Options for Expanding Geyser + Heat pump

[LPZard]

Hey everyone,

I’m in the process of purchasing my first home in place in Cape Town that came with a 100L geyser and a ITS-5HDP (5kW) heat pump which looks 5 or so years old. 100L isn't going to cut it for our household, but I’d rather not scrap a perfectly good 100L tank if

I’m looking for advice on the best way to hit a ~200L capacity

1. Does anyone have experience adding a second 100L tank in series with a heat pump or any other setup options? Any issues with flow rates or the pump’s thermostat?
2. Would it be better to add a separate tank connected to solar evacuated tubes to act as a pre-heater OR, just put as much solar as possible to power the home and the heat pump?

Appreciate any insights or diagrams of similar setups and any contacts anyone has

 

[wingnut771]

150l are cheap. Add that in series with 100l and make heatpump heat 150l which feeds 100l and put 1kw element in 100l set to 55c. Then do an audit of how much power you use during the day and at night (size of battery) and factor in 120W inverter draw.

Then use this calculator to see how much production you can get with roof orientation and angle.

Solar geysers are a waste of roof space imho.

 

[denmendez65]

@Lupus Does he need a bigger geyser if he has a HP. Wont the heat pump heat quick enough that the capacity should not be too much of an issue.

 

[Lupus]

@Lupus Does he need a bigger geyser if he has a HP. Wont the heat pump heat quick enough that the capacity should not be too much of an issue.

Yeah it should 100l will warm up quickly with a 5kw heatpump.

 

[denmendez65]

Yeah it should 100l will warm up quickly with a 5kw heatpump.

I figured. He mind as well leave as is and see how things go with day to day usage rather than blowing money on something that may not be necessary at all.

 

[wingnut771]

@Lupus Does he need a bigger geyser if he has a HP. Wont the heat pump heat quick enough that the capacity should not be too much of an issue.

Yeah it should 100l will warm up quickly with a 5kw heatpump.

Guys, you’re forgetting about storage. If he can heat water during the day for free from the sun then won’t need as much battery at night.

 

[Lupus]

Guys, you’re forgetting about storage. If he can heat water during the day for free from the sun then won’t need as much battery at night.

We have no idea his habits, but even with a 200l geyser the 5kw heat pump will take like an hour and half from 20 degrees.

 

[denmendez65]

Guys, you’re forgetting about storage. If he can heat water during the day for free from the sun then won’t need as much battery at night.

But its a Heat pump? He wont use more than 2 kwh to heat it to temp at night. He can run it with solar during the day but early morning just run the pump, it wont drain the battery much at all.

 

[denmendez65]

We have no idea his habits, but even with a 200l geyser the 5kw heat pump will take like an hour and half from 20 degrees.

So in his case with a 100 litre geyser he will use some 1kWh as I see they use around 1.3kW of instantenous power. Could even be less.

 

[Lupus]

So in his case with a 100 litre geyser he will use some 1kWh as I see they use around 1.3kW of instantenous power. Could even be less.

Yeah roughly, I mean I use 1.2 for a 150l

 

[wingnut771]

We have no idea his habits, but even with a 200l geyser the 5kw heat pump will take like an hour and half from 20 degrees.

True, we need that audit. Especially how many women.

 

[wingnut771]

But its a Heat pump? He wont use more than 2 kwh to heat it to temp at night. He can run it with solar during the day but early morning just run the pump, it wont drain the battery much at all.

Imagine @cavedog using 2kWh to heat water on his 5kWh battery.

 

[denmendez65]

Imagine @cavedog using 2kWh to heat water on his 5kWh battery.

He hasnt told us his battery capcity. Also why spend some 8k on an extra geyser (with installation and pipes) when you can spent 10 to 13k on an extra battery. And just use those 2kWh with the heatpump. There is something beatiful about simplicity.

 

[wingnut771]

He hasnt told us his battery capcity. Also why spend some 8k on an extra geyser (with installation and pipes) when you can spent 10 to 13k on an extra battery. And just use those 2kWh with the heatpump. There is something beatiful about simplicity.

He has, his R40k system is 5kW inverter, 5kWh battery and 3.6kWp solar.

 

[denmendez65]

He has, his R40k system is 5kW inverter, 5kWh battery and 3.6kWp solar.

Ah, must have missed it.

All the more reason to chuck a battery in there. He is in CPT. He needs efficiency rather than storage. Storage wont help him in winter with the crappy weather as he still needs to heat it. Me must stick to the HP and get an extra battery. That will 100% take care of him, even in winter, less units to run the HP for the geyser than trying other methods.

 

[wingnut771]

Ah, must have missed it.

All the more reason to chuck a battery in there. He is in CPT. He needs efficiency rather than storage. Storage wont help him in winter with the crappy weather as he still needs to heat it. Me must stick to the HP and get an extra battery. That will 100% take care of him, even in winter, less units to run the HP for the geyser than trying other methods.

Of course stick with a free heat pump. Its just mad buying a new HP for R35k. Rather get R35k in solar panels.

 

[wingnut771]

That will 100% take care of him, even in winter, less units to run the HP for the geyser than trying other methods.

 

[rh1]

@Lupus Does he need a bigger geyser if he has a HP. Wont the heat pump heat quick enough that the capacity should not be too much of an issue.

In my first house, there was a 100lt geyser. As the house had no showers. We bathed.

We never ran out of hot water. 2 adults and a kid.

I prefer a 100lt geyser, but it cost too much vs a 150lt gesyer.

 

[Speedster]

But its a Heat pump? He wont use more than 2 kwh to heat it to temp at night. He can run it with solar during the day but early morning just run the pump, it wont drain the battery much at all.

That depends on the amount of water the family uses at evening bath time / dishes. It could be substantially more than 2kwh, especially if they need warm water again early morning.

 

[wingnut771]

That depends on the amount of water the family uses at evening bath time / dishes. It could be substantially more than 2kwh, especially if they need warm water again early morning.

Again, waiting for the audit.