Solar Thermal Systems

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A combination solar pv and solar thermal
system for both hot water/radiant heat
and electrical power		 Solar Thermal Systems use infrared heat from the sun to heat a fluid such as water or glycol or a mix of the two. The heated fluid can then be used to heat potable water for domestic use or to provide heat for living space.McDonald Solar and Wind Inc. has the engineering background and installation expertise to work with you or your general contractor to come up with a heating solution for your application.

      
Types of systems: Solar thermal systems can be categorized by their function (Domestic Hot Water, radiant floor heat, forced air or Combi system), their system configuration (closed loop pressurized or drainback), or their components (flat plate or vacuum tube collectors). Let’s look at each of these classifications:

  1. Domestic Hot Water system: Perhaps the most cost effective and least expensive system to install in a residential situation is a solar thermal system for heating the Domestic Hot Water in the home. Typically, this type of system is relatively small, consisting of perhaps one or two solar collectors and a simplified pump system. The purpose of the solar collector loop is to provide  heated fluid to a heat transfer mechanism such as a heat exchanger to move solar heat into the Domestic Hot Water tank in the residence. A small solar thermal system can provide as much as 80% or more of a family’s Domestic Hot Water needs.
  2. Radiant Floor Heating System:  A radiant floor heating system is often used to provide residential heating. Another option which perhaps even more plentiful in the housing industry is forced air heating. Both of these systems can be implemented using solar thermal collector systems. Since the BTU requirement of a home heating system is higher than a Domestic Hot Water system, home heating systems tend to have more collectors than a Domestic Hot Water system. As an example, a 2000 square foot house might have 8 to 9 flat plate collectors or perhaps 6 evacuated tube collectors to provide heat to the home. Since the heating required by the home is often required when the sun is not shining (at night) the percentage of heating provided by a solar thermal radiant heating system will be less than that provided for domestic water use. A good design goal might be to provide 50% of the home’s radiant heating requirement as opposed to 70 to 80% of a family’s personal hot water.
  3. Forced air heating: While a radiant floor heating system uses solar heated or gas heated fluid to heat a space, a forced air application uses hot air to heat the air space in the home. In order to use solar thermal heated fluid to heat air for a forced air heating system, coils of tubing carrying the heated fluid are placed in the forced air path to pick up solar heat and route it to the living space.
  4. Combi-system: A combination Domestic Hot Water and radiant floor heating system uses the solar thermal array to provide heat for both the Domestic Hot Water and the space heating functions in the house. Typically, two circulation loops are involved, one to move BTUS into the Domestic Hot Water tank and the other to move heat into the radiant floor heating system.

McDonald Solar and Wind Inc. is a dealer for SunMaxx solar thermal products. Their product line, excellent support structure and robust warranties make SunMaxx products an outstanding choice for solar thermal applications.