ABSTRACT
Most systems in use are for commercial applications, principally office blocks, and this has driven the design ethos. Where systems have been required for commercial applications other than office blocks, a system originally developed for treating offices has often been adapted to suit the different use, for example, providing fan coil units for hotel bedrooms. For industrial applications the approach has been quite different, the needs of the industrial process generally dictating the form of the system design. The fluid that is thermodynamically desirable in the system is the refrigerant but oil must also be present for the proper mechanical working of the compressor. A liquid receiver is then essential and it must be big enough to contain all the refrigerant from the rest of the system. It is strongly recommended that direct-expansion air-conditioning systems include pump-down control, particularly if the compressor is likely not to be running for any length of time.
