Water Heating System Designs

At a glance..

This publication features an interview with Rob Harlan of Mendocino Solar Services on Solar Water Heating System Designs for domestic hot water, radiant floor heating, hot tubs, and pools — in any climate.

The details..

Solar-water heating systems got popular in the 1970s when tax credits were offered by state and federal programs. However, this movement slowed down after the tax credits ran out. In this book, Rob Harlan shares his experience of designing solar water heaters over the past 30 years.

The author discusses some flawed designs from long ago that lacked adequate protection against freezing or overheating. He also talks about how newer manufacturers have learned from these lessons to offer reliable products today.

The book covers basic parts of most solar water-heating systems such as collectors, storage tanks, heat transfer medium and interconnecting plumbing. It also explains terms used to describe these systems like active vs passive or open vs closed system.

Passive solar design requires little or no electricity to operate while an active system uses pumps to move heat around but is more expensive due to its reliance on electricity. The author recommends choosing a closed system over an open one if you live in areas with hard freezes since it offers better freezing protection.