Types of Solar Hot Water Systems/ Solar Thermal Systems

The Differences are Measurable

There are different types of solar hot water systems for commercial and residential applications. Solar Hot Water Systems, also known as Solar Thermal Systems (STS) operate differently from photovoltaic (PV) systems. Solar thermal systems run water or fluid through their system. The solar panels are heated and the water running through them gets heated. The heated water is ready for use. In the case of fluid systems the heated fluid is used to heat water. . For more detail please see Understanding Solar. There are two types of solar thermal systems:

1. Active System- An active solar hot water system means there is a pump that circulates water through the system. Active hot water systems will reduce water heating costs by up to 90%. There are two types of Active Systems;
2. Direct Circulation Systems which are also known as Open Loop Active Systems. These systems pump water directly into the solar collectors and through the house. There are several advantages to these systems:

• They are good for environments like Florida where it rarely freezes.
• Usually the least expensive type of active system to install.
• Integrates easily with most existing systems
• It is easy to add capacity to system if needs change.
• System operates at standard line pressure
• Qualifies for 30% Federal Rebate
1. Indirect Circulation Systems also known as Closed Loop Active Systems- These systems require a heat exchanger and instead of moving water through the system like a direct circulation system, pumps circulate a heat transfer fluid, which in turn heats the water. In Florida, the typical use of an indirect circulation system is when there are multiple uses for the heated water, i.e. hot water, pool and spa heating.
1. Passive System- The passive solar hot water heating system does not use a pump and instead relies on convection to move water through the system. These systems can supply homes with 80-90% of their hot water use. They have the fastest payback of solar thermal systems, usually 3-5 years and are less expensive to install than active systems. While they are not usually as efficient as active systems, they can be more reliable and last longer. They will not reduce water heating costs as much as active systems, but they will reduce water heating by up to 75%. As with active solar systems there are 2 types of passive solar systems:
1. Integral collector also known as Storage Passage Systems
2.  Thermosyphon Systems

The advantages to passive thermal hot water systems include;

• Less expensive to install
• Quicker payback time
• Provides hot water during a power outage
• Easy retrofits
• Qualifies for 30% Federal Tax Rebate

If you are considering installing a solar hot water system, we will be happy to thoroughly go over all of the options available and help you figure out which is the best for you.