Solar Hot Water Systems-Prof Edition

Solar Hot Water Systems
1977 to Today - Lessons Learned
Professional Edition
by Tom Lane

     Just before and during the Carter-implemented 40% solar tax credit era (1977-1986), a wide menagerie of solar water heating equipment and system designs were introduced. Often, both homeowners and contractors were guinea pigs. Large corporations such as Northrup, Olin Brass, Exxon, Sears, Lennox, Grumman, General Electric, Reynolds Aluminum, Ramada, Owens Corning, Revere Copper and Brass, along with smaller companies introduced, systems to the market place. Many of these corporation systems suffered from major design flaws, were overly complex, or very expensive. Less than 1 % of these systems were still operational by the year 2000. However, basic designs, pioneered by smaller companies such as Solar Energy Products, Colt Morningstar, Gulf Thermal, Solar Development Inc., Pulstar Corp., and US Solar Corp. were a proven success when installed by factory trained contractors. These systems did have a few component failures, especially with early differential controllers and sensors. Today, 80% of these closed loop glycol and drainback systems are still operational where contractors are available to service and maintain them. After the tax credit era these systems typically saved $6000 to $10,000 in nontaxable income over the first 20 years.

     Few government energy agencies or mechanical engineering departments as of 2001 are cognizant about what was successful during this era. The Florida Solar Energy Center (FSEC) has had some brilliant test programs developed by Charles Cromer and surveys by Tim Merringan. However, little practical experience with closed loop systems was recorded by FSEC. This is understandable since 98% of the state's solar contractors were located in central and south Florida and used open loop systems. Most of the university and academic papers presented at solar conferences and seminars, other than the Charles Cromer research work previously mentioned, have missed the point. The research has had no useful connection to the real world of solar contracting with currently available products that really work, and will serve the homeowner well. The small details gained from experience over the years make the real difference between a successful installation and a fiasco or "Sunburn" fostered on trusting homeowners. Hopefully, this book will help those who want to use currently available products with success and to avoid mistakes of the past.

     The Professional Edition contains a number of charts and diagrams reproduced in crisp clear full color. This material is inserted at strategic points throughout the book. They say, "a picture is worth a thousand words" and nowhere is this more true than when explaining the structure and functioning of solar water heating systems and their components where subtle differences can greatly effect performance. The Homeowner's Edition has all the diagrams you'll ever need in black and white.

Click on the images below to see enlargements.

Typical Diagram