Hydronic Study

[kurt]

Coming to the end of the trip, and I've been in discussions with a few contractors about sourcing and differences between here and there. Understand, things like heating companies are a relatively new concept in modern China. It's extremely common to go over to someone's house (condo) and there's no heat; everyone sits around in winter coats. Same thing in restaurants; common to see everyone in winter coats talking and eating. You'd think that with 4000 years of history, they'd have figured out central heating....nope. Bourgeois luxuries like heating got nixed under Mao...the country is only now getting modern, and folks are figuring out heat is a good thing.

Forced hot air and ducts don't exist. Heat, where one might find it, is a heat pump and air blower (lousy, lousy), or hydronic using low temp radiators, wall hung boilers, PEX, i.e., European stuff.

One of the guys, Ming Xian of Guanghua Heating, is at the point where the company needs to advance the skill level.

There's only 200-300 people doing heating installations in Wuhan, a city of 10 million. Same thing in Beijing, Shanghai, which are cities of 15-20 million, etc. Guanghua has satellite offices in all the big cities.

Ming is in the vanguard of folks installing heating. Really competent tradespeople, courteous, clean, everything you and I like. But, they've put the company together like gifted amateurs...finding parts here and there, figuring out how to do it by trial and error, etc.

They've had some problems in balancing heating systems in larger buildings; they're not familiar with primary and secondary loop distribution, multi-zone control systems, or the sorts of engineering you or I would expect. I've explained the stuff as much as hand signals and pencil drawings can do, but I need some manual or other industry publications to help point the way.

Who's got some good books and guidelines for how to lay out systems? Forget radiant floor for the time being, although I think that's coming. I'm primarily interested in hot water with multi zone radiator systems.

[Marc]

I'm not into heating as much as others since I'm from a warm climate but my guess would be two things:

i) J calcs until the contractor gets the ability to approximate heat demands from a mere visual observation of the zone.

ii) Installation instructions from the manufacturer of multi-zone systems that the contractor plans to install.

That should do it. Doesn't need a lot of book knowledge.

Maybe add some information on the materials and products that are going to be used.

Aqua Manual 2.4 MB download

Get me some manufacturer names sold there and I'll hunt for manuals in small file sizes. Maybe in both languages.

Marc

[kurt]

J calcs don't exist; not at a residential level. Remember, I said very few individuals have heat in their homes. Even if they have heat, it's usually a minimally sized mini-split that's so undersized, it's not worth running.

We're starting at zero here. Think America 100 years ago, central heating was a new concept. When you say "central heat" here, folks make a little "O" sound with their mouths, like, "oooooohh"....meaning, this is serious luxury.

I'm working on mfg's. manuals. Having trouble downloading the link you provided.....damn Chinese internet.

[Marc]

J calcs don't exist; not at a residential level. Remember, I said very few individuals have heat in their homes. Even if they have heat, it's usually a minimally sized mini-split that's so undersized, it's not worth running.

We're starting at zero here. Think America 100 years ago, central heating was a new concept. When you say "central heat" here, folks make a little "O" sound with their mouths, like, "oooooohh"....meaning, this is serious luxury.

I'm working on mfg's. manuals. Having trouble downloading the link you provided.....damn Chinese internet.

Then don't bother with downloading it. Only page 22 has something of value.

Still trying to figure what to look for.

Marc

Edit: I'll use my Adobe to remove relevant pages from pdf's. That'll make it easier.

[Marc]

As best I can figure, you need to choose a system that Ming will sell then download technical and installation info on that system to guide the installers on coming up with individual layouts.

If you're in the design phase, you'll need more than a basic understanding to end up with a design. Let the manufacturer do that.

Marc

[Tom Raymond]

I found an engineering article on designing hydronic heating that has some really good info in it. The pdf is attached. Translating it is on you.

Download Attachment: www.pmengineer.pdf

168.29 KB

[Yooper]

Kurt

A simple method I use often, is a five line calculation that can be used in a block/thermal envelope manner or room by room.

The five load points are:

Infiltration

Roof

Walls

Floor

Glass

U value (inverse of R value) X area X delta T or temp differential = load in BTU/hour

If a job requires it, I use Manual J but often this simple method works very well.

Happy to work through an example if it would be helpful.

Scott

[John Kogel]

If the ductwork has not been installed, why not go with electric baseboard heat, or wallmount electric fan heat? Installation is easy, so many watts/ sq ft.

I know, they will need to burn more coal to generate more electricity, but the big dams on the Yellow River are in the works. In the meantime, my province has coal for sale, and we ship most of it to China. Sorry about the smog, eh? []

[kurt]

Raymond....the link takes me to an Alibaba (Chinese) shopping site; typical Chinese internet stuff. I was able to backtrack to the right place, though...thanks. I'm telling you, Chinese internet is a pile of dung.

Yooper, this is interesting. How do you (reasonably) calculate U values for roofing, walls, and insulation? It'd be great if you'd run through a basic calc, I think I got it, but I'd like to see you do it.

Kogel...For all the sheeet Chinese put up with, they're remarkably sensitive about health and the environment of their homes. They hate electric baseboard heat. So do I. If anything is going to catch on, it's going to be the hot water radiators...that's what they seem to go for. Nobody has a clothes dryer; nobody. They don't exist. All buildings, even skyscrapers, are covered with drying racks for clothes. There are specialty companies that do nothing but install these hanging systems, cabling systems so they can be pulled up to the ceiling, etc. Folks have discovered you can hang clothes on the radiators to dry them; it's a big sales plus.

What you and I might think is a logical approach doesn't compute here.

[Yooper]

Kurt,

I'll try to be brief...

In our example we'll use a 30' x 40' ranch house with 8' ceilings on a crawlspace, 120 sf glass and doors. Geographic location is northern Michigan where we design to 10 degrees above zero. I often use a lower temperature of 10 below 0 to cover the brief times like it was last night for a few hours.

The U values are from the Manual J book and are the inverse of R values.

Infilatration is on volume and air changes per hour. We'll use .018 U value and .25 air changes per hour on a newer well constructed home.

The roof (attic) area is 1200 SF and an R value of 40 (required here in Michigan)

Net wall area is 1000 SF R value 21

Floor over an insulated crawlspace is U value of .06

Glass U value is .35 again required by energy code. I use the same for entry doors but they would actually have a better U value.

1 / R value = U value

Infiltration .018 x 9600 (vol) x .25 air changes/hr x 60 (temp diff) = 2592

Roof .03 x 1200 (SF) x 60 = 2160

Walls .05 x 1000 x60 = 3000

Floor .06 x 1200 (SF) x 60= 4320

Glass/Doors .35 x 120 x 60= 2520

Total BTU load per hour is 14592

So.... a furnace that has an output of 15,000 Btu minumum would be required to heat this house. If hydronic heat is used, 25' of standard baseboard of 580 BTU output per foot (reference Weil-McLain ThermaTrim baseboard) would be required - along with a boiler of adequate size.

There is more to it from here, zoning and flow would be taken into consideration to select proper valves, thermostats, etc.

If you wish to go into in a separate communication, I would be glad to try to be a help.

Scott

[kurt]

Thanks, very helpful. I'll relay the information to Ming.

Gaylord is a beautiful place. When I was a kid (60's), I was big on fishing the S. Branch. We'd stay at Wakely's cabin by Wakely Bridge. I met Wakely a few times; heck of a nice guy.

Also used to fish the Sturgeon and Pigeon, before fly fishing became a yuppie obsession. I remember when there were still elk in there...are there any elk left?

[Yooper]

There are elk to see. The bulls are incredible with their huge antlers.

We stay out of the rivers in the early part of trout season for the very reason you mentioned. After visitors leave we get out and enjoy mostly quiet waters.

I work in applied sales for the HVAC business so if you need any information, please let me know.

Scott