Enertech ZS., Руководство по установке и эксплуатации, Страница: 28 / 89

28 Enertech Global IOM, ZS/ZT Models
Interior Piping
All interior piping must be sized for proper flow
rates and pressure loss. Insulation should be
used on all inside piping when minimum loop
temperatures are expected to be less than
50°F. Use the table below for insulation sizes with
different pipe sizes. All pipe insulation should
be a closed cell and have a minimum wall
thickness of 3/8”. All piping insulation should
be glued and sealed to prevent condensation
and dripping. Interior piping may consist of the
following materials: HDPE, copper, brass, or
rubber hose (hose kit only).
Note: PVC is not allowed on pressurized
systems.
Water Quality
The quality of the water used in geothermal
systems is very important. In closed loop systems
the dilution water (water mixed with antifreeze)
must be of high quality to ensure adequate
corrosion protection. Water of poor quality
contains ions that make the fluid “hard” and
corrosive. Calcium and magnesium hardness
ions build up as scale on the walls of the system
and reduce heat transfer. These ions may also
react with the corrosion inhibitors in glycol based
heat transfer fluids, causing them to precipitate
out of solution and rendering the inhibitors
ineffective in protecting against corrosion. In
addition, high concentrations of corrosive ions,
such as chloride and sulfate, will eat through any
protective layer that the corrosion inhibitors form
on the walls of the system.
Ideally, de-ionized water should be used for
dilution with antifreeze solutions since de-
ionizing removes both corrosive and hardness
ions. Distilled water and zeolite softened water
are also acceptable. Softened water, although
free of hardness ions, may actually have
increased concentrations of corrosive ions and,
therefore, its quality must be monitored. It is
recommended that dilution water contain less
than 100 PPM calcium carbonate or less than
25 PPM calcium plus magnesium ions; and less
than 25 PPM chloride or sulfate ions.
In an open loop system the water quality is
of no less importance. Due to the inherent
variation of the supply water, it should be tested
prior to making the decision to use an open
loop system. Scaling of the heat exchanger
and corrosion of the internal parts are two of
the potential problems. The Department of
Natural Resources or your local municipality
can direct you to the proper testing agency.
Table 2: Water Quality
SECTION 5: UNIT PIPING INSTALLATION
Potential
Problem Chemical(s) or
Condition
Range for Copper
Heat Exchangers
Range for Cupro-Nickel
Heat Exchangers
Range for Stainless Steel BPHE
Calcium & Magnesium Less than 350 ppm Less than 350 ppm Less than 0.1 ppm
pH Range 7 - 9 5 - 9 7 - 9
Total Dissolved Solids Less than 1000 ppm Less than 1500 ppm No rigid setpoint
Ammonia, Ammonium Hydroxide Less than 0.5 ppm Less than 0.5 ppm No Limit
Ammonium Chloride, Ammonium Less than 0.5 ppm Less than 0.5 ppm Less than 2-20 ppm
Calcium Chloride / Sodium Less than 125 ppm Less than 125 ppm Not Allowed
Chlorine Less than 0.5 ppm Less than 0.5 ppm Not Allowed
Hydrogen Sulfide None Allowed None Allowed Less than 0.05 ppm
Iron Bacteria None Allowed None Allowed Not Allowed
Iron Oxide Less than 1 ppm Less than 1 ppm Less than 0.2 ppm
Suspended Solids Less than 10 ppm Less than 10 ppm 16-20 mesh strainer recommended
Water Velocity
Less than 8*/s
Less than 12 ft/s Less than 5.5 m/s in the port
1. Hardness in ppm is equivalent to hardness in mg/l.Notes
2. Grains/gallon = ppm divided by 17.1.
4. Saltwater applications (approx. 25,000 ppm) require secondary heat exchangers due to copper piping between the heat exchanger.
5. Filter for maximum of 600 micron size.
Scaling
Corrosion
Biological
Erosion
3. Unit internal heat exchangers are not recommended for pool applications or water outside the range of the table. Secondary heat
exchangers are required for pool or other applications not meeting the requirements shown above.