Quantitative vs. qualitative methodologies to investigate environmental control in the workplace: neutral thermal sensation and thermal environmental intention

This study compares the application of qualitative and quantitative methods to investigate user comfort and environmental control in the workplace. This is examined by environmental measurement and user satisfaction in two workplaces with respectively low and high levels of individual environmental control. An open plan office in Scotland is selected with automatic displacement ventilation, where users have access to limited windows. In contrast, a cellular plan office in Norway is chosen that provides every user with control over a window, in addition to the ability to adjust heating and cooling. Complimentary quantitative and qualitative methodologies are applied with particular emphasis on Grounded Theory methods. Questionnaire, environmental measurements and semi-structured interviews are used. A new visual recording method is applied to analyse the subject in its context qualitatively. Information regarding all users and their environment is applied as colour codes to floor plate layouts. The results are compared with the quantitative analysis. The study examines the significance of applying a qualitative method to question the ‘Neutral Thermal Sensation’ and expand on the importance of the ‘Thermal Environmental Intention’. This paper suggests that the quantitative appraisal could be associated with a risk of misjudgement

Environmental control and sick building syndrome; a comparison between a low carbon open plan and a cellular plan workplace

This study investigates the effect of environmental control on Sick Building Syndrome (SBS). This is examined by environmental measurement, user health and satisfaction at two workplaces with respectively low and high levels of individual control over the thermal environment. The Anglo-Saxon practice of the open plan workplace is compared to the traditional Scandinavian practice, with a greater preponderance of cellular office accommodation. The research will lead to the formulation of specific strategies to enhance opportunities in providing thermal comfort in the workplace. Two case studies are described with respectively low and high provision of individual environmental control. A low energy open plan office in Scotland is selected with natural ventilation, where limited users have access to windows. In contrast, an air conditioned cellular plan office in Norway with excessive use of energy is selected providing every user with control over a window and the ability to adjust heating and cooling. Complementary quantitative and qualitative methodologies are applied. Particular emphasis is given to Grounded Theory methods. Building users’ health conditions and perception of their thermal environment are recorded through a questionnaire and empirical building performance through the measurement of the thermal environment. These traditional techniques are further reinforced with semi-structured interviews to investigate the environmental control. A new visual recording method is applied to qualitatively analyse the subject in its context. Information regarding all users and their environment is applied as colour codes to floor plate layouts. The study examines the significance of environmental control and its effect on Sick Building Syndrome in a comparison between a low carbon open plan and a cellular plan workplace with higher energy consumption. Through this a balanced appraisal can be made of comfort profiles and user’s health between the two benchmarked buildings

Computational and field test analysis of thermal comfort performance of user-controlled thermal chair in an open plan office

In this study, a thermal chair prototype was developed that allowed personal control over the temperature settings of the back-rest and the seat. Limited research focuses on different methods to provide individual user control over the thermal environment. This is particularly difficult to achieve in an open plan office setting, where changing the temperature in one area directly influences the comfort and satisfaction of other occupants seated nearby. In this study, the application of the thermal chair was analysed using Computational Fluid Dynamics (CFD) and field-test analysis in an open plan office in Leeds, UK during winter. The results of the CFD model indicated an improvement in the local thermal comfort of the user. The CFD analysis provided detailed analysis of the thermal distribution around a siting manikin and was used to design and construct the thermal chair. The results of the field data survey indicated a great improvement in users' comfort (20%) and satisfaction (35%). This study concludes that local thermal control of the occupant improves their overall thermal comfort. It recommends further work to optimise the design of the thermal chair and to improve the modelling for better predictions

Building Related Symptoms, Energ, and Thermal Comfort in the Workplace: Personal and Open Plan Offices

This study compared building-related symptoms in personal and open plan offices, where high and low levels of control over the thermal environment were provided, respectively. The individualized approach in Norway provided every user with a personal office, where they had control over an openable window, door, blinds, and thermostat. In contrast, the open plan case studies in the United Kingdom provided control over openable windows and blinds only for limited occupants seated around the perimeter of the building, with users seated away from the windows having no means of environmental control. Air conditioning was deployed in the Norwegian case study buildings, while displacement ventilation and natural ventilation were utilized in the British examples. Field studies of thermal comfort were applied with questionnaires, environmental measurements, and interviews. Users’ health was better in the Norwegian model (28%), while the British model was much more energy efficient (up to 10 times). The follow-up interviews confirmed the effect of lack of thermal control on users’ health. A balanced appraisal was made of energy performance and users’ health between the two buildings

Impact of cultural behaviour on indoor comfort: examining the air quality in homes and exploring observational and experimental methods of representation through filmmaking

There is a limited understanding of householders’ cultural differences and their impact on spatial organisation and energy behaviour in dwellings. Indoor air quality directly impacts the health and well-being of occupants. The airborne COVID-19 epidemic has highlighted shortcomings of controlled ventilation systems in recent reports (PHE, Dec 2020). While efficiency interventions can make homes more affordable to heat, they can exacerbate conditions such as asthma, due to reduced indoor air quality and ventilation. Preliminary research conducted in Plymouth by the applicant indicates that British Asians use their homes differently compared to native British in terms of spatial organisation, cooking habits (on average, they spend five times more time cooking the daily meal) and ventilation strategies, all of which have an impact on indoor air quality. This project sets out to establish the impact of culturally informed choices on indoor air quality and the extent to which the norms that guide the design of energy-efficient homes ignore potentially significant cultural and behavioural differences. It will achieve this by focusing on the impact of energy behaviour and choices related to cooking on the indoor air quality of British-Asian households. The project aims to quantify temperature, humidity and air quality by data collected by a pilot study in Plymouth, UK. We will engage the community in a participatory methodology using correlational research and survey questionnaires and IAQ Data Loggers to evidence anomalies from the design norms currently used in the UK. In addition to traditional data analysis, our methodology includes artistic research, utilising observational and sensory ethnographic filmmaking techniques, to support, document, and evidence the impact of cooking in the home. We aim to explore how the intersection between these two methods can reveal and communicate new perspectives. The main outcome is to evaluate the impact of cultural behaviour on the air quality of super-insulated British-Asian homes through an interdisciplinary methodology. This project lays foundations for larger-scale research working with diverse ethnic minority communities to promote engagement in a low-carbon society

Numerical Analysis of a Wind Catcher Assisted Passive Cooling Technology.

Buildings are responsible for almost 40% of the world energy usage. Heating Ventilation and Air-Conditioning (HVAC) systems consume more than 60% of the total energy use of buildings. Clearly any technology that reduces HVAC consumption will have a dramatic effect on the energy performance of the building. Natural ventilation offers the opportunity to eliminate the mechanical requirements of HVAC systems by using the natural driving forces of external wind and buoyancy effect. One technology, which incorporates both wind and buoyancy driven forces, is the wind catcher. Wind catchers are natural ventilation systems based on the design of traditional architecture. Though the movement of air caused by the wind catcher will lead to a cooling sensation for occupants, the high air temperature in hot climates will result in little cooling to occupants. In order to maximise the properties of cooling by wind catchers, heat transfer devices were incorporated into the design to reduce the supply air temperature. The aim of this work was to investigate the performance of a wind catcher integrated with heat transfer devices using numerical modelling and wind tunnel experiment. The wind catcher model was incorporated to a building, representing a small room of 15 people. Care was taken to generate a high-quality CFD grid and specify consistent boundary conditions. An experimental model was created using 3D printing and tested in a wind tunnel. Qualitative and quantitative wind tunnel measurements were compared with the CFD data and good correlation was observed. The study highlighted the potential of the proposed wind catcher in reducing the air temperature by up to 12 K and supplying the required fresh air rates

Effect of urban street canyon aspect ratio on thermal performance of road pavement solar collectors (RPSC)

Studies on RPSC (road pavement solar collectors) have shown the potential of reducing the urban heat island effect by dissipating the heat from the pavement for energy harness. In our previous work, performance analysis of RPSC system was carried out to compare the RPSC embedment in two scenarios; within an urban street canyon and within suburban or rural area. The current study expands the analysis of the RPSC system in urban areas by assessing the impact of varying canyon aspect ratios on the performance of RPSC. De-coupled Computational Fluid Dynamic (CFD) approach was proposed to investigate the integration of RPSC system in an urban canyon. The CFD tool ANSYS Fluent 15.0 was used to simulate the fluid flow and heat transfer on the pavement/road surface by enabling three models: (i) energy model, (ii) standard k-epsilon model, and (iii) coupled DO-solar load radiation model. The results showed that a significant pavement surface temperature increase was found when the aspect ratio (AR) was increased from 1 to 2 while minimal increase was observed for the canyon with AR above 2. At the particular simulated time (13:00) and location, it was found that the overall performance of the RPSC system significantly increased by up to 13.0 when AR was increased from 1 to 2, but the performance of RSPC in shadow area (due to the shading effect of building) had significantly dropped (up to 30.0) from AR 3 to 4. Findings of this study showed that the canyon aspect ratio had a significant impact on the temperature distribution of the ground surface and should be taken into consideration when assessing the performance of RPSC in urban areas

A user-controlled thermal chair for an open plan workplace: CFD and field studies of thermal comfort performance

This study aims to improve user comfort and satisfaction regarding the thermal environment in the open plan office, which is a current challenge in the workplace addressed by limited research. The main difficulty in an open plan setting is that changing the room temperature in an area affects all occupants seated nearby. This issue in addition to individual differences in perceiving the thermal environment create a great challenge to satisfy all occupants in the workplace. This study investigates the application of an advanced thermal system, a user-controlled thermal chair, which allows individual control over their immediate thermal environment without affecting the thermal environment and comfort of other occupants. The performance of the chair was further analysed through Computational Fluid Dynamics (CFD) simulations providing a detailed analysis of the thermal distribution around a thermal chair with a sitting manikin. The results indicated that user thermal comfort can be enhanced by improving the local thermal comfort of the occupant. A prototype of an office chair equipped with thermal control over the seat and the back was produced and examined in an open plan office in November in Leeds, UK. Forty-five individuals used the chair in their everyday context of work and a survey questionnaire was applied to record their views of the thermal environment before and after using the chair. The results of the field study revealed 20% higher comfort and 35% higher satisfaction level, due to the use of thermal chair. Thermal measurements showed acceptable thermal conditions according to the ASHRAE Standard 55-2013. Over 86% of the occupants set the temperature settings of the seat and the back of the chair between 29 °C and 39°. 82% of the occupants expressed their satisfaction level as “satisfied” or “very satisfied” regarding the performance of the thermal chair. The thermal chair energy consumption was relatively low (0.03 kW) when compared with that of typical personal heaters, which are about 1–1.5 kW. Further research is recommended to improve the design and application of the thermal chair to improve user overall thermal comfort and also further reduce energy consumption

Does a neutral thermal sensation determine thermal comfort?

The neutral thermal sensation (neither cold, nor hot) is widely used through the application of the ASHRAE seven-point thermal sensation scale to assess thermal comfort. This study investigated the application of the neutral thermal sensation and it questions the reliability of any study that solely relies on neutral thermal sensation. Although thermal-neutrality has already been questioned, still most thermal comfort studies only use this measure to assess thermal comfort of the occupants. In this study, the connection of the occupant’s thermal comfort with thermal-neutrality was investigated in two separate contexts of Norwegian and British offices. Overall, the thermal environment of four office buildings was evaluated and 313 responses (three times a day) to thermal sensation, thermal preference, comfort, and satisfaction were recorded. The results suggested that 36% of the occupants did not want to feel neutral and they considered thermal sensations other than neutral as their comfort condition. Also, in order to feel comfortable, respondents reported wanting to feel different thermal sensations at different times of the day suggesting that occupant desire for thermal comfort conditions may not be as steady as anticipated. This study recommends that other measures are required to assess human thermal comfort, such as thermal preference