English

Flow and heat transfer calculations have been operated in a typical office room equipped with a displacement ventilation and a chilled ceiling system. Results show quasi-periodic flow when the values of internal thermal loads are high. They also show lateral oscillations of the plumes above heat sources which create after impact on the cold ceiling recirculating flows in the room.

Suggests that particularly for outdoor thermal comfort assessments in cold conditions, non-steady state models should be applied. This and other new aspects are to be considered in a new internationally standardised Universal Thermal Climate Index (UTCI), at present being developed by the International Society of Biometeorology. Psychological factors also need to be considered, such as diverging thermal expectations indoors and outdoors. States that as a consequence, different approaches are needed to assess indoor or outdoor thermal comfort.

Describes the thermal model available, both simple and complex and outlines capabilities and limitations. States that all of the models have limitations for use in standards, including the accuracy of the physical simulation and the accuracy of the inputs to the model. States that the biggest limitation is probably the accuracy with which comfort perceptions can be related to the physiological variables simulated in the thermal models.

States that existing standards and models are not sufficient to characterise the satisfaction and pleasantness for end-users which is provided by heating or air conditioning. The project described here was devised with the aim of using sensory evaluation techniques in the design of HVAC systems. A dual evaluation is used for sensory evaluation in the food cosmetics, phone and automotive industries, comprising of sensation measurements carried out be a small panel of trained expert assessors and preference studies performed by a large panel of representative consumers.

An analysis was done to look at the differences in the way occupants perceive the office environment. The surveys were done in an office with multinational workers in Japan. The 406 returned questionnaires were grouped by nationality and gender. 26% reported a comfortable working environment. There was a significant neutral temperature difference of 3.1 deg. C between the Japanese female group and the non-Japanese male group. Japanese females reported the highest frequency of sick building syndrome of any of the groups.

The paper compares a long and short term study of naturally ventilated buildings in a city in western Iran. For the hot season the neutral temperatures from the short and long term studies were 28.4 and 26.7 deg. C. For the cold season the short and long term neutral temperatures were 20.8 and 21.2 deg. C. Good agreement is shown between both studies. The results showed how acceptable conditions varied widely, a good relationship between neutral temperature and room temperature and between indoor comfort and outdoor conditions.

Summarises a study that found a clear impact of activity and overall thermal sensation on human sensitivity to air movement, while no interaction effects of exposure to several local thermal discomfort factors were observed. States that current standards tend to consider only sedentary light activity and a neutral thermal sensation.

Presents a series of laboratory studies into thermal comfort requirements. Groups of 16 persons were used in two studies, to look at the effects of gender over three-hour exposures in simulated living room and office environments. Only small differences were found in the thermal comfort response of male and female subjects in identical clothing conditions, for neutral and slightly warm environments. In cool conditions, females felt the cold more than males. Behavioural studies were conducted for persons maintaining thermal comfort by adjusting their clothing. A temperature of 18 deg.

Discusses, in the context of the Predicted Mean Vote (PMV) model, the representation and measurement of clothing parameters and metabolic rate. Identifies several problems and provides solutions to a few. Results showed the importance of the effects of body motion and air movement for clothing insulation, and suggests they should be incorporated into the model. The results also showed only small effect on dry heat exchange for stationary light work at low air movement. Suggests that algorithms for convective heat exchange in prediction models should be reconsidered.

Describes the current design standard BS EN ISO7730 - 'Moderate thermal environments - determination of the PMV and PPD indices and specification of the conditions for thermal comfort'. States that it is based on Fanger's work and comprises a steady-state human heat balance model that leads to a prediction of the sensation of human thermal comfort for a given set of thermal conditions. Questions the applicability of this standard when confronted with the more complex environment of a chilled ceiling operated in combination with displacement ventilation.