Stealing electricity in Southeast Asia

[u/ashsabre]

[u/halpfulhinderance]

It’s much more efficient to heat water up with a heating element inside an insulated container. That’s why we have water heaters. Trying to heat up a liquid as it’s flowing is… well the water is flowing per unit time and the heat is being transferred to each unit of water per unit time so you hit the inverse square rule. It’s exponentially less efficient than heating it in a tank. The shower head would have to be ridiculously hot to get even a little bit of temperature change in the water hitting you. Ntm it’s less surface area for the heat to transfer through, given that it’s a tiny shower head and not a coil. And it’s uninsulated and open to the air so it’s losing a lot of heat that way too, and the metal for the shower head isn’t as efficient a heating element as what you’d normally use…

TL;DR: The shower head would practically have to be glowing hot to get you a steamy shower, assuming the water is cold to begin with. And it would use a TONNE of electricity. This is all not even considering the safety concerns

[u/less_unique_username → u/halpfulhinderance]

Any heater is 100% efficient in heating things. The only problem might be, it could be heating the wrong things. But what else, if not water, could it heat here?

[u/halpfulhinderance → u/less_unique_username]

You are technically correct in terms of thermodynamics, but incorrect in terms of design lol. In this case we’re trying to heat each unit of water to a comfortable temperature, and spending more power to do it compared to a traditional water heater. Primarily because because the water needs to be heated a lot faster

Edit: Also, it would be losing heat to the air, as I mentioned. It’s normal for water to lose heat to the air (steam) but not so much for the heating element to do the same

[u/less_unique_username → u/halpfulhinderance]

Just not seeing how heating something faster leads to higher losses. The losses in the wires are perhaps a little bit higher and that’s it? As for loss to the air, I doubt it’s a thing given that the heating elements are completely surrounded by moving water.

[u/halpfulhinderance → u/less_unique_username]

Ik it’s been 3 days but what it comes down to is we’re spending more power, even if overall we’re spending the same amount of energy (which I’d quibble over, but I did misunderstand that the heating element is inside the shower head rather than being the actual shower head itself). Spending more power (same amount of energy over a shorter period of time) places more strain on the grid. If every shower on your grid worked like this you’d see a significant spike in demand.

There’s also energy loss in the sense of like, you’re spending a lot of energy really fast to get the heating element going, it’s not offering as much resistance initially because it’s cooler (and the water is cooling it), and the resistance is what creates the heat. And then when you turn off the shower, that element is still hot and any residual heat is getting wasted. You don’t have the same problem with a traditional boiler, since the whole thing is insulated and that energy remains in the system. An example could be how a pot boils a lot faster when you put a lid on it, and loses that heat a lot faster when you take that lid off. But this is quibbling.

And gas powered boilers are more efficient anyways, assuming the infrastructure is there and the grid is using gas powered generators. Much better to use gas for heating purposes directly than burn it to turn a turbine, lose a bunch of energy from resistance in the lines, and then transform it back into heat to boil water. It’s silliness. This is part of why micro generation and a battery network are critical to a greener energy grid, as they remove a lot of the losses.