Energy Matters Forums

[Ozpete]

Hi all, just contemplating a hybrid system consisting of a heat pump HWS and flat plate or evacuated tube solar collectors feeding the heat pump (like a convention solar HWS). Do heat pumps have this ability? Almost free hot water in summer and cheaper hot water in winter. Could this be done???

[Gordon-Loomberah]

Evacuated tubes are more efficient than flat plate, and there is no reason you couldn't have a collector feeding a tank that has a heat pump for boosting when required.
I've thought about adding another tank with a bolt on HP to my system, but it's well beyond my budget for now. If you already have a tank, a bolt-on HP is the best way to go, IMO.

Depending on location and HW demand profile, a suitably sized evacuated tube system can supply your hot water for 350+ days per year without boosting in sunny areas, so the expense of a HP may not be justified. If you have very cloudy weather, then a HP is well worth it. I think Nambucca is reasonably sunny, so just an electric boost may be more cost effective.

[Ozpete]

Hi Gordon, thanks for the fast response. Yeah we have very similar weather to you mate probably just more humid here on the coast.

[Gordon-Loomberah]

In town the annual average is 4.9kWh/m^2/day, and I'd be a fraction under that up here in the hills, so only a bit sunnier than you at 4.5.

See here for Nambucca Heads data: http://www.energymatters.com.au/solar-l ... eads-2448/
or search for any other location.