Some indices of the optimal thermal state for different levels of energy expenditure

Thermal sensations (generalized and localized) are evaluated according a 7-point scale): cold – 1; cool/chilly – 2; mild cool –3; comfortable – 4; mild warm – 5; warm – 6; hot – 7.

Appendix

Air humidity measurement technique

The relative air humidity can be measured with an Assman psychrometer. A psychrometer consists of two thermometers, notably a mercury thermometer and an alcoholometer. The reservoir of one of the thermometers is covered with a cloth which is moistened with distilled water. As water vaporizes, the reservoir of the thermometer is cooled. The difference of the temperatures of the dry and moist thermometers is used to evaluate the air humidity, as vaporization depends on the content of water vapors in the air. The reservoirs of the thermometers in the Assaman psychrometer are protected from radiant heat with metallic shields. There are ventilation channels around the reservoirs through which the air passes. To estimate the air humidity, the thermometer covered with the cloth should be moistened with distilled water. It is necessary to start the ventilator and place the thermometer at a designated point. The readings of the dry and moist thermometers should be recorded for 4 – 5 min after the ventilator is started. The relative air humidity is estimated using psychrometric tables.

Air velocity measurement technique

If the air velocity is lower than 0, 5 m/s, it can be estimated with the help of a bulb katathermometer. The katathermometer is heated in a glass of hot water above 40 Cº. It should be dried then and let stay for some minutes. It is noteworthy that the temperature necessary for the katathermometer to cool is from 40 Cº to 33 Cº. Cooling air capacity (per 1 sec.) can be calculated using the following equation:

F/3 ∙ (40-33)

H= -------------------,

T

where F is the readings of the katathermometer scale.

To take into account the fact how the cooling of the device depends on the air temperature, one should calculate:

Q= 36, 5º - tº,

where 36, 5 is the middle point on the katathermometer scale;

tº is the temperature of the air in the given point.

H/Q should be calculated first and according to Table 1, the air velocity in the given point should be determined.

Table 9

Air velocity (V) at various temperatures of the air