Conference Agenda

Overview and details of the sessions of this conference. Please select a date or location to show only sessions at that day or location. Please select a single session for detailed view (with abstracts and downloads if available).

Please note that all times are shown in the time zone of the conference. The current conference time is: 17th May 2022, 07:21:30 CEST

 
 
Session Overview
Session
Session F4.7 (Online Track): Improving indoor environmental quality
Time:
Friday, 03/Sept/2021:
15:00 - 16:30

Location: Virtual Meeting Room 1

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Presentations
15:00 - 15:18

Numerical study on the performance of the temperature-controlled airflow ventilation system during the movement of a patient from the operating room to the MRI room

Parastoo Sadeghian1, Henrik Skredsvik2, Marco Baroni2, Cong Wang1, Sasan Sadrizadeh1

1KTH Royal Institute of Technology, Stockholm, Sweden; 2Avidicare, Lund, Sweden

Aim and Approach

(max 200 words)

Ventilation systems have an important role in controlling infection risks during surgery in the operating room. Ventilation systems supposed to remove bacteria carrying particles from the clean zone that are released from the surgical staff members. Human movement is among the important factors that may break the stability of airflow field and reduce ventilation performance.

This study numerically investigated the performance of the temperature-controlled airflow (TcAF) ventilation systems while moving the patient from the operating room to the MRI room during a given brain surgery. Moreover, effect of the internal constellation of staff members on airborne particle distribution was also studied.

Scientific Innovation and Relevance

(max 200 words)

Using temperature-controlled airflow (TcAF) ventilation system for controlling infection risks during the imagining in the MRI room and movement of the patient is a new approach.

Preliminary Results and Conclusions

(max 200 words)

In this regards, the computational fluid dynamics method was used for simulating the airflow field and bacteria carrying particle distribution in the operating and MRI room. The simulated results showed that the TcAF ventilation system can reduce the infection risks to an acceptable level in both rooms. Moreover, the location of the surgical personnel had considerable effect on limiting the concentration of bacteria carrying particles in the MRI device, where the patient located.

Main References

(max 200 words)

[1] M. Alsved, A. Civilis, P. Ekolind, A. Tammelin, A.E. Andersson, J. Jakobsson, T. Svensson, M. Ramstorp, S. Sadrizadeh, P.A. Larsson, M. Bohgard, T. Šantl-Temkiv, J. Löndahl, Temperature-controlled airflow ventilation in operating rooms compared with laminar airflow and turbulent mixed airflow, J. Hosp. Infect. 98 (2017).

[2] C. Wang, S. Holmberg, S. Sadrizadeh, Numerical study of temperature-controlled airflow in comparison with turbulent mixing and laminar airflow for operating room ventilation, Build. Environ.

[3] F. Memarzadeh, A.P. Manning, Comparison of operating room ventilation systems in the protection of the surgical site, ASHRAE Trans. 108 PART 2 (2002) 3–15.g room ventilation, Build. Environ. 144 (2018) 45–56.



15:18 - 15:36

Interdisciplinary parametric modelling and modularization to improve air quality, acoustics and lighting in school buildings

Clara-Larissa Lorenz, Tobias Burgholz, Maximilian Schildt, Jérôme Frisch, Christoph van Treeck

RWTH Aachen, Germany

Aim and Approach

(max 200 words)

Poor indoor air quality and acoustics can affect well-being and productivity in classrooms[1][2]. . In naturally ventilated buildings, weather conditions and outside noise may prevent necessary window openings, necessitating technological solutions. The implementation of solutions to mechanically ventilate spaces may however be met with resistance, either due to the perceived effort and cost of renovation measures, or disruptions to school activities. The aim of this study is therefore to improve air quality and acoustics in classrooms and furthermore facilitate interventions by reducing complexity in planning and installation via integrated parametrization and modularization.

The study is done in three stages. First, a parametric model is developed to design any variant of a typical classroom configuration. Second, parametric rules are implemented to automate the generation of solutions for the layout and distribution of a ventilation unit, acoustic panels and lighting. These three cross-disciplinary components are then formulated as a new product unit and modularized to facilitate assembly and installation. Third, the model is implemented to assist with renovation measures for a classroom in three different schools. Parametric rules are adjusted and effectiveness in facilitating planning and installation are evaluated.

Scientific Innovation and Relevance

(max 200 words)

Environmental qualities including air-quality, acoustic and visual aspects are known to improve occupants’ attention and performance[2]. Mechanical ventilation can help ensure appropriate levels of CO2, which can fall below appropriate levels in manually aired classrooms[3]. Acoustic measures can improve speech communication and reduce noise from ventilation units and good light conditions can improve attention[4], highlighting the need to consider all three aspects when designing for occupant well-being in classrooms. This work provides a tool that considers the interdependencies of all three aspects in practical implementation.

The implementation divides design parameters into design rules and module parameters as a process of modularization[5]. This work is made unique by establishing building component related to ventilation, acoustic and lighting as a new product unit. By doing so, competition for space (e.g. ceiling space) is reduced, which keeps interactions outside modules at a minimum, as recommended by[6]. Another contribution can be found in the integration of parametric modeling and modularization, which allows for the design non-repetitive modules. This reduces restrictions to design in advance.

Preliminary Results and Conclusions

(max 200 words)

Results are presented on i) the process of developing a highly customizable parametric model to replicate any given classroom configuration, ii) the dependencies and constraints implemented to generate an integrated design solution for ventilation, acoustic and lighting, iii) the modularization of product components to an assembly unit to speed-up preassembly and montage, and iv) model performance and limitations when applied to three case studies.

The parametric model was developed in Grasshopper with 20 required, and 12 optional input variables to reconstruct typical classroom configurations through simple slider adjustment, therefore ensuring ease-of-use for planners.

The rules imposed to generate solutions are based on availability of spaces, structural constraints, cost effectiveness (e.g. installing supply and exhaust air outlets over the window head, into the wall or in place of a top light), and compliance to regulations requirements DIN18041 for acoustics. The modularization of all components, including lighting, ensures that clashes between components and with building structure are avoided, thereby reducing planning efforts through interface reduction. Through modularization, renovations are expected to take one day, thus hardly interfering with school operation. Modularization is expected to reduce onsite resources and improve project quality.

Main References

(max 200 words)

[1] J. Toftum, B. U. Kjeldsen, P. Wargocki, H. R. Menå, E. M. N. Hansen, and G. Clausen, “Association between classroom ventilation mode and learning outcome in Danish schools,” Build. Environ., vol. 92, pp. 494–503, 2015.

[2] S. P. Corgnati, M. Filippi, and S. Viazzo, “Perception of the thermal environment in high school and university classrooms: Subjective preferences and thermal comfort,” Build. Environ., vol. 42, no. 2, pp. 951–959, 2007.

[3] L. Stabile, M. Dell’Isola, A. Frattolillo, A. Massimo, and A. Russi, “Effect of natural ventilation and manual airing on indoor air quality in naturally ventilated Italian classrooms,” Build. Environ., vol. 98, pp. 180–189, 2016.

[4] A. Astolfi and F. Pellerey, “Subjective and objective assessment of acoustical and overall environmental quality in secondary school classrooms,” J. Acoust. Soc. Am., vol. 123, no. 1, pp. 163–173, 2008.

[5] S. Isaac, T. Bock, and Y. Stoliar, “A methodology for the optimal modularization of building design,” Autom. Constr., vol. 65, pp. 116–124, 2016.

[6] A. Mohamad, G. Hickethier, V. Hovestadt, and F. Gehbauer, “Use of modularization in design as a strategy to reduce component variety in one-off projects,” 21st Annu. Conf. Int. Gr. Lean Constr. 2013, IGLC 2013, pp. 285–294, 2013.



15:36 - 15:54

A new method for comparing long-term thermal conditions in buildings

Shide Salimi1, Holly Samuelson1, Esteban Estrella Guillén2

1Harvard University, United States of America; 2Universidad de Monterre, Mexico

Aim and Approach

(max 200 words)

This study aims at developing a new discomfort index based on equivalent temperature sensation, such as Standard Effective Temperature (SET), which accounts for all six main personal and environmental factors affecting thermal comfort and measures the severity of discomfort experienced. Expressing discomfort in building-related terms (i.e., temperature) helps building engineers to easily relate thermal comfort to building performance while using it in building simulation and/or optimization analyses.

The proposed method can be applied to both air-conditioned and naturally-ventilated buildings. For the former, a comfort zone is plotted on a psychrometric chart per ASHRAE-55 to determine reference thermal zones. The proposed method then includes nuances of how variations in thermal comfort affecting factors, such as metabolic rate impact reference zones. For an uncomfortable point in question, the closest point on the comfort zone boundary to the point is determined. The difference between the SET of a point and that of its boundary line projection determines the severity of discomfort. When applied to naturally-ventilated buildings, the proposed method calculates the discomfort severity by determining the difference between the SET of the point in question and that of the corresponding upper or lower limit based on the Adaptive Comfort model.

Scientific Innovation and Relevance

(max 200 words)

In current practice, thermal comfort is determined by expressing environmental conditions in terms of a given index and comparing the results to thermal comfort ranges suggested in predefined standards or models. Most of the proposed indices define the duration of discomfort by accumulating periods in which indoor conditions exceed comfort conditions. In these indices, the severity, if presented, is accounted for by using weighting factors. Yet, most of such indices rely on PMV and PPD and are unintuitive when used for building performance analysis (especially for optimization purposes), therefore, expressing discomfort in building-related terms is of great importance when using a discomfort index.

Existing temperature-based weighting factors, which can be better related to building performance, only account for differences between operative and the limiting acceptable temperatures, ignoring the effects of other personal and environmental factors, such as humidity. Furthermore, in current practice, Fanger- and adaptive model-based indices are separately utilized in mixed-mode buildings to report discomfort in air-conditioned and naturally ventilated spaces, respectively. Here, SET is used to express the severity of thermal discomfort. This index could help building engineers to easily relate thermal comfort to building performance, and the same index can be used regardless of conditioning mode.

Preliminary Results and Conclusions

(max 200 words)

Preliminary comparison between existing comfort indices and the Exceedance Degree-Hours index indicates the proposed index captures more information with regards to changes in factors affecting thermal comfort. The proposed method allows the differentiation between different points with the same PPD or opposite PMV, an important aspect to consider in simulation-based building optimization. For evaluations based on the Adaptive Comfort model, environmental and personal characteristics can be taken into account when measuring discomfort severity. Furthermore, in mixed-mode buildings, the overall discomfort severity for air-conditioned and naturally-ventilated periods can be summated in a single value, expressed in terms of building-related parameters (i.e., SET differences). This applicability can be extrapolated to simulation and/or optimization analyses, which would in return have a high positive impact on the building industry.

Main References

(max 200 words)

Kim, J., Tartarini, F., Parkinson, T., Cooper, P., & De Dear, R. (2019). Thermal comfort in a mixed-mode building: Are occupants more adaptive? Energy and Buildings, 203, 109436.

CEN, E. (2019). Energy performance of buildings - Ventilation for buildings - Part 1: Indoor environmental input parameters for design and assessment of energy performance of buildings addressing indoor air quality, thermal environment, lighting and acoustics. Brussels: CEN.

ASHRAE. (2017). ASHRAE Standard 55-2017: Thermal Environmental Conditions for Human Occupancy. ASHRAE.

Capozzoli, A., Piscitelli, M. S., Gorrino, A., Ballarini, I., & Corrado, V. (2017). Data analytics for occupancy pattern learning to reduce the energy consumption of HVAC systems in office buildings. Sustainable cities and society, 35, 191-208.

Hoyt, T., Schiavon, S., Piccioli, A., Cheung, T., Moon, D., & Steinfeld, K. (2017). CBE Thermal Comfort Tool. Center for the Built Environment: http://comfort.cbe.berkeley.edu

CIBSE. (2013). The limits of thermal comfort: avoiding overheating in European buildings. London: CIBSE.

Carlucci, S., & Pagliano, L. (2012). A review of indices for the long-term evaluation of the general thermal comfort conditions in buildings. Energy and Buildings, 53, 194-205.

Borgeson, S., & Brager, G. (2011). Comfort standards and variations in exceedance for mixed-mode buildings. Building Research & Information, 39(2), 118-133.



15:54 - 16:12

Application of coupling of the human and clothing thermal system and computational fluids dynamics in the evaluation of energy and comfort in occupied spaces

Eusebio Conceição1, Mª Inês Conceição2, Mª Manuela Lúcio1, Hazim Awbi3

1University of Algarve, Portugal; 2Instituto Superior Técnico, University of Lisbon, Portugal; 3School of Built Environment, University of Reading, United Kingdom

Aim and Approach

(max 200 words)

This numerical work develops a HVAC system, based in a ceiling mounted localized air distribution systems. The study is made in winter and summer typical day conditions.

This work presents and applies a numerical model, developed by the authors in the last years, that considers the coupling of the CFD (Computational Fluids Dynamics) and HCTS (Human and Clothing Thermal System). The coupling system, itself, generates the occupation presence and transfers the inputs/output between the CFD and HCTS numerical models.

The input of the compartment, using the Computational Aid Design (CAD), the location of the occupants and the external environmental variables are introduced in the software, while the occupants’ geometry is generated by empirical equations, based in height and weight.

The study is made in a virtual chamber occupied by twelve virtual manikins, six desks and twelve seats and equipped with a new ceiling mounted localized air distribution system. The inlet airflow and the exit is located above the head level.

In the present study the thermal comfort level, the air quality level and the ADI (Air Distribution Index) are calculated, in winter conditions. In accordance with the obtained results the ADI index is highest for highest inlet air velocity.

Scientific Innovation and Relevance

(max 200 words)

This study considers a coupling of the Computational Fluid Dynamics, CFD, and the Human and Clothing Thermal System, HCTS numerical models.

The ADI is used to evaluate simultaneously the occupants’ thermal comfort, occupant s’ air quality and ventilation effectiveness for heat removal and effectiveness for contaminant removal.

This HVAC system considers an inlet (located above the head level) and an exhaust (located above the desk level).

The twelve occupants are seated in six desks. The desks are placed in two rows and three columns.

This new HVAC system promotes good thermal comfort levels, because promotes air recirculation and renovation around the occupants.

This new HVAC system promotes good indoor air quality levels, because the inlet air goes straight to the face and, afterwards breathing, goes straight to the exit.

Preliminary Results and Conclusions

(max 200 words)

The thermal comfort, the indoor air quality, the Draught Risk, the effectiveness for heat removal, the effectiveness for contaminant removal and the ADI, are evaluated.

In accordance with the obtained results the airflow around the human body increases and the temperature around the occupant decreases when the airflow rate increases.

Draught Risk around the occupants’ increases when the airflow increases. In summer conditions is acceptable and in winter conditions is uncomfortable, in accordance with the international standards.

The thermal comfort level increases during summer and decreases during winter when the airflow rate increases. However, the thermal comfort levels are acceptable in accordance with the international standards.

Finally, the ADI increases when the airflow rate increases.

Main References

(max 200 words)

E. Conceição, M. Lúcio. Numerical simulation of the application of solar radiant systems, internal airflow and occupants’ presence in the improvement of comfort in winter conditions. Buildings 38 (2016) 1-20.

E. Conceição, M. Lúcio, S. Rosa, A. Custódio, R. Andrade, M. Meira. Evaluation of comfort level in desks equipped with two personalized ventilation systems in slightly warm environments. Building and Environment 45 (2010) 601-609.

E. Z. E. Conceição and M. M. J. R. Lúcio, “Evaluation of thermal comfort conditions in a classroom equipped with radiant cooling systems and subjected to uniform convective environment,” Appl. Math. Model., vol. 35, no. 3, 2011.

E. Z. E. Conceição and M. M. J. R. Lúcio, “Evaluation of thermal comfort conditions in a localized radiant system placed in front and behind two students seated nearby warmed curtains,” Build. Environ., vol. 45, no. 10, 2010.

E. Z. E. Conceição, V. D. S. R. Vicente, and M. M. J. R. Lúcio, “Airflow inside school building office compartments with moderate environments,” HVAC R Res., vol. 14, no. 2, 2008.



16:12 - 16:30

Pre-retrofit monitoring of indoor air quality and energy use in a low-rise block of flats in the UK

Rajat Gupta, Alastair Howard

Low Carbon Building Research Group, Oxford Brookes University, United Kingdom

Aim and Approach

(max 200 words)

The UK government has set a target of net-zero greenhouse gas emissions by 2050. To meet the national carbon reduction target, deep retrofit of the existing 28 million dwellings, around half of which was built before 1960, will be necessary (1). Since the UK housing stock varies in terms of age, construction materials, dwelling form and to avoid unintended consequences, a bespoke approach to retrofit is necessary, that considers the building fabric thermal performance, energy use and indoor environment of dwellings targeted for retrofit (2).

This paper presents an empirical investigation and statistical analysis of the energy use and indoor environment (temperature, relative humidity (RH), CO2 and TVOC levels) in three flats located in a low-rise 1950s block of flats (UK) prior to undertaking deep energy retrofit. Occupant survey was used to gain deeper understanding about household characteristics such as occupancy levels and patterns, and heating habits. The results of the analysis were used to inform the retrofit strategies adopted and calibrate PHPP model predictions.

Scientific Innovation and Relevance

(max 200 words)

Research into performance of retrofit projects has identified a number of trends that reinforce the need to examine buildings prior to retrofit. In a pre- and post-retrofit evaluation of fifteen homes in Ireland, improved air tightness helped to improve occupant comfort and building temperature, but post-retrofit reductions in air exchange rates were linked to increased concentrations of CO2, TVOC and PM2.5, highlighting the importance of considering indoor air quality as well as energy efficiency in the scope of retrofit projects (3).

Occupant behaviour has been found to play a significant role in the effectiveness of retrofit projects (4), given that number of occupants and occupancy patterns influence dwelling energy use (5). For energy retrofits to meet their expectations, it is vital that examination of physical characteristics of dwellings is augmented by consideration of occupancy related factors.

This study adopts a systematic socio-technical approach that deepens the understanding of the physical and social characteristics that affect the energy use and indoor environment of a block of flats to ensure that building fabric upgrade and ventilation strategies selected enhance IAQ as much energy reduction.

Preliminary Results and Conclusions

(max 200 words)

For the pre-retrofit investigation, sensors were installed to record at five-minute resolution, indoor and outdoor temperature and relative humidity (Hobo UX100’s), and indoor CO2 concentrations (Tinytag TGE-0011) in living rooms and main bedrooms of the three flats from January to August 2019. TVOC levels were measured using Graywolf DS11-5 device, at one-minute resolution for one hour in the living rooms of each flat on one day in February 2019. Occupant surveys gathered insight into household characteristics and occupancy patterns that influence indoor environment and energy use.

Gas consumption was found to be higher than the national median in two out of the three flats. Cross-relating energy performance with indoor environmental data and occupant surveys revealed that heating costs were the main reason for the relatively low gas use and consequent cold, damp and mouldy conditions, particularly during the heating season in the third flat. TVOCs were found to be higher in two flats with smokers. Measured TVOC levels when cross-related with concurrent temperature, RH and CO2 concentration revealed statistically significant and strong correlation. The pre-retrofit monitoring results also enabled calibrating PHPP model predictions using real occupancy data and demand temperature.

Main References

(max 200 words)

1. Skidmore, C. (2019). "UK becomes first major economy to pass net zero emissions law." Retrieved 6th December, 2019

2. Baeli, M. (2019). Residential retrofit: twenty case studies, Routledge.

3. Broderick, Á., M. Byrne, S. Armstrong, J. Sheahan and A. M. Coggins (2017). "A pre and post evaluation of indoor air quality, ventilation, and thermal comfort in retrofitted co-operative social housing." Building and Environment 122: 126-133.

4. Ben, H. and K. Steemers (2017). "Tailoring domestic retrofit by incorporating occupant behaviour." Energy Procedia 122: 427-432.

5. Gupta, R., A. Howard and A. Kotopouleas "Meta-study of the energy performance gap in UK low energy housing."Proceedings of ECEEE 2019 summer study, France.



 
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