Energy Tech Laboratories Homes Northwest Users Manual ESHNW GSHP Supplemental SPECS_04 20 05
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ENERGY STAR® Homes Northwest
GEOTHERMAL HEAT PUMP
DESIGN AND INSTALLATION STANDARDS
April 20, 2005
ENERGY STAR Homes Northwest
Geothermal Heat Pump Design and Installation Standards
ENERGY STAR Homes Northwest
Geothermal Heat Pump
Design and Installation Standards
1.0 CLOSED LOOP GROUND HEAT EXCHANGERS................................................... 1
1.1 INSTALLATION PERSONNEL AND TRAINING REQUIRED. .................................................... 1
1.4. DESIGN METHODS AND COMPLIANCE................................................................................ 2
1.5 EQUIPMENT INSTALLATION................................................................................................ 2
1.6. GROUND HEAT EXCHANGER MATERIALS.......................................................................... 2
1.7 PIPE JOINING METHODS ...................................................................................................... 3
1.8 FLUSHING, PURGING, PRESSURE AND FLOW TESTING ....................................................... 3
1.9 PIPING ARRANGEMENT ....................................................................................................... 4
2.0 PIPE PLACEMENT AND BACKFILLING ................................................................. 4
2.1. HORIZONTAL SYSTEMS ...................................................................................................... 4
2.2 VERTICAL BORE HOLES. .................................................................................................... 4
3.0 INDOOR PIPING AND CIRCULATION SYSTEM.................................................... 5
3.1 CIRCULATOR SIZING AND SYSTEM AND COMPONENTS ..................................................... 5
3.2. ANTIFREEZE SELECTION AND USE. .................................................................................... 5
4.0 GROUND SOURCE HEAT PUMPS.............................................................................. 6
4.1 WATER SOURCE HEAT PUMPS............................................................................................ 6
4.2 HEAT PUMP PIPING AND MATERIALS. ................................................................................ 6
5.0 COMMISSIONING AND VERIFICATION FOR GROUND SOURCE HEAT
PUMPS.............................................................................................................................. 7
ENERGY STAR Homes Northwest
Geothermal Heat Pump Design and Installation Standards
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1.0 CLOSED LOOP GROUND HEAT EXCHANGERS
1.1 Installation Personnel and Training Required.
1.1.1 The loop contractor shall have a certified installer (technician) trained by
IGSHPA or an IGSHPA certified manufacturer's training program.
1.1.2 Ground heat exchanger fabricators shall have completed a heat fusion school
in which each participant has performed a heat fusion procedure under direct
supervision of an IGSHPA Association Certified Heat Fusion Technician or
DOT certified heat fusion technician.
1.1.3 Certified technicians shall attend a retraining school annually. A single
failure of a fusion joint will void the certification, and the technician shall be
retested to demonstrate satisfactory performance.
1.1.4 Local and State laws and ordinances as they pertain to buried pipe systems
shall be strictly followed, or the necessary variance obtained from the proper
jurisdiction.
1.2 System Sizing
1.2.1 The recommended method and form for heating and cooling load
calculations is available in the Air Conditioning Contractors of America
(ACCA) Manual J. This or an equivalent method shall be performed using
Component U-values and F-values in the heat loss and heat gain coefficients
that reflect the actual construction of the building. Heating loss calculations
shall be made using 70°F indoor design temperature. The recommended
ASHRAE winter design temperature and cooling design temperature for the
nearest weather station representative of the installation shall be used. Heat
pump system shall be sized to meet or exceed the heating design load of the
house. Installed auxiliary heating shall not exceed 150% of the heating
design load. All supplemental heaters greater than 5 kW shall be staged.
Sizing documentation shall be provided to the ENERGY STAR Homes
Northwest Verifier.
1.3 Thermostats
1.3.1 An electronic thermostat shall be installed to control the heating and cooling
system. Thermostats used for both heating and cooling shall have a manual
changeover feature or heating/cooling lockout to prevent cross-cycling
between heating and cooling.
1.3.2 Heat Pump Thermostat Capability: Heat pump thermostats shall have the
capability of supporting a lock out to limit supplemental heater use. The
thermostat shall have a minimum of two stage heating control.
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Geothermal Heat Pump Design and Installation Standards
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1.3.4 Thermostat Staging: Resistance electric heat shall not be energized under the
first heating stage of the indoor thermostat. Thermostat indicator lights shall
provide a visible indication when the auxiliary stage or emergency heat is
operating.
1.3.5 Emergency Heat Relay: All indoor thermostats shall include a manual
selector switch to permit all supplemental heaters to be energized under
control of the indoor thermostat (with the bypassed) when the compressor or
refrigerant system is inoperative.
1.4. Design Methods and Compliance
1.4.1 The manufacturer of GSHP equipment shall provide design standards for
minimum ground heat exchanger lengths.
1.4.2 The manufacturer's design procedure shall follow a recognized methodology
such as presented in:
1.4.2.1 Closed-Loop/Ground-Source Heat Pump Systems: Installation
Guide, GSHPA Publication, Oklahoma State University.
1.4.2.2 Data Design Manual for Closed-Loop/Ground-Source Heat Pump
Systems, ASHRAE.
1.4.3 The ground heat exchanger design shall be clearly documented as complying
with manufacturer's standards.
1.5 Equipment Installation
1.5.1 All equipment shall be located and installed according to manufacturer
specifications and guidelines, all applicable codes and standards, and
accepted industry practices.
1.6. Ground Heat Exchanger Materials
1.6.1 Acceptable pipe materials for the underground buried portion of the ground
heat exchanger are polyethylene and polybutylene.
1.6.2 The pipe and fittings of the buried system shall be warranted by the
manufacturer for ground source heat pump service.
1.6.3 Sufficient information shall be permanently marked on the length of the pipe
that allows the pipe to be properly identified.
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1.6.4 Specification of Polyethylene pipe will be by cell classification number. The
specification for PE pipe shall be as follows:
"Polyethylene pipe furnished under this specification shall be manufactured
in accordance with dimensional specifications of ASTM D-2513 or ASTM
F-714, as appropriate, using a resin having a cell classification of ######Z as
defined by ASTM D-3350. This resin shall exhibit not more than 20%
failures (F20%) when tested for 192 or more hours under ASTM D-1693,
Condition C.
1.6.5 The minimum cell classification number acceptable for polyethylene pipe is
PE3455434C or PE355434C when tested under ASTM D-3350.
1.6.6 The specification for PB pipe shall be as follows:
Polybutylene pipe furnished under this specification shall be manufactured in
accordance with ASTM Standard ASTM D-2581. The material shall be:
1.6.6.1 Either Class B (general purpose and dielectric, in colors) or Class C
(weather resistant, black in color containing not less than 2% carbon
black).
1.6.6.2. Type II (density, 0.91 to 0.92 g/cm).
1.6.6.3 Grade 1. (Low rate 0.25 to 0.75 g/10 min).
For fusible pipe, dimensional standards are given by ASTM D 2666 and
D3000.
1.7 Pipe Joining methods
1.7.1 The only acceptable method for joining buried pipe systems is by a heat
fusion process. No other method is acceptable.
1.7.2 For polyethylene pipe, butt fusion is recommended.
1.7.3 For polybutylene pipe, socket fusion is recommended.
1.8 Flushing, Purging, Pressure and Flow Testing
1.8.1 Vertical loops will be pressure tested before installation.
1.8.2 All horizontal components of the ground heat exchanger will be flushed,
pressure and flow tested prior to backfilling.
1.8.3 Heat exchangers will be tested hydrostatically at 150% of the pipe design
rating, or 300% of the system operating pressure if this value is the smaller of
the two.
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1.8.4 No visible leaks shall occur within a 30 minute period.
1.8.5 All fusion joints and loop lengths shall be visibly checked to verify that no
leaks have occurred due to fusion joining or shipping damage.
1.8.6 Flow rates will be compared to calculated values to assure that there is no
blockage or kinking of any pipe.
1.8.7 A minimum velocity of 2 ft/sec in each piping section shall be maintained for
a minimum of 15 minutes to remove all air.
1.9 Piping arrangement
1.9.1 All piping arrangements, including pipe diameters, header arrangements,
parallel and series loops, reverse returns, etc. shall conform to
manufacuturer’s recommendations and approved design criteria. Field
substitutions shall not be allowed without prior approval.
2.0 PIPE PLACEMENT AND BACKFILLING
2.1. Horizontal Systems
2.1.1 Sharp bending of pipe around trench corners shall be prevented by using a
shovel to round corners. Manufacturer's recommendations shall be followed.
2.1.2 Backfilling procedure will include prevention of any sharp-edged rocks from
coming into contact with the pipe by removal of the rocks before backfilling,
backfilling through a coarse screen for a 6 inch cover, or use a 6 inch cover
of sand. Clods resulting from use of a backhoe shall be broken up so air
pockets formed around the pipe will not reduce heat conduction between the
earth and the pipe. In some types of soils, wetting or flooding may be
required.
2.1.3 Horizontal return bends shall be backfilled by hand to properly support the
pipes and prevent kinking.
2.2 Vertical Bore Holes.
2.2.1 The dry section of a vertical bore holes shall be backfilled to ensure good
heat transfer. Local and State codes as to backfilling requirements shall be
followed. In some cases a bentonite grout/slurry will be required.
ENERGY STAR Homes Northwest
Geothermal Heat Pump Design and Installation Standards
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3.0 INDOOR PIPING AND CIRCULATION SYSTEM
3.1 Circulator Sizing and System and Components
3.1.1 The circulator wattage should not exceed 100 watts/ton. For circulation
systems with water control value does not apply. The use of water control
valves on closed loops is not recommended unless required by the
manufacturer.
3.1.2 Proper sizing of the circulating pump will be within the Heat Pump
Manufacturer's recommended flow rate for the specified unit.
3.1.3 Particulate contaminants shall be removed if they exist or could become a
problem for the circulation pump.
3.1.4 Pressurization of the circuit shall be to a minimum of 10 to 15 psi when
installed in the summer and 25 to 30 psi when installed in the winter.
3.1.5 The circulation system shall incorporate flow and temperature sensing for
testing the performance of the water side of the heat pump system. Pressure
and temperature sensing ports at the inlet and outlet of the heat pump water
heat exchanger are required, even if permanent sensors are also installed. The
sensing ports should be within two (2) feet of the heat pump, and should be
at the unit connections whenever possible.
3.1.6 Service valve handles should be removed and the port plugged.
3.1.7 Boiler type service valves are not recommended.
3.1.8 Garden type hose connections shall not be left on the circulation system.
3.1.9 Transition fitting shall be inside or accessible.
3.1.10 All indoor piping, including the heat pump water heat exchanger shall be
insulated to prevent condensation.
3.2. Antifreeze Selection and Use.
3.2.1 Manufacturer's recommended/required antifreeze solutions shall be stated
and meet Local and State requirements.
3.2.2 Acceptable circulation component material for the antifreeze specified shall
be given.
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3.2.3 Manufacturer shall provide a list of all known acceptable materials used in
the closed-loop circulation system. All metal parts contacting the circulating
fluid shall be defined in terms of metallurgical content.
3.2.4 Manufacturer's recommendations should be followed when charging an earth
loop with antifreeze.
3.2.5 In cases where the antifreeze is considered flammable, the antifreeze shall be
diluted with water to a point at which it is nonflammable before it can be
used indoors.
3.2.6 All systems shall be labeled and identified at the service ports. The labels
shall be of a permanent type with the following information:
3.2.6.1 Antifreeze type and concentration
3.2.6.2 Service-date.
3.2.6.3 Company name.
3.2.6.4 Company phone number and responsible party or person.
4.0 GROUND SOURCE HEAT PUMPS
4.1 Water Source Heat Pumps.
4.1.1 Water source heat pumps used in conjunction with ground heat exchangers
shall be certified by the respective manufacturer to operate satisfactorily at
the recommended maximum and minimum entering water temperatures as
set forth in the design of the ground heat exchanger.
4.1.2 The maximum and minimum design entering water temperatures shall not
exceed the manufacturer's published data.
4.1.3 The water source heat pump will be ARI certified under rating ARI 325 for
ground water heat pumps. For ground heat exchanger designed with EWT in
the heating mode of 60 degrees Fahrenheit or greater, ARI 320 is acceptable.
4.1.4 Maximum and minimum entering liquid temperatures will be determined by
the local ground temperatures and acceptable practice and within the
manufacturer's limits.
4.2 Heat Pump Piping and materials.
4.2.1 All indoor piping, including the heat pump water heat exchanger shall be
insulated to prevent condensation.
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Geothermal Heat Pump Design and Installation Standards
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5.0 COMMISSIONING AND VERIFICATION FOR GROUND SOURCE
HEAT PUMPS
5.1.1 Participating Installer shall refer to manufacturer’s guidelines during
installation and shall adhere to the manufactures start-up procedures. A copy
of the start-up procedure and results shall be submitted, along with the
factory performance data on the specified unit, to the verifier.
5.1.2 If not included in the start-up procedure, submission shall include
documentation of loop type and size, as well as steady-state run time
measurement of the ground loop pump amps, volts, and pump run-time
fraction (if it does not run continuously).
5.1.3 Measure airflow across across the unit’s coil to verify system meets design
criteria, per ENERGY STAR® Homes Northwest SPECIFICATIONS AND
TECHNICAL REFERENCE FOR SITE-BUILT SINGLE FAMILY HOMES
