5
July 2020
1.3 SYSTEM PRINCIPLES
When the differential temperature controller
detects an adequate temperature difference
between the collector temperature sensor
“
T1
”
and the bottom tank temperature sensor
“
T2
”
the pump begins circulating the propylene
glycol heat transfer fluid (HTF) through the
system with the solar pump. HTF moves
through the collector and absorbs energy from
the sun, increasing the HTF temperature. The
heated HTF then moves through the heat
exchanger. the potable pump moves the heat
from the heat exchanger to the storage tank.
Hot water is then available for delivery.
This system
’
s solar loop contains pressurized
HTF which can protect your system at
temperatures up to –
60
degrees Fahrenheit.
This system should not be installed in any area
that has experienced ambient air temperatures
below
-
60°F. Use
Table 3.3.1
in section 4 to
determine the required concentration of
propylene glycol and distilled water to provide
adequate freeze protection in your specific
climate. HTF shall be used in this system as
the primary freeze protection agent.
Unauthorized fluid substitutions can result in a
threat to health, welfare and safety and may
cause the system piping to freeze.
When the system is operating, the pumps
should be on when the sun is shining and there
is an adequate temperature differential. The
pumps should be not be running at night or
when the solar tank has reached its default
maximum set point temperature T2 of 140
degrees Fahrenheit. The top of tank
temperature sensor T3 can be checked to
ensure your system has hot water ready for
use.
1. SYSTEM COMPONENTS AND PRINCIPLES
Notes:
•
Array piping sizes to be determined by the array size
•
The solar expansion tank size to be determined by the array size
•
A potable water expansion tank Should be sized per the solar storage volume and installed
on the cold water supply.
1
Figure 1.3.1: SolarStation HX Installation Diagram
*Piping connections for electric water heater shown
3
2
1
2
3
HOT TO FIXTURES
DRAIN TEE
COLD PORT TEE
SOLAR RETURN
SOLAR FEED
COLD INLET
3
