Online educational resource on achieving indoor environmental quality with radiant based HVAC systems
Not for profit educational resource on indoor environmental quality.
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Should you fully insulate under concrete slabs on or below grade?
Below grade comparison
Downward heat loss tools

Why is design validation important?

So many radiant designers with good intentions have bought into the benefit of radiant as being exclusively about comfort often having to defend the price for customized, complex and expensive systems. Ignored are the simple affordable systems with significant  sustainability benefits.

No doubt, comfort through mechanical solutions is a consideration it is also a prime function of the building enclosure where high performance structures such as Canada's R2000 home or Germany's Passivhaus could in many cases negate the use of distributed heating and cooling IF one comes at it from the sole perspective of comfort and looks at a home as a stand alone load.

However energy and exergy analysis of combustion and compression equipment provides reason to use low temperature radiant heating and high temperature radiant cooling when many high performance buildings with micro loads can be collected and served by a single, small, simple and energy efficient central cooling and  heating plant such as those typical of district energy systems, especially if these systems incorporate thermal energy storage such as direct coupled earth energy systems.

To ensure the highest energy and exergy efficiency made possible with the lowest possible temperatures in heating and highest temperatures in cooling whilst delivering high quality thermal comfort, it is important to validate the design of low temperature heating and high temperature cooling systems such as radiant floors prior to construction.

www.healthyheating.com has developed two detailed tools for this purpose.


Sample screen shots from our new design validator


radiant heat transfer plates
Radiant sub-floor heating with heat transfer plates
Click to enlarge


radiant cooling using concrete slabs
Radiant floor cooling embedded in poured screed on a suspended floor.
Click to enlarge


radiant heated floor
Radiant floor heating in poured topping
Click to enlarge


Visitors to this page have also visited:

An Illustrated Guide to Radiant Based HVAC Systems for Energy Efficient Indoor Environmental Quality.

In-floor Radiant Design Guide: Heat Loss to Head Loss

Typical Radiant Surfaces for Cooling and Heating

Radiant Cooling - Facts and Myths

 

Validating radiant cooling and heating design services

For additional support visit our visitor services page.

If you've taken or are enrolled in one of our courses and have a project that needs to be validated against industry protocols such as ISO Standards for the design, construction, and operation of radiant heating and cooling systems - then we can help you out.

We've co-produced with two industry experts, one in finite element analysis (FEA) and another in Excel(tm) powerful radiant design software tools that we use to validate design projects based on the following four common assemblies:

radiant cooling and heating - poured floor (wet system)
a) Poured floor -
slab
radiant cooling and heating - poured floor (wet system)
b) Poured floor -
topping
radiant cooling and heating - subfloor (dry system)
c) Subfloor -
plates on top
radiant cooling and heating - subfloor (dry system)
d) Subfloor -
plates below

Radiant cooling and heating design model
Value Coordinate Model (VCM)

We can provide detailed evaluation of poured floors such as slab on grade (a) and topping systems (b) and sub floor systems with or without heat transfer plates above (c) and below the sub floor (d). Any of the variations can be validated in heating or cooling mode. Shown to the left is our Value Coordinate Model (VCM) - each point represents a value that we can predict with reasonable accuracy using either the FEA or Excel tool (shown below).

Excel validator for radiant cooling and heating designs
I/O screen shot from the Excel validation tool. Useful to check answers and demonstrate relationships between tube spacing, conductivities, fluid temperatures etc.

Another thing we can help students with, is how to solve internal fluid temperatures in different loop layouts (below). Please note: any of the illustrations you see here, represent a hypothetical case for a specific set of criteria. Another application might behave completely differently so it's best to model each case on it's own criteria.

radiant tube layouts
An example question might challenge students to determine the fluid temperature in three common tube patterns at a 10C ∆t at the room centerline and make a graphical prediction as to the quality of the floor surface at some point in time (shown below).

floor surface temperatures with radiant heating
The FEA tool can take the calculated values from the Excel tool and model the floor surface temperature profile as shown above for the serpentine example.


The FEA tool will also be able to make temperature predications with reasonable accuracy within the model by developing 'thermal meshes' (l) and isotherms (m) illustrated in a color contour (r).

We trust you'll be able to take advantage of this service for your projects.

Not a student but need us to look at your system? Email us your challenge and we'll suggest a donation amount in exchange for the evaluation.

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