2 – EnerWorks Solar Water Heating Appliance
The EnerWorks Solar Water Heating Appliance has four main parts – the solar collectors, the line-set,
the Energy Station and the solar storage tank.
The Energy Station uses a pump to circulate a heat-transfer fluid through the “collector loop”. This
collector loop includes the solar collectors, the fluid lines or “line-set” and a heat exchanger. The
collector loop is a “closed loop”, meaning there is no contact of the heat transfer fluid with your potable
water or with the atmosphere. The collector loop contains only a small volume of heat-transfer fluid
which is freeze-protected. Though freeze protection may not be necessary in all areas, the heat-transfer
fluid also has an elevated boiling point and so is suitable throughout North America.
When exposed to sunlight, the solar collectors get hot. Passive overheat-protection prevents
temperature exceeding 275°F (135°C); pressure and flow conditions depends on the system. As the
heat-transfer fluid passes through the collectors, it absorbs heat and then travels down the line-set to
the Energy Station. The hot fluid passes through the heat exchanger and heat is transferred to the
potable water. After giving up its heat to the potable water, the cool heat-transfer fluid is pumped back
to the solar collectors to be heated again. Hot potable water is stored in the solar storage tank.
In the Pre-Heat Solar Water Heating Appliance (Fig. 2.2), the solar storage tank is a standard, North
American, electric hot-water tank. No power is connected to this tank – it only stores solar-heated water.
The solar storage tank is plumbed in series with the original water-heater (electric, fossil fuel, or on-
demand). Whenever hot water is used in the home, solar heated water leaves the solar storage tank
and enters the original water-heater. The original water-heater now requires much less energy for water
heating.
Thus, the Appliance displaces energy, but it does not replace the original water-heater. The original
heater guarantees hot water even under poor solar conditions (at night or when very cloudy). It also
ensures that hot water is stored or supplied at an appropriate temperature to kill harmful bacteria. The
acceptable temperature set-point is specified in local plumbing codes. Do not turn off or bypass the
back-up water-heater. Even in summer months, additional heat from the back-up heater may be
required.
The Single Tank Solar Water Heating Appliance (Fig. 2.3) incorporates solar water-heating and
auxiliary water-heating in a single tank. The Single Tank Appliance is the solar solution for homes (in the
United States) that cannot accommodate two tanks. For more information on Appliance components
and function, please see the Owner Manual.
2.1 Description
Solar Collector
Installation Manual
4
Module 4
Summary of Contents for EWRA1
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