Adaptive model of thermal comfort for office buildings in GCC

The Gulf Cooperation Council (GCC) nations top the world in CO2 emissions/ capita. However, plummeting oil prices and increasing energy demands necessitate rethinking on thermal comfort delivery. This region has warm desert climate throughout. In GCC states, the adaptive comfort standard or the precursor field studies to develop one are non-existent. We carried out thermal comfort field studies in Qatar for thirteen months. In ten typical air-conditioned office buildings, 1175 voluntary subjects completed 3742 questionnaires, while their thermal environments were simultaneously measured. This paper proposes the adaptive model of thermal comfort for GCC. Adopting variable indoor comfort standards that track the outdoor conditions may be effectual in meeting the sustainability goals of the GCC and Qatar Vision 2030.qscienc

A Bibliometric Study of Visual Quality Research in the Context of Urban Open Spaces

Visual quality assessment has received much attention in research by forest management and landscape researchers after the mid-twentieth century with the advent of legal frameworks enacted to protect natural resources, including scenery. Since then, the field has gained momentum that is mostly attached to landscape change and assessing the environmental impact of changes. Urbanized areas, however, received less attention and just started to receive some exposure in the last two decades (concurrently with the emergence of new technologies of GIS and remote sensing). Developing a comprehensive understanding of the visual quality assessment research requires a reconnaissance survey of its history and the trends of its research growth. This study undertakes an analysis of visual quality assessment literature in the context of urban settings using bibliometric tools. The paper employs quantitative techniques to analyse 3,221 journal papers retrieved from the Web of Science using keywords co-occurrence, citation burst, and direct citation analyses with the help of VOSViewer, CiteSpace, and Gephi software. Here we show the discipline’s status quo, trends, and patterns of development. They confirm the recency of urban-related research. Our study touches on the chronological emergence and decay of major visual quality notions. It also highlights the most central studies and the journals and research groups actively working in the field. Moreover, it points out research gaps related to urban spaces for future studies guidance

Necessity of the Adaptive Comfort Standard for the Middle East in the Times of Rising Energy Use

Middle East (ME) supplies more than 47% oil exported in the world (IEA 2013) and has highest energy self-sufficiency in the world. It includes 12 countries and has a population of 205 million in 2010, which increased by about 61.4% from 1990 (IEA 2010). Its energy demand has increased astronomically at the rate of 7% per year, since 1971-2013, faster than in any other region in the world. Buildings majorly contribute to this. Building energy (residential, commercial and public use buildings) use in the ME has increased by about 46% in the period 2003-13 (IEA 2010). Ironically ME houses only about 3% of the world's population, but it contributes to 13% of global CO2 emissions. Understandable, its per capita CO2 emission is one of the highest in the world at 7.53 tons of CO2/capita, 68% higher than the world average. Therefore improving the energy efficiency remains a key challenge for the region. International Energy Agency (IEA) identifies the development and enforcement of building energy codes coupled with energy consumption data generation as the top energy efficiency policy recommendations for this region (IEA 2014). Qatar's per capita energy consumption is one of the highest, consuming 30.184 TWh as of 2012 (IEA 2012) Buildings contribute majorly (80%) to this, with air-conditioning taking a lion's share. With the absence of custom-made energy/thermal comfort standards, the buildings tend to follow western standards meant for colder climates verbatim. Cheap energy availability and tariffs exacerbate this practice (Fattouha and El-Katiri 2013). Often times, energy analysis and conservation come as postmortem ideas than at the design stage. And the energy subsidies often prove to be unrealistic and unsustainable in the long run. Qatar has little research on occupant thermal comfort and preferences in buildings. Energy efficient building design necessitates this. As part of large energy conservation web tool design for Qatar, we conduct year long occupant surveys in office buildings to understand the nature of the building stock and occupant thermal comfort and preferences along side their thermal adaptations. Saudi Arabia stands sixth in world's oil consumption and already uses a quarter of its own production. Building energy consumption in Saudi Arabia went up astronomically by 60.8% in five years from 2007 to 2012. Energy analysts argue that Saudi Arabia could turn into a net oil importer by 2030 if current demand, growth patterns continue. Air conditioning majorly contributes to this. Recent research posits that the building envelope codes have a limited role to play in reducing energy consumption (Radhi 2009). Saudi building code specifies two design temperatures of 20 C and 25.5 C for winter and summer, for all climate and building types, much similar to the building codes of other countries like UAE (SBCNC 2007). Relying on Fanger's heat balance model (Fanger 1972), the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) Standard -55 (1992) formed the basis for this. This Standard is long since superseded (ASHRAE 1992). Environments designed based on this model produce thermal monotony (uniform indoor temperatures yearlong), with the indoor environments delinked from the outdoors. It ignores the local climate, clothing, culture or comfort practices of Saudis. Researchers all across the globe criticized such rigid and unsustainable indoor temperatures. The Adaptive model of Thermal Comfort on the other hand hinges on the field studies in real life buildings. People in their everyday environments are studied in order to develop the temperature standards that truly represent local climate, people, their comfort practices and adaptation mechanisms. Saudi Arabia is yet to develop its Adaptive Thermal Comfort Standards (ACS) (Nicol and Humphreys 2009) (CIBSE, (The Chartered Institution of Building Services Engineers) 2006, Indraganti, et al. 2014) (ASHRAE 2010) (ASHRAE 2010). The potential of occupant's adaptation and the ACS is in producing sustainable indoor environments is long since been recognized. Therefore, this presentation highlights the necessity of the Adaptive Comfort Standards for the ME in the context of its growing energy concerns. It relies on the results of the first field studies we have conducted in Japan and India, KSA and Qatar and also draws heavily from the current research around the world.Qscienc

OCCUPANT PERCEPTION OF THERMAL COMFORT IN SLEEP ENVIRONMENTS IN QATAR

A thermal comfort field survey in sleep environments in winter and spring seasons in Qatar collected 833 sets of objective and subjective thermal and sleep quality responses before going to bed and after getting up. The subjects felt cooler sensations most of the time, preferred warmer sensations and the sleep environments are considered comfortable overall. Griffiths comfort temperature (Tc) was 24.3 ˚C and 20.2 ˚C in FR and AC modes respectively.  Subjects used air-conditioner (AC)s adaptively in heating mode in winter.  In 82.7% cases in air-conditioned (AC) mode, the comfort temperature was below the lower limit of the international standard. Subjects enjoyed quality sleep in Qatar. Overall self-declared sleep quality improved with thermal acceptability. Depth of sleep was higher in AC mode (mean = 3.86). On the other hand, mean global Pittsburgh Sleep Quality Index (PSQI) score was high in general (mean = 10.7), indicating good quality sleep, and significantly so in free-running mode (mean = 11) than in AC mode (mean = 10.4). It increased as subjects liked their AC systems. This study suggests that overcooling in spring can be avoided by increasing the air movement without compromising sleep quality

An Epistemic-Deontic-Axiologic (EDA) agent-based Energy Management System in office buildings

In the UK, buildings contribute about one third of the energy-related greenhouse gas emissions. Space heating and cooling systems are among the biggest energy consumers in buildings. This research aims to develop a novel Building Energy Management System (BEMS) to reduce the energy consumption of the heating, ventilation and air-conditioning (HVAC) system while fulfilling each occupant’ thermal comfort requirement. This paper presents a newly developed novel method, Epistemic-Deontic-Axiologic (EDA) Agent-based solution to support the Energy Management System meeting the dual targets of occupant thermal comfort and energy efficiency. The multi-agent solutions are applied to the BEMS. The problem decomposition method is used to define the architecture of the system. The Epistemic-Deontic-Axiologic (EDA) agent model is applied to develop the rational local and personal agents inside the system. These EDA-based agents select their optimal action plan by considering the occupants’ thermal sensations, their behavioural adaptations and the energy consumption of the HVAC system. The Newly-developed personal thermal sensation models and group-of-people-based thermal sensation models generated by support vector machine (SVM) based algorithms are applied to evaluate the occupants’ thermal sensations. These models are developed from the data collected in a real built environment. Simulation results prove that the newly-developed BEMS can help the HVAC system reduce the energy consumption by up to 10% while fulfilling the occupants’ thermal comfort requirements

Thermal adaptation of the elderly during summer in a hot humid area: Psychological, behavioral, and physiological responses

Elderly demand for thermal comfort and energy conservation in senior citizen centers is increasing in an aging society. To reveal the thermal responses of the elderly in a warm summer environment, a field study involving experimental measurements was conducted in Chongqing, China. The study included 333 subjects in 17 residential buildings and 119 subjects in 6 elderly nursing homes; it showed that elderly persons as passive users of air conditioners preferred cooling by natural ventilation. The mean thermal sensation vote was lower than estimates obtained from the PMV model in warm environments. The physiological responses of eight elderly subjects (65 ± 3) were measured in a climate chamber at 18 °C and 34 °C and compared with those from eight college students (22 ± 1) and eight middle-aged subjects (50 ± 5). In this chamber, oral temperature, blood pressure, and heart rate of elderly and middle-aged persons were determined to be almost constant as the air temperature was changed to a hot/cold environment for 30 min, a different result from that of the young subjects. However, the skin temperature for all age groups showed variation with air temperature, suggesting skin temperature as an optimal monitoring parameter for the entire population

The impact of occupants’ behaviours on building energy analysis: A research review

Over the past 15 years, the evaluation of energy demand and use in buildings has become increasingly acute due to growing scientific and political pressure around the world in response to climate change. The estimation of the use of energy in buildings is therefore a critical process during the design stage. This paper presents a review of the literature published in leading journals through Science Direct and Scopus databases within this research domain to establish research trends, and importantly, to identify research gaps for future investigation. It has been widely acknowledged in the literature that there is an alarming performance gap between the predicted and actual energy consumption of buildings (sometimes this has been up to 300% difference). Analysis of the impact of occupants’ behaviour has been largely overlooked in building energy performance analysis. In short, energy simulation tools utilise climatic data and physical/ thermal properties of building elements in their calculations, and the impact of occupants is only considered through means of fixed and scheduled patterns of behaviour. This research review identified a number of areas for future research including: larger scale analysis (e.g. urban analysis); interior design, in terms of space layout, and fixtures and fittings on occupants’ behaviour; psychological cognitive behavioural methods; and the integration of quantitative and qualitative research findings in energy simulation tools to name but a few

Effect of thermal comfort on occupant productivity in office buildings : response surface analysis

Thermal environment is one of the main factors that influence occupants' comfort and their productivity in office buildings. There is ample research that outlines this relationship between thermal comfort and occupant productivity. However, there is a lack of literature that presents mathematical relationship between them. This paper presents a research experimental study that investigates effects of indoor environmental quality factors on thermal comfort and occupant productivity. This study was conducted by collecting indoor environmental quality parameters using sensors and online survey for twelve months. Data analysis was done using Response Surface Analysis to outline any mathematical relationship between indoor environmental quality and occupant productivity. The outlined relationships confirmed dependencies of occupant thermal comfort and productivity on various indoor environmental factors. These dependencies include the effect of CO2 concentration, VOC concentration. These relationships were analysed to rank nine indoor environmental parameters as per the degree of effect on occupant thermal comfort and productivity. These findings would help design professionals to design better office design that would improve occupants’ comfort and their productivity. Study results have different implications for professionals working in design, construction and operation of office buildings. It is recommended that design guidelines for office buildings should consider occupant productivity and incorporate recommended range for indoor environmental quality parameters in respective categories and criteria