Monday, July 27, 2009

Hydronic installation

The image at right shows the hydronic heating components in the utility area near the house entrance. Not that the hot water tank also provides domestic hot water. The circuits are color coded for clarity. They are not exactly to scale, but give an idea of the space involved.

The following circuits are mounted on the wet wall. Cylindrical tanks represents expansion tanks. Long boxes represent circulation pumps.
  • Hydronic floor circuit: this circulates hot water through the pex tubing in the hydronic slab. Water enters and leaves the slab through a slab manifold. Hot water leaves the circulation tank at the top. A valve allows hot water to be drained from the circuit for domestic use (not shown). Cold water from the well reenters the system through a valve further on in the circuit, so water continuously gets pumped into the floor. It renters through the bottom of the tank to be reheated.
  • Solar loop: Heated antifreeze comes from the solar panels on the roof. It enters the heating exchanger coils in the bottom of the tank. It exits about halfway up the tank and flows back to the heating panels. A heat dump short-circuits this flow when the fluid entering the tank exceeds 160 F. This protexts the solar panels form overheating. The fluid is run through a copper coil buried under the house designed for this purpose.
  • Electric boiler: An electric boiler acts as a backup heating device for when there is not enough sun to supply the system. The heating contractor recommends a 13.5 kW boiler. The circuit feeds into a coil at the top of the water tank.

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