EcoSolar Energy Conscious Design Limited
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Pumped Systems
In addition to the control requirements of the thermosyphon systems, pumped solar systems also
need a differential temperature controller to only turn on the circulating pump when there is heat to
be recovered from the collector, i.e. when the water temperature in the collector is warmer than that
of the water in the bottom of the cylinder.
Figure 20. Closed loop solar system showing the placement of the temperature sensors, T1, T2 and
T3, in the top of the collector, bottom and top of the cylinder respectively.
Temperature sensor installation
Temperature sensors should be installed such that they monitor the water temperature and are not
influenced too greatly by their surroundings. Sensors are often installed in dry pockets and attached
to the surface of the actual water cylinder vessel. A heat transfer paste should be used to improve
heat transfer between the surface being measured and the temperature sensor. The sensor should
also be adequately insulated from the ambient conditions.
Variable speed drives
The EcoSolar ESR21D and UVR61R3 controllers both come standard with a variable speed drive.
Utilising this speed drive will considerably increase the system performance and its reliability.
