LaDouche, a water heater that recovers the heat from waste water

At the last ces Las Vegas a French start-up has launched LaDouche. This tankless water heater recycles the heat from the hot water used during the shower, to warm up the cold water in the bathroom. A solution that would save 80% of energy for heating of sanitary water, and also serves as a pump to lift and dry-towel.
When you take a shower, the hot water that you use is drained by the bung up to the water network, sewage. The calories that helped to heat the water consumed by your water heater or your ball) have served for only a few seconds, the time you wash it. And if we could recycle the heat from these waste water to heat cold water ? It is the idea rather skilfully crafted in LaDouche, a water heater thermocyclique rewarded when THESE 2017 in Las Vegas.


This system, designed by Solable, a French start-up, is connected to both the cold water current, and the drain of the shower. Concretely, LaDouche works as a pump to lift, that is to say that the device, which is fixed at the height of a man, such as a conventional water heater, pump water that drains through the plughole, to move within the system (blue rectangle in the diagram below).


Then, in the waste water, but always hot (red arrows) will heat up the cold water for the shower (light blue arrow). This clean water and this hot comes water the user, and then will return in the circuit to exchange, in turn, its calories with the cold water of the network, and so on.



A resistance booster helps to heat the first water jets, but also to supplement this heating alternative if the user wants a very hot water. However, the concept is flanged at 42°C, a temperature high enough for a shower, but not for household use in the kitchen for example. And even the concept of the product limits its use to the shower, as opposed to a bath.

Recycle the calories to save up to 80% energy

According to Solable, the recovery of calories allows you to save 80% of the energy consumed to heat the water. LaDouche also allows you to have a instant hot water and, thus, reduce the waste cold water until the water warms up in the ball (about 15 L of water to each shower, depending on the designer). Finally, the residual energy is used to heat the towels that you have placed on the towel rail built-in.


Only downside : the price of the device has not yet been announced. It may be a beautiful solution for a bathroom with Italian shower (in which it will replace, also the pump lift), it cannot be used as a shower, and you will therefore have to be equipped with multiple models if you have several bathrooms…

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