Automobile air conditioning

Automobile air conditioning Medical aerosols Industrial refrigeration... 

Automobile air conditioning R-12 SUVA 134a SUVA MP52 SUVA 134a... 

CFCs have been used widely in all kinds of cooling systems, including automobile air-conditioning systems. But for their atmospheric pollution problems, they are excellent refrigerants. 

CFC-12 (CCI,F,) -30 Domestic refrigeration, automobile air-conditioning, supermarket fresh food stores, industrial air conditioning, hot climate air-conditioning medical aerosols... 

RECEIVER DEHYDRATOR - Small tank which serves as liquid refrigerants reservoir and which also contains a desiccant so remove moisture. Used on most automobile air conditioning installations. 

Automotive air conditioning - The manufacturers of new automobiles have chosen HFC-134a as the fluid for air conditioning units, and retrofit kits are now available to allow older automobiles to convert to this alternative. 

Automotive air conditioning systems provide simple heating and cooling/dehuniidification functions. There is no provision for filtration of the air. All current automotive air conditioning utilizes vapor-compression refrigeration systems coupled to the automobile s engine. 

Direct current motors are most appropriately used in applications where a dc power supply is available or where a simple method of speed control is desired. The fans used in automobile heating and air conditioning systems are driven by direct-current motors. 

Today belts are used in automobiles to drive aux-iliaiy devices such as air conditioning, power brakes, power steering, the alternator, and the cooling fluid pump. Belts also can be found in household appliances such as vacuum sweepers, on lathes in machine shops, or inside copying machines. 

At issue is a group of man-made chemicals called chlorofluorocarbons (CFCs), which are used as the refrigeration fluids (Freon) in the air-conditioning and refrigeration units of automobiles, homes, and industry and which, in the past, were used as the pressure gas in spray cans of paint, deodorants, and so forth. There are a number of compounds containing... 

In a majority of buildings and nearly all residences, automobiles, and other forms of transportation, comfort cooling systems operate on command—that is, the air conditioner is on or off in obedience to the thermostat. Thus, the air conditioner starts and stops a number of limes during a 24-hour period. Studies have shown dial the performance of cooling equipment operates at highest efficiency when used continuously. It has been estimated by authorities that about 25% of tile total power consumption of an air-conditioning unit can be attributed to discontinuous operation. 

Sodium azide (NaN3) yields N2 gas when heated to 300° C, a reaction used in automobile air bags. If 1.00 mol of N2 has a volume of 47.0 L under the reaction conditions, how many liters of gas can be formed by heating 38.5 g of NaN3 The reaction is ... 

A typical countermeasure used by sleepy drivers is to turn on the air conditioner or open a window. Two aspects of this stimulus can be considered in analyzing it as a countermeasure. The first is the cold temperature of the stimulus, or in the least a change in temperature. There has been very little study of the effectiveness of cold temperature as a countermeasure. The simulated automobile drive study cited above also included a cold-air condition produced by the automobile air conditioner (22). As with the radio, cold air had a minimal and transitory alerting effect. The fact that temperature change may be the critical factor is seen in a study that showed heat (92°F) improved performance from basal levels during sleep deprivation, although the impact was very time-limited (24). 

The condenser on a certain automobile air conditioner is designed to remove 60,000 Btu/h from Freon 12 when the automobile is moving at 40 mi/h and the ambient temperature is 95°F. The Freon 12 temperature is 150°F under these conditions, and it may be assumed that the air-temperature rise across the exchanger is 10°F. The overall heat-transfer coefficient for the finned-tube heat exchanger under these conditions is 35 Btu/h ft2 - °F. If the overall heat-transfer coefficient varies as the seven-tenths power of velocity and air-mass flow varies directly as the velocity, plot the percentage reduction in performance of the condenser is a function of velocity between 10 and 40 mi/h. Assume that the Freon temperature remains constant at 150°F. 

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