Air may be pre-cooled using thermal mass before it is supplied to an occupied space. One option is to pre-cool the air in a basement space and exhaust the air at high level through stacks. However, the thermal forces that determine the direction of airflow, including heat gains in the occupied space, thermal mass cooling and the external air temperature may counter each other, and result in flow reversal.
Adequate ventilation and good air quality are essential for the comfort of occupants and productivity. Excessive ventilation however, may result in discomfort and high energy loss. A study was carried out to examine the influence of ventilation on indoor thermal conditions. The results show that ventilation has profound effect on lowering the indoor temperature, particularly the night time ventilation. Derived PMV is compared with actual votes (thermal sensation) and found that PMV is lower than actual votes.
An intervention study in eleven schools with approximately 1000 children age twelve to thirteen has been carried out in the period 1997 to 1999. Four schools with poor ventilation standard, three schools with carpets and four reference schools participated. In the schools with carpets, these have been removed and in the schools with poor ventilation systems, these have been upgraded to Norwegian standards for new buildings. A questionnaire was answered three times during a two-week period, asking how indoor environment-related symptoms were perceived.
This paper presents a recent field measurement study undertaken in 1999 on 73 recent Frenchdwellings. The study presented the opportunity to assess the conformity and the performancesof the dwelling ventilation systems and to assess the impact of infiltration on airchange rates.The following aspects were analyzed : (1) the type of ventilation facilities in the dwellings ;(2) the defaults in the installed systems and in their operation ; and (3) the measured air flowrates, as compared to the French standard required levels.
Ventilation is essential for the maintenance of good indoor air quality, although there is evidence to suggest that energy loss through uncontrolled or unnecessary air infiltration is excessive. In this study, estimates are presented for air change (ventilation and infiltration) energy use in non-industrial buildings for 13 countries. Various methods are used for the estimates, but they are mainly based on calculating the total annual enthalpy change needed for the conditioning of air. The potential for reduced energy use by improved ventilation control is also briefly reviewed.
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