30 points on embedded cooling and heating pipes every architect, engineer and contractor should know for radiant cooling and heating systems - 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 embedded cooling and heating pipes 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.

Note: links below will take you to additional study content. We encourage you to follow these links to develop a broader understanding of radiant based HVAC systems.

Figure 1: Each item listed above is important as a standalone consideration, but also as a woven element within the system design process. Designers should know what these terms and formulas represent and why it’s important to work within conditions which enable maximum exergy and energy efficiency from the system.

Figure 2: Embedded pipe radiant systems are on site fabricated heat exchangers; where characteristics of each element are important when analyzing the heat exchanger design.

Figure 3: The panel surface characteristics are important. Smooth shiny surfaces like aluminum foil (left image 10,000 magnification) have lower emissivities and lower absorptivities (think light coloured polished concrete with a lacquer type finish) and make for less effective radiators whereas rough surfaces (right image, painted surface at 500 magnification) have higher emissivities and generally (but not always) higher absorptivities (see role of color below).

Figure 4: Color is important in short wave (solar and some high intensity lights) energy absorption and must be considered for radiant cooling systems. Color is not important in radiant heating systems. Ergo reversible floors (those that are designed for heating and cooling) should have flooring selected to promote the effectiveness and efficiency of the system in the cooling mode. This is one of several reasons why it is important to work with interior designers when it comes to architectural surfaces used for radiant cooling and heating.

Figure 5: Shown are the inward and outward energy flows and resistances for cooling and heating respectively. Also note the co-efficient of expansion/shrinkage of the concrete which must be considered alongside the co-efficient of expansion/contraction for the embedded pipe.

Figure 6: The output from various heat terminal units is a function of several items as shown. What is rarely discussed is the power exponent (n) which is a function of the radiant/convective split.

Figure 7: Not all concrete is alike…what differentiates one from another and how does this relate to the design of radiant systems?

Figure 8: Not all pipes are alike especially when it comes to linear expansion. Why and where to use one type over another is another item every designer should know.

Figure 9: Have you ever considered what happens to the molecular stresses created when encased pipe ( at a higher coefficient of expansion than concrete) is heated up and can’t relieve it's stress in the longitudinal direction? We'll be discussing this and other concepts in the three day program. Shown is an Excel™ based calculator to compare the unrestrained expansion of concrete to the unrestrained expansion of pipe.

Figure 10: As per Figure 9 except in cooling mode.

Figure 11: Based on our informal survey, 95% of all radiant designers are not aware of the various building code requirements for conduits and pipes embedded in concrete. Virtually all designers and contractors will specify and pressure test to plumbing code requirements unaware of the pressure and temperature restriction of the concrete codes (see last slide for comparison).

Figure 12: As above in Figure 11, but get this...as of this upload the temperature and pressure restriction in the U.S. ala the ACI documents are different from Canada ala the CSA documents - is there something we should know about concrete in Canada versus the U.S...go figure.

Figure 13: I don't know how many times we've witnessed premature operation of a radiant slab. Again most designers and installers are not aware of the structural consequences of starting up a system before the concrete has cured to its 28 day state.

Figure 14: Again, we seen too many cases where radiant installers and designers have been blamed for the cracking of concrete when in reality every concrete engineer knows concrete can crack regardless of whether it has pipes in it or not. Pre-planned and placed control joints are just one strategy to control where the concrete will crack; primarily due to shrinkage - not expansion - as often thought.

Figure 15: Not all control joints are alike - which one or ones are right for your project?

Figure 16: The great debate...vapour barrier above or below the insulation? We'll be exploring the options and discuss why ( at the time of this upload) the military needs to change its specifications.

Figure 17: Again the concrete codes define the limitations of pipe spacing, pipe diameter and placement depth...it'll be a rare radiant designer that owns a copy of the concrete codes yet the concrete codes will  take precedent over the heating design due to structural safety concerns.

Figures 18 to 21: Different buildings use different strategies for structural floors ( those floors not on grade)...in each case there are a number of options and considerations which affect the thermal diffusion, surface efficacy and response time of the radiant cooling and heating system. Above is a metal deck system with sections shown perpendicular and parallel to the pipes. Also shown is an FEA analysis of the thermal diffusion and surface efficacy for one simulation.

Figure 19: As above but for hollow core; showing pipes embedded in the structural panel (top), in a topping pour (middle) and in a topping pour above insulation (bottom).

Figure 20: Typical details showing the structural rebar with supporting stands. Working on top has obvious benefits from an installation perspective (see below)!

Figure 21: On high rise construction its not uncommon to be working with a single slab where everything from steel reinforcement, electrical, plumbing, security, communications and radiant all have to be coordinated before the pour...the sight of all that conduit and steel reinforcing can be intimidating but that's why we have structural engineers!

Figure 22: As noted earlier, conditioned slabs are on-site fabricated heat exchangers where space temperatures, fluid temperatures, tube depth, spacing, inside/outside pipe diameter, and materials conductivities must be considered to optimize the thermal efficacy, plant efficiency and thermal comfort. See below for our FEA simulations for a cooling slab and heating slab to understand the effects of manipulating the various elements. Visit our visual demonstration of tube depth effect.

Figure 23: Noted above are the design criteria for the FEA cooling simulations below (in S.I. units).

Figure 24: Using the input values in Figure 23, we've ran the FEA cooling simulations to show the surface efficacy and thermal diffusion using tubes at various depths. Notice the temperature differentials between the point right above the tube to those temperatures adjacent to the tube.

Figure 25: Shown above are the tabulated results from the cooling simulations in Figure 24 but include data for changes to tube spacing. Note: these values do not represent all models - only the model simulated...which means if you put in different values you'll get different results (eureka!). Make note of the differences created by spacing and depth...does it matter? We'll be discussing this in the class.

Figure 26: Noted above are the design criteria for the FEA heating simulations below (in S.I. units).

Figure 27: Using the input values in Figure 26, we've ran the FEA heating simulations to show the surface efficacy and thermal diffusion using tubes at various depths. Notice the temperature differentials between the point right above the tube to those temperatures adjacent to the tube.

Figure 28: Shown above are the tabulated results from the heating simulations in Figure 27 but include data for changes to tube spacing. . Note: these values do not represent all models - only the model simulated...which means if you put in different values you'll get different results (eureka!). Make note of the differences created by spacing and depth...does it matter? We'll be discussing this in the class.

Figure 29: Shown is a summary comparison of temperature, tube spacing and tube depth for the heating simulations; ultimately one wants to deliver the surface efficacy appropriate for the project using a fluid temperature maximized to enable the highest plant efficiency.

Figure 30: Shown is a summary of Canadian testing requirements from various authoritative resources but all apply to embedded pipes. Throw in the U.S. ACI requirements into the mix and you can see the conflict created when an item like pipe falls into multiple jurisdictions.

So there you have it, a few sample slides from our embedded pipes in concrete 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.