Timeline for Inverter requirements for instantaneous water heater
Current License: CC BY-SA 4.0
18 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Jun 30, 2022 at 11:21 | vote | accept | Pangolin | ||
| Jun 29, 2022 at 22:18 | answer | added | DrMoishe Pippik | timeline score: 2 | |
| Jun 29, 2022 at 21:36 | comment | added | brhans | 3rd-world problems ... these tankless systems assume that there'll always be electricity available to power them, while a 'traditional' tanked system will easily ride through a few hours of power-loss (with moderate usage of the stored hot water). You'd be much better off installing a tank-ed solar water heater with electric 'top-up', but that may be difficult in an apartment... Although even here in the "1st world" a storm is likely to knock out power for a few hours at a time due to all lack of (imo much more sensible) underground power distribution. | |
| Jun 29, 2022 at 21:27 | comment | added | Graham Nye | "a 18kW inverter is needed" It would be worth investigating if installing a traditional water tank-based geyser would be more practical. | |
| Jun 29, 2022 at 21:17 | comment | added | winny | @brhans Ah! Innovation. That would explain it. | |
| Jun 29, 2022 at 21:17 | comment | added | brhans | @winny yes, that's what happens. It only heats when water flows (so there's a minimum flow rate required before it'll turn on), and while the water is flowing it applies as much energy as is required to raise the water temperature to the setpoint. | |
| Jun 29, 2022 at 21:07 | comment | added | winny | @brhans No, mixing is safe. Perhaps these on-demand devices function differently than what’s commonly installed here. Even the “on-demand” ones here have a thermostat and some amount of tank volume, although small. Does the one we discuss here not have a thermostat but rather sense water flow and only turn on once water is flowing? | |
| Jun 29, 2022 at 20:06 | comment | added | brhans | @winny so do you feel the same way about anti-scald mixing valves? The end result of either is exactly the same thing... Where exactly is your concern? Where is the legionella going to grow? | |
| Jun 29, 2022 at 19:55 | comment | added | Pangolin | @rdtsc 18kW from a 48V battery would mean 375A (at 100% efficiency). But that's still a lot! | |
| Jun 29, 2022 at 19:47 | review | Close votes | |||
| Jul 6, 2022 at 14:05 | |||||
| Jun 29, 2022 at 19:29 | comment | added | winny | @brhans Should be much better. My alarm bells start ringing any time below 65 degrees. | |
| Jun 29, 2022 at 19:01 | comment | added | brhans | @winny it's an on-demand water heater. There's no tank full of 45° water to grow bacteria in. | |
| Jun 29, 2022 at 18:59 | comment | added | winny | Could be exceptions but here you’ll be thrown in jail for manslaughter or deadly neglect (doesn’t translate well to English). No real concern for healthy young people but the elderly and people with respiratory problems are at risk and there are people dying from it every year. | |
| Jun 29, 2022 at 18:56 | comment | added | rdtsc | Back-of-the-napkin sounds close. Now keep in mind that 18kW from 240VAC implies 75A... so that much power from 24V, with a 100% efficient inverter, would draw 750A for those 20 minutes. Wire probably won't do... we're talking big buss bars. | |
| Jun 29, 2022 at 18:39 | history | edited | Pangolin | CC BY-SA 4.0 |
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| Jun 29, 2022 at 18:22 | comment | added | Pangolin | Very interesting @winny, I didnt know that! Given that the water never stands still at that temperature and only heats up when you open the tap and it flows (similar to a gas geyser), I'm assuming that's not an issue? That being said- will investigate further. | |
| Jun 29, 2022 at 18:05 | comment | added | winny | ”The water heater's max temperature is set to 45°C.” Nothing to do with EE but 45 degrees is just about sweet spot for legionella bacteria growth. It would not be legal (at least here) to run a water heater that cool. | |
| Jun 29, 2022 at 18:00 | history | asked | Pangolin | CC BY-SA 4.0 |