thermal comfort

Large sets of thermal comfort field data have been analysed in detail to inform generalized thermal comfort standards, but there is specific information that might be relevant to particular projects that is not easily accessed by practitioners. We developed interactive tools that allow users to explore the data and look at the subsets that are most interesting to them because of location, culture, building type, etc.

This study aims to assess the thermal conditions of an indoor environment deemed unacceptable by workers. For this purpose, Ostracon, a voting device, was developed to record the physical environment at the time a worker presses a button to express a complaint. Ostracon was used to record the opinions of 90 workers about their thermal environment in six offices during the summer. The results show that workers found the indoor thermal environment unacceptable even when the static thermal conditions were within a range that was predicted to be comfortable.

The skin temperature and thermal comfort are closely related and change in skin temperature can predict thermal discomfort even before it is consciously perceived. The effect of changing thermal environment is most significant on the body extremities, particularly hands in cool and head in warm conditions. The skin temperature of the extremities can thus become a feasible control signal for personalized conditioning. In order to use a skin temperature of the extremities in practice as a control signal, it is necessary to measure it in a way that does not hinder a user.

This study is designed to investigate the relationship between the thermal comfort environment and stress using brain wave analysis. To achieve this purpose, an experimental approach in a climate chamber based on PMVs was adopted. Environmental factors were set with the PMV scale ranging from -3 to +2. The brain waves of each of the participants (N=7; males) were measured in six conditions, in the PMV order from cold to hot, i.e. one condition per day. The results suggest that the participants felt least stressed under the PMV 0 and most stressed under the PMV -3 and +2.

The indoor climate is an important factor with respect to human health and comfort since we spend most of our time, no matter if awake or asleep, in the built environment. Building occupants influence their thermal environments to maximize thermal comfort by inducing thermoregulatory behaviour. In the last decades, overheating of cities and buildings became an important issue. However, the effect of a mild hot environment on human thermoregulatory behaviour remains unclear.  To study the effects of a mild warm environment we propose a mild warm acclimation study.

In a case study on outdoor mist cooling, 141 people attending an open campus event were surveyed over 2 hot summer days. Nozzles mounted on an oscillating fan sprayed about 18L/h of mist with average droplet diameter of 25μm. Subjects stood in the misting area where they wished. Time spent in the misting area was recorded. Skin temperature of the forearm and face were taken with IR surface thermometers before entering and after leaving the misted area.

Metabolic heat production is one of the key parameters in maintaining the body’s heat balance with the environment. Levels of accuracy and methods for estimation of metabolic rate for various activities are given in most of the commonly used standards, and estimated metabolic rates for an average adult are tabulated to be used where direct measurement is not practical. However, determination of metabolic rate is expected to be different in a younger population compared with that of adults.

Mixed mode (MM) buildings open up a new arena for energy efficient design. Zoned MM buildings are the most common, particularly in the developing world where only some areas in a building are air- conditioned (AC) based on programmatic requirements while the rest of it is naturally ventilated (NV). Occupants in the NV zone frequently visit the AC zone and are well aware of the conditions there.

Beijing is in the Cold Climate Zone of China. This study carries out a long-term survey of indoor environmental parameters, the clothing of occupants, and the metabolic rate of occupants as well as people’s voting of their sensation in classrooms in Beijing. The study was conducted in 2011 and 2012, trying to explore people’s requirement of indoor thermal environment. Relationships between thermal parameters and people’s sensations are found. The acceptable temperature range can meet the requirements of most of users.

This research suggests that the thermal preference of occupants is subject to change; hence, a particular thermal setting may not be able to constantly satisfy everyone. On the contrary, individual thermal control in the workplace is more likely to increase user comfort and satisfaction. This is examined through environmental measurements, comfort surveys and semi-structured interviews in two office layouts with high and low thermal control.