Current house: Difference between revisions

Revision as of 21:31, 30 June 2019

We purchased our new home after Christmas 2017 and started an ambitious remodel, completely gutting the basement to add a second master space and create a Data Center. We also elected to covert it to 100% geothermal heating and air-conditioning and install tankless hot water (to supplement the "free" geothermal hot water). geothermal is dedicated to the geothermal installation process and results.

Addition

Basement Remodel

Geothermal Installation

In 2017 there was still a 30% Federal tax credit for residential geothermal installations, and since we bought a big house with HVAC units right at the edge of their life expectancy my (accountant) wife talked me into replacing everything with geo.

We opted for the Climate Master Trilogy (Heat/AC/Hot Water) systems, a pair of 4 ton units, and a 3 ton split system for the upstairs - that's because there was no good way to get the geo piping up there, so we installed the heat exchanger/heat pump downstairs and reused the line set for the old AC system to take geo cooled refridgerant upstairs to a more traditional space pack, which has gas back-up heat.

We chose Gallagher/Hauser HVAC to do our installation, as the local company with the most experience. Their work has been technically quite good, but their customer service (for us) has been abysmal from start-to-finish, with scope creepy, cost overruns, and schedule delays at every turn so I would not recommend to anyone. For the kind of money we spent with them it's shocking how little regard they gave even the simplest requests.

The geothermal installation was really interesting to watch. First Jackson drilling showed up and installed 8 wells, each 300' deep. Each well provides 2 tons of heating/cooling capacity, through it's 600' of 1" PVC tubing, and there were two well fields installed in a line below our driveway to provide 8 tons each. The wells are 20' apart to allow them enough ground to extract heat from. The tubing was premade with a 'U' shaped connection at the tip. I think the holes are 3" in diameter, and the tubing is encased in Benseal (a bentonite mixture for casing the well) for heat dispersal. They liked drilling at our house because the asphalt made the process really clean for them, they could easily rack the tailing from the drill away and they had a nice solid base for thier rig, and since we have mostly shale and sandstone they were going through a 20' section of drilling pipe about every 2 minutes, or a well about every half hour. They made quite a mess, but the drilling was done in a couple of days. Or, rather, it would've been if they didn't break the bit on the next to last hole - and they didn't have a spare on this rig.

Drilling

1" PVC tubing
Setting up the drilling rig
The drilling started around my birthday and made quite a mess... I didn't like that, so Elizabeth got me a cake to ease the blow
The front wall by shower where the well field will enter the house
Tubing will route through here
Drilling
Sweeping the tailings away
Tubing installed
Adjacent wells
Bentonite has been pumped in
The white tube was used to feed bentonite
The last well on this field - this one is next to the gas line (but we didnt' know it)!
They typically use this pan for tailings, but didn't need to here
U bend at tip of tubing
610' of tubing per well (in a 'U')
The business end
Starting the second field
Benseal Bentonite
Benseal Bentonite

These were connected via a trench about 3' deep (pretty close to the frost line here in Cincinnati) manifold system so the could equalize the flow to each well in parallel and bring the cooling fluid (a mixture of glycol) into the house. The soutern field's last well was drilled without a boot's width of an unknown (and thus not marked by the utiltiy protection folks) of our neighbors gas line - which the ripped out while trenching. One field runs to the south end of the house into the front utility space and provides 3 tons of cooling for the front of the house through a Trilogy 45 unit service the the front of the basement and first floor, and a 4 ton split unit that feeds cooled fluid to a standand line set to the otherwise conventional HVAC unit for the second floor. The front Trilogy has cooling dampers and thermostats for the following zones.

Basement Office
First Floor Dining Room

The northern well field comes into the house in the full bath and routes up the wall and into the ceiling to reach the rear utility space where there is a 4 ton Trilogy 45 system for the back of the house - basement and first floor. In the ceiling is a T for the 3 ton HVAC unit for the addition. 1 Ton of excess capacity was planned. The rear Trilogy has cooling dampers and thermostats for the following zones.

Basement Master Bedroom
Basement Family Room
First Floor Master Bedroom
First Floor Family Room

Well Fields

The southern trench
Wells complete and trenching
The northern trench
Connecting the wells into a field
Pressure testing the tubing

Each of the 2 Trilogy units gets added efficiency by using some of the excess heat from the heat pump and well system to heat hot water for the house as well. This makes it the most efficient unit you can get in the United States. We will use this hot water as preheat to a system of tankless (Navien) hot water heaters that can provide endless full-flow hot water, and the electric backup heat in the Trilogy tanks will be deactivated.

Heat Pump Installation