Can of worms...

Rich_49

Whats the matter Paul ? Moving 300% more fluid and sacrificing any wire to water efficiency doesn't make sense for a miniscule increase in output per hour ? But hey , that 4 gpm certainly is turbulent so it must be better . Don't forget the disclaimer about guaranteeing 4 gpm , can that even be done ? Maybe frictional pressure never does positive work .

Gordy

Harvey Ramer said:

I suggest a big table with a couple pitchers of select beer. We can all sit down around the table and keep pouring beers till we have the answer.

Now Harvey we both know the tapper would go dry before this got settled

Paul48

No Rich.....The point is, what would you have to slow it down to , to get any appreciable change. I believe in Maine, they say," You can't get there from heeyah". According to Planck's Law.."The higher the temperature of a body the more radiation it emits at every wavelength". So as you put it, you might as well move that miniscule amount of heat difference out to the radiation. That's a good law...I'll start using it more, to make my point.

RJMCTAFO

@SWEI THat makes sense now that I think about it. Even though we have a delta of whatever it's still moving less btu. Hmmmmmm


Hydronic theory beer summit. Should be an annual event!!

Harvey Ramer

@Gordy
You are correct, no doubt. Lol It would be fun though!

As far as the topic of the thread, I have my opinions that I have expressed a couple times. At this point I just enjoy watching the fervor of the discussion.

4Johnpipe

@SWEI This is where it gets a bit sticky. Less BTU's leaving the boiler should make the boiler hit its high limit sooner.

This only happens when the return water still has BTU;s in it. In other words when its still hot. This is exactly what VDT pumps provide. They leave the water out in the system side longer so physics can do its thing and extract the BTU's.

The boiler will add everything that was used up out in the system.

4Johnpipe

Basic step process...1) boiler makes heat, 2) circulator transports heat and 3) emitters transfer the heat to the room. These each operate independently. 1 and 3 are completely reliant on Delta T for their operation. Until recently #2 was the red headed step child of the equation and wouldn't talk to 1 and 3. Now we can marry the circulator to the Delta T of both 1 and 3 so Delta T can be allowed to take place both in the boiler and at the emitter through a range of conditions all based on Delta T or if you will heat loss and heat gain.

4Johnpipe

What are you talking about? If we have heat transfer we have a Delta T to measure. The entire principle of heating revolves around Delta T?!?

Harvey Ramer

Where are you measuring the stack temp on the ES2?

On each test, are you starting with a cold boiler and system?

How is your boiler piped? Bypass, loading valve, straight through, primary secondary?

Every emitter delivers more BTU's the warmer the average surface temp. For the vast majority of emitters, increasing the flow will achieve a higher average surface temp. Some emitters can be overpumped, reducing the heat transfer rate. Cast iron radiators with supply and return piped at the bottom. They depend on gravity flow within the rad itself, to properly distribute heat to the upper portion of the rad. As water enters the supply side, gravity should allow the water to rise through the tubes on the first half of the rad, as it cools off it should pass along the top and drop through the last half and out the return. If you over pump, the water shoots directly across the whole bottom of the rad and stymies this internal flow thus slowing the heat transfer to the room while simultaneously narrowing you DT.
A DT pump is perfect for this type of system as it insures proper rad performance. In the same breath, I would say a DT pump is not the best selection on an entire gravity piped system. The pipes are typically to large with fluctuating temps fooling the pump sensors.

SWEI

Methinks we may be starting to chase our collective tail again?

There are two ΔT's at work here (technically three if you count the fire side of the HX in the boiler.)

AWT across the emitter determines the rate of heat transfer to the space. As the space warms up, the ΔT between the water side and the air side (of the emitter) decreases. Less heat flows out of the water and into the air. Return water to the heat source warms up.

Harvey Ramer

Hatterasguy said:

Each test is started with the system warm at LL. There is no benefit of starting with a cold system as the output from the emitters is varying for the entire warmup period and you cannot effectively test DT under that condition.

The boiler is piped direct without a bypass.

If you seek true and correct data, you will start with a cold boiler and system for every test and compare the performance of a delta t pump against that of a fixed speed. If one or the other keeps the boiler condensing longer, there will be your gain or loss of efficiency. You won't necessarily detect it in the stack temp alone but rather in the combination of run time and combustion efficiency until the room reaches setpoint.


By the way, your boiler is bouncing off the high with emitters at max capacity. You are oversized.

hot_rod

SWEI said:

Methinks we may be starting to chase our collective tail again?

There are two ΔT's at work here (technically three if you count the fire side of the HX in the boiler.)

AWT across the emitter determines the rate of heat transfer to the space. As the space warms up, the ΔT between the water side and the air side (of the emitter) decreases. Less heat flows out of the water and into the air. Return water to the heat source warms up.

And there are multiple efficiencies in a hydronic system.
Building efficiency, defined by heatload calc
Boiler efficiency, energy input divided by actual measured output
Distribution efficiency, wire to water and heat emitter design

bmwpowere36m3

Hatterasguy's results and strong stance is based around a very specific set of conditions and system (CI boiler, non-mod and/or con and baseboard convectors).

I think people who read these discussions miss some of those details. Hatterasguy is making statements wrt to delta t pumps and those might only be true in his or similar systems.

It depends...

Harvey Ramer

To get any relevant data, your testing parameters must match the system as it operates normally.

Are you set up as a cold start boiler?

Are you running ODR?

All of it is relevant.

Every cast iron boiler condenses when it starts cold or if the water temp in the heat exchanger is to low. The length of time it spends doing this has an impact on the overall efficiency. This cannot be detected by stack temp as flue gasses are condensing.

Gordy

What Harvey is saying is every system has unique characteristics. If a system is tested at normal conditions there is very little time to get relevant stack temp data in a cold start set up.

4Johnpipe

@Hatterasguy when are you installing this VDT?
When you do keep notice to the blinking light. This is the speed indicator. You will see on initial start it will flash rapidly until the RWT raises.
I would like you to notice how slow it will flash as the boiler reaches HL and the room T stat is close to or just as it satisfies.
The raise the T stat a few degrees and watch for the flash again.
The sensors adjust the flow difference between the supply and return temperature only.
This entire discussion will be much easier to follow when you get to see this.

Rich_49

You know Hat as I had earlier mentioned during a phone conversation . Cold start would be best since that is the way these systems work . T Stat satisfies and turns back on when temp drops , there is no steady room temp . Usually when a boiler fires the emitter and room are cooler than when they reached setpoint . Testing with these parameters we can actually see that in the beginning of a call the emitter dumps much more heat than as it nears setpoint and that less gallons per minute are required as we near that condition . This may actually show evidence of how the Delta T pump can hold the boiler from reaching high limit longer than when you are shoving fluid through a system .
You keep stating that the thermostat is very important , well , let's see the proof . We can determine nothing the way you are suggesting that would show a difference . This is what I have been saying .
The thing is this , we do not design boilers then emitters then circulator size , we design systems . Define system then think about what I have been saying . you are testing one zone , in a true one zone system the thermostat would satisfy and turn back on in a little while after the emitter and boiler have had a chance to cool . What is the aversion to performing the test that way ?

Gordy

I agree with @Rich let the test be done as the system is designed to actually perform.

Paul48

It might be interesting to time the cycle with a 20* DT, then with a fixed speed at max allowable velocity. That's one of the claims about DT circs...they reduce short cycling.

Rich_49

Paul,

Ultimately hat will be performing 10* & 20* Deltas . We just have to convince him to base both on cold starts . The cold start and through the entire cycle is the only way to get the information we want accurately . Sneaking suspicion is that in the beginning flows will be higher and lessen as the cycle nears setpoint .

Only way to really tell this is with 2 cold start cycles at similar outdoor and indoor temps within reason .

By the way , I think we should maybe give a hats off to this tool for offering up his time for this research which will benefit us much more than he .

Paul48

I don't thinks that anyone doubts that it will do,just that. I think the question is...if it will maintain the delta t that much better than fixed circulation, and reduce short cycling. Is the HX more efficient pumping faster or slower, within manufacturers guidelines. A big hats off to Hat!

Rich_49

In a cast iron boiler such as we are dealing with i still cannot believe anyone questions that the boiler with the higher average water temp will reach high limit faster .
I am assuming this test that will happen this coming week will be taking place at well above design ODT . Possibly cold start might be defined as an average starting boiler temp while cycling normally on a given day , any day . Let the boiler start on a call after the stat has been satisfied , wait for beginning of call and let run until satisfied . Sit with thumb up butt and wait for next call from Tstat after emitters and boiler have cooled as they would on that day .

Harvey Ramer

@Rich
Data logger would be the best to accurately quantify the whole system and come up with comparative results.

Rich_49

Would be great I agree but aint gonna happen during this round . Unless you or someone else can get hat the stuff to perform it . Fortunately for me I have gas usage to compare with the average new house of similar size and system for new construction and old bills versus new bills after retrofit or reno work .
I never thought the industry would be at odds over something we have been taught to design for to make an efficient SYSTEM . seems some do not quite get the system is a system much less the house as a system concept . Our industries' educational branch has failed us miserably apparently .

Paul48

Average= 300,200,100 or 200,200,200. I know it's exagerated,but....The delta t circ loses on cycle time. The slower pumping raises the temperature at the boiler sooner.

Gordy

http://forum.heatinghelp.com/discussion/153977/burnham-es23-with-grundfos-alpha-and-dt-at-discrete-speeds#latest



Took the liberty of linking the original thread.

Gordy

Yes thank you Hat for taking the time to perform these tests. And to @Rich, and @hotrod for offering equipment for the event.

Gordy

What have the outdoor temps been doing Hat? 66 here today forecasted high. Pretty hard to accomplish real data with Warmer OAT.

Paul48

Gordy....Send some of that warmth up here. It rained all day yesterday, and felt raw. Same crap today. At least it wasn't snow. We would have gotten a foot.

Gordy

Paul It's going to be short lived a week. Then back down in the forties. At least March did not come in like a lion.

Rich_49

Hatteras ,

Maybe cold start is not possible but as I stated above normal cycles during regular operation . Leave the damned window open though so we can get an idea .

Paul48

It's not that big a deal....He will have to come up with a window open and close procedure., and not use the first cycle. Beyond that it should be apples to apples, with say a 5* temp drop at the t-stat. Five degrees, turn the heat back on, and start the stop watch

Gordy

This is starting to sound like Hat needs to pull a couple of teeth, and pipe a still in with the boiler to get controlled results.

Charlie from wmass

I was told Taco , who I like, made a DT pump because they did not have access to the patents to make the DP pumps. It is hard to be the second on the block with "new" tech. DT works DP works. the minutia of cost we save between one or the other for a given system is impossible to justify being this inflamed over. I use Taco for my fixed speed pumps, simply because I am used to using them and have had good results. I use Grundfos for variable speed pumps as they are regularly available and I have had good results with them.

Rich_49

Charlie ,
With all due respect , this discussion goes much deeper than cost minutia . It goes down to the very basics of system design and performance and first cost and operating costs although part of the larger picture have very little to do with this discussion .

Charlie from wmass

will a customer really notice the difference between each style of pump if the rest of the system is piped properly? No Nay never.

Paul48

The customers would not notice the difference with a lot of the things you do on systems, yet you do them anyway. This is being done to answer questions about improved efficiency. It's not a laboratory and will not quantify anything. It'll answer "yes" or "no", in a hillbilly, kind of way. That being said...I've seen some hillbilly creations that would boggle the mind.

Rich_49

Charlie ,
The customer will not notice anything if they are warm . I guess the issue here is that I know . Maybe that doesn't matter to you and good enough is good enough ? Good enough is not acceptable to some , as well kit should not be .

Charlie from wmass

I provide the most efficient that is practical for my customers. I can install as efficient as possible systems too. The budget is often the deciding factor. Both circulators can get you to a very good install.

Rich_49

Both circulators also cost roughly the same . This is not about budget , but since you brought it up .
Are you the guy that won't put in the P or T circ because it would cost you an extra 100.00 without rebates ?
i will readily absorb that to install a better system with the proper circ . VS is my tech of choice and hardly find the need anymore for a single curve unit .
Could it be possible that there is nothing for Charlie to learn from this test and others that may happen in the future ? If so feel free to let the discussion follow it's path .