Taco Question

Paul48

Would running the VT2218 in DT mode, and not applying heat to the supply side, force it into minimum flow?

Paul48

The answer would seem obvious, but I figured I'd ask it anyway. Had you in mind, when I asked it.

Paul48

Yeah.........There are inexpensive inline ones, but are they going to last? You can't bypass through it to check flow, then revert back because it adds head itself.

Paul48

You're back to having to know(accurately) the head of the system. Make some tools......Fixed speed pump with gauges on either side to determine head. To be replace by permanent, circ flange- gauge- valve- gauge- circ flange. Use the valve to add the necessary head. Will the gauge across the valve work?

Paul48

I always thought it would be cool if Taco had plugged ports on it circs, or flanges for that purpose. Then again, they have to put the arrow on them for a lot of installers. For them, head is just a place to put the gimme hat.

Paul48

You can buy covers designed for lock-out tag-out for the valves, if you choose. Hang a tag on them, explaining they are not to be tampered with.

Paul48

P.S.......That's why your an engineer, and I ain't.

Gordy

I would not bother with flow meters. If your getting your deltas that's all that counts. I suspect you will get what you need on the high fire, and pretty close to low fire. You'll just have to pick a happy medium if it does not work out.

Gordy

The display on the veridian gives you supply, and return temp read outs right? So you will know whether you need to tweak your globe valves to get the desired head and delta through the temp readouts outs on the veridian lcd.

Gordy

I agree the psi version would be faster. Find a 0-5 gauge.

Gordy

Righto. Lol

Paul48

Thanks.......I feel a little smarter now..

Gordy

Do you know the present zone head losses? Are all three similar?

Paul48

Once another zone opens, the headloss drops and the pump can easily increase speed to compensate

Hah?

Gordy

Hmmm I'm trying to picture zones opening, or closing simultaneously, and how the pump will react. The boiler will modulate up eventually when opening additional zones. The pump will slow because the delta will widen due to a drop in temp until the boiler over takes the cold zone dump.

Looking at the head end of it, the pump would decrease speed with less resistance when opening another zone because with less resistance to the pump the flow rate would increase narrowing the delta. Pump reacts slowing speed.

Gordy

It's putting together how everything reacts, and the speed at which it does........ intriguing to say the least.

Rich_49

There may very well be answers here . Although these links are presented by Taco , be assured , the MATH does not lie .

http://flopro.taco-hvac.com/images/Delta-Tblogs2.pdf

Explanations of each blog entry above . Links to the blogs below .

http://jbblog.flopro.taco-hvac.com/

You may be required to join the Neighborhood to access , not sure .

http://commercial.taco-hvac.com/products/water_circulation_pumps__circulators/variable_speed_products/viridian_family/index.html

Paul48

Kinda like reviewing a couple years worth of classes, trying to find directly relevant information. What was the question?

hot_rod

Just keep in mind that just because the math work out on paper, the system may not perform as the formulas predict.

I'm waiting for a documented, datalogged system, proving the actual measured heat output if flow is allowed to drop to laminar conditions.

Anyone care to demonstrate a system running at an 800°∆T delivering 80,000BTU/hr?

The math indicates it is possible.

http://www.pmmag.com/articles/95877-nature-vs-math

Steve Thompson (Taco)

Interesting blog to say the least!

I suppose we could add Pete's Plugs on the volutes (or companion flanges) but my guess (repeat guess) would be the same answer as out old "spinny" flanges - cool idea but most (not all) are willing to pay for this feature.

A bigger concern for me other than the economics is finding a pressure gage that's accurate enough (and maintaining it's accuracy) to measure pressure in low pressure applications. I assume a test gage or U Tube manometer (like the one I still have from years of troubleshooting a certain pulse combustion boiler back in the early 80's).

Rich_49

There you go with the ridiculous math again in a futile attempt to mislead people or keep them less than what this industry is striving to acheive . I mean let's face it , as long as there are stupid designers installers there will be a need for more unnecessary components and complexity . I'm not gonna debate this P vs T thing any longer , especially with you Bob . You wanted logged proof and studies , I now have plenty of it , funny thing is this . It has been provided by manufacturer presentations from sites whose employees are the very same one's arguing that Delta T circulation cannot work or is undesirable . You keep asking and I'll keep providing .

Please view the following presentation from IAPMOs youtube channel from July , 2015 presented by Dave Kandel from Bellimo . Welcome to the time where an entire industry can stop listening to a few self serving individuals and OPERATING IN THE WASTE ZONE . ENJOY Bob . Watch the whole thing by all means but the unflattering news for P strategy starts at around 30 minutes .

https://www.youtube.com/watch?v=8re7q1Ejg1U&index=1&list=PLmcHo13VjwLlMcNbRS-rDgEHWk8CMf1xA

hot_rod

Rich, I know all about those VARIABLE PICCdelta valves, we build many of them notice it is a PI (pressure independent) valve. It's not the same function as a delta T pump as you know it.

Boilers and mixing valves, as shown above, do a great job of maintaining temperature in hydronic systems and distribution , why try to force a pump to do that?

Funny how you embrace math when it serves you, but call it ridiculous when it doesn't.

Rich_49

I am quite sure that I am not the only one that would look at your math example as ridiculous .

You have stated again and again that declining Deltas are just a way of life . You have also pointed to the fact that Boilers , emitters , don't want a specific Delta but as can be seen in the following ; Pay special attention to what this very wise man explains beginning at 48:05 . But , by all means watch the entire thing , very interesting .

https://www.youtube.com/watch?v=6mNECDHgDrg&feature=youtu.be

Bob , at some point you and what is rapidly becoming a very small % of folks will have to admit that maybe this has evolved past what we were forced to accept . My next question is this . Why in the world would Grundfos be faced with a problem and make the decision to use temp sensors on a Magna to address that problem ?
Just because Taco chose to produce a Delta P series of circs don't for a minute try to exploit that fact to bolster your nonsense and see it for what it is , Market share .

hot_rod

Rich said:

I am quite sure that I am not the only one that would look at your math example as ridiculous .

You have stated again and again that declining Deltas are just a way of life . You have also pointed to the fact that Boilers , emitters , don't want a specific Delta but as can be seen in the following ; Pay special attention to what this very wise man explains beginning at 48:05 . But , by all means watch the entire thing , very interesting .

https://www.youtube.com/watch?v=6mNECDHgDrg&feature=youtu.be

Bob , at some point you and what is rapidly becoming a very small % of folks will have to admit that maybe this has evolved past what we were forced to accept . My next question is this . Why in the world would Grundfos be faced with a problem and make the decision to use temp sensors on a Magna to address that problem ?
Just because Taco chose to produce a Delta P series of circs don't for a minute try to exploit that fact to bolster your nonsense and see it for what it is , Market share .

The math is straight out of John Siegenthalers articles, hence the link, he has covered the topic, along with water moving to fast for btus to jump on and off (not true) multiple times over the years. So take that up with him if you feel the math or physics is incorrect.

I am well aware of Jodys webinar, I assume you have talked with him for his take on delta T pumps on distribution side? If so, maybe share his opinion here. Obviously as a Viessmann guru Jody realizes the value of variable speed pumps tied to the boiler modulation, Viessmann has done that for years, Lochinvar also offers that option.

I have also talked with the engineers from several of the major pump brands and have their opinion on using pumps to regulate temperatures in hydronics. Again I assume you have and will share the opinion of Wilo, Grundfos, and AquaMotion on the topic?

Are you talking about the small % of guys here that tried delta T pumping on mod con boilers? From what I read it didn't work out as well as expected and explained in the blogs?

If it is a new revolution in the industry, great, I'd be glad to share that in my trainings. Lets see the white papers and non biased testing and proof, not a couple hearsay examples.

SWEI

Steve Thompson (Taco) said:

A bigger concern for me other than the economics is finding a pressure gauge that's accurate enough (and maintaining it's accuracy) to measure pressure in low pressure applications.

We use a Dwyer Capsuhelic. Took about a year, but I managed to find one on eBay that reads in feet of water.

Rich_49

Bob ,

Are you implying that Jody lied ? His opinion need not be interpreted , it is archived . No , I have not spoken with him , no need to , he did just fine with his explanation of maintaining a Delta T on both sides of the system . Don't you think ?
In other news , maybe you didn't hear but Delta T on the boiler side recently became quite doable with HTP's UFT boiler . Maybe you would like to help teaching how system design and careful attention to minimum head can eliminate the need for P/S piping , LLHs , buffers , multiple circs and the plethora of other cost adding components . Of course Delta T circs had issues working on the boiler side when a 12000 BTU low end boiler required a minimum of 4 -? gpm through the heat exchanger . Just to clarify , I never stated using a DeltaT circ on the boiler side was a good idea , UNTIL NOW . But only for a boiler that will readily accept 1 GPM . Identifying that boiler I will leave up to others as they see fit .

I get the idea that you believe I am just blindly following what this or that manufacturer tell me , I assure you that this , if so , could not be farther from the truth .

hot_rod

Not trying to bust your butt here Rich.

In a nutshell this recent delta T concept has been floating around for 3- 4 years now. The BB was conceptual and being tweaked for years before it hit the shelves. Before that the tekmar and UPC methods of variable speed temperature mixing were tried., not all successfully as you may remember.

What seems to be a big grey area for some is how low can you go with flow rates and still transfer adequate heat out of a fluid stream with the various distribution products and methods we currently embrace.
The R&D on delta t circ products seem to be done more in the field instead in a documentable lab condition where actual data comes from the testing with lab quality gauges and equipment.
Does ∆T pumping work in all systems, are their limitations, if so what are they? These seem like fair and logical questions, and not all have been answered, and some of the answers have changed since the first training I sat in on in RI about 4 years ago. And as you have observed some of the ∆T pumped systems have not performed as expected.

Thus far Hatteras has done most of the heavy lifting trying putting some real numbers to the question of how low.

As for mid mass, high water content modcon boilers, I've lived with one in my shop, 3 feet from where I sit since 2006. It may have been one of the first HTP Phoenix out of the factory, as it is half Phoenix and half Voyager parts. It has had at least 6 pumps connected to it over the years, ∆T, ∆P, PWM, fixed speed, and AutoAdapt
Even prototype pumps that never made it to the market, or have not yet made it to the US market. So I do know the pros and cons of that design and how the various circulators interact with it, fairly well.
Keep in mind there are good reasons why we moved away from high mass, high water content in cast boilers, there are drawbacks to every technology.

Storing heat energy in a tank, boiler, or vessel with a flue pipe attached, even a small diameter one will not provide ultimate system/ energy efficiency, in my experience. A low mass, low water content boiler, post purged into a tank completely sealed in 3" of foam works better, from my shop experience. But it may not be the best package for every buyer.

SWEI

I had a rather lengthy discussion with Dale Pickard last month about this. He did manage to persuade me that ΔP is a better fit for drainback solar than ΔT is.

I believe ΔT is the best option for single emitters, coils, or zones without control valves. Dale believes it is not the best option for boilers and that slowing down the flow (stacking the HX as he puts it) is not beneficial there. I have more reading to do on that.

hot_rod

I have learned a lot from Dale over the years, he thinks mechanical and technical "things" through to another level. There are few that I have met that have a good handle on heat transfer from practical experience, Dale has pursued the low temperature HX "angle" with solar for a long time, I appreciate his non biased opinion.

Watch what the HVAC industry is doing to increase performance in refrigeration piping and circuits. They are constantly look for way to lower energy consumption, as we are but at the same time increase turbulence ( heat exchange) inside the tubing and HX walls. Tube with turbulators, or rifling inside, for examples.

Engineers have used laminar flow designs to move heat in a pipe over long distances with the least amount of energy loss through the pipe wall, underground piping between buildings for example.
There must be a definable point in all systems where heat transfer drops to unacceptable levels, the heat generator as well as emitter. Numbers and formulas exist to define that point, if they need to be re-examine, the industry should look into that with definable testing and proof, is all I'm asking.

SWEI

I need to re-read Hydronics #8 and call him back when I have some time to debate. It's always enlightening but I have to prepare

Rich_49

Bob ,
The only unacceptable level is one where the required heat cannot be delivered . That is where the whole turbulent / laminar discussion falls apart . There must be a realization that one only needs turbulent flows when that is what is necessary to achieve the desired effect . Flowing water that is doing no work is a ludicrous idea just to keep flows turbulent when turbulence is not needed to accomplish the task . I think the dead guys understood it and don't know why it was lost . Before reading , remember that gravity systems worked , solar thermal panels can overheat , all without friction , turbulence or mechanical force being applied . Listen to the dead guys , they got it .

https://en.wikipedia.org/wiki/Heat .

Rich_49

Kurt ,
Can you stack heat in a heat exchanger where the system is offloading all the heat that is being added ? Thats the question .

hot_rod

Rich I think it goes further than this, you said:
"Bob ,
The only unacceptable level is one where the required heat cannot be delivered ."

add the word efficiently to the end of that sentence, that seems to be where we disagree

hot_rod

Rich said:

Bob ,
The only unacceptable level is one where the required heat cannot be delivered . That is where the whole turbulent / laminar discussion falls apart . There must be a realization that one only needs turbulent flows when that is what is necessary to achieve the desired effect . Flowing water that is doing no work is a ludicrous idea just to keep flows turbulent when turbulence is not needed to accomplish the task . I think the dead guys understood it and don't know why it was lost . Before reading , remember that gravity systems worked , solar thermal panels can overheat , all without friction , turbulence or mechanical force being applied . Listen to the dead guys , they got it .

https://en.wikipedia.org/wiki/Heat .

Remember too that gravity systems needed balancing valves as the heat transfer, due to temperature induced bouyancy provided overheating in the higher levels.
The higher velocity rates established at the upper levels needed to be reduced to provide adequate heat at the lower levels. Gravity induced flow doesn't necessarily mean absence of turbulent flow, does it?

The addition of "boosters" was to allowed smaller pipe size and longer horizontal runs.

Sure water overheats in direct sunlight, but you cannot transfer that energy efficiently without "bumping" it into heat transfer surfaces. Within reasonable pumping power requirements we want very low delta T across solar panels to harvest the energy before the ambient grabs it. We want to move energy efficiently, that can coexisit with turbulent flow rates.

Isn't the buzz phrase "system efficiency" that includes the transfer going on inside the pipes.

Rich_49

hot rod said:

Rich I think it goes further than this, you said:
"Bob ,
The only unacceptable level is one where the required heat cannot be delivered ."

add the word efficiently to the end of that sentence, that seems to be where we disagree

No Bob . Where we disagree is that you think system efficiency can be had at excessive flow rates . That is not efficient , think Siggy's wire to water efficiency . Or does that not fall under system efficiency ?

Rich_49

Bob said ,
"Remember too that gravity systems needed balancing valves as the heat transfer, due to temperature induced bouyancy provided overheating in the higher levels.
The higher velocity rates established at the upper levels needed to be reduced to provide adequate heat at the lower levels. Gravity induced flow doesn't necessarily mean absence of turbulent flow, does it?
Not necessarily but my thought is they were not all that turbulent as the flow rates would show , especially after you added balancing valves to REDUCE the FLOW . Turbulence in a natural process is not that common unless of course you are looking at a waterfall .

The addition of "boosters" was to allowed smaller pipe size and longer horizontal runs.

Sure water overheats in direct sunlight, but you cannot transfer that energy efficiently without "bumping" it into heat transfer surfaces. Within reasonable pumping power requirements we want very low delta T across solar panels to harvest the energy before the ambient grabs it. We want to move energy efficiently, that can coexisit with turbulent flow rates.

Isn't the buzz phrase "system efficiency" that includes the transfer going on inside the pipes. "

Why yes it is Bob , you should learn about it .

hot_rod

If I can circulate my systems, turbulent flow, within 2-4 fps as industry standards suggest with 7- 37 watts of power, I see no reason to "tempt" energy transfer,or lack of with laminar, or non flow conditions.

Hydronic systems want, no need, adequate circulation flow rates to transfer heat, remove air, dirt, magnetic particles, and to provide valve authority in the control components.

If you want simple heat transfer, try a campfire.

Gordy

What about radiant systems? This discussion seems to flow around base board, panel rads with trvs, and kick space heater IIRC.

In the end the definitive moment is when the set point is reached. Whether the flow is laminar, and may take longer, or turbulent transfering heat faster, and taking less time. So if it's laminar, and we use pump energy longer, or turbulent, and we use more pump energy for a shorter period is anything lost, or gained is the question. At the other end on the boiler with heat transfer is it not the same thing?

It would seem prudent to keep deltas in the 10* range for floors, and 15* for ceilings, and walls, and stay in that 2-4fps range.

Why do we seem to question the universal hydronic formula just because it works outside the parameters of usefulness?

"If I have a lever, and a place to stand I can move the world". Is another. The formula works, but it's inconceivable to perform.
Both from the stand point in materials, and the vast distances.

In case you were wondering to move the earth 1mm.
The individual being capable to exert 75 kg of force, and the fulcrum was 3 meters from earth. The lever would have to be 8.45 million light years long, and the distance to move the lever 8.45 million light years. The lever would way roughly two earth masses. There would also be a chance that a singularity would occur at the fulcrum point from the extreme pressure exerted on it, and a black hole could form.

Rich_49

Ya know Bob , it's kinda funny that my installs and remote designs suffer none of the issues that you mention . I place air elimination in the appropriate places , get rid of dirt and the like when commissioning using a nice Caleffi flush cart , my valves have all the authority they require and I use a bit less electrical power than you mention . At the end of the day the phones keep ringin and most of my work is by recommendation form happy customers . The houses I design use on average less than 50% less resources than those in neighboring homes as I'm told by customers and lots of those neighbors call to have us look at their systems .

I do things alot different than many , even guys that are very good . I have had no complaints to speak of in roughly a decade and have a good reputation .

I'll presume you did not read the link above or that if you did you just did not catch the pertinent parts . Standards are only standards until they are updated which I believe should be done soon with many of them since new technology does not lend itself well to those standards . One of the things holding the efficiency back is those standards .

At present I am enjoying the partnerships I have built with manufacturers am not scared to put my own thoughts out there along with practices I have used for years with favorable results . I think on my feet and unlike you am not magic . I am water and air and know where I am going and where I am gonna get out . i hardly refer to others in my efforts and speak what I know instead of citing standards that were written 35 or more years ago . Lead , follow or get out of the way is what i believe in . You mention equipment that uses compression cycles to perform work as if that somehow is similar to the discussion that is ongoing .

You mention the folks at engineering departments of firms whom produce other technology in an attempt to give yourself credibility . Hell , you even threw the idea out there that Jody's presentation meant something completely different than what he said . Maybe I will e mail Jody and ask him what he meant or maybe you'd like to tell us what these men say because we all must be mistaken and saw something other than what was presented .

Delta T pumping goes back a bit further than you state , hell , I've been using it for at least 5 years with spectacular results I might add . I got it ! I only perform work in areas where the laws of physics as known by all others cease to exist . That must be it .

By the way , I'd bet with an 800* Delta delivering 80,000 BTUs with no flow would not be difficult . You and your brethren should at least try to use math that makes sense

Heat loss is a moving target Bob . Only recognizing flows necessary at the higher end of the spectrum is wasteful . Your friend wrote in his books that there are 2 ways to vary the output of an emitter , those are temperature and flow as you well know , must we choose one or the other or can we use both ? I know the answer and you may want to explore .

Eastman

@Hatterasguy Have you looked into Belimo's energy valve for your HTP install? ...it looked like it had some killer data logging capabilities and the ability to regulate flow, delta T, and or btus which I would think would make it a great platform for experimentation.

Eastman

@Rich Do you use delta T pumps a lot?

meh... this doesn't add much to the discussion. (I couldn't think of anything to say. I'm pretty tired.)