Heat Pump hot water

[Newcastle George]

Dave, we currently pay just 11.27c/kwh for our off peak heating, the reason we have not looked to change. Our last August bill (winter) was $182

George

[T1 Terry]

Peter, as we are currently sending excess solar to the grid every day at just 7c/kwh and mid winter our off peak hws used approx 9kwh/day, would that solar assist the heat pump if a timer was included so that it would heat during the day?

George

Dave, we currently pay just 11.27c/kwh for our off peak heating, the reason we have not looked to change. Our last August bill (winter) was $182

George

So, you sell the excess solar for 7c and buy it back for 11.27c and you consider this to be a good deal? Just buy another off peak water heater, send the excess solar to the hot water element and the off peak only needs to heat the last few degrees till it switches off via the thermostat. That way, you are 4.27c per kwh ahead of the game.
The heat pump hot water systems, ok if the ambient temperature never drops below around 7*c, but they are noisy and short lived, the compressor unit is not easy to swap out so the thing has to be replaced and unless it's still under warranty when it dies, the replacement isn't free ......
We had an evacuated tube type solar water heater and bought a second tank that could circulate the heated water to get the best out of the solar set up. It had a bung in the bottom that we removed and replaced with an electric element so if the conditions were bad we could heat the water electrically. We brought this system with us to SA but unfortunately it was still upstairs and lost in the fire, it would have been brilliant to couple with our off grid system.

T1 Terry

[dream4red]

George, if I had my choice of all the current systems, it would be an instantaneous gas heater. It only heats what you need and never runs cold.

We have the system of evacuated tubes up on our roof, with a big storage tank that only heats over night, when needed. I dread the day when it wears out. Was made by the Hills company, which has stopped making them totally.

Ok to get the freeby one, but you have now been able to choose with an edumicated guess instead of just being guided by the initial price.

Good luck deciding which way to go.

[Newcastle George]

Deb, luckily, we don't have gas connected to our property, don't need an extra bill.

George

[T1 Terry]

Here is link from another forum where they are discussing heatpump water heaters https://forums.aeva.asn.au/viewtopic.php?t=6148 Brand seems to be important along with capacity ... keep in mind there is both a lower ambient temp and an upper ambient temp .....
For my money, I'd go for the tank and add the heater element using the voltage that suits your set up, then buy cheap panels from solar systems that have been upgraded and use that to power the water heater, along with the excess solar if needed .....

T1 Terry

[Newcastle George]

We have decided to go ahead with the 215litre Heat Pump hws (total cost $33 including disposal of old system) and installation is scheduled for 3/8/23 due to us being in QLD for most of July. Operation timer can be adjusted to daytime so that our existing solar can provide necessary power.

George

[Newcastle George]

Our $33 Heat Pump HWS was installed last Thursday with a max setting of 50* in the tank as now mandated by government. I have been able to set the timer to only make heating possible between 8am - 4pm, using our solar power and this morning it turned off at 9:20 after reaching 55* at the pump under a cloudy sky. We are happy with that and do not find it noisy at all.

George

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[T1 Terry]

Our $33 Heat Pump HWS was installed last Thursday with a max setting of 50* in the tank as now mandated by government. I have been able to set the timer to only make heating possible between 8am - 4pm, using our solar power and this morning it turned off at 9:20 after reaching 55* at the pump under a cloudy sky. We are happy with that and do not find it noisy at all.

George

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Well, there you go. I've talked about combining a split system air con unit with a hot water storage tank using the loop to either dump the heat into the water storage or draw the heat from it to conserve energy make the house heating more effective so the defrost cycles for the outside unit could be avoided ..... and have been told there wasn't enough heat transfer to do what I was suggesting .... yet here is half that system installed as a water heater
the water storage tank is basically the same as the solar hot water tank idea where the heat exchanger is mid tank, cold in the bottom and hot out the top. I think one of my next projects will be building my idea of an energy conservative air con/water heater that uses both traditional solar water heating and photo voltaic/battery power to drive all the pumps and the air recirculation fan for the house inside unit.

T1 Terry

[Peter and Sandra]

Looking at that picture of Georges new HWS it looks like as Terry said that it's basically a normal off peak HWS tank coupled to the external unit of a split aircon system. If that is the case then as both of those units have been around for many years and have had the bugs sorted it should be a good unit.
I've always suspected that jamming the aircon bit into the small space at the top of the water tank meant that the unit was probably undersized and less efficient than what Georges system is.
Does it have an electric heating element in the tank for emergency water heating George?

[Newcastle George]

Yes Peter, there is a setting on the control panel to switch on the electric heating element.

George