Delta-P/Delta-T Part #5

hot_rod

80W vs 10W

or 80 vs 40W maybe more average. This is where I was going. If you install or replace a circ, up-selling to an ECM just for the energy savings, even running on a fixed speed mode component may appeal to buyers.



Keeping in mind consumers spend 10- 20 K for SDHW systems to to offset 300 bucks a year worth of energy savings. Same with multi thousand dollar PV systems, when a KW is 7 cents in my area, 4 cents for off peak in some states.



I doubt many consumers know or care about the ∆ twins, or could follow the discussion if you were to engage them Even the pros here have spinning heads watching this T vs P discussion. Offer your customer nicer, more efficient equipment, they often say yes!



I doubt phones will be ringing off the hook with customers gushing about how much more comfortable their building is with a few degrees different control of the ∆T. But they will brag about efficient light bulbs, appliances, cars, etc.

Eastman

Right

The marketing war is for the contractor not the consumer.  The flow pro blog isn't being read by the average homeowner, it's intended for people that are already considering ECM or would like to utilize the delta function.  I'm sure Taco would be more than happy if the end user even associated them with hydronic systems.



I don't think the goal should be up selling at all cost, but clearly ECM has a place in this industry.  How does one decide which version to pick for a given situation, though?  I don't feel like there is framework of thought out there that is totally convincing.

Rich_49

Eastman

will the pressure in the system change with differing flows at differing temperatures ?   I think so and this is my case for Delta T over Delta P . One can do what the other can and one cannot perform the added function . I will spend my customers money on the higher level of control and options .   By the way , I don't know if anyone has noticed but most of the Delta T bashing has been originating from those paid by competitors as far as I can tell through researching the names associated with starting the discussions .  Remember that Taco produces both technologies .

CMadatMe

Bashing

My entire point has been that John has not been bashing. He's been showing how both pumps operate under the conditions in his blog. It's information and education for contractors that haven't a clue as to how either pump operates.



Take the knowledge apply both pumps operation to your job and pick the one that fits best for you. What's wrong with that. He hasn't said anything that is not 100 percent true.

hot_rod

questioning fuzzy logic is bashing?

I thought the intent of "The Wall" was to question, learn and share experiences. Share what we have all learned from the years of collective knowledge. That's why I signed up.



Care to substantiate that claim about paid competitors asking the tough questions?





Why would anyone keep starting a fresh thread about this topic unless they wanted to hear more opinions?



Can't take the heat, stay out of the boiler room, or let the ∆T be free

knotgrumpy

Wow!

That is quite a claim.  I've asked questions about this topic.  Am I a spy from Grundfos? Wilo? Xylem?  Nah.  Just a guy who likes to tinker with and think about mechanical things.



Besides - if the 'competition' is going to rush to produce Delta T circs soon anyway, why would their moles question the technology?

NRT_Rob

I have

a lot of respect for john... he was the first trainer I ever experienced in this industry. he's a great guy.



but the fact is you cannot make a pump speed up by closing zones. can. not. happen. ever, in any circumstances, no matter what.



so he is NOT educating and he is NOT being even handed in this matter. he's wrong. and he's using sales BS... either intentionally, or mistakenly. but either way, this is a fluff piece, not serious analysis.



Delta T has a place. Delta P has a place. but Delta T doesn't get its place by being misleading about how Delta P operates.

CMadatMe

How Can You Say

You cannot change pressure by opening and closing zone valves? Are you saying each zone has the exact same head loss and flow requirement? So no matter what, I'm moving x gpm consistently no matter the zone length, head loss or btu/hr requirement 24hrs a day seven days week or as long as the pump is running?

Eastman

Address payments to...

How do I sign up?



Rich, I hope I don't sound like I'm trying to promote delta P.  I think there are uses for delta T, delta P, and fixed speed ECM.  (And all the hybrid modes that are available on some units.) 

NRT_Rob

nice

straw man there. I didn't say you couldn't change pressure.



I said: you cannot SPEED UP a pump by CLOSING zone valves. not in a real, operating system. but his analysis says, in fact, you can.

Eastman

Conditions A, B, and C

implicitly define two different head requirements at the same flow for some of the zones.  Hence the erroneous conclusion.  

Rich_49

You cannot

Speed up a pump by closing zone valves ! Rob , you may possibly want to read the blog you are referencing . I believe John said as zone valves close the circ will slow down .

NRT_Rob

Read it again.

John is saying that 2 small zones running could run faster than all 3 zones calling. in his blog, condition "b" vs condition "c".



that is not possible in a real system with the equipment he is talking about.

CMadatMe

Show Us

What happens Rob so we can all see. Your throwing opinion and not seeing any facts. Chart it, plot it and write it. Show us what happens. We are all here to learn more. I need more information then just opinion. I'm a, have to visually see guy.

Eastman

From the article

Edit failure.  Somehow everything got erased.



From the article



"But it’s when the two smaller zones are calling that this gets

interesting.  If you calculate out the system curve of 4 GPM at 2′ of

head (Red , plot the points and connect the dots, you see where that

system curve intersects the pump curve (Purple .  Not only is actual

flow rate more than 2.5 times what it needs to be (10.5 GPM vs. 4 GPM),

the pump will be running close to full speed.



In fact, it’ll run faster with two zones calling than it will with all three zones calling.



Program the Delta-P pump more accurately, the situation improves, but the same dynamic exists: 



see attached image



The circulator is dead on with all three zones calling, but when the

small zones are calling, the supplied flow rate will be double what it

required, and the circulator will still go faster with two zones calling

than it does with three zones calling."



*****************************************************************************

I think this is a good example of why balancing is important.  Adding hydraulic resistance to zones 1 and 2 actually improves efficiency while leaving additional pumping capacity for future zones.



For reference:  Condition A is zone 1 calling, B is zones 1 and 2 calling, C is 1, 2, and 3 calling together.  Zones 1 and 2 required 2gpm at about 1' of head.  Zone 3 required 3 gpm at 4'.  The problem here is that John added the target flows from zones 1 and 2 at 1' of head to the target flow of zone 3 at 4' of head, and then called that condition C.  (the red one)  This is not a physically possible condition though, as at 4' of head, zones 1 and 2 will be moving much more water then required.

Rich_49

Bob ( Hot Rod)

so if a system

has a mix of slab with floor coverings, and quick trak or Warmboard operating at the exact same design temperature, do you set for a 10 or 20 ∆T?



The beauty of a design software is it allows you to adjust tube spacing, loop length, or flow rates to match temperature requirements. This eliminates having multiple mixing devices, reduces cost and complexity. Also the entire system can operate on one ODR device.



       I would do as I always do in this instance .  Use a single temp , zone it appropriately ( actuators) , 2 remote manifolds , 2 circs , 1 for each Delta . 

    " Wants " comes into selecting Design Delta from the following philosophy :

Smith's Environmental  Low temp convectors open on 110* , close on 130* .

Buderus Panel radiator  18*F or 36*F Delta T

Warm board recommends 10 Delta T to insure rated output

Uponor recommends 10* Delta for floors except Quiktrak which is to be 20* Delta T .Uponor CDAM  " Flow rates for ALL Quiktrak installations are calculated to a 20*F temperature differential "   Appendix F is only Generic flow charts for 10 & 20 * Delta T with (100% water) or without differing %'s of Glycol



   If you start a concrete slab at 35* . 

If you have a concrete slab that is 35* that has been operating call an attorney .  But in the instance that it did happen on a 10,000 sq ft slab in Eau Claire ,Wi on a -13*F day this is what would be required .  178,789 BTU , 53 loops , room design temp 55*F .

10*T   SWT = 77 ,  87* from boiler , returning 67* , 35.8 GPM @ 5.4 '

50*T   SWT = 97 .  122*F from boiler , returning 72* , 7.2 GPM @ .33'

Now how long do you think it will take that slab to get up to temp ? Probably just in time for everyone to punch the clock , turn the heat off in the warehouse , and hope the whole place does not freeze up overnight . Let's try to heep things realistic for the sake of progress .  I would point out that the 10* Delta system's boiler will enjoy an albeit ever so slight higher efficiency .  Maybe someone will create the pump that will allow multiple , modulating Deltas in the future .



Care to substantiate claims about compensated folks ?  No Bob not particularly . You Know better than that . But feel free to do the research I have done on those who start threads about all sorts of stuff .  





 

Rich_49

Bob (Hot Rod)

First question ;

1 SWT , 2 manifolds , ? zones ( actuators) , 2 Delta Ts .

35* slab .

If this were to happen I would recommend contacting an attorney .

10,000 sq ft slab , Eau Claire , Wi , -13*F ODT , 55*F  IDT, 4 large garage doors on 1 wall , 12" spacing , 1/2 pex , 53 loops , 178,789 BTU .

10* Delta T     77* SWT = 87* from boiler , 67 returning . 35.8 GPM @ 5.4 feet .

30* Delta T    87* SWT=  102* from boiler , 72* returning .  11.9 GPM @ .81 feet .

 Will the 30* slab even heat up before it is time to punch the clock and go home . You know this slab would never be less than 60* surface temp except at startup , by the way we probably should not let this or any slab suffer such temperature swings . Keep it real Bob for progress's sake .



Substantiate claims . You know better than that . Anyone should feel free to research those who start the debate to find out who feeds their families .

Rich_49

The other Green pump

also can be made Delta T with the use of IR package .

hot_rod

come on Rich

Everyone of these ∆ posts were started by Chris, I suspect he wants to learn and hear other opinions. I don't feel he is bashing anyone or product?



I'm not attacking you, bashing a product or person. I am, like others questioning some fuzzy math, and how it relates to actual heat transfer.





So, again if you are hurling accusations in a public forum, man up and tell us who you refer to. You owe it to all that are following this post. Feel free to PM me if you'd like to carry on this conversation.



I suspect we will see some non biased opinions and articles on the topic of heat transfer and what actually happens to heat emitter output when you force the flow laminar.



Let the installers make choice which technology best suits their job and customer, once the math and concepts of thermaldynamics is applied together in a non biased way.



Also, no need to call an attorney when you start a snowmelt slab on a 35F day Or even a building slab for the very first time on winters day. It happens, the ∆T changes a lot as they warm, and they are just fine.







By the way , I don't know if anyone has noticed but most of the Delta T bashing has been originating from those paid by competitors as far as I can tell through researching the names associated with starting the discussions . Remember that Taco produces both technologies .

Rich_49

Chris

is not who I am referring to . Don't quite know how anyone got that idea but if they did I apologize . I refer to others Bob , from other forums . Please see one of my first posts here titled " How it got started " .  Did not think you were talking about a snowmelt slab , accept my apologies but again I have not encountered snow at 35* but then I would start the slab early in forecast of snow .

  I too have no problem with laminar flow vs turbulent and if you read that How it got started discussion my viewpoint on things , old standards , agencies that think they know will become quite apparent .  

  I will PM you to discuss other things further .

Eastman

Payroll

Rich, conversion with paid reps is a lot more entertaining and should be the norm on contractor oriented sites.  What forums are they on?  Get them over here if you can.  I think a lot corporations use marketing proxy wars, which is really too bad.  Engaging the curious customer directly is always a positive strategy and eliminates the possibility of miscommunication.  I'm surprised we don't hear from more people on the take.



Edit:  I meant to say ~conversation~, but I guess ~conversion~ could work too.

CMadatMe

I Posted Them

Because from the 1st one there was a lot of opinion and wanted to make sure the entire process of the blog was seen. There still is one more to finish it out.



I enjoy reading each and every opinion. You never no what you might learn or pick up on. I'll still stick my stance of, use John's blog and what you know about a Delta-P pump and choose the one that works best for you.



There is not a right or wrong nor a good or bad. In any case both styles of pumps will work. One may tend to working better in a particular application over another and that's for you, the installer to choose.



That in my opinion, is what his entire blog is about. Remember the first blog? Information, take it how you choose.