This information dossier describes the general principles of natural ventilation, the calculation of air flows and the strategies for building cooling. It presents case studies of six office buildings, with the lessons learned.
In natural ventilation, the airflows stream in opposite directions. One enters the room while the other leaves it. A neutral zone exists where pressure difference between the inside of the room and the outdoor environment is equal to zero. This paper deals with an experiment conducted with a model of a room in order to investigate the influence of the height of the neutral zone on thermal comfort.
This thesis was based on numerous experiments operated in a full-size cell in order to study ventilation efficiency and thermal comfort associated with several positions of air inlet and outlet, taking into account different sources of disturbance (heating systems, occupants, etc.).
The research in this thesis aims to provide information about the uncertainty attached to the prediction of thermal comfort in buildings, in the context of the specific case of a naturally ventilated office building.
This paper deals with the case of a very important thermal discomfort due to wide open arcades and corridors beneath a building, especially under windy and rainy weather. Building thermal simulations (with ESP-r) and field measurements were operated for a building at Coimbra University (Portugal) to suggest architectural corrections (e.g. closing the arcades with windows and doors) in order to reduce discomfort outside and inside the building sand save energy.
This paper gives the results of a field study in Danish office spaces with displacement ventilation systems. Draught was identified as a serious problem. Half of the 227 occupants were not satisfied with indoor air quality. Occupants counteract draught discomfort in blocking air supply diffusers or asking the maintenance staff to increase the supply air temperature. So a very careful design for displacement ventilation is required in order to perform satisfactorily in practice.
Thermal comfort for 227 occupants in 8 office buildings with displacement ventilation was investigated. The occupants' thermal sensation was close to the predictions by the PMV index. The main conclusion is that draught is the major local discomfort factor for the occupants, mainly at lower leg. The effect of vertical temperature gradients on occupants local discomfort did not appear as evident.
This paper describes a method for the determination of optimal indoor conditions, using three parameter indexes: PMV (predicted mean vote) for thermal comfort, CO2 concentration for indoor air quality and cooling/heating load for efficient use of energy. A performance index of the HVAC system is calculating by adding square errors between actual and desired values. It is then minimized to find optimal indoor air conditions.
In 2 tropical countries such as Singapore and Indonesia, the perception of thermal comfort is different for people according to their living standards. The higher the standard of living is, the better comfort in living environment is required. A comparative study has been conducted with subjective and objective measurements.
Operative temperature which takes in account air temperature and radiation is of great importance when one defines human comfort.This paper gives information about definition, calculation and measurement of operative temperature.
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