Alternate Energy Technologies EAGLESUN, Инструкция по установке, эксплуатации и обслуживанию

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DXR Drainback
Page 18
CLOSED LOOP FLUID HANDLING SYSTEM
In locations where there are more than 15 freezing nights per year, or where corrosion or mineral build-up is a
problem and pipes can be drained, an EagleSun drainback system is recommended. The drainback system provides
protection from freezing conditions, inhibiting corrosion and mineral buildup. The design of the system will aid in
controlling excessive temperatures which may occur due to a loss in power. Manual intervention is required as a
secondary precaution to protect components from freeze damage, when air temperatures fall below -60° F (-51.1°C).
The drainback tank is equipped with an immersed, single-wall, finned coil heat exchanger for the potable water
loop. The coil is designed to meet the requirements of the ASME pressure vessel code. The solar loop/drainback
tank is on the low pressure side of the heat exchanger which provides protection against fluid leaks into the potable
water system. This EagleSun drainback system is a two-pump system, incorporating a high head pump to provide
flow to the collectors while a secondary pump circulated potable water through the heat exchanger, transferring heat
to the water heater. When the collectors are at a higher temperature than the tank, the pumps are switched on. This
function is controlled by a differential temperature controller.
The solar loop plumbing requires no check valve to limit “reverse-thermosiphoning” of the solar loop. This prevents
the loss of thermal energy from the water heater when the system is not in operation and/or during the evening hours
when the tank temperature exceeds the outdoor ambient air temperature. Typical plumbing configurations are shown
in the diagrams at the end of this manual.
The drainback system is filled at atmospheric pressure and should not exceed the normal operating pressure of the
potable water system. The drainback tank is equipped with a 30 psi pressure relief, included to prevent excessive
pressure build-up in the system.
DO NOT PRESSURIZE THE DRAINBACK TANK! Pressurizing the solar
loop/drainback tank can cause damage to the system and void warranty coverage.
The water heater is to be UL listed for water heating applications. A 240 VAC, 4.5 kW backup element is provided
in the top of the tank to supply hot water during inclement weather and when the solar system is being serviced or
where solar contribution is low. A thermostat with reset is included to limit over-temperature conditions.
The water heater is equipped with a temperature and pressure relief valve to handle over-temperature and/or over-
pressure conditions. The R-Factor of the water heater is provided by the tank manufacturer. Refer to the
manufacturer’s documentation for specific instruction on the tank installation.
The following chart is used to approximate the performance of your solar water heating system, as-well-as, collector
fluid volumes and the recommended flow rate, design pressure and design temperature.
System Model
No
Collector
Model No
Collector
Qty
BTU's*
per Day
Collector
Fluid
Volume
(gal)
System
Flow Rate
(gpm)
System
Design
Pressure
(psig)
System
Design
Temp (°F)
DX-50-26 AE-26 1 26,000 0.90 1.25 < 30 < 250
MSC-26 1 26,000 0.90 1.25 < 30 < 250
DX-50-32 AE-32 1 32,000 1.05 1.25 < 30 < 250
MSC-32 1 32,000 1.05 1.25 < 30 < 250
*Btu’s are based on testing through SRCC for Category C, Clear Day (36°F) application.
Go to: http://www.aetsolar.com/certifications.shtml for more information.