Taco Question

Eastman

I just think fixed deltaT is kinda boring. I want more options.

SWEI

A couple of sensors and a few lines of code and you can do pretty much anything you can think up.

Gordy

Harvey I don't know how much you followed the interconnected threads. What kind of started this is HTP new boiler the UFT-80

It's the smallest line up in their medium mass boilers. 10:1 TDR FT HX which seems to have a little twist. 80k unit with 8k low end.

In theory you could maintain an 8k output at .8 gpm at a 20* delta. Something other mod/cons don't allow.

@Hatterasguy is trying to pull it off in his own experiment. Using the delta t pumping. Direct piped. 3 zones with rads, and ci baseboards. What's trying to be accomplished is that boiler starting the season, and never short cycling so long as an 8k load, or more is needed. He will consider it a success if he can maintain 1 gpm through that boiler without P/S , and never bouncing off high limit. Through all this trying to keep the boiler in condensing the whole time to get the highest efficiency it can provide.

Possibly one light off per season so long as Mother Nature cooperates.

So,the debate is how different flows laminar, transient, and turbulent will affect heat transfer. At both the emitter, and the HX.



Please give your input I always respect your point of view Harvey.

Rich_49

Design Delta T is not just meant to happen @ Design . Harvey just said what I have been unable to convey .

hot_rod

Harvey Ramer said:

Disclaimer, I didn't read every single post.



But..



I have a completely different veiw on dt pumping than anything I have seen here. I have experimented with it probably about 6 or 7 years ago.



Delta-t pumping coupled with ODR are like a hand-in-glove properly handled. I really don't care about the turbulence, laminar, or transitional flow. The DT gets dialed in according to the connected radiation in an effort to achieve the best comfort at acceptable pumping power. Don't go nuts. What happens is you create an animated system that is even more preemptive than standalone ODR can provide. Particularly well suited for high mass. I don't have to go in detail. Just picture the water temp rising or falling with the outdoor temp. What does the pump do? If the outdoor temp is dropping, it actually allows the boiler to inject btu's at a higher rate than fixed pumping with odr. The exact opposite occurs when the outdoor temp rises. It will go a long way to eliminate flywheel effect and prevent indoor temp fluctuations.



The only thing you have to be aware of is, your bottom end of the ODR curve may have to be held slightly higher. Depends on the emitter system.



The other thing is, the boiler electronics have to play nice.

I really don't care about the turbulence, laminar, or transitional flow.If the outdoor temp is dropping, it actually allows the boiler to inject btu's at a higher rate than fixed pumping with odr

You say you don't care, in reality you are embracing and leveraging the concepts when you "inject BTUs at a higher flow rate.

As the heat load increases, you increase the supply temperature, makes sense.

Gordy

In a nut shell...... Literally. The goal is over all system efficiency. To obtain that there are also many sub efficiencies in the whole system to try and control as much as possible. With proper design, and proper use of available technology. In the end keeping it as simple as possible with the least amount of components.

Paul said many posts ago on another thread we are looking to much at pictures when in reality it's a movie .......with a plot.

hot_rod

Hatterasguy said:

Gordy said:

Hatterasguy said:

Gordy said:

Something I have thought about @Hatterasguy strap on temp sensors, and their delayed response time verses well sensors. Especially in laminar flows. The water to pipe pipe to sensor sensor to circuitry chain. Is it enough to make the circ chase its tail.

Actually, I prefer the delayed response time.

The boiler is quite slow to respond to changes in demand and it would be possible to smack into the HL if the circulator response is faster than the boiler response.

Slow response of the VT2218 is welcomed.

Depends if your coming down in modulation, or going up. Maintaining no big deal. Quick load changes. Weather, setback etc.

I see as an automatic transmission as the goal, and part of this being manual transmission. Even manual transmission when the passenger is telling the driver when to shift.

Obviously, I'm concerned if the unit needs to come down and cannot manage it fast enough. It only has five degrees margin on its floating SWT, so if the circulator were to slow the flow fairly quickly (I don't believe it can) and the UFT cannot modulate down fast enough, it will shutdown on HL.

There is an operating point with a quick load change and that is when a cold zone starts. The pump is going to see a large ΔT and increase speed fairly dramatically in an attempt to narrow it. The boiler is also going to see a large ΔT and a high flow rate and will very likely go to full fire.

This cold flow will quickly end once the RWT climbs after the supply makes the full loop. The circulator will slow dramatically . The question is whether the boiler can keep up and not hit HL in a valiant attempt to modulate downward. The boiler, thankfully, has a bit of mass


The automatic and manual transmission analogies are not very good as there are no discrete steps. You might think of two CVT's in series with each other.

A few things to consider when you trinkle low ph condensate, say 4 ph across an aluminum material... Especially one with tight passage ways, just saying. Keep an eye on that, the condensate drain assembly is where I would keep an eye out. Have a chat with the early Ultra and GB installers.

Funny how the big name German boiler manufacturers differ opinion on aluminum boilers. One warrantied truck loads of them when the went south, they still sees a future, the other cringes, look like they are going to throw up, when you even mention AL and condensing by products

What is the current scrap price for AL or aluminum oxide sludge? may want to factor that into your ROI.

Actually some of the solar thermal simulation programs allow you to project scrap copper prices 20 years down the road into to the economics parameter of the program.

Paul48

The UFT has a stainless HX.

Gordy

Yeah but there is aluminum fins in the passages. Worst that could happen is they disappear.

Gordy

My concern is long term with ss and aluminum contact points, and heat. Copper and stainless are much happier together. Google it in metallurgy. When in contact with each other they will corrode.

Paul48

That's the stupidest thing I've ever heard. Why in the world would they use aluminum?

Paul48

Two steps forward, one step back

hot_rod

Gordy said:

Yeah but there is aluminum fins in the passages. Worst that could happen is they disappear.

along with the heat transfer and efficiency

Gordy

I won't get to excited yet the description indicates aluminum in hx passage ways. Outside or inside I can't imagine inside to add pressure drop. Still though.

Paul48

That would be enough of a stumbling block, for me to pass on that boiler.

hot_rod

Paul48 said:

That's the stupidest thing I've ever heard. Why in the world would they use aluminum?

Just be aware of the crucial water quality in any mixed metal system.

Test the fill water, filter if necessary, always a good step, Hydronic conditioner may be good insurance, Rhomar has some of the best.

Condensate and by products of combustion. Dial in the burner for clean combustion, an obvious step.

Gordy

This turns into why forced air captivates most common people. Maintenance. Most people don't want to baby sit, or pay someone to do same. I would be curious about stated forced air efficiencies verses field. Most HE furnaces always condense.

Just sayin. Most people want to just walk over to a thermostat and maybe change a filter. Kiss

Paul48

I'd like to know how they are isolating the 2 metals to prevent galvanic corrosion.

Gordy

How do you isolate a material that is suppose to add conduction to facilitate better heat transfer?

Paul48

What's the warranty? Same as a water heater?

Gordy

An extremely durable laser welded 316L stainless steel heat
exchanger features aluminum fins that are inserted into the individual fire tube circuits to increase heat transfer
capabilities and resists corrosion

Downward fire tube design,
provides optimial condensation drainage and produces self-cleaning for low maintenance

Low pressure drop compact storage size

Gordy

I'm not sure what resists corrosion implies here.

Paul48

I think that refers to the stainless parts Gordy. Notice the way it's written. I must say it's rather disappointing.

hot_rod

You need O2 present in the system to support corrosion. Once the initial fill consumes the O2 in the water you should be fine.

If you take an iron body pump apart the day after you first fill notice it is red colored, oxidized from the original O2.

It's the non-barrier tube system that keep allowing O2 in that have serious corrosion.

Or O2 getting in thru vents, packings, seals, etc.

The hydronic chemicals add a very important function when used after cleaners, they put a very thin microscopic film on everything, think or anodized aluminum.
This is to prevent the metals from being attacked by aggressive fluids, or O2 supporting corrosion.

Wasn't such a big deal with 1/4 thick cast iron boilers, it is now.

Paul48

I'm no expert, but I believe galvanic corrosion is different. It is not rust per se.

Paul48

...

hot_rod

need O2 me thinks.

From The Beginners Guide to Corrosion

Paul48

You do for oxidation. Galvanic corrosion isn't that, and you don't need oxygen.

Mark Eatherton

https://www.galvanizeit.org/corrosion/corrosion-process/galvanic-corrosion

The lesser of the two metals will plate out towards the opposing component. It has to be in an electrolyte, which is essentially an aqueous (water, or di-hydrogen monoxide) solution in order for the reaction to take place.

I am not a chemist nor do I play one on the weekends.

I just google a lot.

ME

Paul48

I think most of us did that Mark. I knew of it, but didn't know the specifics, until I searched it.