At about mid-century, refrigerators were streamlined like automobiles on the outside, but inside they contained a freezer compartment no larger than a breadbox. It had to be defrosted of caked-up ice regularly and with no little mess left on the floor. Making ice cubes became trouble-free as the process became automated behind the freezer door. But even opening the door to retrieve some ice cubes was apparently seen by some inventor-engineer as something to improve upon, and the ice cube dispenser was introduced into the front of the door. Clearly, they can improve in the way items are stored inside, for it is certainly inconvenient to have to grope behind the turkey carcass to find the cranberry sauce for a late-night Thanksgiving snack.
Air conditioning works wonderfully when there are wonderful air conditions.
But when too many people crowd into a room on a hot and humid day, the room too often feels too crowded, too hot, and too humid. In such circumstances, the greatness of the engineering achievement might understandably be called into question. Air conditioning, perhaps the most unglamorous of achievements next to agricultural mechanization and codes and standards, seems also to be the most finicky. Well-controlled air conditioning, for all of the technological progress made in the field since air was fanned over a block of ice, seems to remain one of the great open problems of mechanical engineering. It should not be surprising to see comfort control among a list of great achievements of the 21st century.