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Other Pic Pages: Foundation - Radiant Slab - Geothermal Loop - Wood Framing - Mechanical Systems - Equipment Room - Monitoring - Interior Trim - Exterior Trim

Construction Timeline: (Geothermal Equipment Room)
Here's the stuff I've been waiting for: The plumbing, pumps, compressors and fans that go together to heat and cool our house. (2/12/2003 - 3/12/2003)  

NOTE: Newest pictures at the top.
Click on any image for an enlargement. 

Here's the system diagram for my HVAC system.   See the LIVE data here!!!
(Read the system description on the HVAC Page). 
All this stuff (with the exception of the actual ground loop) is installed in the Equipment Room, located in the back corner of the house.
Ground Source Heat Pump diagram (geothermal)
March 2, 2003.  The HVAC equipment is nearly all in, and we're trying to schedule the start-up.  Too bad that 22" of snow turned into the Blizzard of '03 with 52" of snow in 3 days.
Here's a neat shot of the Radiant Heat side of the system.  Hot water from the DHW tank (see below)  feeds the Heat exchanger (a) on the left.  This heats the circulating slab loop water.  This heated water feeds the 4 zone pumps (c) via a mixing valve (b) to limit the thermal shock to the slab.  Water flows past the Temp gauge (d) and through the one way valve (e), past the air bleed (f) and down to the hot water manifold (g) for Zone # 3.  Returning cool water is collected by the cold water manifold (h), flows past the expansion tank (i) and back into the heat exchanger.  The makeup valve(j) ensures that the loops are always pressurized.  You can also follow the flow for the 3 other zones.  The zone pumps (circulators) are switched on/off by the relays in the zone controller (k).

The large 80 Gal tank (left) is used to store domestic  hot water (DHW).  It is kept hot by the 34,000 BTU water-water GSHP.

Water from this tank is circulated through the small heat exchanger (see "A" above) by the small bronze pump that can be seen just above the large tank (on the left hand pipe).

This configuration keeps the domestic hot water separate from the radiant slab fluid, which can then contain an additive to prevent freezing.

This is the radiant slab circulator control unit.  As each zone thermostat calls for heat, the appropriate relay energizes and sends 110v to the circulator pump.  When any zone is activated, a separate relay closes which energizes the circulator pump on the DHW side of the flat plate heat exchanger.

Oh Look. A Pressure tank. This is needed with any domestic water system that's fed from a well. 

The tank is pressurized by the well pump and can maintain water pressure once the pump turns off.

It's effectively a water buffer, and pressure stabilizer.

This is the "Works" of the water-water heat pump.  It actually looks pretty simple, and that's because in essence it's really only a compressor, and a pair of heat exchangers. The heat exchangers are on each side and they are wrapped with insulating foam rubber. 

Here's the water-water heat pump electrical works.  Once again there are very few parts.  A simple controller board, some pressure switches and a power transformer.

When the thermostat calls for hot water, this unit sends a Slave signal to the Water-Air unit to turns on the Ground Loop circulators.  In addition, it turns on a separate circulator to send the generated hot water into the DHW storage tank.


While the W-W unit looks simple, the Water-Air unit looks extremely complicated.

I imagine this is because this unit also has the variable speed DC brushless fan motor which requires it's own set or electronics and wiring.

In addition, this unit has two stages of heating, and two stages of cooling, so the switchover between these 4 modes required additional control.

February 12, 2003.  The HVAC equipment installation begins in earnest.  All these photos are taken in the Equipment Room.  The two interior walls are sheathed in Sheet rock, the tow exterior walls are sheathed in Plywood.

Dan and Gary return to complete the job of installing the HVAC system (with a short break for a predicted 18" Snowstorm :)
The Water/Air Heat Pump from WaterFurnace gets mounted below the ductwork termination.

More of that cool insulated ductwork is used to complete the air circuit.  The smaller box on the floor in the foreground is the WaterFurnace water/water heat pump used to generate the hot water for DHW and the Radiant Slab. The box mounted on the wall is the Heat Recovery Ventilator. It's not plumbed into the ductwork yet.

Here you can see the ground loop being split between the two Heat Pumps.  The unit on the left is Water-Air, the unit on the right is Water-Water.  Each section of the loop has a pair of shut-off valves (white with red handles).

Oops, spilled a bit of water hooking it up.  I think I should have sealed the floor before they started adding equipment.

Other Pic Pages: Foundation - Radiant Slab - Geothermal Loop - Wood Framing - Mechanical Systems - Equipment Room - Monitoring - Interior Trim - Exterior Trim

© 2000-2018, Phil and Lisa's relaxed lifestyle home.
An exercise in Energy Smart, Not So Big living. -


This site is all about building a cool, energy efficient house, that makes maximum use of earth sheltered design, passive solar heating and cooling, geothermal exchange energy management, and right sizing of the house for it's designated use. The home's placement is on a south-facing hillside in Deep Creek Lake, Maryland. This site describes the design process, the technologies used and the expected results. We also have a comprehensive Links Page for anyone who is also interested in designing a similar project.