Total Home Automation

GreenTip: Airflow - A Waste of Energy

The practical reality of every home, and the truth behind the challenge of energy efficiency, is that what a manufacture says savings will be, and what happens once something is installed are two different things.  Low refrigerant in home air conditioning systems and poor airflow are two big issues in home energy usage.

My house, as many homes do, uses the space between the floor to bring air back to the air handling system.  In 1960 it was a nice cheap and effective way to build a HVAC system.  With today's concerns about air quality and material out gassing, return air is brought through a duct system.

The contractors arrived today to remove my old air handling units, and install the rest of my geothermal.  They ripped out one of the current air handlers.

It did not take long to find the first issue.  The supply air duct which comes down to the back of the green air handlers (Silver duct to the left and behind in this picture). has an obstruction in floor joist area.

Looking up into the duct, that has been cut out, you can see another grey/silver duct running across above the vanes coming down.  This is hard to see, but essentially the duct blocks 80% or the return air flow.

 

These are 5 ton air handling units, so the blowers for 40 years have been operating with the added burden of drawing a lot of air through a space the faction of intended design.  You cn bitch and scream about the idiots who made the mistake, but this is not a surprising revelation.  These units for years have been running with a lot more load to attempt to make up the desired temperature in the zone.

When undertaking these kinds of projects it is super critical to have a contractor with the integrity to point these kinds of problems out.  It could have been real easy for them to have masked this issue and I would have been left wondering why I was not getting the right performance from my system.

Geothermal Project: What is going away....

Since I am replacing my heating and cooling system, all the interior air handling units need to be replace, along with the exterior compressors.  My current system is made up of 3 big old air handlers....

These units have heat exchangers in them fed by a boiler and outdoor air-conditioning units.  The Boiler feeds 5 units all together, these three green ones in the basement and two newer units in the attic.  The Boiler was built the year I was born and probably is only about 70% efficient if that.

The part my wife really likes is that all the outdoor compressor units go away.  With that goes the related noise.  These units are stacked in the back end of the house out of the way a bit from everything, but just below our bedroom window.

 

The green colored air handlers, boiler and out door compressor units are all being replace with the white unit shown in the picture (Note its size vs one of the old green colored air handlers).

 

The air handlers in the attic are modern variable speed units, so we are keeping them.  They also use the new 410A refrigerant systems, so we can install what is called a split system.  Essentially, the big white thing includes a compressor, ground loop water pump, and an air handler.  With a spit system, it deletes the air handler - passing hot and cold refrigerant to the air handlers in the attic.  We wanted to save space in the basement so we mounted them in a rack (I stole this idea from President Bush's ranch where he did the same thing for his Geothermal system).

Geothermal Project: Horizontal Boring is realy cool......

I placed the Geothermal wells in my lower driveway.  The primary feeders need to come up from the driveway, around the front of the house, and into a corner of the foundation.  Unfortunately we have some nice old trees in front of the house in the way of where the pipes needs to go underground. 

 

So, the contractor proposed something called horizontal boring.  With a horizontal bore, they can go under the trees, horizontally, without damaging the trees.  Not only can they go under, they can actually steer the bore left, right, up and down in various ways to dodge the foundation, water pipes, natural gas, etc.

The Horizontal Bore machine, made by Vermeer, is about 15 feet long by 4 feet.  Unlike a bore that uses a spinning bit, a horizontal bore essentially pushes through the ground using hydraulic force.  The end of the bore has a asymmetric wedge.  the wedge can be turned 90 degrees, more or less, to cause the bore to move left, right, up or down as it is pushed through the dirt.

 

A technician follows the bore head, as it moves through the dirt, with a hand held device (an advanced metal detector) that tells him how deep the bore head is, and its general location.  With that information, he helps the operator decided how to run the bore. 

 

The bore was pushed some 90 feet to a hole the contractor dug at a corner of our foundation.

 

Once the bore pushes through at the far end, they attach a cutting bit(About 6 inches in diameter) to the end.  The bit has a swivel, that is then attached to the pipes that needed to be pulled back through the hole.  The bore machine then rotates the bore and pulls the drill bit back through the hole, expanding its size from 3/4" to 6 inches, dragging the pipes along the way.

Geothermal Project: Connecting the Wells....

With the wells drilled, the next step is to link the wells through a "header pit", the bring the wells into the house.  Essentially the 20 wells are integrated into 2 supply lines and 2 return lines going into the house.  The back hoe dug 6 foot deep channels adjacent to each well, and toward the central location where the header pit will be placed.

 

With the channels cut in, the well pipes are laid down towards the header pit.

 

Each of the wells are integrated into the header pit into these long plastic pipes.  The end of the pipes feed into the set of 4 larger pipes that feed into the house systems.