humidity

The calculation of the infrared absorption in humid air (Schenker et al. 1995) has suggested an influence on the temperature and velocity profiles of the natural convection boundary layer. The profiles have been measured and confirm a small effect on the profiles in the laminar region of the flow but a strong one on the transition from laminar to turbulent flow. In a first approach based on the analytical solution for the conduction regime expressions could be deduced showing at least qualitatively the same modification of the temperature and the velocity profiles as measured.

A small commercial building was monitored before and after energy-saving retrofits to study the impact of retrofits upon ventilation rates, humidity, building pressure, and air-conditioning energy use. Duct airtightness testing identified severe duct leakage as a significant source of uncontrolled airflow. Differential pressure and infiltration measurements using tracer gas indicated an attic exhaust fan as another significant source of uncontrolled airflow. Duct repair resulted in a 31% drop (30.5 kWh/day) in cooling energy and an increase in relative humidity from 72% to 76%.

Acceptability of clean air and air polluted by building materials was studied in climate chambers with different levels of air temperature and humidity in the ranges 18-28°C and 30- 70% relative humidity (RH). The acceptability of the air quality immediately after entering a chamber and during the following 20-min whole-body exposure was assessed by 36 untrained subjects who maintained thermal neutrality by modifying their clothing.

The aim has been to determine ventilation rates and risk of moisture damage in three modernschools with passive stack ventilation. The users are supposed to control the ventilation byusing the lantern windows and the outdoor air is assumed to enter through an undergroundduct. The paper presents results, analysis and conclusions from the performed measurementsand calculations.The ventilation rates are sometimes low and vary with the use of the windows in the facadeand the lantern. It is, however, always possible to arrive at a sufficient ventilation rate.

The inadequate dissipation of hurnidity fiom living spaces and bathrooms has become asignificant problem area in recent years. This can be attributed both to the replacement of old,poorly sealed windows by new windows with better seals, and to the increasing use of tilesand other building materials which hinder an adequate absorption of water vapour.The residents tend to reject repeated opening of the windows for ventilation purposes ongrounds of the ensuing energy costs.

It is known that water mist occasionally fonns near ice surfaces in roofed skating facilities depending on the indoor environmental conditions. The mist can lead to problems such as decreased visibility during skating competitions. The objective of the present paper is to clarify the relationship between indoor air conditions and water mist formation and to provide a useful design method for preventing mist formation in roofed skating facilities. In the first section, studies concerning the indoor air conditions for preventing water mist formation near the ice surface are described.