Saturday, November 15, 2008

2.The small bathroom heat exchanger - miljødusj

I thought I should give Norwegian websites a try in my urge for finding a small heat exchanger for our shower. To my surprise, a new product had just been introduced to the Norwegian market by (Norwegian only). (It should also be available in Austria, Slovakia and Germany. More information on the product can be found at the SUP technology site in the Czech Republic ). There it was. Just what I had been looking for. I talked to the salesperson who explained a bit more how it worked. Cold water from the house pipe connects to 1. Drainwater from the shower flows into 4 and heats the copperpipes of coldwater inside the box, before it exits out and down the drain at 3. Preheated cold water will exit from 2 and on to cold water pipe of the shower. The salesperson said the coldwater would increase 12-15 C (53-59F). He claimed it to be actual measured numbers.

I ordered it and prepered to put it to the test.

Continue reading here: 3.Looking inside the heat exchanger


chrugel said...

How is the testing going?
I'm thinking about getting one my self. There is just some potential problems i'm worried about: oe is that is is going to be wery hard to adjust the temperature to the desired level. When the initial adjustments has been made the temperature will slowly rise as the cold water gets warmer.
The other problem is that cooling and slowing down the waste water will case fat, soap and hair to settle in the exchanger. This will severly impact the preformance and eventually close it up.


chrugel said...

Ops, I kept reading in saw you have done quite extensive testing! looks very nice! thank you!


frehak said...

Hvordan går det med testingen av miljødusj ?

Svein* said...


Du får se videre i arkivet. Det er hvertfall 6 deler med informasjon om Miljødusj. Legg gjerne igjen en kommentar om det er noe du savner.

Glen said...


I'll write in English to widen the audience. This unit was mentioned in an article in the Norwegian newspaper Aftenposten yesterday - unfortunately not by name so I had to dig a little. Your information and tests are great - thanks. But have you thought about Chris' issue about gunk filling up the unit? The manufacturer says you can just use drain cleaner but I have my doubts. Do you know of an inline filter or other similiar device that could protect it?

Regards, Glen

Svein* said...

Hi Glen,

Our shower cabinet has a standard filter on the floor before water enters the flexi pipe and into the Miljødusj. I clean it perhaps once a week. Soap and hair makes the water flow too slowly, and the water level on the shower cabinet floor rises. If you look at the pictures taken from inside the Miljødusj unit, it should be clear that it would be almost impossible to make it clog up completely. It is wide open in there. Of cours, anything that settles on the copper pipes will insulate a bit and degrade performance. I have made a habit of pouring the left over boiling water after making pasta for dinner into the shower. This will hopefully clean out the unit, at least somewhat, while I also recover some of the heat from the pasta water. I do not want to use any chemicals, such as Plumbo. My believe is that the shower cabinet filter and alomst boiling water will keep the unit clean. If it should ever clog up, I would rather think it would be somewhere in the flexi pipes going to or from the unit. It is important that all the flexi pipes have an even slope inclination, both for obtaining enough water flow, but also to prevent an accumulation of "clog material". If it ever clogs up, I will defenitely post it on my blog.

adson stone said...

Tell Them Everything
Be sure to communicate all pertinent information regarding your application to the manufacturer when you request a quotation. Two liquid streams, referred to as the "hot side" and the "cold side," go into and come out of a heat exchanger (figure 1). As a result, there are four temperatures to consider when sizing the heat exchanger: hot side inlet, hot side outlet, cold side inlet and cold side outlet.

The minimum information needed to size the heat exchanger for both the hot and cold sides are: fluid names, flow rates, inlet temperature, outlet temperature, operating pressures and maximum pressure drop allowed across the unit. For fluids that are uncommon or proprietary, physical properties such as viscosity at inlet and outlet temperatures, thermal conductivity, specific gravity and specific heat will be needed. Most manufacturers have a design questionnaire available for you to use when collecting data for a heat exchanger application and would be eager to furnish you with a copy.
click here

adson stone said...
This comment has been removed by a blog administrator.