Diploma in Engineering - Air-conditioning and Refrigeration


Conditioning air involves both temperature adjustment and humidity adjustment. Refrigeration is downward heat adjustment whereas heat pumps are generally for upward temperature adjustment.

Conditioned air is generally utilised in buildings occupied by humans and to a lesser extent by animals. It may be used in specialised green-houses and in such circumstances may have additional carbon-dioxide added to it to stimulate plant growth. Other conditioned environments are those where fruit, in particular, may have ripening suspended by atmospheres which have had much of the oxygen replaced by carbon-dioxide thereby inhibiting particular chemical processes.

Downward temperature adjustment generally involves systems of evaporative cooling which may involve open or closed evaporative cycles.

The volumes of air to be conditioned may vary from a few cubic feet as in a refrigerator to room, hotel, office-block and factory volumes. Most but not all cooling systems rely on a closed system where cool air is re-circulated thereby reducing the amount of work to achieve the lower temperature. It is rare for conditioning systems not to use closed systems. On the other hand in industrial applications cooling may be desirable but humidity adjustment not needed so open cooling systems may be the only practicable methods in such circumstances.

Aircraft air-conditioning adds another dimension as the air-pressure has also to be attended to, the external air at high altitudes is extremely cold and dry.  The air therefore needs to be heated, pressurized and humidified. Between take-off, cruising altitudes and landing he external air source characteristics change dramatically with altitude.

Air-conditioners come in a variety of modes and levels of complexity generally including refrigeration components. As such they include electric motors, compressors, metal pipes and ducting, refrigerants, control mechanisms including temperature and humidity probes, electronic control circuitry, pipes, hoses, mountings and other items.


Thermodynamics Moisture in Air The role of Insulation Electrical Controls Estimating Heat Load Conditioning Requirements

Air conditioning assessments relating to latitude, typical humidity levels,sunlight & shade, diurnal variations, windows, building materials and orientation for Ducts & Grilles Installation of air-conditioning systems for Mis-functioning systems Safety Tools and Equipment for Sources of Supplies Standards Safety Business Legislation  and Administration