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Re-using the heat in bathwater in Britain

dynomight.net

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Re: Re-using the heat in bathwater in Britain

#201
post #190

Earlier quoted context omitted.

> SE Asia where you can drink the tap water A very verbose way of saying Singapore.

You can drink it other countries! It's risky, but you can drink it!

Taiwan, Japan, Singapore. Only countries you can safely drink tap water in Asia AFAIK.

Re: Re-using the heat in bathwater in Britain

#202

Tangentially related: has someone found something less energy intensive than taking a bath while bringing the same degree of warmth? I've been looking at heated blankets but they're all made of polyester which is not comfortable due to the moisture being trapped under the blanket. Heated seats in some cars are the closest sense of comfort I've found but that technology doesn't seem to exist for regular seats.

Isn't bathing the worst heating method for energy usage perspective? I don't think it's heating method but cleaning.

Maybe, but wet warmth like a bath has excellent thermal properties when it comes to human perception. Warm air doesn't have the same feeling.

Re: Re-using the heat in bathwater in Britain

#203

Earlier quoted context omitted.

Britain is not suffering a water shortage, nor is it likely to in any foreseeable future. Not that I'm encouraging people to waste water, but conserving water doesn't address the unfavorable economics of energy.

Saw this a couple of years ago in the Grauniad: https://www.theguardian.com/environment/2019/mar/18/england-...

[redacted for cynicism]

Re: Re-using the heat in bathwater in Britain

#204
post #38

I read a lot about district heating systems yesterday after seeing an article on NYC's steam system on HN ( https://news.ycombinator.com/item?id=33388473 ). District heating systems allow you to capture waste heat at the power plant (called co-generation), and use that to heat & cool (via cooling compressors) many, many buildings at once. The wikipedia article about it is very informative as well: https://en.wikipedi…

District heating here in The Netherlands is a great way to be screwed by a supplier. We have pretty good competition between suppliers for gas and electricity(). Households that get their heat from district heating can only say yes or no to one supplier. They will generally pay the maximum price regulation allows.

() This competition has led the way in greenifying electricity usage for Dutch households. Dutch electricity was mostly coal and gas generated, but there were energy suppliers that guaranteed green electricity. Green-minded people could use market mechanisms to increase carbon neutral electricity(*) usage. I've always liked that personal power in market mechanisms.

(*) Similar contracts exist for gas usage, but it's mostly based on "compensation", which at best isn't very good, and at worst completely useless.

Re: Re-using the heat in bathwater in Britain

#205
post #45

Earlier quoted context omitted.

Exactly. Space heating is the most energy-intensive an expensive item on the list of things you can save on in a detached house - especially that you only really need the heat to be where you are.

It heavily depends how they use bath, and how cold. In Japan, 25-40% (vary depending on research) of energy at home is used for heating water because people prefer bathing. Heating water is expensive.

Japanese houses are more likely to be cooler but have local sources of heat, from what I understand. For example a kotatsu is a warm space.

Heating locally is such an interesting idea to me.

Re: Re-using the heat in bathwater in Britain

#206

Turning your thermostat down by one or two degrees per week and getting acclamation to cold is a better alternative. 5 degrees on the thermostat would be a far better measure than tub heat. Short showers, or 'sea showers', to conserve water and heating would likewise be a far better option than a 50 gallon bath.

And not just short showers, but managing the amount of time the water is actually running. Here’s my strategy for an efficient shower: 1. turn on the water, get in, rinse down, soak a wash cloth 2. turn off water 3. lather hair with shampoo 4. lather wash cloth with soap and scrub body 5. turn on water and rinse down The majority of the time we’re standing in the shower, we don’t actually need the water to be running…

Ufff. I’m not doing that when it’s 4c outside and because I turned the heating off at 9pm my house is 14c. I need the shower to warm me up and stop me turning the heating on early in the morning

Re: Re-using the heat in bathwater in Britain

#207
post #91
post #33

Earlier quoted context omitted.

It could also be that your windows are not insulated enough. For 20C and 40RH the windows need to be colder then 6C to get condensation.

Moisture has to go somewhere even if you don't see it visibly condensing on windows. Either it's being absorbed or you have something removing moisture from the system (venting, etc).

House code in Finland requires mechanical ventilation with vents in the bathroom. I only see brief condensation on my bathroom windows when I leave the sauna door open in the winter (approx. 100 celsius, 80%RH).

With good building codes, you won't have condensation issues.

Re: Re-using the heat in bathwater in Britain

#208

Earlier quoted context omitted.

You could place a plastic mat on top to limit evaporation.

You could also switch to a water conserving mist shower and reduce the amount of heated water used for the shower. You could also reclaim the water from the shower for use in the toilet by turning the supply to the toilet off and manually transferring it to the toilet tank. There are lots of things you could do to save resources but most things are not done and are not going to be done because it is inconvenient and…

I've noticed that when I put my shower on mist I have to turn the water temperature up quite a bit to have the same felt temperature. The small water droplets seem to cool a lot faster. I'm not sure that it is actually more energy efficient.

Re: Re-using the heat in bathwater in Britain

#209

I've noticed that people wildly overestimate the environmental impact of things they personally touch. This, I theorize, is why sub-rounding error things like plastic straws, plastic bags, cups, etc get such disproportionate attention. Bathwater that heats every pore of our naked bodies is probably even more susceptible to this bias.

You may not be wrong - however, what's your suggestion then? Not doing these things? IMHO, every little bit counts towards a livable future.

Most people not in the Nordics / Germany / Switzerland would most likely see way more energy savings per year by simply spending the money used to install a waste water energy recovery system to instead just insulate their house.

Re: Re-using the heat in bathwater in Britain

#210
post #190

Earlier quoted context omitted.

You can drink it other countries! It's risky, but you can drink it!

Taiwan, Japan, Singapore. Only countries you can safely drink tap water in Asia AFAIK.

Also South Korea, Brunei and Hong Kong (apparently).

But I have friends who rinse their mouth, brush with tap water in Vietnam and haven't gotten sick. It obviously varies a lot by which city (or even within the city), but the water is tested and obviously highly chlorinated (by smell).

I mean, I wouldn't drink it regularly because I don't think they look for non-biologic toxins like metals.

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