文档介绍：Section 2: Solar Water Heating
Systems focuses primarily on mon
solar system design types.
• Module: System Types describes and
illustrates the main types of solar water
heating systems, along with variations of
each type, as well as various freeze
protection strategies and designs.
• Module: ponents details
the ponents of solar water
heating systems and their individual
function.
System Types
Section 2
Module: System Types
I. System Types
This module describes the mon types of solar water heating systems. Factors
that influence the selection of a specific system type include the amount of water that
needs to be heated, relative cost and efficiency, simplicity of operation, and climate
conditions in which the system will be used.
Solar water heating systems fall into two general categories:
• active systems, which use a pump to control water flow, and
• passive systems, which use no pump.
Both active and passive systems can be either direct or indirect (Figure 1).
• In a direct system, the potable water circulates from the storage tank to the
collector and back to the storage tank. Thus, the heat collecting fluid is the
same potable water that is in the water heater.
• In an indirect system, the fluid that circulates through the collector may be
water or it may be another heat transfer fluid. This heat-collecting fluid never
comes in contact with the potable water in the storage tank. Instead, it
transfers heat to the potable water through a heat exchanger.
Figure 1 Direct and indirect solar water heating systems
Once again, there are two types of solar water heating systems – active and passive – and
each has two categories – direct and indirect.
Active Passive
Direct Direct
Indirect Indirect
2-1
System Types
The following pages will discuss the mon system types and their subcategories.
Several design variations exis