Runming Yao

Physiological Expression of Human Thermal Comfort to Indoor Operative Temperature in the Non-HVAC Environment

A physiological experiment was carried out in a naturally ventilated, non-HVAC indoor environment of a spacious experimental room. More than 300 healthy university students volunteered for this study. The purpose of the study was to investigate the human physiological indicators which could be used to characterise the indoor operative temperature changes in a building and their impact on human thermal comfort based on the different climatic characteristics people would experience in Chongqing, China. The study found that sensory nerve conduction velocity (SCV) could objectively provide a good indicator for assessment of the human response to changes in indoor operative temperatures in a naturally ventilated situation. The results showed that with the changes in the indoor operative temperatures, the changing trend in the nerve conduction velocity was basically the same as that of the skin temperature at the sensory nerve measuring segment (Tskin(scv)). There was good coherent consistency among the factors: indoor operative temperature, SCV and Tskin(scv) in a certain indoor operative temperature range. Through selfadaptation and self-feedback regulation, the human physiological indicators would produce certain adaptive changes to deal with the changes in indoor operative temperature. The findings of this study should provide the baseline data to inform guidelines for the development of thermal environment-related standards that could contribute to efficient use of energy in buildings in China. SAGE Publications 2010 Los Angeles, London, New Delhi and Singapore DOI: 10.1177/1420326X10365213 Accessible online at http://ibe.sagepub.com Figure 4 appears in colour online Baizhan Li Faculty of Urban Construction and Environmental Engineering, Chongqing University, Chongqing 400030, P. R. China. Tel. 0086 2365127531, Fax 0086 23 65127532, E-Mail baizhanli09@gmail.comA physiological experiment was carried out in a naturally ventilated, non-HVAC indoor environment of a spacious experimental room. More than 300 healthy university students volunteered for this study. The purpose of the study was to investigate the human physiological indicators which could be used to characterise the indoor operative temperature changes in a building and their impact on human thermal comfort based on the different climatic characteristics people would experience in Chongqing, China. The study found that sensory nerve conduction velocity (SCV) could objectively provide a good indicator for assessment of the human response to changes in indoor operative temperatures in a naturally ventilated situation. The results showed that with the changes in the indoor operative temperatures, the changing trend in the nerve conduction velocity was basically the same as that of the skin temperature at the sensory nerve measuring segment (Tskin(scv)). There was good coherent consistency among the factors...

An investigation of thermal comfort adaptation behaviour in office buildings in the UK

Around 40% of total energy consumption in the UK is consumed by creating comfortable indoor environment for occupants. Occupants’ behaviour in terms of achieving thermal comfort could have a significant impact on a building’s energy consumption. Therefore, understanding the interactions of occupants with their buildings would be essential to provide a thermal comfort environment that is less reliance on energy-intensive heating, ventilation and air-conditioning systems, to meet energy-saving and carbon emission targets. This paper presents the findings of a year-long field study conducted in non-air-conditioned office buildings in the UK. Occupants’ adaptive responses in terms of technological and personal dimensions are dynamic processes which could vary with both indoor and outdoor thermal conditions. The adaptive behaviours of occupants in the surveyed building show substantial seasonal and daily variations. Our study shows that non-physical factors such as habit could influence the adaptive responses of occupants. However, occupants sometimes displayed inappropriate adaptive behaviour, which could lead to a misuse of energy. This paper attempts to illustrate how occupants would adapt and interact with their built environment and consequently contribute to development of a guide for future design/refurbishment of buildings and to develop energy management systems for a comfortable built environment.

A review of existing building benchmarks and the development of a set of reference office buildings for England and Wales

The modern built environment has become more complex in terms of building types, environmental systems and use profiles. This complexity causes difficulties in terms of optimizing buildings energy design. In this circumstance, introducing a set of prototypical reference buildings, or so-called benchmark buildings, that are able to represent all or majority parts of the UK building stock may be useful for examination of the effect of national energy policies on building energy consumption. This study proposes a set of reference office buildings for England and Wales based on the information collected from the Non-Domestic Building Stock project and an intensive review of the existing building benchmarks. The proposed building benchmark comprises of 10 prototypical reference buildings, which in relation to built form and size, represent 95% of office buildings in England and Wales. This building benchmark provides a platform for those involved in building energy simulations to evaluate energy-efficiency measures and for policymakers to assess the influence of different building energy policies.

Towards “Zero-Carbon Homes” – Issues of Thermal Comfort

Buildings consume energy for space heating and cooling in order to maintain thermal comfort. Almost half of the UK’s carbon emissions come from buildings, and the domestic sector accounts for more than 30% of final energy consumption. In 2010, 27% of carbon dioxide emissions from energy consumption were due to end users in the residential sector [1]. Space heating and hot water alone accounted for 23% of the UK’s greenhouse gas emissions and accounted for around 80% of UK household carbon emissions. Climate change, depletion of fossil fuels and energy security has become international concerns. From an environmental perspective, governments of many major countries in the world have formulated policies with a common aim to reduce energy

Urban Microclimates and Simulation

This chapter examines the workings of urban microclimates and looks at the associated causes and effects of the urban heat island (UHI). It also clarifies the relationship between urban form and the key climatic parameters (sun, daylight, wind, and temperature). A particular section is devoted to the concepts of UHI intensity and sky view factor (SVF); these are useful indicators for researchers in this area. The challenge of how to model urban microclimates is covered, featuring the six archetypal urban forms familiar to analysts involved in using simulation software. The latter sections address the issues of urban thermal comfort, the importance of urban ventilation, and finally what mitigating strategies can be implemented to curb negative UHI effects. Learning outcomes: On successful completion of this chapter, readers will be able to: (1) grasp the concept of an urban microclimate and how they affect sustainable design; (2) understand the relationship between the urban form and the climatic parameters; (3) appreciate the causes, effects, and principles underpinning the UHI effect; (4) gain insight into how to model urban microclimates; (5) know about urban thermal comfort, the importance of urban ventilation; and (6) know what common measures are taken to help mitigate UHI.

A simplified thermoregulation model of the human body in warm conditions

Thermoregulation models of the human body have been widely used in thermal comfort studies. The existing models are complicated and not fully verified for application in China. This paper presents a simplified thermoregulation model which has been statistically validated by the predicted and measured mean skin temperature in warm environments, including 21 typical conditions with 400 Chinese subjects. This model comprises three parts: i) the physical model; ii) the controlled system; and iii) the controlling system, and considers three key questions formerly ignored by the existing models including: a) the evaporation efficiency of regulatory sweat; b) the proportional relation of total skin blood flow and total heat loss by regulatory sweating against body surface area; and c) discrepancies in the mean skin temperatures by gender. The developed model has been validated to be within the 95% confidence interval of the population mean skin temperature in three cases.

Strategic design and analysis method of natural ventilation for summer cooling

A simplified coupled thermal and airflow model has been developed by integrating the British Standard natural ventilation calculation method for a single zone within a four-node thermal resistance network model, which is called the thermal resistance ventilation model (TRV). By comparison of the results from the TRV with that of the ESP-r program, and subsequently tuning the TRV parameter values, good correlation can be obtained. A two-stage method is proposed for natural ventilation strategic design and analysis. The first stage calculates the constant air rate (CAR) and performs parametric studies in order to propose a design strategy and the appropriate opening area which satisfies thermal comfort. The second stage calculates the dynamic air rate (DAR) and internal temperature and performs analytic studies of the proposed design. An example case has been introduced using this two-stage process. It shows that the method proposed in this paper is simple and straightforward and it is suitable for the strategic design of natural ventilation. Furthermore, it demonstrates how the simplified method can be used to generate detailed and robust comfort data based on both an automatic and a behavioural control model. Practical appilcation: This paper describes a two-stage method to perform parametric and analytic studies of natural ventilation for summer cooling. This method is simple and straightforward, which is suitable for strategic design of natural ventilation. It demonstrates how the simplified method can be used to generate detailed and robust comfort data based on both automatic and behavioural control models.

Sustainability in the Built Environment

This introductory chapter sets the scene for the book, providing an overview of sustainability in the built environment. With a bias towards buildings and the urban environment, it illustrates the range of issues that impinge upon global carbon reduction and the mechanisms available to help bring about change. Climate change, and its impact on the built environment, is briefly introduced and sustainability in the built environment and associated factors are described. The specific topics relating to sustainable design and management of the built environment, including policy and assessment, planning, energy, water and waste technology, supply and demand, and occupants’ behavior and management have been highlighted. This chapter emphasizes the importance of a systemic approach in delivering a sustainable built environment. Learning outcomes: on successful completion of this chapter, readers will be able to: (1) Gain broad knowledge of sustainable built environment, (2) Understand the concept of systemic approach, and (3) Appreciate interdisciplinary aspects of design and management.

An Analytic Hierarchy Process Model for Assessing Occupants’ Adaptations to Thermal Comfort in Offices

The adaptations people utilize in response to ambient physical environmental variations are critical factors for the thermal comfort of occupants in real environments. From the adaptive point of view, thermal comfort is not solely dependent on physical thermal stimuli, but involves complex interactions between the occupants’ adaptations to the physical environmental stimuli and socio-economic-cultural issues. Under certain circumstances, the adaptation of occupants to their environment may be affected by physiological, behavioural and psychological factors. The interaction of the three adaptations further affects the extent of the thermal comfort the occupants finally feel. This paper introduces a method for the evaluation of the weight of contributions of three categories of adaptations to attain thermal comfort in office environments using the Analytic Hierarchy Process (AHP). The AHP is an ideal tool for decision-making where multiple factors are involved. Through solving a pairwise comparison matrix, the weight of each adaptation category can be produced. This paper aims to develop an empirical occupants’ adaptation-based thermal comfort model for office environments. The feasibility and validity of such the model has been verified by a pilot study.

Exploiting a Hybrid Environmental Design Strategy in the Continental Climate of Beijing

Abstract The built environment in China is required to achieve a 50% reduction in carbon emissions by 2020 against the 1980 design standard. A particular challenge is how to maintain acceptable comfort conditions through the hot humid summers and cold desiccating winters of its continental climate regions. Fully air-conditioned sealed envelopes, often fully glazed, are becoming increasingly common in these regions. Remedial strategies involve technical refinements to the air-handling equipment and a contribution from renewable energy sources in an attempt to achieve the prescribed net reduction in energy use. However an alternative hybrid environmental design strategy is developed in this research project. It exploits observed temperate periods of weeks, days, even hours in duration to free-run an office and exhibition building configured to promote natural stack ventilation when ambient conditions permit and mechanical ventilation when conditions require it, the two modes delivered through the same physical infrastructure. The proposal is modelled in proprietary software and the methodology adopted is described. The challenge is compounded by its first practical application to an existing reinforced concrete frame originally designed to receive a highly glazed envelope. This original scheme is reviewed in comparison. Furthermore the practical delivery of the proposal value engineered out a proportion of the ventilation stacks. The likely consequence of this for the environmental performance of the building is investigated through a sensitivity study.