GFX vs home brew

[daestrom]

Okay, *I* read the documents. It is clear that you must have a separate storage tank for the GFX-star setup to work 'as advertised'. Only by using a *cooler* separate storage tank is the setup able to capture the waste heat from 'batch' drains. Once the storage tank reaches the temperature of the greywater (or exceeds it in the conventional heater storage tank), performance will drop off.

This way can effectively 'shift' the heat from outgoing batch drains to a separate storage tank of fresh-water. So the greywater doesn't have to be stored, and you can still use the low-maintenance, straight-bore, GFX heat-exchanger.

For 'best' performance, you would want to route the storage tank outlet to the 'cold' tap for the shower as well. This looks like their 'tempering valve' arrangement. But you might be better off routing straight 'cold' water from the supply directly to sinks and laundry, bypassing the whole setup for cold supply to those usage points. Otherwise you would be wasting some of the captured heat on laundry, and who wants a glass of warm water to drink. Some more plumbing :-(

Someone mentioned some concerns about storage tank of 'warm' water and Legionarries disease. But if you have treated water, that probably isn't too much of a concern.

daestrom

[Robert Gammon]

agreed that water is best, but think of Freon as an alternative.

Yes, and this works well in heating dominated climates where ground water temps average less than 50F year round.

But not here with our ground water already in the high 60s to mid 70s (I measured mine at 75F)

Yes, as that tempers the water to a reasonable temp. My water will come from a well, and I need to set my hot water tank to at least 140F to kill bacteria.

Foam insulation around piping and the heat exchanger seem to be useful ideas to conserve energy as does a water heat blanket for the storage tank.

The flow is from the drain plug at the LOW point of the storage tank thru the pump to mix with fresh water. Then thru the coil, and back in to the lower third of the storage tank. There will be mixing that occurs, however, this storage tank should achieve water temps in the

70-90F range depending on entering fresh water temp.

The idea is shown on the web site best under the solar hot water retrofit. The application data shows efficiency rising as flow rate thru the coil increases for a given flow rate down the drain.

Grey water temps may NOT increase at all due to the higher flow rate (same idea as the heat exchanger itself). This higher flow rate comes at a price of increased pressure loss and expense.

Coil inlet temp will be higher, but then so will coil outlet temp.

[dold]

I have lived on well water for many years. Some people treat water drawn from shallow wells, but I don't know of anyone that does any treatment to deep wells.

I find recommendations to raise the temperature to 170f to kill hydrogen sulfide to get rid of a rotten egg smell, but even those sites say it is harmless.

Most of the advice is to set the temperature to 140 if you have a dishwasher, 120 otherwise.

[Rod Speed]

[e-mail] wrote

Few chlorinate it properly like you see with town water supplys tho.

It is in those small quantitys.

Those that know anything about Legionella dont.

[Rod Speed]

It is with storage water heaters.

[Solar Flare]

In tests of thousands of water heaters 40% were found to contain lethal doses of legionella bacteria.

Further testing found that none of the water heaters were gas fired. Only the electric heated units were the problem below the bottom element.

I believe as long as the water is moving frequently and/or heated past

96F the legionella is rendered inert.

[Rod Speed]

Bet that was just because so few of them were gas fired.

Because most codes mandate a minimum thermostat temp.

You're wrong on that last. Needs to be 140F

And there is no 'rendered inert', its either killed or it aint.

[dold]

Let's go back to Australia:

"Long exposure at 50C or shorter exposure at higher temperatures is sufficient to kill the bacteria." That would be 122F.

I remember The American Legion meeting, but that was warm water in a cooling tower, not a domestic water heater.

"Proliferation of L. pneumophila is promoted by: a wet warm environment (range 25-42C); optimum temperature (35-37C); stagnation or low water turnover; high microbial concentration including algae, amoebae, slime and other bacteria; presence of biofilm, scale, sediment, sludge, corrosion products or organic matter; presence of certain materials such as natural rubber fittings which may be a nutrient source. "

I don't think that describes my domestic water supply. The recommendation for 120F still stands. That won't scald, and it will kill Legionella bacteria.

[Rod Speed]

[e-mail] wrote

No thanks, that specification of the minimum temperature that storage hot water heaters should be set to is just about universal right thruout the first world now.

Because Legionella is a real problem with showers.

Thats on the low side of the recommendations,

60C, 140F is much more common.

Sure, and after that it was realised that storage hot water services could be a real problem with Legionella when they are set a lower temperatures to avoid scalds with kids and the elderly etc.

Presumably we didnt see that much of problem with Legionella in storage hot water systems because most didnt deliberately turn back the setpoint much before that American Legion meeting made it clear what a problem that particular bacteria could be.

Thats just cooling towers, different animal entirely to storage hot water services.

See above.

No it doesnt if you actually have a clue about Legionella

Have fun explaining the common code requirement of 60C, 140F

you are just plain wrong using rigorous science.

[Solar Flare]

Do your comments represent anything?

You need to read some documentati>

[Rod Speed]

Solar Flare wrote

Never ever could bullshit its way out of a wet paper bag.

Never ever could bullshit its way out of a wet paper bag.

[Robert Gammon]

Well in the Solar Heater Retrofit, HE DOES NOT USE A SEPARATE TANK!!!

In NEW construction easy to do, or in a home with ALL plumbing in the basement, this is just a few new runs of 'cold' water. I see the laundry also getting the warm water from the heat exchanger. Only refrigerator water supply, and sinks get untreated water. Most all the clothes washing we do is in Warm water, so if that winds up being a bit warmer than usual, OK.

Its not just Legionnaires, there are an army of bacteria waiting to do damage. Water with chlorine added, ie city water supplies will be ok. Well water needs special treatment. My application will be new construction with a well. All water will be processed thru a Whole House Filter to get rid of sand and silt. Then it goes thru a

1000gal/day RO with UV to a 350-500 gallon storage tank. A 65psi pump thn delivers this water to all uses in the house.

[Robert Gammon]

Warm water to drink is not good, BUT neither is really cold water either. Our preference is for cold water, especially in HOT climates. However we will usually drink MORE water at a time if the water is in the 60-70F range than in the 40-50F range. The really cold stuff, we just sip every now and again. A bit warmer and we'll gulp it down.

So in areas that have 40s year round average cold water inlet temp, treat the WHOLE house to GFX treated water, raising cold water to 65F helps us drink more water and has no significant affect on cold water cleaning performance in the laundry.

Note we almost NEVER use the cold cycle in our laundry, so if Warm cycle water temp changes from 85F to 95F, so what!!!