David GarvinProduct Manager

EarthDirEX Geothermal

Copyright © 2015 Nortek Inc. All rights reserved.

Agenda

• Why EarthDirEX?• Challenges• Ground loops• Features• Charging

Why EarthDirEX?

• No outdoor unit• 30% Tax Credit (until Dec. 31, 2016) • Stable sub-surface temperature• Less maintenance

• No pump, no glycol and no outdoor coil, no fan motor

• Lower operating cost and installed cost• 60% Less drilling = lower cost boreholes

• Direct exchange ~80’/ton • Water source ~200’/ton

Definition - Challenges

• Direct Exchange -There’s no water, no pump, no refrigerant to water heat exchanger. All these items do is reduce system efficiency.

• Heat exchanger is in direct contact with the Earth. • But copper will corrode in the ground!• Less than 1% of the ground is corrosive to copper• Its illegal to bury refrigerant tubing!

• DOE/EPA approved direct exchange

EPA Letter

Earth Loop Sizing

• Two ways to size Earth Loop• use the climate zone map• use the formula below

• Cooling load ÷ heating load =• less than 1, then use 65' per ton• between 1 and 1.75, then use 80' per ton• greater than 1.75, then use 100' per ton

Sizing is 65, 80 or 100 feet per ton depending on the climate zone

65 ft/ton

80 ft/ton

100 ft/ton

Sizing Earth loops

ft/ton 65 80 100 65 80 1002 130 160 200 2 130 165 2003 195 240 300 3 200 250 3254 260 320 400 4 280 325 4005 325 400 500 5 325 400 2/250

12 possible 7 unique to build

Earth Loops

Earth Loops

Earth Loop

Some Earth Loop Details

• Watch out for corrosive ground • Stay away from a ph below 5.5 or over 11

• All liquid lines are ½ inch • Encased in a 1 inch plastic pipe• A vacuum must be pulled before backfilling

• 2 vapor lines are used in the Earth loop • Coming out of the Earth loop is one vapor line

• Up to 250 foot loops are ¾ inch vapor line• Over 250 foot loops are 7/8 inch vapor line

More Earth Loop Details

• The liquid line and the vapor line from the Earth loop to the compressor unit should be buried the deeper of 1.5 feet or below the maximum frost line

• Must insulate both lines from the top of the Earth loop to the compressor section with heavy duty ¾ inch closed cell insulation, capable of withstand 220°f degree

Features

• One bi-directional EXV in compressor section

• Interface control board• Oil separator• Accumulator with sight glass & float

ball for charging• Earth loop seal valve

Efficiency and capacities

Cooling Capacity EER

Heating Capacity COP

2 ton 29400 23.8 21000 4.2

3 ton 42000 21.3 35200 4.1

4 ton 57000 20.1 46500 4.2

5 ton 71000 19.3 58000 3.9

Match ups

Compressor Section

Air Handler

Y1SA-024 B6EMMN036K-B

Y1SA-036 B6EMMN036K-B

Y1SA-048 B6EMMN060K-C

Y1SA-060 B6EMMN060K-C

Refrigerant Charging

Start In Heating Mode & Charge To Sight Glass• let system operate 15 min• check sight glass, add R410A• when the ball is floating in the middle - done

Oil Separator

• Temprite coalescent filters will pick up all dirt and particulates down to 0.3 microns

• Typical filter/driers only catch 50 microns or larger

• A second filter (shipped with the unit) is to be used as a replacement in 24 to 48 hours (no more then 5 psi drop)

Heating To Cooling Transition

• The compressor section includes a hot gas valve• After heating cycle, the earth loop temperature is low

– it was just operation as the evaporator

• In cooling the refrigerant returning to the compressor section could be two phase (flashing)

• In cooling mode after 3 minutes of operation, if the suction pressure drops below 95 psig (29°F), a hot gas solenoid valve opens for 10 seconds every 3 min.

– Compressor discharge gas is injected into the outlet of the EXV in the compressor box

• This process will repeat until the suction pressure is above 95 psig

• If after 60 hot gas injections, the suction pressure is still below 95 psig, the system will go into soft lock out for 60 minutes

Well Seal Valve

• In 4 and 5 ton systems, the compressor section is equipped with a earth loop seal valve assembly to keep the refrigerant in the earth loop during the off cycle

• The assembly consists of a vapor line solenoid valve and a check valve for cooling mode

• The solenoid valve is opened during heating mode operation• The purpose of this assembly is to:

– Minimize the chance of refrigerant leaking indoors during the off cycle– Minimize the chance of leaking a large amount of refrigerant

Nortek Global HVAC is a subsidiary of Nortek Inc. © 2015 Nortek Inc., All Rights Reserved.

Questions?