The paper describes the test procedure and sums up the criteria for the air handling components and systems defined in the Finnish guideline for ventilation equipment Test methods, such as a measuring method of mineral fibres released into airflow, and a method for measuring the odour threshold of processing oils have been added to the guideline.The experience from the labeling system has been very positive .
The author expresses the evaporative efficiency of sweating as a function of wetted skin surface area.This allows to predict mean skin temperature of human body as a function of 4 environmental factors and 2 human factors. With these parameters skin temperature and wettedness for 2 typical cases have been calculated.
A seated, unclothed and bald manikin is used for the experiment. A numerical method calculates the view factors between individual segments of a thermal manikin , and between the outer surfaces and the body segments. The segment to segment radiation is the subject of the research : radiation between segments may be significant and the local differences in radiative heat loss may cause discomfort and cannot be ignored.
This study makes clear that mean skin temperature and skin wettedness do not remain constant but may vary under constant thermal sensations of "slightly warm", "warm" and "hot". The relationship between mean skin temperature and skin wettedness under the constant thermal sensation of "warm" is adequaltely expressed through a convex curve with a negative slope.
The study was carried out on 6 subjects. Each one is seated at a desk with a mounted PVS. During the experiment the room air temperature was controlled at 28C and the personalized air temperature was 25C. Several fluctuations were tested, air movement with a frequency of 0.2 Hz was preferred to 0.1 Hz and 0.3 HZThe subjects had a preference for a lower mean air velocity but were more distracted when air movement fluctuated (0,2 Hz) than when it was constant.
The authors introduce a new airflow characteristic, the equivalent frequency, as an integral measure for the frequency of the random velocity fluctuations in rooms. The aim of that study was to test the impact of the equivalent frequency on draught sensation for human subjects. Further investigation at different air temperatures along with different turbulence intensities of air velocity is recommended.
CFD is used to simulate the effects of respiration in displacement ventilated rooms. It was done in a satisfactory manner.An extra simulation was carried out with "density-corrected" exhalation temperature, to see if the results are sensitive to variations of this parameter. This proved not to be the case. The choice of the flow rate is more important for the flow pattern.
16 segmental and all body heat transfer convective coefficients were determined in tests performed with a thermal mannequin placed in the test chamber of a large wind-tunnel.This paper presents a general table with the numerical coefficients of the equations representing the evolution of the convective coefficient with the flow velocity for all the studied cases (front, back and side flow - at seated and standing postures) . The effect of natural convection is more obvious on the central part of the body. Peripheric parts have stronger losses.
Indoor air cleaners are available on the market but a lot of them are not tested and their performances are not known. The main objective of our study was to develop a laboratory test method which allows to determine the life span of indoor air cleaners. Loading of the device is carried out with tobacco smoke which is an air pollutant that reflects real conditions. Fractional efficiency and air flow rate of the device are measured at the initial stage (clean device) and step by step as the device becomes loaded.
The National Institute for Occupational Safety and Health (NIOSH) has undertaken a long-term performance test of heating, ventilation, and air-conditioning (HVAC) system filters. This testing is being conducted at the NIOSH facility in Morgantown, WV in an air handling unit (AHU) that services the animal quarters. The six-pocket bag filters in this AHU have been replaced with higher efficiency mini-pleat V-Bank filters and have been monitored monthly for filtration efficiency.
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