Heat pump, Good Idea?

Lupus said:
That would finish 300l of water, average baths are about 75l of hot water, even a 5 minute shower can be 20l high flow showerheads make that even higher.
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What's the average time the bath lasts?
 
Tomtomtom said:
So in the vein of figuring out why you're asking about heat pumps in the first place - are you aware there are PV Geyserwise systems? Basically an MPPT and a combined DC/AC element. No evacuated tubes. The DC side does not load your inverter, but you can use excess AC from your inverter in winter if need be (at 2 kW).

Also, it makes no sense to put geyser loads onto batteries under any circumstances. A geyser is a thermal battery, it should be fed directly from an MPPT (whether the excess from the one in your inverter, or via a dedicated unit.)



You don't need energy savings when you have excess solar, which you do (in summer) as soon as you have 2 panels dedicated to a 150 L geyser, nevermind 4.

Panels are cheap and extremely low maintenance. Heat pumps are the opposite.
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Depends on where you are in the country, GP doesn't always have excess solar in summer, its our rainy season. Most of the time summer generation can end up lower than winter.
 
wingnut771 said:
What's the average time the bath lasts?
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45 to an hour by the looks of it, but they want to top up the hot water, cause you know thermodynamics.
I just cannot see myself sitting in tepid water for that long.
 
Tomtomtom said:
You don't need energy savings when you have excess solar, which you do (in summer) as soon as you have 2 panels dedicated to a 150 L geyser, nevermind 4.

Panels are cheap and extremely low maintenance. Heat pumps are the opposite.
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I have a Geysertech system, which has a similar idea to Geyserwise without all the mods. Its true what you say and I love it, but heat pumps have their place and if I were to choose between the 2, funds not being considered, I would have a hard time deciding personally.

I would pick a heat pump probably 60% of the time, and my system 40% of the time. Why? Because If I get hit with clouds for 4 days in a row, I will need to run off the inverter, and I will get nailed by the 2kw element some 6kWh to heat my geyser.

A heatpump? You use some 2kWh to heat a geyser from tap water cold to over 50 or 60 degrees. So which system is really better?

They both have advantages and disadvantages. My system has no moving parts so it will last a very very long time. But a heat pump is also little to no maintenance. There is users hitting 14 years on theirs and have had little to no issues.
 
Lupus said:
Depends on where you are in the country, GP doesn't always have excess solar in summer, its our rainy season. Most of the time summer generation can end up lower than winter.
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Yes I should start calling it the "sunny season" rather.
 
Lupus said:
Well if the average bathtub holds 100 to 150l itself, ours is about 175l or so and for some reason people seem to like filling it up. A 5m shower can be 20 to 40l of water, give a decent mix of hot and cold it's 10 to 20l used, some people don't even add cold, they're lizards.
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So a 70/80 litre bath would use some 30 litres of water at 60 degrees and 40/50 of tap water at 20 to equalise at 40 degrees.
 
denmendez65 said:
So a 70/80 litre bath would use some 30 litres of water at 60 degrees and 40/50 of tap water at 20 to equalise at 40 degrees.
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Nope the 75l is the hot water, not the mix... Lizards man, I swear I have lizards
 
Lupus said:
Well if the average bathtub holds 100 to 150l itself, ours is about 175l or so and for some reason people seem to like filling it up. A 5m shower can be 20 to 40l of water, give a decent mix of hot and cold it's 10 to 20l used, some people don't even add cold, they're lizards.
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You should increase geyser temp to 70c.
 
denmendez65 said:
I have a Geysertech system, which has a similar idea to Geyserwise without all the mods. Its true what you say and I love it, but heat pumps have their place and if I were to choose between the 2, funds not being considered, I would have a hard time deciding personally.

I would pick a heat pump probably 60% of the time, and my system 40% of the time. Why? Because If I get hit with clouds for 4 days in a row, I will need to run off the inverter, and I will get nailed by the 2kw element some 6kWh to heat my geyser.

A heatpump? You use some 2kWh to heat a geyser from tap water cold to over 50 or 60 degrees. So which system is really better?

They both have advantages and disadvantages. My system has no moving parts so it will last a very very long time. But a heat pump is also little to no maintenance. There is users hitting 14 years on theirs and have had little to no issues.
Click to expand...
Not if you have 450l of storage from 3 geysers.
 
denmendez65 said:
Would have to phone them as I said. The man wanted ideas around heat pumps. I just offered him something that I was curious about when I was looking for solutions. The heatpump is on top of the tank so it's probably a cover off and you have access to everything and there is quite a few companies selling this stuff, so the install base should be quite large and fixers plenty.
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Selling to who though? I would imagine heat pumps are more popular with commercial customers, the likes of a hotel with limited roof space for example.

So maybe not short on service options but they might be charging a little more.
 
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