Geyser upgrade advice

[Phoenix Energy]

So. I’m pretty much off the grid now, I only have my geyser and oven connected to eskom.

Everything else is connected to my inverter and runs off the lithium batteries and solar panels.

Now it’s time to tackle the geyser. I want to know from people who have a heat pump installed with a 200L geyser, what the power consumption is like and how often does the heat pump run? I often have power outages over night and it’s getting annoying to wake up and have a cold shower.

I’m highly in the camp of a heat pump that I can connect to my geyser and run the circuit to my 5kW deye inverter. And have it run of the inverter and batteries. I’m hoping it will <2kwhs during the night so that it doesn’t drain my batteries.

At the end of the year I will be adding 1 or 2 more Hubble AM-2 batteries and then my off grid project will be complete.

If the heat pump option doesn’t work. Then would a solar geyser work? PS I wake up at 4AM so I need to know if my geyser water will still be warm enough to have a shower at that time.

 

[Qui_Illustrati]

A solar geyser is waste of time, effort and money. Works decently for summer and poorly outside of warm months.
Rather expand your solar array, change your element to a lower wattage, make sure your geyser and outlet pipes are properly insulated, use PV to heat during the day, perhaps set your thermostat to a bit higher (depending what it is now) and by 4am you should have steaming hot water.
It's what I do and it works for me.

Stove. Go gas.

 

[g0l1athrulz]

gas geyser also works very well

 

[Phoenix Energy]

A solar geyser is waste of time, effort and money. Works decently for summer and poorly outside of warm months.
Rather expand your solar array, change your element to a lower wattage, make sure your geyser and outlet pipes are properly insulated, use PV to heat during the day, perhaps set your thermostat to a bit higher (depending what it is now) and by 4am you should have steaming hot water.
It's what I do and it works for me.

Stove. Go gas.

Yeah I’m really hesitant on the whole solar geyser thing. Especially since I know it won’t really help me with my problem of hot water in the morning.

My element recently died and insurance changed it to a 2kw unit at my request. I’ve been monitoring my geyser consumption with the aide of the CBI smart circuit breaker and I currently use 7-9kwh a day

I’m getting a nice geyser blanket soon and will insulate my pipes as well as possible now and see how that helps.

In hindsight I should have gone with a 8kW inverter back then and just put my geyser on the aux port and cut power when the batteries go below 50%

I have a gas stove for over 10 years and I literally cannot live without it. I even ran a separate breaker that’s on the inverter so that I don’t lose my igniter

 

[Phoenix Energy]

gas geyser also works very well

How long does a 20kg bottle last you? Considering with my plan of moving it to the inverter I’ll be heating up my water for free

 

[g0l1athrulz]

How long does a 20kg bottle last you? Considering with my plan of moving it to the inverter I’ll be heating up my water for free

we use a 48kg bottle, replace it around every 6-7 months

 

[00Mfaan]

Will one gas geyser be sufficient for a 3 bedroom , 2 bathroom house or will you need to install more than one

 

[Phoenix Energy]

we use a 48kg bottle, replace it around every 6-7 months

So give or take R1400 a year?

 

[g0l1athrulz]

So give or take R1400 a year?

no 48kg bottle closer to r1400 each

 

[Phoenix Energy]

no 48kg bottle closer to r1400 each

Wtf. I pay R350 - R380 for a 20kg bottle here in KZN

 

[Scrooloose]

The solar solution we're saving up for includes sufficient capacity for powering the geyser. We're gonna place it on a timer that only turns the geyser on during daytime hours, so that we don't need to hurt the batteries at night.

We have a gas stove and it's amazing. However the amount of heat one needs for water makes me question the cost component of a gas geyser.

 

[Confucius]

So. I’m pretty much off the grid now, I only have my geyser and oven connected to eskom.

Everything else is connected to my inverter and runs off the lithium batteries and solar panels.

Now it’s time to tackle the geyser. I want to know from people who have a heat pump installed with a 200L geyser, what the power consumption is like and how often does the heat pump run? I often have power outages over night and it’s getting annoying to wake up and have a cold shower.

I’m highly in the camp of a heat pump that I can connect to my geyser and run the circuit to my 5kW deye inverter. And have it run of the inverter and batteries. I’m hoping it will <2kwhs during the night so that it doesn’t drain my batteries.

At the end of the year I will be adding 1 or 2 more Hubble AM-2 batteries and then my off grid project will be complete.

If the heat pump option doesn’t work. Then would a solar geyser work? PS I wake up at 4AM so I need to know if my geyser water will still be warm enough to have a shower at that time.

Simple water heating energy calculator to heat 100 liter of water from 20 degrees to 65 degrees.

Assuming a 100% efficient resistance heater and ignoring any tank losses during the heating.

100 litres of water is almost 100 kg .

The specific heat capacity of water is approx 4.2 J / g.K

The increase in temperature is 45Kelvin (65-20)

So the energy needed is 100,000 x 45 x 4.2 = 18.9MJ

1kWh = 1000W x 3600s = 3.6MJ

Hence, the energy needed is 18.9/3.6 = 5.2 kWh.

So 200l needs approximately 10kwh.

At around R2.50 per kWh, that’s about R25 a day to heat the water.

My 5kw alliance heatpump uses around 1.2kw when it is running. In summer it runs for a short time but in winter it struggles to get the temperature to 55 degrees. I still use the resistive element during the day and the heatpump only runs if water temperature drops below 50 degrees so it’s difficult to give you full stats. I have this connected to a 200l tank. But compared to a 2kw element, you are saving 50 percent…. Does that justify a 15-20k install cost and the limited lifespan… I don’t think so.

Better solution is to add another 200l geyser and a small grid tie inverter / micro inverter and use solar PV to heat the your water if the existing capacity isn’t enough. Panels have a lifespan of more than 25 years and a grid tie inverter is pretty reliable.

Gas is good but not as efficient. There are losses but this is minimized as you are not heating the water and storing it. It should be as close as possible to the final outlet. Can be installed as a backup solution and you only use gas if the inlet temperature is lower than whatever you set.

To me it doesn’t make sense to use battery power to heat water. Energy stored in a geyser is multiple times cheaper than energy stored in batteries.

 

[Confucius]

Wtf. I pay R350 - R380 for a 20kg bottle here in KZN

In GP, price fluctuates and is generally higher in winter. 19kg is between 650 and 800 depending where I buy from.

 

[Confucius]

Will one gas geyser be sufficient for a 3 bedroom , 2 bathroom house or will you need to install more than one

A gas geyser heats water as it is required. So this ideally needs to be close to the tap. Depends on how big the house is and how far bathrooms / kitchen are from each other.

Gas isn’t going to be cheaper, it’s just better in terms of going off grid or not worrying about loadshedding

 

[Confucius]

I’m getting a nice geyser blanket soon

That’s a waste of time and money. Lag the pipes definitely as there’s lots of heat loss from the pipes but geysers are well insulated.

 

[EELeat]

Y'all running ceramic elements...right?

XTEND Elements • Energy Efficient - Long Life - Ceramic Elements

XTEND Elements save money every time you heat water. SABS tested to SANS-514. Ideal for hard water. 3 year product warranty.

xtendelements.co.za

 

[Confucius]

Y'all running ceramic elements...right?

XTEND Elements • Energy Efficient - Long Life - Ceramic Elements

XTEND Elements save money every time you heat water. SABS tested to SANS-514. Ideal for hard water. 3 year product warranty.

xtendelements.co.za

That looks like the biggest scam of the century relating to water heating. A resistive element is almost 100% efficient. If this extend is a PTC element, then it actually takes longer to heat… it’s just a little better for the inverter compared to a 3-4 kw element but a 2kw element is also fine.

These things don’t come cheap though.

 

[beanpopper]

I've installed 15lt under counter in kitchen and 30lt for units for bathrooms. Works like a charm ... saves a ton of water.

 

[EELeat]

That looks like the biggest scam of the century relating to water heating. A resistive element is almost 100% efficient. If this extend is a PTC element, then it actually takes longer to heat… it’s just a little better for the inverter compared to a 3-4 kw element but a 2kw element is also fine.

These things don’t come cheap though.

You'd trust a tried and tested South African favorite, hopefully. Plumblink themselved:

XTEND CERAMIC ENERGY EFFICIENT ELEMENT FLANGE MOUNT 2KW

Buy the XTEND CERAMIC ENERGY EFFICIENT ELEMENT FLANGE MOUNT 2KW online at Plumblink | Plumbing, Bathroom & Kitchenware

www.plumblink.co.za

 

[Phoenix Energy]

You'd trust a tried and tested South African favorite, hopefully. Plumblink themselved:

XTEND CERAMIC ENERGY EFFICIENT ELEMENT FLANGE MOUNT 2KW

Buy the XTEND CERAMIC ENERGY EFFICIENT ELEMENT FLANGE MOUNT 2KW online at Plumblink | Plumbing, Bathroom & Kitchenware

www.plumblink.co.za

If I add this, how long would it take to heat up a 200l geyser to 45 degrees?

 

[Qui_Illustrati]

If I add this, how long would it take to heat up a 200l geyser to 45 degrees?

You're asking for trouble dropping the temp to 45 degrees.

 

[Phoenix Energy]

You're asking for trouble dropping the temp to 45 degrees.

This is my current temp.

Im going to be picking it up to 55-65 next week when its cooler in my roof lol. And heat it up in the evenings and see if the water is hot enough for a shower in the morning

 

[Qui_Illustrati]

This is my current temp.

You likely need to make a booking at a pulmonologist ASAP

 

[Phoenix Energy]

You likely need to make a booking at a pulmonologist ASAP

*reads up on Legionnaires disease*

*Grabs a ladder to quickly increase temperature*

 

[Confucius]

You'd trust a tried and tested South African favorite, hopefully. Plumblink themselved:

XTEND CERAMIC ENERGY EFFICIENT ELEMENT FLANGE MOUNT 2KW

Buy the XTEND CERAMIC ENERGY EFFICIENT ELEMENT FLANGE MOUNT 2KW online at Plumblink | Plumbing, Bathroom & Kitchenware

www.plumblink.co.za

No really. Especially when they have a vested interest in the product.

To me, it comes down the physics of energy. Energy is neither created nor destroyed but merely transferred between 2 objects ( its been a while so words may not be perfect)

An electrical element is transferring almost 100% of the energy to the water to heat it. If the PTC element is 25% more efficient then it transfers 120% of the energy which is not possible.

They say that it has been independently tested but I could not find any independent testing. They show a graph on their website comparing to an electrical element and it doesn’t look like it’s 25% better.

It may work better in some scenarios with certain geyser orientations but that’s got nothing to do with efficiency.

So NO, I still don’t trust it.

 

[Morne Jordaan]

Well, I got a heat pump on myne, so I am rocking a 5.5Kw inverter and I got a smart Timer on the geyser so then everyday between 10am - 12am I run the geyser mainly off the solar.

 

[Phoenix Energy]

Well, I got a heat pump on myne, so I am rocking a 5.5Kw inverter and I got a smart Timer on the geyser so then everyday between 10am - 12am I run the geyser mainly off the solar.

How much power does the heat pump pull?

 

[g0l1athrulz]

Wtf. I pay R350 - R380 for a 20kg bottle here in KZN

thats about what we pay for a 9kg

 

[Killerwatt]

How much of PV power do you have installed? If you have the roof space then installing more panels and running the geyser durring the day would probably be the best bang for the buck.

Insulate pipes as mentioned and the temps should still be fine by the morning. If you want to get crafty then you can add a sonoff and pull the data off the Deye into home assistant and switch on the geyser whenever you have extra capacity.

 

[Phoenix Energy]

How much of PV power do you have installed? If you have the roof space then installing more panels and running the geyser durring the day would probably be the best bang for the buck.

Insulate pipes as mentioned and the temps should still be fine by the morning. If you want to get crafty then you can add a sonoff and pull the data off the Deye into home assistant and switch on the geyser whenever you have extra capacity.

12 x 455W panels which gives me a 5.4kW array

I currently export solar power as well so im not too concerned about my energy consumption. Im being a little bitch because I dont wanna have cold showers in winter