Can someone please explain the the VR1816s constant pressure curve

keyote

Hat you are officially invited as you all are

keyote

Gordy I have to admit Hats point is one of the things running through my mind watching the Taco videos thinking about the charts on modcons you posted and imagining my RWT rising because dumb Delta P has fixed head.But I also was trying to think about what i less understood you saying about the BTUs getting off the train meme, and you see above i have thought about that and have a resentment about tenants having furniture on the floor. {and why did i let my simplistic and frugal side win the argument about store bought plates} But I have to admit im not that clear on why you think the pump comes into this. The assumption is the house is triple panes and sprayfoam insulation so loses heat slower than average. what i thought you were saying is my tubes wont tranfer heat but if the pump is under discussion then we are talking flow i think the DP pump can oonly flow at the fixed head curve while the DT can have its flow adjusted by DT change so wont that allow more options ?
But I know you also mention ODR about this and i keep thinking is he saying the boiler can be made to change SWT on a minute by minute basis regardless of odt which is fairly stable compared to pump speed change.

hot_rod

Hatterasguy said:

hot rod said:

I'm not convinced "enforcing" a ∆T is required or even possible. I think the ∆T has a low end lock, via a min speed restriction, so at some point potential enforcement ends.

You really should be convinced based upon the simple premise that lower RWT improves the efficiency of the mod-con dramatically, especially in the sweet spot between 120F and 135F.

Sure, there are "issues" to be managed with the DT pump and the boilers cannot accept flow rates below 1 GPM. However, don't ever consider this pump to be inappropriate for the intended goal.

I've struggled with it myself but am still pursuing a final solution for it. If and when I achieve it, the performance benefit as compared to the fixed speed (based on specific zones calling) DP pump is simply incomparable.

don't ever consider this pump to be inappropriate for the intended goal.

If the intended goal is to vary speed by temperature input "mission accomplished" Although tekmar had that down 20 years ago, without all the bugs and a lot more features, and a lot easier to understand and program.

If the intended goal is a circ pump that works in all systems, boilers and heat emitters, and in harmony with the rest of the components, doesn't sound like we are there yet?

As for "performance benefits" define that better.

Is that comfort, fuel efficiency, reliability, initial cost?

And you believe only a ∆T circ can provide that?

hot_rod

Remind me how many hours you have invested in the "out of the box solution"? 100 hours? At $100- 150.00 hour, or more for someone of your knowledge.
Still no win? If you get it to work the way you want in your specific application, in the end you have what to sell the masses?

Can you sell that dollar amount to a customer to assure possible perfect comfort and fuel efficiency?

Viessmann has had the correct fix with a boiler controlled VS circ for a long time know.

You could have been sailing all this R&D time

Seriously, I applaud you effort and we all learn from it, keep us updated.

keyote

I dont think theres ever going to be a one pump for every system; well actually there will in a way eventually really soon in fact the brains of ecm pumps will allow the same pump to be switched from DP DT Constant pressure infinitely variable fixed speeds and infinitely variable adjustable speeds controlled by boilers or other outside control. many of these pumps already have several options no reason at all they cant be combined into one pump simply in fact ill bet you will also be able to set the high and low parameters in DT or variable outside control as well.
But different systems will always need different pumping styles, I suppose also soon cheap sensors will be available to add wireless feedback at various points in systems and those smarter pumps will take advantage of that perhaps even switching say from one pump format to another after a valve opens. Think about what would happen if you added something to water that can be detected through pipe as flow and temp. I just ordered some little tiles that have motion occupancy and temp humidity wirelessly built in they will tell me when a door, window, draw,toilet seat or refrigerator is opened and the temp and humidity change and logs it all infinitely. and the is no limit how many can be added to system another is a leak detector that differentiates between levels of moisture and if its getting wetter or dryer.
As hot rod anticipates micro ecms will come to america i see them in europe at like 4 watt max Im sure trvs will be made for radiant loop actuators wirelessly controlled by a system of sensors throughout the system inside room floor and at various points in the pipes and with occupancy sensors that use your phone to guess how quickly you can return.With a pump that can change itself from a DP to DT to fixed in a nanosecond. and this is coming really really soon ide say within a decade all of the above will be routine.

keyote

but once all this capability is available economically the raw research will be important so the geeks can code the ECMs to know what works best under given circumstances. I put a ECm alternator on my hydro electric system 15 years ago took a lot of **** around now you can buy one off the shelf and swap out your old alternator on your hydro electric unit did i publish and contribute to development no but someone did and capitalized on it now Im thinking i can 3d print different pelton wheels and play with that it really for fun and satisfaction. yankee ingenuity

keyote

does anyone have an opinion on my "is this a good idea"? post. I put up a drawing but basically i think ill need a hotter water zone for the entry hall and wondered if i pulled it off the return side of the dhw loop it would have an advantage lowering the return temp water of the indirect?

Gordy

Hatterasguy said:

Gordy said:

I have to reiterate this all comes down to the system dynamics.

Mass
Emitter saturation.
Heat loss. How rapidly the structure losses heat.

Here is where we disagree.

Heat loss is irrelevant.

The system only depends on mass and the emitters capability. The boiler and the emitters have no idea of the heatloss and no capability of responding to the heatloss (other than utilizing OAR which doesn't change on an hourly basis). That job is done by the thermostat.

The capability of the emitters is constant at a given SWT and flow rate and at a given indoor temperature. Several folks get confused by this phenomenon.............

We will agree to disagree on that

Gordy

You are failing to see the dynamics of those elements in your attempts to "make" a DT circ work in a specific system.

You must agree there are systems that would require much less intervention with the same circ, and a mod/con.

By systems I mean the whole enchilada. Envelope, emitter, mass, and load.

Gordy

Isn't having more (much more) than just enough emitter for the heat loss a direct correlation to the load, and mass?

If I require 30' of baseboard to meet the load at the BB manufacturers design swt , yet install 60. I have increased the mass of the system, and lowered my swt requirement.

Jamie Hall

Steam's a lot simpler...

More seriously, a couple of points. First, someone up there mentioned "one pump". That is certainly true. One could -- very easily now -- have one pump which would fit a very wide range of systems. All is required of that pump is that it have a maximum flow rate in excess of the maximum flow rate required by the boiler operating at maximum firing rate.

Second, from there, all that is required -- and in the day of digital gadgetry it's pretty close to a no-brainer too -- is a control for that pump to make it do what you want it to do. Constant pressure difference across the pump with variable flow? Can do. Constant temperature difference between two points in the system? Can do. Variable flow? Variable delta T? Can do. Vary one or the other in response to some outside variable? Can do. It's purely a matter of providing the proper inputs and programming the control computer to do whatever you want it to do.

The programming is not quite as straightfoward as one might think, however, as there is the little matter of system lag to be considered and allowed for. With some control strategies the lag is very small (it's never zero) and so controlling the ramp rate vs. setpoint error is not hard. With others the lag is longer, so it gets a little more complex. Some systems might have variable lags (a system with zone valves, in the present instance) which might require additional sensors to allow for that.

None of it, however, is even state of the art -- it's all basic servo mechanism theory and practice, which is third year mechanical engineering.

Where life in the real world gets complicated is sort of what @Gordy is getting at: just what strategy will give you the maximum possible efficiency for the specific system in question, and what input parameters do you need to have to implement that strategy? Do you need to forecast the future value of some of those parameters (e.g. outside air temperature, wind velocity, wind direction, sun load...) and how do you do that? Do you need to vary your strategy to account for imperfections, such as a door left open on a cold day? Do you need to control other parts of the system, such as variable zone valves for instance, to maximize efficiency?

And, of course, it being the real world, one would be wise to set things up so that it was fail operational...

bob_46

To my knowledge "smart" pumps use actual sensors to measure ∆T , there are no sensors to measure pressure other than slip, current draw and a few other electrical characteristics and an Al-Gore-rithm.

keyote

Hat Im curious is the ramp control on the HTp similar, from the video I watched the lochinvar control screen has a graphic of a six stair staircase and a control to literally stretch the risers for modulation percent and the treads for time at that modulation. from what i could tell from the video the modulation is 10-100% and time is infinite i know in one call i had it was mentioned I could eliminate stages by making the time settings zero.

keyote

bob based on the video by taco on smart pumps, you are correct they dont have differential pressure sensors, they are estimating head by increased torque needed or rather the increased power needed to produce the torque.

SWEI

bob said:

T there are no sensors to measure pressure other than slip, current draw and a few other electrical characteristics and an Al-Gore-rithm.

True for the smaller ΔP pumps at this point, though the MAGNA 3 does have an actual pressure transducer mounted in its volute.

Rich_49

Can we fairly compare the UFT to the KHN ? In my opinion the only comparison between an HTP product and a Lohinvar product that could be considered fair is between the EFT and the similar Lochinvar product . The KHN costs about 2 xs what the UFT does while the price point is similar for similar products within each manufacturers' lineups.

Rich_49

Al-Gore-rithm. Love it , perfect !

Rich_49

Hatterasguy said:

Rich said:

Can we fairly compare the UFT to the KHN ? In my opinion the only comparison between an HTP product and a Lohinvar product that could be considered fair is between the EFT and the similar Lochinvar product . The KHN costs about 2 xs what the UFT does while the price point is similar for similar products within each manufacturers' lineups.

You cannot compare the EFT to the KHN. The EFT has 5:1 modulation and the KHN has 10:1 (at 85K and above).

So, you compare the two 10:1 boilers. If you need the capabilities that the KHN offers, you purchase it. Otherwise, the UFT will perform just fine.

Pardon me , I meant WHN . But we could compare the Elite premier with KHN .

Rich_49

I said Elite Premier compared to KHN .

Gordy

Price point is a fair comparison verses the 10:1 TDR being the specific argument. As with any boiler more so mod/cons the depth of control bares most of the cost.

If you know the boiler, and the application then the lack of, or abundance of different control strategies is a mute point. Cost becomes the driver. If you can use the less expensive boiler, and it's controls fit the application, or can be designed into the application why not?

10:1 TDR is not going to full fill all the frustrations. It still takes diligent design, and in that being able to take full advantage of the equipments potential.

Remember the design starts with the heat loss. From there many doors can be opened, or slammed shut.

keyote

I think that con x us internet access is of value to a certain type of affluent client regardless of other factors, its also unbeknownst to the client really built to let contractors both manage diagnose troubleshoot and monitor during break in and maybe service from afar. That thing can be setup to monitor just about any equipment tangential to system and email you. hey soccer mom your boiler just notified me your coil needs cleaning.