Comments on: Solar Heating System New PV Powered Differential Controller Boosts Performance

By: Voice0fEnergy

Voice0fEnergy — Thu, 28 Jan 2010 21:39:43 +0000

That is a very nice control and you have done an excellent job illustrating its installation. But it occurs to me you could eliminate the controller entirely.

Since you are using photovoltaic to drive the pump, there is no need to sense temperature because unless the PV is producing, the pump will be off. Likewise, when the sun is out, the motor will be operating. What could be simpler?

By: solaryes

solaryes — Thu, 28 Jan 2010 21:15:34 +0000

Yes – how we controlled Solartwin successfully for 7 yrs. But you must start the pump at over 10% sunlight, increase speed linearly with light levels and run it very slow, even in full sun, to minimise risk of heat export when the panel is cooler than the water feeding it. A controller removes these (OK) marginal constraints, allowing faster, nonlinear pumps starting at lower light levels only when the controller allows. Using the controller on Solartwin may give 1-10% more energy a year.

By: QVXS77

QVXS77 — Thu, 28 Jan 2010 20:35:53 +0000

scary

By: THECREEL

THECREEL — Thu, 28 Jan 2010 19:39:53 +0000

can you sell this unit to control a mains driven pump without the pvp.

By: solaryes

solaryes — Thu, 28 Jan 2010 19:28:02 +0000

Thanks. Low voltage DC powers the controller, and what the pump must run on. One can run most conventional solar heating systems with this, by getting rid of its 110-240V AC system. Change the power supply to a 30W photovoltaic (PV). Put it on the roof, close to and facing the same way as the thermal panel. Replace the pump with one with a brushless DC motor designed specifically to run on PV power, such as a Laing Ecocirc pump. We can supply the lot including controller (3 items) if needed.

By: solaryes

solaryes — Thu, 28 Jan 2010 19:15:51 +0000

Sorry but no it is low voltage DC not high voltage AC.