Refrigerator Troubleshooting Diagram

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Total loss refrigerants

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Some volatile fluids are used once only, and then escape into the atmosphere. Two of these are in general use, carbon dioxide and nitrogen. Both are stored as liquids under a combination of pressure and low temperature and then released when the cooling effect is required. Carbon dioxide is below its critical point at atmospheric pressure and can only exist as ‘snow’ or a gas. Since both gases come from the atmosphere, there is no pollution hazard. The temperature of carbon dioxide when released will be – 78.4°C. Nitrogen will be at – 198.8°C. Water ice can also be classified as a total loss refrigerant.

Written by sam

April 13th, 2011 at 4:33 am

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Refrigerants for vapour compression cycles

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The requirements for the working fluid are as follows:
1. A high latent heat of vaporization
2. High density of suction gas
3. Non-corrosive, non-toxic and non-flammable
4. Critical temperature and triple point outside the working range
5. Compatibility with materials of construction, with lubricating oils, and with other materials present in the system
6. Convenient working pressures, i.e. not too high and preferably not below atmospheric pressure
7. High dielectric strength (for compressors having integral electric motors)
8. Low cost
9. Ease of leak detection
10. Environmentally friendly

No single working fluid has all these properties and a great many different chemicals have been used over the years. The present situation has been dominated by the need for fluids which are environmentally friendly.

Written by sam

April 13th, 2011 at 4:32 am

Posted in Refrigeration

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