Air to Water Heat Pump for radiant floor

Wayco Wayne_2

I work for the Parks where I live. They are getting away from fossil fuels. We have two new buildings being built next year that are warehouses. In the old days we would have used propane powered radiant tube heaters up above. Not an option anymore. I suggested an in slab radiant floor heated by an air to water Heat Pump. What is out there?

GGross

Why are tube heaters not an option anymore? Just because they are getting away from fossil fuel? Did you ask them if any of that electricity they will power the heat pumps with comes from fossil fuel?

Hot_water_fan

@Wayco Wayne_2 There are options but they're not widespread. Taco, Spacepak, Nordic are some of the residential sized units. For larger capacities, I think you'll have more options but I'm less familiar. You'd get amazing efficiencies out of a radiant floor with A2W, probably crush propane fuel cost wise.

Wayco Wayne_2

We have an Ice Rink that has indirect hot water tanks that the discharge lines from the ice making compressors go through. Tons of hot water. Why not a Residential Heat Pump? Depending of course on the heat loss. They only want 50 F inside temps. For storing batteries I'm told.

Hot_water_fan

Residential would be fine if the scale works. Why a radiant floor for just storing batteries? You have a lot of options, that’s one of the most expensive ones. A ductless or ducted air to air unit would be cheaper for sure. 

hot_rod

What size load do you have?  Cold climate residential A2WHP go up to 5 ton

Output drops with temperature

Wayco Wayne_2

One is storage, the other is an auto repair service bay. Don’t know how many bays. They asked for the radiant floor at the warehouse. I don’t have a blueprint to do a heat load in either case. I’m guessing a ductless would most likely work in the storage building. One problem I have is when it comes from the architects they would rather have certified engineers do it. No problem. I only have 3 decades of practical experience and doing my own designs. Although the certified design engineer is a smart cookie, and has been e mailing me with questions. I’m glad to help.

hot_rod

There is some useful HP info here.

https://idronics.caleffi.com/magazine/27-air-water-heat-pump-systems

Jamie Hall

I'm glad, @Wayco Wayne_2 , that you are willing to help the certified design engineer. That's how they learn the practical stuff.

However, there are two reasons -- at least, while the architects would "rather" have certified engineers do it. The first is that the law requires it. The second is perhaps less obvious: the law requires it because the law also states that the certified engineer is PERSONALLY liable for all defects and damages, direct or consequential, deriving from errors or omissions on the plans which he or she stamps. This liability extends to include everything he or she knew, or should have known, about the design and installation (including installation or construction procedures).

This can be trivial, and sometimes is. Sometimes it can be a little less so (in your example here, for instance, if the building can't maintain design temperature, that certified engineer who stamped the plans is liable for all damages, including putting it right). Sometimes it can be a LOT less trivial -- if the design I did, for instance, for a water supply system for a hospital failed and made some people sick, I'd be liable for the damages -- which could run into the millions of dollars. And, my friend, that's personally liable. Me. My house. My bank account. Which is why a certified engineer will either have no assets at all or, if he or she is any good, will carry errors and omissions insurance (which is quite expensive...)

I might add that if your engineer stamps the plans, and you as the contractor make a substitution without his or her approval, the engineer -- not you -- is still liable if there's a problem. This may explain why engineers tend to be a bit fussy about knowing about changes. He or she would have to show that he or she did not know and could not have known about your change (that was thrashed out in the Hartford (CT) Coliseum roof collapse a few years back).

hot_rod

A number of our reps do design work for the engineers that have little or know experience in certain disciplines.
The biggest hurdle for the engineer or firm is knowing how to properly use the Sim software. I suppose when the design shows up at the engineering office on a tube manufacturers simulation program, done by someone with practical experience, they are willing to embrace the design?

Jamie Hall

Almost always, @hot_rod , yes. But with one reservation: they have to have confidence in the people running the program and their practical experience. Whether it's good, bad, discriminatory, whatever, I and every engineer I've ever known were kind of interested in the reputation of the specialists we relied for some of this sort of thing and, very honestly (I'm retired from all that and in a very different profession now!) I have to admit that in various fields where I relied on specialists, there were always some firms or individuals I'd go to every time -- and some I wouldn't have touched with a ten foot pole.

Sometimes bitter experience. Sometimes just "a feeling". Sometimes gossip among contractors or other engineers.

That positive glow of which the above paragraph is sort of the inverse is "good will". Unmeasurable. Priceless. Hard to develop -- but all too easy to lose.

You all -- that is, Caleffi -- have good will in spades, though! Keep it up!

hot_rod

 Engineers are usually good at ferreting out the knowledgeable partners. They know the questions to ask.  And the factory tech guys can steer them to the reputable ones.
In a handful of cases our reps are also degreed engineers.
No different in other professions I suppose, lawyers, doctors, car mechanics, steam experts, etc

Bad reputations spread more quickly then good in todays SM world, it seems

GGross

@hot_rod
Let's celebrate a great reputation then! Caleffi has been fortunate enough to have one of my favorite reps handling the line in Michigan. Specifically Jim Eardley, who I would put right at the top of my list of reps that I can rely on.

Rich_49

Should be available in November .

https://www.tacocomfort.com/product/system-m/

hot_rod

GGross said:

@hot_rod
Let's celebrate a great reputation then! Caleffi has been fortunate enough to have one of my favorite reps handling the line in Michigan. Specifically Jim Eardley, who I would put right at the top of my list of reps that I can rely on.

Gotta love Jim Eardley, always fun to travel with him

Wayco Wayne_2

Hahahaha. I just checked this thread and the responses to my tongue in cheek comment about me helping the Engineer. In this case they seemed smart enough to listen, and I hope that they take what I say and apply their knowledge to the design. My brother has a good story about a party he went to at his friends house. His friend was an engineer and everyone there was an engineer of some kind. My brother is a master carpenter, and had over the years built many things having to meet code and knows how to draw up plans. Someone came up to him at this party and asked what kind of engineer he was. He told them he was a "Practical Engineer." He said he left the guy with a puzzled look on his face while he walked away pleased with his answer.