Conditioned air in telephone exchanges
14 July 1935
The control of the moisture content of the air is an important factor in the operation and maintenance of telephone exchanges in localities where high relative humidities prevail. Statistics are given showing that the humidity of Shanghai frequently exceeds 70% for long periods at a time, and dust storms occasionally occur. Air-conditioning plants have therefore been installed in the buildings of the Shanghai Telephone Company, and a detailed description is given of the ammonia-compression refrigerating system employed. Calculations for the determination of the size of plant required for one of the buildings are set out in full, together with estimated installation and running costs. It is shown that the water charges can be reduced by about 30% by pumping the water from an artesian well.