Has anyone used domestic water main as a heat sink for a water source

[Jabba007]

heat pump system?

I want to attempt it, but the principal (Owner) is not willing to guinea pig, and wants me to find other successfull installations first.

Essentially I want to "borrow" water from a domestic main, run it thru a plate and frame HX and re-inject it back into the main at a point downstream from where I took it. This will essentially utilize a very abundant heat sink for a large(ish)(400 ton) water source heat pump system.

Any ideas of where I can find examples of where this has been done before?

Jabba

 

[DMSPE]

Jabba007:
Have you considered using WWTP effluent?
How about a river (if possible)?

Check out these two links to geothermal projects in PA.
The first uses a river.
The second (a Google link to multiple project documents)uses city WWTP effluent.

http://www.impactpa.net/geotherm/impact_warren_aug18-05test.html

http://www.google.com/search?hl=en&q=geothermal+"water+tower+square"+williamsport

 

[darkvibe]

Toronto has a system that uses domestic water (AFTER it bas been treated) to cool a chilled water loop via plate and frame heat exchangers. They ensure a leak in a Hx will not contaminate the water in the domestic system by keeping the pressure higher on the domestic side (per an engineer with Enwave at a conference in Toronto 2 years ago).

http://www.enwave.com/enwave/dlwc/

or search for deep lake water cooling in toronto

Sort of off topic but relevant to the heat exchanger/domestic water comments posted above in this thread.

 

[MAragorn]

It has been a long time since I even looked at ground source heat pumps. We considered that on a project for an observatory where the heat generated by a condenser would cause the air to shimmer, disrupting the view of the sky.

But at that time, the thought was to drill a well a couple of hundred feet maybe and run a closed loop down and back, making our own geothermal heat sink.

Is that not done any more? That doesn't depend on the volume of ground water to do the heat transfer.

I do agree with some of what has been said. Minimizing heat loads, running very low pressure drop duct and piping systems, simple, reliable equipment and controls has always served me well in designing energy efficient systems.

As you say, not everything new is bad...nor is everything new good either. I deplore some of the things done these days in the name of energy conservation, that do nothing more than disguise systems that were poorly designed to begin with.

 

[Jabba007]

Yeah we still do earth coupled systems, both with horizontal and vertical fields. The cost of installation for them can be very high. In Indiana there are essentially only two contractors doing the field installation work, and thus... little competition. Vertical well drilling is pretty expensive as well.

I am just exploring ways to use in conjunction with passive methods, to have the most energy effecient system I can dream up, with the lowest installed cost as well.

This is FUN stuff to think about, even if it doesn;t get built.

Jabba

 

[gregreader]

Jabba -

I have client (school district) that wants to try water-main w/ water source heat pump system. How did your situation work out? Greader3@comcast.net

 

[willard3]

The prime responsibility of a Prefessional Engineer is public health and welfare.

Piping potable water through a chiller is an abrogation of this responsibility, whether or not you save energy.

 

[zekeman]

Quote"If I was too harsh in this post, I apologize. I fight a battle at the office every day with a designer that is 65 years old, tired, ready to retire that does not want to LEARN about anything. He applies rules of thumb to everything and screws up a lot of stuff that I have to clean up. I am a little overly sensitive to the industry inertia to just do what we have been doing.'
----------------------------------------------------------
Your concept has zero merit and looks like the brainchild of an eager 14 year old wannabe engineer.
First off, you keep ignoring the fundamental issue of reinjection and pollution.(i.e.don't confuse me with facts) Are you going to guarantee a safe injection system. Second, how do you get this "infinite" supply of cold water and who guarantees the temperature and when you pump it back ,exactly where does this water go and who pays for the water you are using? Are you telling the utility you want credit for the warm water you are returning? Good luck.
And by the way what have you got against 65 year old engineers who don't "think" out-of the box like you, are they "tired".

 

[Jabba007]

Quoted... "Your concept has zero merit and looks like the brainchild of an eager 14 year old wannabe engineer.
First off, you keep ignoring the fundamental issue of reinjection and pollution.(i.e.don't confuse me with facts) Are you going to guarantee a safe injection system. Second, how do you get this "infinite" supply of cold water and who guarantees the temperature and when you pump it back ,exactly where does this water go and who pays for the water you are using? Are you telling the utility you want credit for the warm water you are returning? Good luck.
And by the way what have you got against 65 year old engineers who don't "think" out-of the box like you, are they "tired"."

Response:

My mentor was 67 years old when we met. He was neither old nor tired. He embraced learning new things. Was eager to calculate them properly, and did not take the path of least resistance at every opportunity.

I was not proposing running potable water directly thru a chiller. I was proposing running it thru a heat exchanger to isolate the potable from the chiller water. There are food grade plate and frame heat exchangers. My safety intent would be to have the potable system at a higer pressure than the chillers condenser water system so if there was a leak... it'd leak OUT of the potable system. And I don't know if you have any experience in city water or not, but it's NOT that clean. They get mains that break all the time, and Joe Dirt jumps in the hole and patches it up with little to no regard for cleanliness. It's not like our water system is a sterile, hospital like system anyway. You are the one that does not want to be confused with facts pal. I'm sorry your over the hill, and I'm sorry you think you know all there is to know. Me, I do not know everything, and never will. There is always new stuff out there, and just because it's never been done, done not mean it's a bad idea. You just crawl back in your hole, and keep doing the exact same things you have been doing for the last 40 years. What's the big deal if you re-inject the water 10F hotter than you got it?

I did not think this up. I read an article about it a while back. So it had enough merit to get published in a trade journal. My intent of posting it here was simply to have a discussion of interested parties.

To answer the question of how did it turn out... I knew all along I'd never get to do it, but still like to talk about ways to save energy. We're in desperate need af saving energy now. Our world, and out engineers have been throwing more energy at problems for far too long. It's up to us (The next generation of designers) to help SAVE energy rather than squander it like our predecessors have been doing.

Jabba

 

[AbbyNormal]

maybe the young buck could learn a thing or two from the old guy zeke

Take the "V" out of HVAC and you are left with a HAC(k) job.

 

[AbbyNormal]

sorry zeke, you had the same point of view, will read the whole post next time

Take the "V" out of HVAC and you are left with a HAC(k) job.

 

[gregreader]

This morning the Water Utility rejected the concept for all the legitimate public health concerns noted by many of you.

FYI - The idea of using the utility water supply was being promoted by the Customer and I really appreciate having more than just my opinion to support my no-go decision.

 

[russmech]

I didn't read all the answers to the threads, but I'm glad to see so much interest in saving energy.

I also doubt very much if the water utility company will allow you to do ANYTHING with water except use it; many utilities require backflow prevention devices even on residential system to prevent any water from going back into their system.

However, have you considered using the floor of the parking structure as a heat sink? Imbedded tubing in the cement floor of the parking structure would create a radiant floor system that could act as a heat sink (rather than using such a system for comfort heating or snowmelting as we do up here in the northland). And adding tubing into a floor that most likely already has a wire mesh or reinforcing steel grid would not add that much cost.

 

[Jabba007]

I angled for earth coupleing (geothermal) early in the project and it was rejected. Initially the developer thought he was going to do this with residential style heat pumps. LOL It took almost a year to convinvce them that that was not a practical approach. Eventually we convinced them to go water source heat pumps, and finally to a central plant style system. Now the gagage is already under construction. To effectively use the ground loop for cooling, it really needs to be deeper than in the slab. With the other earth coupled systems I have done here, they have been required to be at least 48" deep and some as deep as 72".

Utility companies are, in MY opinion a little bit hypocritical and over cautious. I understand their position, but I think they are ignoring a great heat sink that COULD be designed to function safely, and could generate them revenue. While conserving natural resources and saving energy. I know, that water delivery mains are far from clean, let alone sterile.

Is 40 considered a "young buck"? If so... thanks!

Jabba

 

[Warpspeed]

Only part of the problem has to do with the fear of contaminants leaking back into the public water supply. There is also the problem of thermal pollution (cold water no longer being cold).

But much more objectionable is that heating water drives out the dissolved gases, especially the oxygen. This changes its taste and "quality" significantly. It is the dissolved gases in water that make the difference between ice cold water from a fresh bubbling mountain stream, and warm water from a stagnant shallow pond that has been sitting out in the sun for a while.

Both may be acceptably chemically and biologically clean water in the strictest scientific analytical sense, but the difference in perceived quality is very obvious to either human or animal.

 

[Jabba007]

Warp speed... that is the best "reason" that I have heard thus far.

Nice insight.

Jabba

 

[BronYrAur]

I haven't read the article, but this recent Trane newsletter addresses water-side heat recovery. I don't know if it covers domestic water, but it may still be of some help:

http://www.trane.com/commercial/navigation/files/PDF/552/ADMAPN023en_0207.pdf

 

[ttsquared]

How about instead of rejecting the water back to the utility, the water is used in the facility for flushing toilets, irrigation, etc.. This does not provide a constant heat sink, but the cooling capability of the utility water is realized and the quality of the water for the purposes mentioned is not an issue.

 

[Jabba007]

TTsquared, that's a great idea too... unfortunately, it would require a lot of additional plumbing to keep the thermally altered water separate from the unaltered water.

Not appropriate for THIS project.

Newest development... there is a lot of ground water at the site. It's still a little undetermined exactly HOW much there will be, but they are thinking in the neighborhood of 500 GPM at it's slowest. The have to collect it and pump it away anyway. I am going to try to utilize this throw away water, thru a HX as a retro-fit to the central plant water source loop once it's established how much water will actually be available.

I'll not be depending on this heat sink, so if it dries up someday the system will still work, but it'll be a nice way to lower the demand on the evap cooler when it's available.

Jabba