An exception are buildings used for healthcare, especially hospitals. There, e.g. in operating theatres, relative humidity (RH) generally is controlled stringently at levels around 50%. From an energy point-of-view humidification is an energy-intensive activity. Currently, more than 10% of the total energy used in healthcare buildings is spent on humidification. The basis for an RH of around 50%, however, is not clear. Therefore, we pursued a scoping review to find evidence for specific RH thresholds in such facilities. In addition, an inventory was made of the current practice in the Netherlands. After analyzing the title and abstracts, the remaining references were read by two persons and scored on several topics. Guidelines and current practice were analyzed by referring to existing (inter)national guidelines and standards, and by contacting experts from Dutch hospitals through a survey and semi-structured interviews. Outcomes from the literature review were grouped into four different topics: 1) micro-organisms and viruses, 2) medical devices, 3) human physiology and 4) perception. No scientific evidence was found for the currently generally applied RH set-point of ~50%. Some studies suggest a minimum RH of 30% but the evidence is weak, with exception of medical devices if specifications require it. A lack of research that addresses more long-term exposure (a couple of days) and includes frail subjects, is noted. It was found that RH requirements are strictly followed in all hospitals consulted, some only focusing on the hot zones, but in many cases extended to the whole hospital. Steam humidification is mostly applied for hygienic reasons. but is quite energy-intensive. The conclusion t is that there is no solid evidence to support the RH-setpoints as currently applied in the Netherlands. It merely appears a code of practice. Therefore, there appears room for quick and significant energy savings, and CO2 emission reductions, when considering control at lower RH values or refraining from humidification at all, while still fulfilling the indoor environment requirements and not negatively influencing the health risk. This outcome can be applied directly in current practice with the available techniques
Designing a decision support tool for high performance office buildings focusing on energy flexibility:supporting decisions on thermal comfort control strategies and building design parameters
No full textBeyond uniform thermal comfort : on the effects of non-uniformity and individual physiology
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