Refrigeration and Air Conditioning 3 E Part 9 doc

... condenser to re-heat, together with the energy supplied to the compressor and the fan motor (since the latter is in the airstream). Figures for this electrical energy will have to be determined and ... factor is therefore one of wet bulb rather than dry bulb temperature, and the closer the upper limits are approached, the less heat can be rejected and so the less work can be done. 23...

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... Maintenance. Service. Fault-finding. Training 33 8 34 Efficiency and economy in operation 35 1 35 Catalogue selection 35 7 Appendix Units of measurement 36 7 References 36 9 Index 37 3 vi Contents The refrigeration ... determined by the requirements of the air conditioned enclosure. BS 56 43: 198 4 The refrigeration cycle 23 Low-temperature compressor Low-temperature conde...

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... contributes CO 2 emission to the atmosphere. The choice of refrigerant is therefore about the efficiency of the refrigerant and the efficiency of the refrigeration system. The less the amount of energy ... copper. This chapter is about the new refrigerants and the new attitude needed in design, maintenance and servicing of refrigeration equipment. 3. 2 Ideal properties for a refri...

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... covered by the provisions of BS.4 434 : 198 0 and require safety pressure relief devices as outlined in Section 6.10. In cases where there is no shut-off valve between the condenser and receiver, ... the condenser heat. If the mass flow is reduced, the temperature rise must increase, raising the condensing temperature and pressure to give lower plant efficiency. In practice, the tempera...

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... and shorten the working life. 11.11 Site pressure safety tests Site-erected pipework, once complete, must be pressure tested for safety and freedom from leaks. Pressures will be 1 .3 times the 118 Refrigeration ... higher condenser pressure is to increase the compression ratio and so reduce the volumetric efficiency and increase the power. There will also be the effect of the gas b...

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... provide an insulated and refrigerated enclosure suitable for the handling and storage of perishable goods, at some predetermined temperature. The shape and size of the cold store will depend on: 1. ... a eutectic solution, and these are frozen down by placing these elements in the domestic deep-freeze cabinet. Once frozen, they can be used in picnic baskets, etc., for the short-term s...

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... hygiene, or the cheese will be damaged. Some cheeses can be frozen for long-term storage, but must then be allowed to thaw out gradually and complete their ripening before release to the market. Other ... plate freezers. Health and safety requirements continue to become stricter in the maintenance of the cold chain and the latest regulations should be adhered to. 178 Refrigeration an...

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... are based on observed practice. The parameters are the size of the store, the enthalpy difference between inside and outside air, and the usage of the doors. The latter is affected by the existence ... capacity below freezing ∆T b = temperature decrease below freezing Some of these components will be zero if cooling does not take place through the range of temperatures above and below...

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... sides of the fan. Such treatment needs to be selected for the particular application regarding frequency of the generated noise and the degree of attenuation required, and competent suppliers ... connecting the inner and outer tappings to the ends of the manometer, the difference will be the velocity pressure. Figure 27.2 Vertical and inclined manometers Figure 27 .3 Pitot tube Sensi...

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... possible refrigerant leaks. Steam drives have also been used. The economics of the heat pump are dependent on the relative costs of the drive power and heat energy from other sources. In the UK, where ... in the UK at the present time is where air cooling is required in the summer and air heating from the same piece of equipment in the winter. The alternatives will be electric resista...

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