What's to Come of Hydronic Heating ... OR At Least What I Hope For
But our industry can’t survive solely on “rediscovering” old ideas. Progress in many technologies is at an all time high. In the computer industry, for example, new ideas and products appear almost weekly, with each new product leap-frogging the previous standard.
Although it operates at a slightly slower pace, the hydronics industry is certainly not without its accomplishments in 1997. And 1998 will undoubtedly see more new offerings. Here are a few things I think will happen in the hydronic heating industry in the near future:
1. Improved Controls: If success in real estate boils down to three principles — location, location and location — then it might be said that future refinements in hydronic heating boil down to controls, controls and controls. Now don’t get me wrong here. I’m not a controls fanatic, (you know the type ... the more LEDs the better). But there’s still room for improvement in delivering exactly the right amount of heat when and where it’s needed, and controls are the key.
Many of our current hydronic systems consist of devices that turn on and off independently, without regard to what other parts of the systems are doing. The accuracy of some controls that oversee these operations is pretty shabby in comparison to what could be attained with current technology. For example, when’s the last time you watched a boiler cycle on and off exactly as predicted by the specifications and settings of its limit control? Does such marginal accuracy produce acceptable results? Well, if you define “acceptable” as anything that doesn’t bring complaints from the customer, I suppose you could say that most systems are acceptable.
But what about energy that could be saved by improving control accuracy, or the control algorithm itself? Savings that neither the owner nor the contractor even realize is possible? Remember, many of us used to drive cars that got 10 or 12 miles per gallon, and we felt just fine about that at the time.
Many of our current controls react to real-time conditions. They can’t anticipate very far in advance. Even an outdoor reset control that ramps up the temperature of a concrete floor slab during a frigid night often can’t prevent overheating from solar heat gains the next morning. It can stop further heat input to the slab once the sun starts to overheat things, but, unfortunately, can’t pull Btus already released into the slab a few hours ago earlier back into the tubing. And once heat is released into the slab, it’s routed by nature, no matter how many microprocessors are back in the mechanical room.
Now here’s a radical idea for you to ponder after watching the evening weather forecast: Imagine a control system that reads digitally encoded weather information broadcast over the Internet and then predicts what the building’s heating load will be several hours in advance based on forecasting algorithms. It then optimizes what the system does several hours in advance to minimize or completely avoid any deviance from desired comfort, or wasted fuel. This control even learns how its building responds to heat input, then fine-tunes its thinking based on this information. Sound far-fetched? A few years ago did you think Americans would be able to watch live pictures from the surface of Mars on their home computers? I think we could see such a control scheme operational within five years.
2. Increased Use Of Variable Speed Circulators: The ability to precisely control flow in portions of various hydronic systems is an integral part of achieving better control of heat delivery. Larger hydronic systems have used variable speed circulators for several years. In Europe, several companies sell small circulators with variable speed capability. And like many other aspects of hydronic heating we’ve only to look across the Atlantic to see the future of circulators.
A good example of where variable speed can help is a multizone system with zone valves. As zones close off, a single speed circulator operates higher and higher on its pump curve. In some systems, the high head differential that develops across a single open zone valve can cause serious noise problems. Enter a variable speed circulator controlled by a differential pressure sensor. As zone valves open and close, the differential pressure is sensed, and circulator speed is adjusted up or down as required by the load. Not only does this eliminate the noise problem, it also saves electrical energy.
3. Expanded Use Of Polymer And Thermoplastic Pipe: No product deserves more credit for reinvigorating the North American hydronic heating market than PEX tubing. Although its introduction into the market launched many a heated debate, its track record is now well established. PEX has become a staple of hydronic heating in North America — so much so that many now refer to it as a “commodity” like copper tubing and thermostat cable.
PEX is not, however, without its competition. PEX-AL-PEX has come on strong in the United States during the last couple of years. Look for other types of thermoplastic piping, both flexible and rigid to vie for their share of the hydronic market in the future. Although copper and black iron will always have their place — the former where heat transfer is paramount — the latter for near-boiler piping, neither can ultimately match the installation flexibility and speed of long-length coiled tubing for distribution piping.
4. Really Smart Design Software: I’ve long been an advocate of making scaled tubing layout plans for every floor heating project. The one argument against this approach points to the time it takes — even with a CAD system — to produce such drawings. But I expect it won’t be long until we’ll see design software that — in addition to determining water temperatures, tube spacings and so forth — will automatically figure out the best way to route tubing circuits within the floor plan of the building, and quickly produce the necessary drawings. It’s a matter of taking existing programming methods, such as those used for computer-controlled machining or printed circuit board design, and adopting it for hydronic applications.
5. “Radiant Friendly” Flooring Warranties: The wait-and-see period is over. Hydronic floor heating is not going to go away, and manufacturers of various flooring products have a choice to make: Jump on the bandwagon by developing consistent, practical and detailed installation procedures for their products that installers can use with confidence over heated floors, or let an ever growing segment of the market slip to their competitors. Last year witnessed progress on the part of certain flooring manufacturers, who realized their need to offer products and installation methods compatible with floor heating. I hope we will see more in 1998. In the meantime nothing gets a manufacturer’s attention faster than letting him know why you can’t use his product over a heated floor, but can use its competitor’s product.
6. Better Information On Floor Heating “Materials Issues:” Although many aspects hydronic floor heating have received much technical attention and refinement, the so-called “materials issues” — such as the effects of heat on finish flooring, plywood and adhesives — remain under-researched (or at least under-published). This is partly because hydronic floor heating systems are created by pulling together materials from several diverse industries, each with their own narrowly focused expertise. The tube supplier doesn’t necessarily know all the details about the flooring, while the flooring salesperson doesn’t know anything about hydronic heating. Meanwhile, out on the jobsite, the electrician doesn’t know much about the tube, the flooring or the boiler — except that given the right drill he can put a hole through anything!
As an industry, we need to encourage the participation of manufacturers of products, such as plywood and flooring goods, to develop optimal floor heating systems that address all the materials issues. We also must be diligent in communicating the necessary details to the GC and other trades on the project. Remember, we’re the ones who are supposed to know how to put all these materials together into a long-lasting system. And who do you think will get the blame if any part of that system fails?
7. Publicized Failures Of “Bad” Floor Heating Jobs: Given the rapid growth of interest in hydronic floor heating, it’s inevitable that some poorly designed or installed systems will fail prematurely in 1998. One has only to recall what happened to the solar industry when federal tax credits instantly created a lucrative market for those seeking profit over professionalism. Given the media’s present zeal for warning the public about anything it deems defective, some of these failures are likely to get much more negative publicity than the industry as a whole deserves. (Remember what happened to American polybutylene plumbing industry after the national media worked it over).
The best defense is a good offense. Witness the work of the Radiant Panel Association in developing installation guidelines, national conferences and training programs — all of which promote high quality, well designed and installed systems. Each of us has a responsibility to hold ourselves to high quality design and installation standards that ensure a strong and respected hydronics industry for 1998 and many years beyond.
The future of hydronic heating is bright and bountiful for those who avail themselves of the materials and design/installation methods currently offered, as well as those soon to appear. I’ll do my best to keep you posted on the technical issues of hydronic in 1998, while many other PM columnists help you manage your business affairs wisely. Stay tuned.