Showing papers on "Thermal comfort published in 1988"

A field study of thermal environments and comfort in office buildings

Abstract: This paper presents the initial findings of ASHRAE research project RP-462, a field study of environmental conditions and occupant comfort in ten office buildings in the San Francisco Bay region. We made a total of 2342 visits to 304 participants during two seasons, collecting a full set of physical measurements and subjective responses at each visit. In this paper we describe the building environments and their conformity to the requirements of tire thermal standards, the distribution of thermal sensation responses, neutral and preferred temperatures, conditions of thermal acceptability, and gender and seasonal effects on comfort responses. A few of the results are as follows: 78.2% (winter) and 52.8% (summer) of the workstation measurements fell within the ASHRAE Standard 55-81 comfort zones; the higher summer comfort zone was judged as too warm based on several rating scales; neutral temperatures were 22.0°C (winter) and 22.6°C (summer), and preferred temperatures were 0.3-0.6°C cooler.

Method for operating variable speed heat pumps and air conditioners

Abstract: A controller and a related method that maintains thermal comfort in an occupied space at a user-defined level while simultaneously maximizing the efficiency of the space conditioning equipment. The controller determines the setting of heating/cooling capacity, indoor airflow rate, evaporator superheat and other system parameters such that a comfort constraint is satisfied. The comfort index may be any arbitrarily-defined relationship of measured or inferred quantities such as air temperature, relative humidity, air velocity, mean radiant temperature, CO 2 concentration, etc. The controller ensures that the error between comfort index and the comfort setpoint is zero while the energy consumed by the space conditioning equipment is minimized.

Thermal Comfort in Passive Solar Buildings

Abstract: Current thermal comfort models and standards are premised on conditions of thermal equilibrium between the building occupants and their indoor climate. Such standards are therefore not intended for use in passive solar buildings where indoor climatic conditions vary both spatially and temporally. The current report outlines the progress of a research programme being conducted in Denmark, Great Britain and France with the intention of developing a non-steady-state model of thermal comfort. In Denmark experiments with human subjects experiencing operative temperature step-changes have been conducted, and experiments with operative temperature profiles are now planned. The British subcontract has designed a research methodology, and a number of schools, offices, hospitals and dwelling-houses have been chosen for data collection, which is now well-advanced and continuing. The French subcontract identified the thermal behaviour of passive solar buildings by means of a literature review and computer simulation program.

Fundamentals of thermal comfort

Abstract: In buildings it is a major aim to provide thermal comfort for the occupants. The comfort concept will be discussed and the parameters influencing man's heat balance and his thermal comfort will be defined. The philosophy behind the international thermal comfort standard ISO 7730 will be discussed and practical applications during the design of buildings and in existing built environments will be discussed. It is emphasized that the presentations of any energy savings are meaningless unless the corresponding quality of the thermal environment and its impact on human beings are assessed. The international standard applies for steady-state thermal conditions. Progress on research to identify thermal comfort requirements during thermal transients will be reported. This is of special importance for assessing the thermal environment in many passive solar buildings. A new model will also be presented for predicting the risk of draught as a function of air temperature, velocity and turbulence intensity.

Effect of behavioral strategies and activity on thermal comfort of the elderly

Abstract: A field survey indicated that 101 elderly subjects (mean age 73.4 years) of good health living independently in Hamilton, Ontario, maintained comfort in winter 1985-1986 with a constant mean clothing insulation of 0.8 clo and mean indoor air and operative temperatures at 21,2/degree/C (70.2 F) and 21.5/degree/C (70.7 F), respectively. The subjects scored 83.5 on the Self-Evaluation of Life Function (SELF) scale. Mean activity level at rest was 1.5 met and during periods of light exercise (walking at 1.3 mph, 2 km hr -1) and light domestic household work was 1.9 met. The subjects mean thermal comfort vote at rest was -0.1, very close to a thermal sensation of neutrality (0.0 on a scale from -3 tp +3). This agrees with corresponding measurement (mean of -0.2) of Predicted Mean Vote (PMV) performed with a thermal comfort meter based on the Fanger Comfort Equation. Their thermal comfort vote and PMV during the two periods of increased activity were the same, 0.03. 20 refs., 6 figs., 4 tabs.

Wearer related performance standards for conditioned clothing.

Abstract: Estimates, based on American experience of work in the heat, indicate that in the UK, half a million workers or more may be working in thermally uncomfortable and stressfully hot environments. In addition, many will be experiencing cold working conditions and associated discomfort. The role of protective clothing as one of the factors involved in imposing thermal stress is emphasized. One method of thermal stress control is to provide conditioned garments which warm or cool the wearer as required. The use of ‘air supplied’ garments for cooling is specifically dealt with and the methods of defining their performance reviewed. The application of the concept of ‘per cent wetted skin surface area’ is discussed as one method of defining the performance of air ventilated garments if thermal comfort cannot be achieved. The use of low pressure air for ventilating garments is proposed. The performance of such a system employing a small battery powered blower is defined in terms of the wearers work rate an...

The Promotion of Energy Efficient Clothing

Abstract: A considerable saving of energy could result from the acceptance of slightly warmer clothing and the consequent lowering of indoor comfort temperature. The general trend towards higher indoor temperatures, and differences in heat energy use for work and domestic premises are examined and the level of saving is estimated. Heat flow from the sedentary human body through the clothing is analysed and a new factor, the Garment Temperature Decrease (GTD) is proposed. The value of GTD (in C) represents the incremental drop in ambient temperature that the garment allows. The comfort temperature for a clothing ensemble is found by subtracting the sum of GTD values for all the garments from the nude base level of 27.6°C. Clothing styles and textiles are examined using this factor and some guidance towards producing more thermally effective, but still fashionable clothing, is given. It is shown experimentally that Infra-red Thermal Scanning may be used to obtain GTD values. This could allow easy thermal labelling of garments as a first step towards promotion of general awareness about the warmth of clothing and energy efficiency.

Using a thermal manikin: Research on indoor thermal comfort

Abstract: There are reputed to be only ten examples of the thermal manikin (a computerized doll) in the world at present. Here, the author discusses their potential in microclimate research, and describes experiments with a thermal manikin at the Hungarian Institute for Building Science (ETI) to identify the quality of indoor comfort conditions. One study revealed that the correct heating system would yield better results than extra thermal insulation.

Solar Gains in Urban Renewal through Roofspace Systems

Abstract: This paper arises from a current demonstration project involving the construction and performance monitoring of 6 dwellings with roof constructions modified to admit solar gains which when convected into the house contribute to the heating load. The application of this technology to re-roofing work within urban housing renovation and the effect on thermal comfort and ventilation requirements of the house are outlined in this paper.

Natural cooling of buildings: a design tool for predicting comfort conditions

Abstract: The interactive effect of physical environment and architectural features on thermal comfort are computer simulated in rooms naturally ventilated. Results of parametric analyses for three Italian locations are given.

Simulation of an occupied building for comfort analysis

Abstract: Thermal comfort is a key problem in passive solar techniques where temperatures vary widely in time and space. A computer program is presented, gathering the thermal behaviour of a house and the thermo-physiological response of a human body. This program gives access to local comfort parameters (feet skin temperature, wettedness, etc.) for variable meteorological conditions; it makes possible an attempt for the thermal environment to meet the best comfort conditions of a human being. Infra-red exchanges between body and inner surfaces of the house are studied with a great attention because they are one of the most effective heat transfer mechanism occuring in a house.

Passive solar performance in america

Abstract: This paper reviews the results of the instrumented performance monitoring of passive solar buildings in the United States, Energy savings, thermal comfort, component performance, and design tool accuracy are evaluated for a wide range of building designs in climates throughout the country.

The use of shading trees for the improvement of thermal comfort in buildings in summer

Abstract: This paper gives a brief description of two computer programs to be used in the assessment of the thermal response of a building in the shade of trees. An application to a low cost Brazilian house, under typical summer climatic conditions, illustrates the use of the programs and the type of results they can provide.