A portable water container which incorporates a solar heating panel. One wall of the portable container consists of an outer transparent/translucent panel and an inner heat-absorbing panel which is spaced from the outer panel. The inner panel may be ribbed or otherwise formed to improve heat-exchang...http://www.google.com.hk/patents/US4239032?utm_source=gb-gplus-share專利 US4239032 - Portable water carriers
