Heat emitters play a key role in sustainable performance.
I began working in the renewable energy field in 1978 as an applications engineer for Revere Solar & Architectural Products in Rome, N.Y. At the time, Revere was one of the largest U.S. producers of flat plate solar collectors. Those collectors were sold as part of solar domestic water heating systems, as well as for “combisystems” that provided both domestic water heating and some limited amount of space heating.
In those “early days,” solar heating essentially boiled down to using solar collectors as the sunny day substitute for conventional boilers or water heaters. Designers focused on the collectors, storage and control aspects of the solar subsystem, but devoted little time to developing compatible means for distributing that solar-derived energy within the building to be heated.
The hydronic distribution systems of that era were designed around relatively high supply water temperatures. Most residential systems used common fin-tube baseboard to release heat from water sent through the piping circuits at temperatures sometimes exceeding 200ºF.
Many designers of that era discovered the relatively high water temperatures required by conventional space heating distribution systems were beyond what solar collectors could consistently produce. Sure, there was an occasional “perfect solar day” in December or January when the storage tank did get hot enough to supply the home’s heating load during the following night. But the average system performance over a typical northern heating season was often disappointing. In short, after owners invested thousands of dollars in collectors, storage tanks and other hardware, many of these early systems spent much of their time distributing heat generated by conventional fuels rather than by the sun.