I've seen an even simpler non-moving device to reduce electricity use in supermarket freezers. Because the air in the freezer gains heat more quickly than the produce, the freezer switches on too often. A simple sleeve for the thermometer made in a material with heat capacity comparable to the produce makes the thermometer measure something closer to the temperature of the food. It got tested by the standards agency in the UK and is getting used in some supermarket chains (I'd post a link if I could find one!).
The Ecodrain: How a simple, non-moving part can reduce hot water consumption by 40%
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Re: The Ecodrain: How a simple, non-moving part can reduce hot water consumption by 40%
#12This doesn't warm up the water to the heater, but rather the water going to the cold side of the mixing valve in the shower.
If it takes me 5 minutes to get the stupid thing at the right temperature now, imagine what will happen when the temperature of the incoming cold water depends on the temperature of the drain water - and it's a positive feedback - the hotter the water, the hotter the incoming cold water, making the output even hotter, etc.
This has the potential for using more water rather than less. Although I assume not all faucets are as sensitive as mine - in less than a degree or so of turning I go from freezing to boiling.
Re: The Ecodrain: How a simple, non-moving part can reduce hot water consumption by 40%
#13This doesn't add up. The drain water is, by definition, cooler than the boiler water. Looking at the diagram, cold water is heat exchanged with the drain water which means it will be heated but to less than what a boiler does.
This heated stream is then pumped directly to the shower to be mixed with the boiler water, which should cool it a bit. Anyone else find this odd?
Personally I'd redesign the system to put the exchanger upstream of the boiler water inlet which means that the boiler would need to expend less energy to heat the water going to the shower head.
Re: The Ecodrain: How a simple, non-moving part can reduce hot water consumption by 40%
#14I'm not sure whether I like this particular design but the idea is very good aand basic.
It is one of those things that are
- rather orthogonal to the existing system (plumbing) - helps a bit in each installation - but cumulates large gains when scaled up over a threshold number of installations.
So far, such ideas for energy consumption haven't typically thriven largely because energy has been cheap but this will probably change. It would be a good idea for the government to subside installation of such devices.
In Finland (and other Nordic countries, I guess, and probably in any country with subzero seasons) we do the same in machinated ventilation systems in homes and buildings. The thermal energy of the warm indoors air (that is exiting the system) is transferred to the air intake where it's used to heat the cold outdoors air (that is entering the system).
Re: The Ecodrain: How a simple, non-moving part can reduce hot water consumption by 40%
#15This doesn't add up. The drain water is, by definition, cooler than the boiler water. Looking at the diagram, cold water is heat exchanged with the drain water which means it will be heated but to less than what a boiler does. This heated stream is then pumped directly to the shower to be mixed with the boiler water, which should cool it a bit. Anyone else find this odd? Personally I'd redesign the system to put the…
The idea is that, instead of using cold water to mix with your boiler water, you use cold water that has been slightly heated by the heat-exchanger. This allows you to use less water from your boiler.
Re: The Ecodrain: How a simple, non-moving part can reduce hot water consumption by 40%
#16This doesn't warm up the water to the heater, but rather the water going to the cold side of the mixing valve in the shower. If it takes me 5 minutes to get the stupid thing at the right temperature now, imagine what will happen when the temperature of the incoming cold water depends on the temperature of the drain water - and it's a positive feedback - the hotter the water, the hotter the incoming cold water, making…
According to their actual website, you can set it up so that it feeds the warmed water back into the water heater, rather than straight back into the shower. Apparently there are thermostatic mixing valves that would probably help with your problem as well (although I just read that in their FAQ and really don't actually know what that even means).
Re: The Ecodrain: How a simple, non-moving part can reduce hot water consumption by 40%
#17Wastewater heat exchange is not a new concept. Here's a 1986 paper on it. http://www.gfxtechnology.com/Pravda.pdf
The GFX "falling-film counterflow" system is mounted vertically, in-line with the plumbing drain, and has a wide-bore drain pipe. It seems to me that this is inherently less prone to clogging than the horizontally mounted Ecodrain would be.
Re: The Ecodrain: How a simple, non-moving part can reduce hot water consumption by 40%
#18This line didn't add up for me: "likely your most energy-intensive daily household activity". I think overall temperature control for my house is vastly more expensive than this, given that my gas bill drops to $45 in the summer but touches $300 in the winter. I also run the dishwasher every day and do an average of one load of laundry per day (kids!). Not a bad idea for new construction, but dialing back your hot wa…
While I pretty much agree with you, and the water heater advice is great, I suspect that a decent part of that $300 jump in the winter is because the temperature of the water entering your home during the winter is much colder than it is in the summer (a.k.a. it costs significantly more to heat the same amount of water in the winter than it does in the summer).
Re: The Ecodrain: How a simple, non-moving part can reduce hot water consumption by 40%
#19This doesn't warm up the water to the heater, but rather the water going to the cold side of the mixing valve in the shower. If it takes me 5 minutes to get the stupid thing at the right temperature now, imagine what will happen when the temperature of the incoming cold water depends on the temperature of the drain water - and it's a positive feedback - the hotter the water, the hotter the incoming cold water, making…
According to their actual website, you can set it up so that it feeds the warmed water back into the water heater, rather than straight back into the shower. Apparently there are thermostatic mixing valves that would probably help with your problem as well (although I just read that in their FAQ and really don't actually know what that even means).
I have a thermostatic mixing valve in my shower. You have two knobs: One for volume and one for temperature. That's all you need to know to use it.
The valve keeps adjusting the mixture of hot and cold water until the desired temperature is achieved. (Alas it can only achieve convex combinations.)
Re: The Ecodrain: How a simple, non-moving part can reduce hot water consumption by 40%
#20This doesn't warm up the water to the heater, but rather the water going to the cold side of the mixing valve in the shower. If it takes me 5 minutes to get the stupid thing at the right temperature now, imagine what will happen when the temperature of the incoming cold water depends on the temperature of the drain water - and it's a positive feedback - the hotter the water, the hotter the incoming cold water, making…
According to their actual website, you can set it up so that it feeds the warmed water back into the water heater, rather than straight back into the shower. Apparently there are thermostatic mixing valves that would probably help with your problem as well (although I just read that in their FAQ and really don't actually know what that even means).
Thermostatic mixing valves use a thermostat to control the ratio of hot and cold water to output a selected temperature. Basically you select a desired temperature and the system attempts to provide you with it. This let's you use the shower while the hot water pipes are still heating up even though the hot water's temperature is changing.