Air conditioning anf health

    Air conditioning has no greater influence on health than heating, although poorly maintained air-conditioning systems (especially large, centralised systems) can occasionally promote the growth and spread of micro organisms, such as Legionella pneumophila, the infectious agent responsible for Legionnaire's disease (болезнь легионеров). On the contrary, air conditioning (including filtration, humidification, cooling, disinfection, etc.) can be used to provide a clean, safe, hypoallergenic atmosphere in hospital operating rooms and other environments where an appropriate atmosphere is critical to patient safety and well-being. Air conditioning can have a positive effect on people who suffer from allergies and asthma.

    In serious heat waves, (период сильной жары) air conditioning can save the lives of the elderly. Some local authorities even set up public cooling centres for the benefit of those without air conditioning at home.

 

    Air conditioning systems can generate sound levels which contribute to the loss of hearing if exposures are endured for a long time. These levels are similar to those of a busy highway or airport.

 

Exercise IX. Task to the text:

List the advantages and disadvantages of modern air conditioning. Give some more examples if you know them.

 

UNIT V

Exercise I. Make sure you pronounce the following words correctly:

Thermodynamics, energy, supply, refrigeration, refrigerant, cycle, fluid, liquid, surround, machine.

 

Exercise II. Give the Russian equivalents of the following words and word combinations:

Heat pump, extra energy, to move the heat, to provide energy, electric heater, to gain heat energy, cooling side, heating side.

HEAT PUMP

A heat pump is a machine that moves heat from one place to another. A refrigerator is a heat pump because it moves heat from the inside to the outside and keeps the food inside cold, so it won't spoil. An air-conditioner is a heat pump, as it moves heat from the inside of a building to the outside

Some buildings are heated with heat pumps. In winter, a heat pump moves heat from the outside to the inside. Sometimes this works better than heating with a radiator. Usually, heat flows from a hot place to a cold place, according to the second law of thermodynamics. Heat will not move from a cold place to a warmer place by itself. Because of this, a heat pump must use extra energy to move the heat. Most heat pumps use electric motors to provide energy. Some heat pumps use heat energy, supplied by a flame or an electric heater.

Most heat pumps use a refrigeration cycle. A refrigeration cycle uses a fluid (a refrigerant) which moves through tubes and carries the heat. During the refrigeration cycle, the refrigerant changes from a liquid to a gas and back to a liquid. When it changes from a liquid to a gas, it gains (absorbs) heat energy.

The heat pump is set up so that the refrigerant gains heat from one place that will be cooled, and moves it to another place that will be warmed.

When a heat pump forces the refrigerant to change from a gas to a liquid it uses a compressor to do this. Often, an electric motor drives the compressor. The compressor compresses the refrigerant, and it changes from a gas to a liquid.

At the other end of the cycle, the refrigerant boils again. It changes from a liquid to a gas. But it needs heat to do this. When it takes up heat from its surroundings, it cools them down. So, where the refrigerant is changing from a liquid to a gas, it feels cooler.

This is the complete cycle, from the cooling side to the heating side. If the cooling side is the inside of a refrigerator, it gets cold. If the cooling side is the inside of a building, and the warming side is the outside of the building, the inside of the building gets cold. This is how an air-conditioner works.

Exercise II. Translate the following attributive groups into Russian:

    A refrigeration cycle, a heat pump refrigeration cycle, heat pump refrigeration cycle stages; heat energy, heat energy absorption, refrigeration cycle heat energy absorption; an electric heater, an electric heater operation, electric heater operation problems, electric heater energy supply.

Exercise II. Complete the sentences with the words from the list below according to the text: