Portal de Periódicos da CAPES

Riding in comfort : Part I

1999; Elsevier BV; Volume: 41; Issue: 8 Linguagem: Inglês

0001-2491

M. S. Bhatti,

Sports and Physical Education Studies

attention turned to comfort-cooling systems for mobile applications. In 1930, C&C Kelvinator outfitted a customized Cadillac owned by John Hamman Jr. of Houston, Texas with a 0.5 hp (0.37 kW) Kelvinator refrigeration unit powered by a 1.5 hp (1.1 kW) gasoline engine. Two flues on either side of the front seat took the air down to a fan, which circulated cool air throughout the passenger compartment. As seen in Figure 1, the unit looked like a trunk and fitted compactly on the back of the car.2 The development of the automotive air conditioner began in earnest in 1930 when General Motors Research Laboratories conceived the idea of the vapor compression system with R-12 refrigerant. On Sept. 23, 1932 a proposal was made to General Motors management to develop such a system. The Cadillac Division evinced interest in the proposal. However, it was not until the summer of 1933 that work started. The cooling capacity of the automotive air-conditioning system was determined to be 1 ton i.e., 200 Btu per minute. This estimate was half of the cooling capacity of the present system. There were two reasons for the lower estimate. First, the tests t the turn of the century, the only way to provide comfort cooling in an automobile was by ventilation. In the earlier days of motoring with open-body automobiles, no special provisions were required. This changed in 1908 with the gradual introduction of the closed-body automobiles. The only way to keep cool in a closed-body automobile prior to 1940 was to raise an adjustable windshield that opened vertically or to remove the side curtains. The opening of the windshield was restricted to about 0.5 in. (13 mm) so that the passenger compartment was sufficiently pressurized while minimizing infiltration of the hot air from the engine. Subsequently, windows could be cranked up and down for the desired airflow. Also, vents under the dashboard facilitated air circulation. Convertible tops permitted airflow upon being lowered. These ventilation systems were rudimentary, as they did not filter dirt, dust, pollen or insects from the air. Thus, the quality of the air circulating through the passenger compartment was poor. Beginning in 1940, there was a gradual acceptance of fresh air heaters. With this advance came an improved method of summer ventilation that was provided by cowl ventilator. Later, the car heater blower was used to increase ventilator airflow since the air inlet for the heater was located in the ventilation duct.