值得注意的是，房间空调行业和塑料行业的增长模式相似。这两家公司成立于20世纪30年代初，都在20世纪50年代中期开始了一个充满活力的增长期，至今仍在继续。这种平行增长模式的结果是形成了一种独特的互动局面。为这两个行业提供了挑战和机遇。这一挑战要求开发新的塑料材料和工艺，以满足快速增长的房间空调行业的需求。技术进步是房间空调行业增长的一个主要因素。如今的产品重量更小，尺寸更小，外观和功能得到改善，可靠性更高，成本更低。例如，考虑到40年前由通用电气开发的一个非常早期的单元。 这是一台笨重的机器，重量超过400磅，完全由钢制成。今天建造的一个单元可以带回家，安装起来很方便。然而，直到最近，在传热、压缩机设计和气流技术方面取得了重大进展。塑料的广泛使用并不是一个主要因素，但在20世纪70年代，塑料将在空调设计中发挥重要作用。这些应用程序只是未来更动态概念的先驱。引文:研讨会，ASHRAE交易，第80卷，第2部分，蒙特利尔，QC

It is signific~nt to note that both the room air conditioner industry and the plasticsindustry have had similar patterns of growth. Both had their inception in the early 1930's.and both began a dynamic period of growth during the mid 1950's that still continues today.The result of this parallel pattern of growth has been a unique situation of interaction.providing challenges and opportunities for both industries. That challenge calls for thedevelopment of new plastic materials and processes to meet the needs of a rapidly growingroom air conditioner industry.Technical improvements have been a major factor in the growth of the room air conditionerindustry. Today's product has less weight, a smaller size, an improved appearance andfeatures, greater reliability, and lower cost. Consider, for example, a very early unitdeveloped by General Electric over 40 years ago. It was a large and bulky machine thatweighed over 400 lbs, and it was made entirely of steel. A unit built today can be carriedhome and easily installed. Until 'recently, however, the major advances have been made in theareas of heat transfer, compressor design, and air flow technology. The broad use of plasticshas not been a major contributing factor, but in the 1970's plastics will playa major role inair conditioner design. These applications are only the forerunner of more dynamic conceptsto come.