Online educational resource on achieving indoor environmental quality with radiant based HVAC systems
Not for profit educational resource on indoor environmental quality.
 Bookmark and Share
not for profit educational resource


21 points every architect, engineer, contractor and their clients should know about heat terminal units - sample slides. For additional support visit our visitor services page.

Our integrated design program has over 2100 slides illustrating architectural, interior design and HVAC engineering principles which contribute to indoor environmental quality and energy allocation for conditioning the occupants and building.

The following course materials on heat terminal units (HTUs) are samples from the lecture and based on a Steven Covey principle of "Begin with the End in Mind". They are a very small but important sample of the Covey principle and are provided here to give you an idea of what kind of materials we'll be discussing during the program.

The course is also registered with AIA and participants can earn up to 21 Learning Units.

For more sample slides visit our list of training modules.

Figure 1: I don't know about you but these old style heating devices (aka heat terminal units aka HTU's) have a mystic aura about them that I really love. I credit my good friend Dan Holohan for helping me to find my inner appreciation for these old systems.

Figure 2: Just north of our Calgary office are the guys from TWA Panels who make chilled beams and radiant ceiling panels - a few of their products (above) conditioning a classroom.

Figure 3: Michel Cinier says this about his products (above), "The union of the best technology and creativity for the Art of heating. Being surrounded by beauty is a way of living." I agree...I've seen a lot of beautiful radiators in my days and these ones are up there with the best."

Figure 4: I was privileged to have had a private tour (courtesy of Tim Doran), of the TACO HVAC Innovation & Development Center; on display in the new facility are fine examples of how to condition people and spaces. Shown above are low profile radiators (left and right) and chilled beams (center). Photo Courtesy of Taco Inc.

Figure 5: I had been to the Taco plant many years ago when we represented them in Southern Alberta. I remembered this wall radiator and swore the next time I got back to the plant that I would take a picture to show a industrial application for conditioning people an spaces in a large manufacturing facility. So many large facilities try to blow hot air down from the roof which is an exercise in futility - it just doesn't have to be that way with so many other better choices in HTU's. Photo Courtesy of Taco Inc.

Figure 6: At one point or another in my career I've worked with almost all of the radiant floor heating manufacturers. For the past decade Uponor and I have partnered up on various programs to communicate to industry the importance of creating better human environments. Without their support for industry education much of what we see on the North American continent would likely not be at the same calibre. Shown is one floor of a multi-story building in Toronto, On., using radiant floor cooling and heating. Perhaps one of the best commercial installations I've seen. Also shown is a prefabricated manifold and mixing station (foreground and right side). This model came out of our own manufacturing facility before we sold the plant several years ago. Photo's courtesy of Uponor.

Figure 7: I don't recall the brand name of these heat terminal units but they are an actual fan/convector. I was so impressed that a forced convection device could look so slim and functional I just had to talk about them and so they have become part of our presentation. If anyone knows the manufacturer please let us know.

Figure 8: We were very successful in our rep business and one of the thoroughbreds we had was Myson which included fan/coils, fan/convectors, panel radiators (above) and towel warmers (below).  These are the traditional European method for space heating and you'll find them everywhere you go when visiting the UK, Sweden, Denmark, Germany, Noraway, Italy etc...

Figure 9: There is something elegant about towel warmers and heated benches - how could you not want one or both of these beautiful devices in your home or offices. We've just finished a new design project in Calgary where we have specified three of these wonderful heating elements.

Figure 10:  Our industry colleagues from Uponor are mastering the art of connecting heat terminal units to boiler and chiller plants by running pre-insulated flexible PEX pipe in ground and even above in truss spaces. If you can go low it makes more sense from a labour and material cost as well as job site safety. It's fast and effective and you should be doing this on all your residential or commercial projects.

Figure 11:  After all these years this is still one of my favourite residential mechanical rooms! It's clean and professionally assembled using manufactured control appliances. Not all homes are this big but even the more conservative project can still have a great looking mechanical room that won't destroy the value of the home when it comes time to sell the property.

Figure 12: Here's my good friend Tim Doran from Taco-HVAC. Tim gave me a tour of the TACO HVAC Innovation & Development Center which included a tour to the heating and cooling plant. Without a doubt one of the nicest commercial boiler rooms I've been in. They walk the talk at Taco as do many other manufactures I've worked with...they use solar, evaporative cooling, radiant cooling and heating, chilled beams, panel radiators - you name it- they use it; and use the new facility to demonstrate the fundamentals in equipment applications. Photo Courtesy of Taco Inc.

Figure 13:  Ok back to the engineering side of systems. In our heat terminal unit lecture we'll introduce the math behind the equipment including this fundamental formula in heat transfer.

Figure 14:  I don't know how many jobs I've been to where the flow in a heat exchanger was all matters if the flow is in parallel or counter flow and we'll demonstrate this with the log mean temperature calculation.

Figure 15:  This summary chart lays out the control and compensation methods for various types of heat terminal units. Notice how only the hybrid systems at the bottom really cover all the basis for conditioning people and spaces.

Figure 16:  Here are some typical ranges for heating and cooling for different heat terminal units. This is not trivial stuff as low temperature devices enable high performance in heating systems and high temperature devices enable high performance in cooling systems. See our discussion on the importance of using aluminum heat transfer plates in radiant systems.

Figure 17: Ohhh this not be good (grin)...see how Denmark and Finland have earned high effectiveness coefficients by their choice of heat terminal units and operating temperatures and differential temperatures? Historically our culture has been one of small and low cost heat terminal units but use very high temperatures to achieve heating. This has destroyed our ability to enable maximum efficiency from our boiler plants and essentially eliminates any opportunity to connect to community based systems using low temperature fluids.

Figures 18: All heat terminal units do not behave the same way - they in fact have different personalities based on their responsiveness, i.e. low mass to high mass and forced convection vs. natural convection. Because they have different personalities they need to have different controls and we spend significant time discussing this in class. Credit to TA's retired Professor Robert Petitjean for passing on his passion for pressure. We used to represent TA as well back in the day and still specify their products when we can.

Figure 19: I'm always keeping my eyes out for equipment that is designed to fit into developing trends in HVAC and this product by Daikin is one such device. It's an HRV with a cooling coil which fits my needs for doing radiant cooling with dedicated outdoor air system (DOAS). The ventilation component takes care of the air exchange and the coil takes care of the dehumidification.

Figure 20:  Where hydropower, wind or PV is in play - we'll specify heat pumps with low temperature radiant heating and high temperature radiant cooling to really enable maximum exergy efficiency.

Figure 21:  Likewise we'll use solar for those clients with demonstrated economics or if they just want to lead the way in sustainability - for some clients it just feels good to do good things. Solar will do that for you.

Figure 21:  Here it is - one of the key messages in outcomes from mixing buildings with mechanical systems. Where do you want to be? 

So there you have it, a few sample slides from our heat terminal lecturer...just a hors d'oeu·vre from our library of over 2100 slides addressing a small but important element of integrated design and radiant based HVAC systems. In the program we will get into this and a whole lot more? How much more? Well just follow the links to the other parts of our website and you’ll get a feel for the scope of materials that we’ll be covering.

See you soon.

Robert Bean, R.E.T., P.L.(Eng.)
Registered Engineering Technologist - Building construction (ASET #8167)
Professional Licensee (Engineering) - HVAC (APEGA #105894)
Building Sciences / Industry Development
ASHRAE Committees: T.C.61. (CM), T.C.6.5 (VM), T.C. 7.04 (VM), SSPC 55 (VM)
ASHRAE SSPC 55 - User Manual Task Leader

Note: The author participates on several ASHRAE and other industry related committees but be advised the materials and comments presented do not necessarily represent the views of these societies, only the president of the society or nominated representative may speak on behalf of the organization.


Home | Seminars | Solutions | Heating Cafe | Contribute | Online Help | Bean's Blog | About Us | Glossary
Privacy Policy | Legal | Contact Us | Site Map |
Carlson-Holohan Award| Send Us Your Comments

Copyright © 2012 Healthy Heating. All rights reserved.1 2
Site developed by 
PayPal funding contributions accepted online  
 Healthy Heating accepts Visa, Mastercard, Amex and Discover.