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Re: Any threads on tankless water heaters?
Murph #382175 08/27/12 01:32 PM
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Originally Posted By: Murph
Re. "water going right back into the environment"...

While that is true as a simple statement, the net local effect is usually nothing so simple. Ground water systems are almost always autonomous and utility companies rarely (probably close to never) put water back into the same systems that they are taking from. Too much risk, plus there is usually a shorter route to the 'dumping' area than the distance to pipe it back to the source.

It is very possible to entirely drain a localities water source as the water does not go full circle (evaporation, redistribution) in a timely manner. That is happening right now in the City where I work due to an unusually dry summer and combined with city planners who are approving record numbers of building permits (mostly for multi-unit dwellings) while still trying to run the city on it's old single reservoir.

This can be accentuated by looking at people who use wells in their own back yards for heat pumps. Some heat pumps operate on a dual well system where they draw from one well, use it for home heating, then dump the water back into another well. Even though both wells might be in your back yard, it is very possible that both wells touch entirely different underground water systems. It is possible to entirely drain your input well dry, even though you are dumping water back into the ground only 100' away.

I'm not preaching conservation here as I don't know your local situation. I just wanted to share a very tiny bit of what I've been learning lately about water tables.

Actually this can be true depending on your local situation Murph.
A city that draws water from a groundwater source (although alot less common b/c it would have to be one amazingly large and fast recharging aquifer for a large city), the water return would be to a surface source.
The key for such cities/houses is to know what their recharge rate is and not to exceed it, or even more conservatively, not exceed say 75% of its recharge rate. Many systems have not accounted for this rate (e.g. a typical farmer's plot out in rural areas) and just start drawing water, digging down deeper when the well runs dry after x many years.
In our city case, they draw from a lake and it goes back into a river which all follows the same watershed path. The water is simply taking a diverted course, so to speak.

Do any of the PEI towns/cities use desalination of ocean water for a source?
It has its inherit problems but would provide a lesser concern about drawing down freshwater aquifers on the island.

In re: to heat pumps, are you referring to the heat pump geothermal systems to heat a house?
If so, i've never heard of anyone using water in those systems (maybe this is an older design?). Typically it is propylene glycol in a sealed loop that runs through the earth under the frost line. Some friends of ours have a system that runs along a lake bottom using the lake water instead of earth as the moderating heat/cooling source.


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Re: Any threads on tankless water heaters?
chesseroo #382177 08/27/12 02:24 PM
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Originally Posted By: chesseroo
Originally Posted By: Murph
Re. "water going right back into the environment"...

While that is true as a simple statement, the net local effect is usually nothing so simple. Ground water systems are almost always autonomous and utility companies rarely (probably close to never) put water back into the same systems that they are taking from. Too much risk, plus there is usually a shorter route to the 'dumping' area than the distance to pipe it back to the source.

It is very possible to entirely drain a localities water source as the water does not go full circle (evaporation, redistribution) in a timely manner. That is happening right now in the City where I work due to an unusually dry summer and combined with city planners who are approving record numbers of building permits (mostly for multi-unit dwellings) while still trying to run the city on it's old single reservoir.

This can be accentuated by looking at people who use wells in their own back yards for heat pumps. Some heat pumps operate on a dual well system where they draw from one well, use it for home heating, then dump the water back into another well. Even though both wells might be in your back yard, it is very possible that both wells touch entirely different underground water systems. It is possible to entirely drain your input well dry, even though you are dumping water back into the ground only 100' away.

I'm not preaching conservation here as I don't know your local situation. I just wanted to share a very tiny bit of what I've been learning lately about water tables.

Actually this can be true depending on your local situation Murph.
A city that draws water from a groundwater source (although alot less common b/c it would have to be one amazingly large and fast recharging aquifer for a large city), the water return would be to a surface source.
The key for such cities/houses is to know what their recharge rate is and not to exceed it, or even more conservatively, not exceed say 75% of its recharge rate. Many systems have not accounted for this rate (e.g. a typical farmer's plot out in rural areas) and just start drawing water, digging down deeper when the well runs dry after x many years.
In our city case, they draw from a lake and it goes back into a river which all follows the same watershed path. The water is simply taking a diverted course, so to speak.

Do any of the PEI towns/cities use desalination of ocean water for a source?
It has its inherit problems but would provide a lesser concern about drawing down freshwater aquifers on the island.

In re: to heat pumps, are you referring to the heat pump geothermal systems to heat a house?
If so, i've never heard of anyone using water in those systems (maybe this is an older design?). Typically it is propylene glycol in a sealed loop that runs through the earth under the frost line. Some friends of ours have a system that runs along a lake bottom using the lake water instead of earth as the moderating heat/cooling source.


Hey Chess,
I think we are largely stating the same thing in different ways. The important part is understanding and respecting what you can draw vs. how fast it can be refreshed, regardless of where and how it loops back into the environment.

Interesting that you mention your water goes back into the system upstream of your water source. In my province and several neighbouring ones, I was told there are laws stating that municipalities may not reintroduce treated waste water back into any feeder system directly or upstream. This may not be as much due to strictness, as it might be simply because of the fact that our rivers tend to be on a much smaller scale her in the Maritimes, certainly on PEI for sure.

Yes, I was referring to geothermal heating systems. Back when I looked into it as a possibility for my new home, there were locally two commonly used methods. The dual pump method (which is now discouraged but still available here) or a 'closed system' much as you described. However, during that time a closed system still used strictly water within the loop. I refused to go dual pump after researching it and coming across tons of photos of the sink holes and unplanned wading pools that the dual pump systems were creating in areas of Europe. The few of contractors doing geothermal at the time were not "into" closed systems (Guess what, the geothermal guys were well drilling companies at that time. Duh!")

So, in short, I never bit the bullet on geothermal. Also, we ran out of budget for the significant initial investment it added back then.

All that aside, you are correct though, knowledge and responsible use is the key.


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Re: Any threads on tankless water heaters?
Murph #382183 08/27/12 03:20 PM
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Quote:

Hey Chess,
I think we are largely stating the same thing in different ways. The important part is understanding and respecting what you can draw vs. how fast it can be refreshed, regardless of where and how it loops back into the environment.

For localized groundwater pumping, this is far more true compared to lake or river pumping.
I have yet to hear of a Canadian lake drawn down to the point of it turning to a swamp due to the use by a town or city.
Typically water levels decline more often due to changes in weather in a particular year. We have some groundwater recharge problems in communities south of the city that do not use the city water source. They are now working on management plans for those aquifers.
Inland aquifers need to be carefully managed more so than surface water sources, broadly speaking.

Quote:
Interesting that you mention your water goes back into the system upstream of your water source.

I think you misunderstood.
Winnipeg water is drawn from Northern Ontario (Shoal Lake off the side of Lake of the Woods, a rather large lake even by Canadian standards).
From there it is pumped to Winnipeg, then treated and discharged into the Red River which heads north to Lake Winnipeg and eventually to Hudson Bay. Shoal Lake drainage flows north (it is above the Arctic Watershed line; http://www.ontarioplaques.com/Plaques_STU/Plaque_Timiskaming04.html) and essentially is part of the same drainage basin as the Red River (Hudson Bay via Nelson).
http://atlas.nrcan.gc.ca/site/english/maps/environment/hydrology/drainagebasins
So in a sense, the water removed from Shoal Lake for Winnipeg water use is taking a diverted route to end up in the Hudson Bay regardless.

Quote:
So, in short, I never bit the bullet on geothermal. Also, we ran out of budget for the significant initial investment it added back then.

Friends of ours built a summer home in the Muskokas in the past 2 years. They have a newer geothermal system; glycol based, closed loop, using the lake as the thermal zone instead of having to dig into the earth. Expensive, yes. Works incredibly well and energy efficient, yes.


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Re: Any threads on tankless water heaters?
chesseroo #382199 08/27/12 05:26 PM
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Quote:
For localized groundwater pumping, this is far more true compared to lake or river pumping.
I have yet to hear of a Canadian lake drawn down to the point of it turning to a swamp due to the use by a town or city.


True but it has happened in Australia and numerous other countries with climates much hotter than ours. Drained is perhaps too dramatic a term. Shutting down a particular reservoir though to avoid 'draining' does happen though.

Again, scope is important to consider. Closer to my home, Saint John and Fredericton both have come had to stop pumping from specific reservoirs in the last few years as they approached dangerously low levels. Of course, they both have multiple reservoirs so they still get by.

This year, several main tributaries which are part of the watershed system that is the lone reservoir for City of Charlottetown have completely dried up. It happened last year as well for the very first time but this year much larger sections have gone dry. We just have had not enough rainfall to meet the demands of the pumping. The city is calling for voluntary conservation measures but most recently, the federal government has actually warned the City that they must do more to conserve water or fix the problem. Conserve Water, Ottawa Warns Charlottetown
Very embarrassing for the City as just months ago, they felt the repercussions of ignoring the Feds. on another warning to clean up a sewage into the river issue and ended up with an ultimatum to correct the problem in two years or face financial& legal repercussions.

Quote:
I think you misunderstood.

True to some degree. I never thought about the size of the body(s) of water you were referring to and certainly had no geographic knowledge of the details of how it your system worked.
However, like my entire post, I wasn't arguing a point, merely discussing something of interest. I was merely stating that I found your situation interesting because of the limitations I explained here. Again, size is the key as to why it is different and why we think in the somewhat same but somewhat opposite ways.

Quote:
(Geothermal) Works incredibly well and energy efficient, yes.

Agreed. I would have loved to have put in a closed loop, geothermal system. I just couldn't afford to bring in somebody from out of province who was willing to do it the way I wanted it. Now, that would not be a problem as there are many more people offering the service than just the well drilling companies.

Last edited by Murph; 08/27/12 05:40 PM. Reason: used wrong markups

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Re: Any threads on tankless water heaters?
Murph #382201 08/27/12 05:41 PM
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So again, i know they have their problems but why is there not more effort in developing desalination plants in places like PEI?
Even with passive osmosis screens (low energy but higher maintenance compared to boiler systems) obtaining freshwater from the ocean seems a more useful thing to do than drain freshwater from areas that don't have freshwater reservoirs or deep aquifers.

Maybe some water engineer knows more about that.
Anyone?

On the topic of sewage, the city of Winnipeg was charged under the Fisheries Act a few years ago for an accident but nonetheless a spill from a broken valve.


Last edited by chesseroo; 08/27/12 05:43 PM.

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Re: Any threads on tankless water heaters?
chesseroo #382202 08/27/12 06:21 PM
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Originally Posted By: chesseroo
So again, i know they have their problems but why is there not more effort in developing desalination plants in places like PEI?
Even with passive osmosis screens (low energy but higher maintenance compared to boiler systems) obtaining freshwater from the ocean seems a more useful thing to do than drain freshwater from areas that don't have freshwater reservoirs or deep aquifers.

Maybe some water engineer knows more about that.
Anyone?

On the topic of sewage, the city of Winnipeg was charged under the Fisheries Act a few years ago for an accident but nonetheless a spill from a broken valve.



I have little knowledge at all about desalination or it's efficiency so I couldn't offer a reply. Considering that they predict our Oceans to do nothing but rise for the next while, it seems like a worthy pursuit.

However, I do know from discussing it with a friend who lives in Dubai where there is a very large scale plant in operation, that it is very expensive process on a cost per litre basis. She told me how many times more expensive vs. fresh water collection but I can't recall. Also, that the plan in general comes under fire by ecological watchdog groups because the process of desalination also almost completely devoids the water of all of it's tinier organisms living in it. I must also assume that it produces a waste product. I'm speaking whimsically but maybe we can further refine that into road salt that we use so much of here in the winters?


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Re: Any threads on tankless water heaters?
chesseroo #382203 08/27/12 06:35 PM
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Cheeseroo, it comes down to cost... Desalination plats are ridiculously expensive, both to build as well as operate... Especially the ones that operate off of electrolysis, the amount of electricity used is CRAZY... Towards the end of my time in the Navy the submarine i was stationed on had a reverse osmosis system installed as a solution to the desalination issue for fresh water generation.. Prior to that they had a boiler system.

Re: Any threads on tankless water heaters?
chesseroo #382208 08/27/12 07:28 PM
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I just recently relocated just outside of Ottawa, and the "open loop" twin well type of geothermal system is very common here.

Take a look at this map. The shaded blue areas indicate aquifers that yield a minimum of 0.4 litres per second. (About 6 gallons per minute)

Anyway, back to tankless water heaters. At work, we exclusively sell the Rinnai, as they tend to be one of the most trouble free brands. Having a water softener is a must, as well as doing a "flush" of the unit yearly. Past that, I don't find the other issues a problem. I currently have an R75 that I'm thrilled with.

Wait time for hot water:
In our last house, the conventional tank was on the opposite side of the home, so we were used to waiting the 30 to 40 seconds anyhow. This has been an absolute non-issue for us.

Dishwasher / Laundry:
Again, I was used to letting the water run at the old house, so I do the same here. Turn on the kitchen tap until the water runs hot, then start the dishwasher. Once I am positive it is filling, I turn the tap off. Same for the washing machine.

In my opinion, not running out of hot water is worth the potential drawbacks. And whether it is more efficient or not, I still really like the idea of not keeping a tank of water hot while I am sleeping, or at work.


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Re: Any threads on tankless water heaters?
real80sman #382210 08/27/12 08:07 PM
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I really appreciate the feedback from people who already have the tankless system.
The more people i hear from, the more i am to decide yes, that would work for us, or no, the little things still cannot be easily overcome.

Originally Posted By: real80sman

At work, we exclusively sell the Rinnai, as they tend to be one of the most trouble free brands. Having a water softener is a must, as well as doing a "flush" of the unit yearly. Past that, I don't find the other issues a problem. I currently have an R75 that I'm thrilled with.

From what i read in reviews of various brands, the Rinnai had the least complaints about failure and mostly the typical complaints i mentioned earlier. I think if we go tankless, i'll probably buy Rinnai.

Water softener?
Ok, we can't do that. It adds a whole new issue of space, installation and maintenance in our situation, aside from the cost of salt. Winnipeg water has a moderate to hard total hardness of about 70-90 mg/L (as CaCO3) and i expect that would be an issue w/o a softener.
I have also read about this annual flush of the unit which supposedly requires some special hookup connection or other equipment that a homer owner generally would not have.
Correct me if that information is wrong.
That's more maintenance than what i do with our tank system, which is nothing (ya ya i know you probably should be trying to drain sediment once a year, etc. etc. but the tank is from 1999 and still going without having received any maintenance so how does that compare to tankless??).

Quote:

Wait time for hot water:
In our last house, the conventional tank was on the opposite side of the home, so we were used to waiting the 30 to 40 seconds anyhow. This has been an absolute non-issue for us.

I can understand that. It still takes time to flush a line whether it is tank or tankless.

Quote:

Dishwasher / Laundry:
Again, I was used to letting the water run at the old house, so I do the same here. Turn on the kitchen tap until the water runs hot, then start the dishwasher. Once I am positive it is filling, I turn the tap off. Same for the washing machine.

Considering how much laundry we do with kids in the house, i doubt this is something that would go over very well with the wife.
This goes back to the 'wasted' water concept. I wonder if the washer and dishwasher would even draw enough volume to get the tankless system to turn on. When they pull in water for use, its not the same flow rate as turning on the tap to full. As such, it could start with hot water but during its rinse cycle for example, it may not pull hot water from the tankless system and i won't be around during its cycle to ensure i've turned on a sink tap prior to the rinse part.

I'm just cycling this possibility around in my head. Maybe the draw of the washers do trigger the tankless to turn on. I don't know what the flow rates and thresholds are for each.

Quote:
In my opinion, not running out of hot water is worth the potential drawbacks. And whether it is more efficient or not, I still really like the idea of not keeping a tank of water hot while I am sleeping, or at work.

I agree.
Which is why we are considering it.
But i think the back breaker or perhaps the final straw is the softener conditioning.
I also know that if the power goes out, the tankless system is useless where the tank at least has a reservoir for a short period.

Originally Posted By: real80sman
I just recently relocated just outside of Ottawa, and the "open loop" twin well type of geothermal system is very common here.

You moved?
Doesn't anyone keep me up to date with these important announcements anymore?


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Re: Any threads on tankless water heaters?
chesseroo #391646 04/03/13 06:42 PM
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Just bumping this thread since we are finally in the midst of making a decision on a water heating system.
Two options:
Keep the present water heater and add an additional storage tank with a recirculation pump between the two (50 gallon plus another 80 gallon for a total of 130 gallons BUT have two tubs which together when full consume 80 alone).
or
Go with a hybrid tankless design.
http://www.hotwater.com/water-heaters/residential/hybrid/next-hybrid-gas/

Pluses and minuses:
Extra storage tank means reduced storage space and would not have unlimited hot water (estimating that the extra volume would be enough is still an uncertainty). Cheaper installation and can keep present venting (steel pipes connecting to and out the furnace chimney).

Hybrid means smaller footprint, high efficiency, endless hot water and based on the design, no cold water sandwiches (our main issue with the standard tankless system).
However, new ventilation is required (cpvc piping and not out the furnace flue) which means higher installation costs.
Potential for higher maintenance (the tech is still a bit new and we've heard downsides to the required annual flushing of a tankless setup as previously mentioned). At least the AO Smith unit has a 6 year warranty for tank AND parts which provides a bit of confidence in the product.

Just waiting to hear on prices for these options which could also be a deal breaker.
If the extra tank idea comes in around 2k but the hybrid option is say 8k, the choice is easy.

Last edited by chesseroo; 04/03/13 06:46 PM.

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