Wellington Electricity Network - Ripple Load Control Failing to Turn Off

Forums › Home Workshop DIY › Wellington Electricity Network - Ripple Load Control Failing to Turn Off - Request for Half Hour Meter Data

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#3234525 25-May-2024 10:59

Hinko:

Show me data that proves your theory. In the absence of better data from you I am unlikely to change my conclusion.

1) It's not my theory. It's school level physics using principles that have been firmly established with evidence for 100s of years. Here's a good starting point.

2) None of your graphs plot power anywhere on them. They plot energy used.

3) If you really want to measure and compare different days with ripple on or off then you will also need the following at a minimum: Input water temp, output water temp, ambient air temp around the cylinder, exact volume of water used (all for each day) and a far far more precise way of isolating the electrical energy used by just the hot water cylinder, not the entire house.

RunningMan

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#3234529 25-May-2024 11:18

Hinko: When the Ripple control and element are both on there is a continuous stream of drips from the pressure relief valve. So we do have a leak which will explain some of the lost energy.

OK, so there's your answer. Your hot water system is faulty and using additional energy while it's turned on. By turning it off periodically, you have got rid of the wasted energy use.

Additionally, the days you have presented have different outside temperatures in Wellington. The day you used more energy was a colder day. https://www.accuweather.com/en/nz/wellington/250938/september-weather/250938?year=2023

Hinko

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#3234539 25-May-2024 11:57

RunningMan:

Hinko: When the Ripple control and element are both on there is a continuous stream of drips from the pressure relief valve. So we do have a leak which will explain some of the lost energy.

OK, so there's your answer. Your hot water system is faulty and using additional energy while it's turned on. By turning it off periodically, you have got rid of the wasted energy use.

No its not faulty, its expected normal behaviour.

As a consumer of power we are entitled to receive a power service to the stated specification (to say the least) regardless of how inefficient our devices may be.

Device efficiency is not relevant to the question of provision of power to a stated and promoted standard.

Hinko

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#3234540 25-May-2024 11:57

RunningMan:

Additionally, the days you have presented have different outside temperatures in Wellington. The day you used more energy was a colder day. https://www.accuweather.com/en/nz/wellington/250938/september-weather/250938?year=2023

Thanks for the interesting and useful link. We heat the house with gas. Any difference from temperature difference of a mere 2 degrees is not sufficient to explain the large difference in power used over the 24 hours. (31.16 vs 47.31 KW/hr as noted on the graphs by Flick as totals for the days shown)

This thread is about seeking actual metered data from other people.

If you want to debate theory or our power consumption efficiency and compare it with actual data please start another thread.

Jase2985

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#3234543 25-May-2024 12:12

The pressure relief valve on a standard HWC should not be operating at its normal operating temperature. It's for if the thermostat gets stuck on, and it starts to heat over its working temp. Mine doesnt leak as far as i know, and if i were to change the set point from 60 to 70deg I'm sure it also wouldn't leak.

Bung

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#3234547 25-May-2024 12:35

Wellington Electricity promote "Time of Use" pricing.

"Time of use prices let you save money by using electricity during the day or at night.

Peak

Weekdays (including public holidays) 7am to 11am and 5pm to 9pm

Off-peak

All other times "

On their site the only references I can find to hot water control by ripple are for network load shedding. How would it work for pricing as individual customers can't be targeted?

At the moment we are with Contact. They talk about using the meter to control the water heating

"Great question! We use special software to seamlessly connect your meter to the 4G network to turn your hot water off and on again. We’ll do this at a peak time that is right for your household so it shouldn’t have any impact on your hot water needs.

Isn’t hot water already controlled?

In some areas yes, it is, but it is only very occasionally turned off by the local network company. We will be doing it more often to hopefully save customers a little bit of money and reduce reliance on fossil fuels."

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RunningMan

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#3234548 25-May-2024 12:35

Hinko: (31.16 vs 47.31 KW/hr as noted on the graphs by Flick as totals for the days shown)

You are still confusing power, energy etc.

Power is measured in watts. A typical hot water cylinder element will be 3000 watts - 3 kilowatts, abbreviated 3 kW. For comparison an incandesant light bulb may be 100 watts.

Energy is measured in joules or watt-hours. The energy usage is the power of the device, multiplied by the time it is running. So the typical 3 kW water heater heating for 30 minutes would use 1500 watt-hours of energy, abbreviated to 1.5 kWh. The light bulb on for 2 hours would use 200 Wh. It is energy use that you are charged for - i.e. 20 cents per kilowatt-hour would be a typical price for electrical energy.

Hinko

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#3234551 25-May-2024 12:49

Bung: Wellington Electricity ........ On their site the only references I can find to hot water control by ripple are for network load shedding. How would it work for pricing as individual customers can't be targeted?

See https://www.welectricity.co.nz/assets/Ripple-control-signals-v3.1.pdf and https://www.welectricity.co.nz/disclosures/pricing/2024-pricing/ and the downloads at the bottom of that page. Search for Night Boost, "NB"

Hinko

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#3234558 25-May-2024 12:52

Bung: At the moment we are with Contact. They talk about using the meter to control the water heating

Which region are you in and which lines company are you fed by?

Hinko

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#3234559 25-May-2024 12:54

Jase2985:

The pressure relief valve on a standard HWC should not be operating at its normal operating temperature. It's for if the thermostat gets stuck on, and it starts to heat over its working temp. Mine doesnt leak as far as i know, and if i were to change the set point from 60 to 70deg I'm sure it also wouldn't leak.

How about you put a bucket under the relief valve outlets and report back to us in 24 hours the volume of water you collect please?

RunningMan

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#3234560 25-May-2024 12:54

Octopus is another energy company that will do this. Your meter has to support it though so may have to have the meter replaced.

New World

Shop on-line at New World now for your groceries (affiliate link).

Jase2985

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#3234562 25-May-2024 13:03

Hinko:

Jase2985:

The pressure relief valve on a standard HWC should not be operating at its normal operating temperature. It's for if the thermostat gets stuck on, and it starts to heat over its working temp. Mine doesnt leak as far as i know, and if i were to change the set point from 60 to 70deg I'm sure it also wouldn't leak.

How about you put a bucket under the relief valve outlets and report back to us in 24 hours the volume of water you collect please?

"RMC’s Pressure and Temperature Relief (P & T Relief) Valves are safety controls which ensure that the temperature of the water in a pressurised unvented water heater cannot exceed 99° C in the event that the normal thermostatic controls fail. These valves may be used to guard against overtemperature and over-pressure hazards wherever water is stored in unvented containers."

I would love to put something under it, but I can't due to the way the plumbing runs.

Hinko

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#3234565 25-May-2024 13:17

Jase2985:

"RMC’s Pressure and Temperature Relief (P & T Relief) Valves are safety controls which ensure that the temperature of the water in a pressurised unvented water heater cannot exceed 99° C in the event that the normal thermostatic controls fail. These valves may be used to guard against overtemperature and over-pressure hazards wherever water is stored in unvented containers."

I would love to put something under it, but I can't due to the way the plumbing runs.

From https://www.hotwatercylinders.nz/category/cylinder-valves/

Cold Water Expansion Valve (CWE) does all the day to day reliving of pressure, the valve is fitted to the cold water inlet of the cylinder. The CWE is the first valve to relief pressure on a mains pressure system, it will be set to relieve at a lower pressure setting when compared to the TPR valve, they are designed to be the first to relieve because they are fitted to the cold water inlet, this means all the day to day relieving of pressure is through cold water, and not hot water, this in turn will save you money on power as it will not be wasting hot water.

I'm not sure from which which relief valve the small volume of water comes from (Hot or Cold). Might check to be sure we're not paying for more power than we need from our inaction.

That does not mean the power companies should be excused their inaction.

If you can't collect the relief released water how do you know there is none discharged?

Jase2985

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#3234566 25-May-2024 13:19

I'm wondering if it is leaking has the LSV(Limiting Stop Valve) or LVT (Limiting Valve) failed and letting too much pressure into the tank causing the P & T Relief valve to be opening when heating.

Just trying to rule out alternative things to your theory

Jase2985

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#3234568 25-May-2024 13:23

Hinko:

Jase2985:

"RMC’s Pressure and Temperature Relief (P & T Relief) Valves are safety controls which ensure that the temperature of the water in a pressurised unvented water heater cannot exceed 99° C in the event that the normal thermostatic controls fail. These valves may be used to guard against overtemperature and over-pressure hazards wherever water is stored in unvented containers."

I would love to put something under it, but I can't due to the way the plumbing runs.

From https://www.hotwatercylinders.nz/category/cylinder-valves/

Cold Water Expansion Valve (CWE) does all the day to day reliving of pressure, the valve is fitted to the cold water inlet of the cylinder. The CWE is the first valve to relief pressure on a mains pressure system, it will be set to relieve at a lower pressure setting when compared to the TPR valve, they are designed to be the first to relieve because they are fitted to the cold water inlet, this means all the day to day relieving of pressure is through cold water, and not hot water, this in turn will save you money on power as it will not be wasting hot water.

I'm not sure from which which relief valve the small volume of water comes from (Hot or Cold). Might check to be sure we're not paying for more power than we need from our inaction.

That does not mean the power companies should be excused their inaction.

If you can't collect the relief released water how do you know there is none discharged?

Because i can see where the valve is, i can hear when it's discharging, and i can feel the pipe temperature. Plus you have seen my power graphs, which are recorded every 6 seconds, so i would know if it were leaking as its always been 6-7h between reheats when its not being used.

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