Hydronic Heating

Common Solar Radiant System

At SteamBack Renewable Thermal we know how to harness the heat from the sun and integrate it into your home heating system.  If you do not have an opportunity to make your home a passive-solar home, our Solar Radiant systems are the next best choice for directly heating your home with solar energy.

The heart of any good Solar Radiant system is the collector.  We use only the SunEarth TRB Series.  They outperform all other collectors.  Below you can see an array of 6 mounted on the ground as opposed to the roof.

Good Picture

The above is a 1200 SF home near Ithaca, NY.  The heating system and domestic hot water are a single system.  The electric backup is integrated directly into the solar water tanks and itself (2x4500watt elements) can heat the building when no solar heat is available.

Solar Radiant Example

The customer also has a large Solar Electric array which accumulates enough credit over the year to essentially provide all of the backup electric heat necessary.  Essentially, this home is fully independent, except for the need for net-meetering.

It’s worth noting that if the grid disappears, then so does the effectiveness of the grid-tied solar electric and the ability to heat the building using that accumulated electric credit.  And, the house would freeze.

However, for the solar thermal system the total required electrical load to heat the building when sun is present and the grid is gone is a modest few hundred watts.  This can be supplied by a very small battery-based solar electric system.  And except for the coldest days of the year, such a system would on average be able to prevent the building from freezing for a day or two even without sun.

Below we list why our Solar Radiant systems are better…

  • Collectors
    • SunEarth TRB-32.  These feature blue-sputter coating on the absorber plate and are designed for commercial applications.
  • Solar Thermal System Design:
    • Either Drainback or Steamback.
      • Drainback preffered if scenario allows.
      • Steamback is backup type – 5 + years experience at Steamback Renewable Thermal.
  • Upgraded circulator pumps
    • Grundfos ALPHA
      • Low electricity consumption
      • Built-in flow meter
      • Built-in watt meter
  • Outdoor Reset Controls
    • Tank backup heating regulated by outdoor reset controls which make or break a line voltage connection to the tank electric elements.
      • Contactors used to interface outdoor reset with electric elements
  • Propylene Glycol Radiant Fluid
    • During an extended grid failure during a winter freeze condition the radiant loop will not be damaged.
  • Better Thermostat
    • Radiant simply cannot function well with an air-sensing only thermostat.  Our systems use baseline thermostats which are simple to operate and also control building temperature while considering floor temperature.
  • Heat Transfer Plates
    • Double-channel aluminum sheet plates from sheet material
      • Pros
        • Easiest way to cover entire floor area
        • Much lower cost than extruded product alternatives
        • 2x application of plates possible for same cost as extruded
        • Potentially better for spray foam applications
      • Cons
        • More difficult to transfer heat from PEX to plate
        • Less plate mass
  • PEX: Wirsbo HE-PEX
    • Semi-transparent
    • Best-in-class minimum bend radius
    • Easy to fix accidental kinks with an application of heat
  • Fittings
    • Extensive use of Pro-Press fittings on radiant loop and DHW side.  No use of Pro-Press on Solar Thermal side (all sweat).
  • Manifold
    • Use of only manifolds with integrated flow meters for each manifold loop.
  • Full use of insulation
    • On non-heating radiant PEX lines
    • On all non-essential solar thermal components




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