Meteorological measurements

Measurements of temperature and humidity in a louvred boxes located outdoors. Lattices, allowing air circulation outside the natural way for the instruments, but protect them from rain and sun. Because the movement of air over any wet bulb mounted in such a shielded enclosure by natural means, the speed of the air flow is too low (less than 4.5 m s_1)to minimize interference from radiation effectively and so, 'check' wet-bulb temperature values will be some degree higher than the " slingshot " wet values. While wet values on the psychrometric chart, published CIBSE are sling values taken from the data of the meteorological tables are always based on the verification of values, and with consideration should be made for this when using such data.

In modern meteorological stations hourly measurements are made and recorded dry bulb thermometer temperature, humidity and other relevant climatic variables. The highest and lowest values of the temperature for each month, the average figure for the last accordingly, the corresponding period of years and in quotation marks, as the average daily maximum and the average daily minimum temperature for that particular month. These values represent the typical high and low temperatures in the month.

In extreme high and low values of the temperature in each month is noted, averages are calculated on the number of years for which observations are made. This gives the average monthly maximum and minimum values of the dry bulb thermometer, which are typical for warm and cold weather. Other records of temperature on, but this is largely irrelevant to the study of air conditioning. In underdeveloped countries, records may not be so extensive, but the principles remain the same.

As regards the entries relative humidity, the picture is not so comprehensive. Records do not always hold wet bulb temperature, but instead of measurements of relative humidity can be made twice a dayone about 09.00 h and about 13.00 Readings taken at a height of approximately 1.5 m above ground level.

Hourly values of the dry bulb and wet bulb temperature affect many meteorological stations and process data to show their frequency. In CIBSE (1999) covers both cold and warm weather, but also gives the information to several places in the UK with data from Heathrow corresponding to London. The percentage of the total hours in the four summer months, from June to September inclusive, presented in two ways: as a set of matching dry bulb and wet-bulb temperature values and, separately, as a percentage of the total number of hours in the summer months, - quotes the dry bulb and wet-bulb temperature values are not exceeded...