Why the egg on the face of Hydronic Coooling (The Younster)

Steamhead (in transit)

in humid climates you need to dispose of the condensate. This can be a problem with in-floor radiant. Sweaty floors.....

Edwards Engineering used to market fin-tube units that mounted high on the wall for hydronic cooling. This would of course allow condensate to drain by gravity

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Josh_10

Radiant cooling has a standard now. ASHRAE has published guidlines. Why don't we have controls yet? Why hasn't Siggy or others (to the best of my knowledge) written application articles about it?

We have reverse cycle chillers now (available through Aqua Products, Inc.) that can utilize any heat pump for both radiant heat and cooling.

Why do we associate Hydronic with heating. We have been associating it with cooling in the commercial and industrial world for years.

We have a powerful tool at our hands when we can transfer heat to/from a heat pump with water. Radiant cooling supplemented with Hydronic air handlers simplifies combination Radiant Heating cooling systems.

How come we don't talk about it?

Josh_10

Hey Steamhead,

Check this out!

http://www.healthyheating.com/Page 55/Page_55_i_cooling_eq.htm

Dave_4

Google \"radiant cooling\"

I'm not sure what you "haven't seen about radiant cooling- there have been numerous discussions here about it, as well as on the Radiant Panel ****'n discussion board, and as well there are numerous (too many to list) operating radiant cooling systems throughout North America now. One of the largest radiant slab cooling systems is under construction right now in Winnipeg, Manitoba (Manitoba Hydro Headquarters). If radiant cooling can work in the summer climate of Winnipeg, well, I guess it can be appplied anywhere (93F at 85% RH). The worlds largest radiant cooling installation is in the Bangkok Airport, speaking of hot'n'humid climates.

Link to a recent article about the Manitoba Hydro Building in Winnipeg:

http://www.canadianconsultingengineer.com/Issues/ISarticle.asp?id=184911&story_id=10825095943&issue=03012007&PC=

Google the Bangkok Airport radiant cooling for some articles on that one.

Geo-exchange systems that provide both low temperature heating, as well as moderate temperature cooling water, are an ideal source for a combined radiant heating/cooling system, and there are many examples of those in my world.

Paul Pollets

A Perspective, Grasshopper

We're just starting to see a maturity in the radiant floor heating market. The means of installation has not been standardized and I notice the bastardization of piping/loop layouts that are incorrect in more than 70% of every repair my company looks at. That happens with Siggy's books, the RPA and all the manufacturer's training available. If we can't get the radiant heating right, radiant cooling would be a major disaster, at this point in time. Besides, the expense and costs of doing it "right", make it far too expensive for most contractors...certainly residential contractors.

Large mechanical contractors will be able to get it right, with proper training and engineering assistance. Radiant cooling will be more popular as the Euro controls become more accessible, and the costs are defined in "return on investment" strategies and comparative costs of operating the systems, at the time of sale. Most residential contractors do not have the ability to make these points...yet.

I agree with Geoff, who has massive experience in this field. I also think the market for radiant cooling will be taken over by HVAC contractors, not radiant heating contractors, with few exceptions.

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The Wire Nut

We have talked about it...

... search for mentions of the KARO system, for example.

I briefly considered it for my own home, but without the benefit of an experienced installer, I didn't want to play guinea pig. It's a nifty system for any climate, really, as long as you can handle the latent heat removal.

In older homes like mine it would have been ideal because you need much smaller duct work (only worry about ventilation / latent heat removal). KARO has no O₂ barrier, uses small capillaries in the ceiling, so a HX is required. However, I bet that the system can work really well.

Dave_4

Sigh,....

Unfortunately, Paul, I agree- there is still way too much radiant heating "design" using "cheap, fast, and gut-feel" as the design guidelines. And this also extends to the larger projects I am familiar with. I tend to go overboard on any new set of trades I have to work with for laying radiant tubing in slab systems, and have developed an "all-trades" educational session for the group of formwork, steel, concrete placers, and mechanical trades that will be doing the job, and then continually police the project all the way through so the group has "bought into" the installation quality.

The residential sector has a much higher impact on how radiant systems in general develop. There are way too many contractors out there, along with the "do it yourselfers" that botch these systems up and give the whole industry a bad name. I spend a lot of time responding to the mis-information and horror show radiant system problems due to the jungle telegraph of screw-ups that become mainstream "factoids". Witness the recent radiant ceiling heating discussion here - so many assumptions, myths, and legends get dragged out as "factual" debating points. All we need is that one Client who heard from a friend how his radiant floor system was screwed up, and then we have a huge uphill battle to deal with.

We just have to keep educating people. Wish we could clone a few thousand Siggies and Beans and get the education out there. Hmmm Siggies and Beans, sounds like a nice meal....

Tim Doran_4

In the works

I have two projects in the works at present. Both will be radiant cooling and heating. Danfoss has a tried a true control that is reasonable in cost and easy to set up. It is called the ECL 300. Brian at ZCP is the authority on this control and can help with any applications that you may want to try.

There should be a design tool comming from ASHRAE soon. I wrote one last year before I had to leave the technical committee. I am not sure where it is in the process.

Tim D.

Jeff Lawrence_25

Here's one

Actually it's not too far from me. They mention getting the RH inside down, as I recall.

Dave_4

I hope it includes some Building Physics

One of the key issues is educating the HVAC designers about how the building envelope works and all about Mean Radiant Temperature. I find the style of most HVAC designers is to design in a very "reactionary" mode - that is, they design whatever heating and cooling capacity is required to react to the building/room physical design as provided by someone else. That "someone else" who designs the building, or room envelope may not be designing a room envelope with the necessary performance to allow basic human comfort in the first place, and the HVAC system ends up as a band-aid to try to make up for the envelope non-performance. It's fine to have a radiant heating and cooling system, but if the architect/building designer has allowed poor perimeter envelope specifications to result in cheap glazing selections, and poor thermal bridging details, the interior surface temperatures of the space must also be factored into the basic load calculations, and none of the traditional HVAC calculations and software include much, if any, mean radiant temperature load calculations. The closest we have is the ASHRAE-55 Human Comfort calculations (PMV estimates), which MUST be integrated with the basic HVAC load calculations.

This is especially critical with radiant systems that have limits on their sensible temperature control capability. I hope the "design tool" includes more of the "whole building design" aspects of radiant systems applications and doesn't treat radiant cooling as just another nifty "supplemental cooling specialty".

Unknown

I've been looking at radiant cooling a bit. I just read the Chatanooga article and I'd like to know HOW they are controlling water temp to be a constant 5* above outdoor dewpoint? With the large house I just did using warm/chilled water I've been wondering if I could cool the floors and use the air handlers as dehumidifiers. If not this one (because it wasn't designed for this) but maybe the next one?

Another point is the transfer of heat from one area to another. Robur makes a unit that will do that. It heats and cools water simultaneously and can use the heat picked up from the return chilled water to heat another area and vice versa. For example it can take the heat from your computer room or kitchen in mid winter and use it to heat another area of the structure. It requires 4 pipes naturally. I haven't totaly looked into the machine yet but I like the idea.

Plumdog_2

You really nailed it

These "botched jobs" are going to be the bane of this industry. I see that Real Estate Disclosure forms are including an area for Radiant Heating. "Does your home have Radiant Heat? If so, what kind of tubing is installed?" etc.
Soon, they may have to expand the form to include a whole page with more specifics. It's right there with Mold, Leaky Roofs, and Cracked Foundations. Standards are a good thing, and better late than never.

Josh_10

Some interesting perspectives here. We are embarking on both radiant cooling projects and combo projects with duct work.

Water is a great way to transfer heat both ways. Whether it be chilled water or heated water. Perhaps the only way to zone a cooling system without killing the heat pump compressor is by way of a buffer tank and hydronic coils in the ductwork. In fact you don't even really need a defrost cycle when implemented properly.

Forget Radiant cooling for a second. There are so many applications for heat pumps in hydronics in general. I think we should start talking about proper piping and application. And begin to embrace some of this new technology.

Heat pumps are way more efficient in the air industry. And now that we can use them for Hydronics it opens up a whole new world of efficiency and green heating. Boilers are great but they will never be as efficient as a heat pump.

Paul Pollets

But...

Heat pumps are not able to provide enough heat for recovery of an indirect DHW Tank, or a high temp circuit for radiators or baseboard. That means a separate gas fired or electric water heater would have to be used.

Since the DHW tank usually consumes 30% of the yearly energy load for a residence, finding the most efficient means to supply DHW should be part of the "efficiency" equation for system design.

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Perry_3

Humidity control

In my area we need humidity control far more than a lot of cooling in the summer. Radiant cooling with conventional heating systems will not allow for the removal of humidity.

I have long considered that if I were to build a house. Installation of hot water/chilled water room units typical of hotels would be ideal. They can remove humidity from the room and are readily available. For heating; they could work on a outdoor reset curve.

Perry

Plumdog_2

Like a Univent

found in classrooms. Heat, Cool, Ventilate, with coils, fan, dampers; right thru the wall but unobtrusive and compact for residential use.

GMcD

Climate Specific

You are right - radiant cooling is not a Latent cooling system - but, look at it a bit differently: in a hot'n'humid climate, you need the dehumidification for healthy comfort anyway, and that will do the majority of the comfort cooling anyway as an "on the way by" effect as per ASHRAE-55. Once you have that source of dehumidified air, it "may" allow some sensible cooling via radiant cooling to be used as part of the overall comfort systems in the building to help reduce the total amount of conditioned air you need to circulate anyway. Basically it may help downsize the main AHU to be more of a DOAS unit supplying the dehumidified ventilation air component while more of the sensible cooling could be done via radiant cooling.

The key is still a very good envelope design to reduce the sensible cooling loads down as low as possible, with a tight envelope to minimize infiltration of that humid outdoor air as well.

Tim Doran_4

System Design tool

It is basically a system design tool but it does integrate AUST, MRT & Operative temperatures and adjusts things like transfer coefficients accordingly. I am not certain what it has become over time but as I left it, it would consider the load, develop the transfer coefficients, do all of the hydraulics, incorporate control valve authorities, develop criteria based on 6 variable layers above the tube and 4 layers under. Each layer can be an individual material of any thickness. It had an extensive pick list of materials and all of thier associated properties and it understood panel orientation. It also addressed short wave impact and the resulting implications. I'll have to check with Peter simmonds to see what is going on with it.

Tim D.

GMcD

Sounds like fun

If P. Simmonds is tweaking it, maybe he'll add some of his proprietary PMV calculators in there too. He alluded to them last time I co-presented a seminar with him for PG&E last fall. Simmonds is my kind of guy- he denigrates the Architects even worse than I do!

Josh_10

We are using a Vitdens 100 for back up heat to the heat pump and for domestic with indirects. Boiler backup is recommended.

I'm not saying this stuff should be mainstream. It's expensive no doubt, but in our area it actually has a pay-off where Geothermal doesn't.

Unknown

VERY interesting! It makes me think I should give this floor cooling a shot over at the new install. The house has a very tight envelope and the best windows and doors. There's actually a chance we could achieve some benefit by cooling the floors. I'll let you all know what happens as time goes by.

[Deleted User]

It's not egg, it's...

condensate.

Remember, we live in a very litigious society, and at present, mold is gold to the lawyers.

In speaking with some German nationals about why it is that they haven't introduced their products to the N.A. hydronics market, they stated simply "Too many lawyers..."

I think it has an excellent potential, but needs to be done under the strictest of control lest our house of hydronic cards come tumbling down.

In looking to our neighbors to the north (Canada), they are on the verge of realization of hydronic licensing, and that is what I think its going to take to keep things under control.

Many thanks to the North American pioneers moving towards eventuality of utilization. You can tell a pioneer by the arrows in his back :-) Seriously, thanks for all your work. It will be rewarded in time.

ME

Tim Doran_4

PMV Tools

I was working on a version with a PMV tool when Uponor decided to change direction on me. Since then I have had no time to think about it. The stuff that Peter has is so far over my head that I can't even think about it without getting a migrain. I was basically working on incorporating the ASHRAE comfort tool into the back end so that we could verify the designs' compliance with STD-55. One of the other cool features of the tool was a series of hyperlinks to the supporting ASHRAE text for the particular calculations, for those of us that like to understand how we get the answers.