Nick Baker

Thermal comfort in outdoor urban spaces: understanding the human parameter

The research being undertaken seeks to achieve a better understanding of the richness of microclimatic characteristics in outdoor urban spaces, and the comfort implications for the people using them. The underlying hypothesis is that these conditions influence people’s behaviour and usage of outdoor spaces. The initial results demonstrate that a purely physiological approach is inadequate in characterising comfort conditions outdoors, and an understanding of the dynamic human parameter is necessary in designing spaces for public use. The thermal environment is indeed of prime importance influencing people’s use of these spaces, but psychological adaptation (available choice, environmental stimulation, thermal history, memory effect, expectations) is also of great importance in such spaces that present few constraints.

Thermal comfort for free-running buildings

Abstract The growing demand for air-conditioned buildings and the resultant demand for electrical energy has prompted research into passive cooling, such as the European Union funded PASCOOL programme. One of the tasks in this programme is to develop comfort criteria appropriate to free-running non air-conditioned buildings, where environmental conditions are likely to vary much more widely than mechanically controlled buildings. Conventional comfort theory has criteria which are more appropriate to controlled buildings. These criteria fail to account for the adaptive behaviour of the occupants to improve the thermal conditions actually experienced. This paper briefly summarises the results of the comfort monitoring surveys, conducted within the research programme during 1993 and 1994, which have provided information on room and local thermal conditions, and simultaneous subjective responses. Although limited in scope, the results show clearly that the subjects were exercising a considerable amount of adaptation both in regard to their person and their immediate surroundings during the surveys. More discursive comment is made on adaptive behaviour such as metabolic rate adjustment, followed by speculative comments on the nature of environmental tolerance. Finally, an outline for an expert system to assess thermal satisfaction is proposed.

Improvements to the Globe Thermometer for Outdoor Use

The rapid changes in radiant conditions outdoors, require a fast response globe thermometer. As part of a research project entitled “Thermal Comfort in Outdoor Urban Spaces”, extensive field studies are being carried out involving environmental monitoring and interviews, thus the development of such an instrument was crucial. This paper describes a series of parametric studies of five 38 mm-diameter globe thermometers, of different thickness and materials, with the objective of reducing the thermometers response time to approximately 4 min, similar to the duration of the interviews. Contrary to current belief, it is not only the slow heat transfer from the globe to the heat sensor that is responsible for long response times, but the heat capacity of the system as well, and by reducing it, shorter response times were achieved.

LT Method 3.0 — a strategic energy-design tool for Southern Europe

The LT Method is an energy-design tool which responds to parameters available early in the design development. It provides an output of annual primary energy for lighting, heating cooling and ventilation. This paper introduces LT 3.01, a version for Southern Europe which includes a procedure to evaluate the affect of shading devices on cooling loads and on lighting.

The irritable occupant: recent developments in thermal comfort theory

This paper explores thermal comfort, following recent renewed interest in thermal comfort standards. It also reports on findings from the Thermal Comfort Task in the EU funded PASCOOL project which had an overall objective of promoting passive cooling and avoiding air conditioning. Finally, some tentative conclusions are developed together with their implications for architectural design.

A BEHAVIOURAL APPROACH TO THERMAL COMFORT ASSESSMENT

The paper1 describes the use of field study data to identify and quantify the individual contributions of adaptive actions by subjects in order to achieve thermal comfort. These actions include operating building controls, responding to spatial variation of room conditions, modifying posture and clothing, and metabolic rate. In order for these actions to occur, the adaptive opportunity must exist, which to some extent is a property of the building. Suggestions for the integration of adaptive effects into comfort-predicting models are made including a way of avoiding temperature as an input, which is shown to have poor correlation with reported thermal satisfaction.

Comfort criteria for passively cooled buildings a pascool task

The application of passive cooling techniques to buildings in warm climates creates the need for appropriate comfort criteria. Conventional comfort criteria, usually based upon laboratory experiments, seem to be unnecessarily severe. The paper describes preliminary findings of the PASCOOL Thermal Comfort task which, responding to renewed interest in behavioural aspets of thermal comfort, sets out to establish appropriate limits by field studies and theoretical considerations.

Urban infoscapes: new tools to inform city design and planning

During the past decades, many computer tools have been developed to assist in the environmental design of individual buildings. Heat, light, sound and especially energy consumption can be analyzed in many different packages. This is not generally true for urban design, especially at the medium scale. Although it is widely assumed that urban texture – the pattern of streets, building heights, open spaces and so on – will determine environmental quality both in the buildings and outside, tools for investigating the connections are sparse. The need for medium-scale understanding is confirmed by Givoni (1989): ‘The outdoor temperature, wind speed and solar radiation to which an individual building is exposed is not the regional “synoptic” climate, but the local microclimate as modified by the “structure” of the city, mainly of the neighbourhood where the building is located.’ This paper describes how novel image-processing algorithms could be applied in urban areas to calculate a wide number of parameters. These parameters allow the construction of what we could call ‘urban infoscapes’: a layered collection of information on cities, that can be successfully used to inform urban design and planning.

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.

The influence of thermal comfort and user control on the design of a passive solar school building-Locksheath primary school

Abstract This article describes the design of a Primary School at Locksheath, Hampshire, England. The design is the result of collaboration between the Hampshire County Councils Architects Department and the Martin Centre for Architectural and Urban Studies, University of Cambridge. The design has been strongly influenced by considerations of energy conservation, maximum use of solar energy, and thermal comfort. Stress is placed on the role of the occupant in the control of the building. Predictive analysis indicates that the large conservatory incorporated makes a considerable reduction in heating energy demand.