thermal comfort

In this study, an office with mixing ventilation is considered. The CFD analyses show that for high cooling loads it is useful to couple a cold ceiling to primary air system

This paper deals with the integration of CFD analysis tool with genetic algorithms. This integrated process presents advantages in generating design alternatives that tally with multiple design, thermal and ventilation criteria.

This paper deals with experiments made to test the performance of a personalised ventilation system (PVS). 30 human subjects have participated to the experiment in an office with 6 work stations equipped with a PVS supplying outdoor air.The perception of air quality and the thermal sensation for each participant has been reportedduring their exposure to combinations of 3 levels of personalized air temperature, 4 airflow rates and 3 levels of room air temperature.

30 human subjects participated in a 3 h 45 min. experiment, that took place in an office with mixing ventilation and personalised ventilation systems (PVS).Each person could choose the position of the personal air terminal device, the direction of the air supplied and the flow rate (up to 15 l/s.person).The subjects were exposed to 4 following experimental conditions : PVS supplying outdoor air at 20C, then 23C ; PVS supplying re-circulated room air ; mixing ventilation, without PVS.Results allow to know how the PVS were used by participants (choice of position and flow rate).

This work deals with the characterization of the thermal performance of a LHS (Local Heating System) tested on 18 persons (9 males and 9 females) working in a real free-running office with mean room temperatures varying from 16C to 18C. Local heating systems investigated consist in a combination of two radiant panels and a foot heater. During the measuring tests, the metabolic rate, the tympanic and local skin temperatures were monitored.

For workers sharing the same office, there is normally a need for slightly different temperatures to fit their own optimal thermal comfort. In a laboratory experiment with thermal manikin, local radiant heaters have been placed behind office chair , providing heat at their backs, shoulders and necks .
The heat loss from the whole body or from specific body segments was measured during the experiment. The system proved efficiency for keeping the heat balance of the body and reducing the sensation of draught.

Concerning thermal comfort (number one complaint in most offices), the range of occupants needs is very wide. An individual control ventilation system based on VAV (varying air velocity) and integrated into desk was installed in a bank in 20 work areas. The article describes several possible arrangements of this system and mentions air temperatures and flow rates to achieve individual thermal comfort as determined from a preliminary study with a mannequin in laboratory.

Performance on a long-term period of time of an HVAC installation to ensure thermal comfort conditions can be evaluated by estimating the number of hours when the thermal condiitons are outside a given range. Another method consists in weighing this number of hours according to the indoor temperatures. These methods are demonstrated and discussed using data from measurements in an existing building.

A special garment was developed to measure heat transfer coefficients (convective and radiative) of the clothed human body. It was tested on male subjects operating seated office work in a environmental room. The measured convective and radiative heat transfer coefficients are in good agreement with the PMV model and a number of previous publications.

Monitoring of temperature and relative humidity was carried out in an air-conditioned office building during the heating season. In addition, occupants filled in health and comfort questionnaire. Without informing the occupants, humidity was reduced in an experimental area compared to the control area. As this reduction was not so great (2% relative humidity), the differences of occupants perception between areas are not significant. A slight reduction of building related symptoms was observed at higher humidity.