Heat, Air and Moisture Modelling :: HAM

Online educational resource on achieving indoor environmental quality with radiant based HVAC systems

Fundamentals of indoor environmental quality / thermal comfort and air quality solutions using radiant based HVAC

Our 2013 Program: Energy and Indoor environmental Quality in Modern or Modernized Buildings Popular Topics Academic Scores due to IEQ Advice for Consumers Building Efficiency Categories Building Orientation Building Enclosures Built to Code: Means what? Comfort: A Condition of Mind Conduction Animation Control Valve Theory Convection Animation Dedicated Outdoor Air System Duct Tape: Not for Ducts Effectiveness Coefficients Earth Tube Heat Exch.'s Energy and IEQ Energy/Exergy Efficiency Embedded Pipes in Concrete Exergy & Sustainability Filter Fist-a Cuffs Floor Temperatures Flooring R values Flooring and Boiler Efficiency Forensic Services Health and HVAC systems Health and IEQ Heat, Air, Moisture Modelling Heated Hardwood Flooring History of Radiant Heating Human Factors Human Thermal Plume Humidity & the Environment HVAC & Energy Efficiency Hybrid HVAC Systems IAQ Investigator IEQ Research Infiltration Is slab insulation needed? 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Building Enclosures: A Filter, Sponge and Capacitor 29 bits of wit, wisdom & witticisms Visitors Feedback Others are saying... Awards The Carlson - Holohan Industry Award of Excellence Indoor Air Quality Images Want to See a Sneeze? Humidity/Condensation Particulate Matter Arsenic Mercury Lead Asbestos Allergens Up Close Viruses Bacteria Mold Pollen Other Resources Indoor Air Quality @ Home Quotes on IEQ Suggested Resources For the kids Indoor Air Quality A Thermal and Moisture Transport Property Database for Common Building and Insulating Materials, Final Report from ASHRAE Research Project 1018-RP, 2002 Includes: Dry density Heat capacity Thermal conductivity Equilibrium moisture content (Sorption, Desorption and Pressure Plate Measurements) Water vapour permeance or permeability Water absorption coefficient Moisture diffusivity and Air permeance or permeability Suggested reading: Building Science for a Cold Climate Water in Buildings: An Architect's Guide to Moisture and Mold Building Science for Building Enclosures Journal of Building Enclosure Design Thermal Performance of Building Envelope Details for Mid- and High-Rise Buildings (ASHRAE 1365-RP) Combined Heat and Moisture Transport Modeling For Residential Buildings There are many more references manuals and research papers that we have reviewed, and yet to review but do a Google search of the topic for an endless supply of research. Have a book, paper or software you'd like us to review? Send us an email.	Heat, Air, Moisture Modelling: Basic to advanced tools For additional support visit our visitor services page. Over the years we've done some heat, air and moisture modelling using various hand calculations and software tools; and well really the exercises were done more for academic purposes rather than real world applications. Why? Because the principles affecting mass and energy flows across building materials and assemblies are already well understood. When there is a problem with an enclosure the modelling isn't going to tell you anything you shouldn't already know - that being the loss of control over pressure (leaks in the air barrier), moisture (vapour leaks ala air leaks, diffusion and; liquid capillary and drainage) and heat (sensible/insulation). Having said that, it is useful to the student of the building sciences to learn how to use the various tools for furthering ones knowledge of how combinations of materials and assemblies may perform under modelling conditions. The four tools that we have used are Microsoft Excel, The Heat, Air and Moisture Tool Kit (Quirouette Building Science Software), NRC-IRC hygIRC-1-d and WUFI. We've assembled some screen shots below of sample files and provide some descriptions for your information.
	Microsoft's Excel You can't beat Excel for a utilitarian tool for number crunching and so long as you get the formulas and inputs right - it will spit out the answers. We set up the wall assembly below using the example from Hutcheon & Handegord 1983 classic, " Building Science for a Cold Climate (NRC-IRC)" to validate the spreadsheets accuracy. Once you get the spreadsheet set up you can use it to model whatever your heart fancies.
	Figure 1. Screen shot of the temperature profile through a wall assembly. The results of the model are based on the formula and inputs shown in Figure 2. below.

	Figure 2. Formula and inputs for modelling the wall assembly above. This is steady state temperature only, as such it is simplified in comparison to real world performance which would also include the transient characteristics of vapour pressure differentials, material permeability and moisture absorptivity.

	Figure 3. The results for the air space only of an uninsulated section of the wall assembly.

	Figure 4. The results for the wood stud only, i.e. does not include the insulated portion.

	Figure 5. The results for insulated section of the wall assembly; does not include the framing factor.


	Figure 6. The weighted average results for an uninsulated wall assembly, i.e. includes resistances of the wood stud and air space (no insulation).


	Figure 7. The weighted average results for an insulated wall assembly, i.e. includes resistances of the wood stud and insulation. It is this performance which will have an affect on the mean radiant temperature of the space.

	Figure 8. Upon completion of the analysis, one can then evaluate the temperature profile of the wall and dew points within the wall assembly for identifying surface planes of concern.
	The Heat, Air and Moisture Tool Kit (Quirouette Building Science Software) For a multi tool with a really low learning curve, you'll be hard pressed to find another program with such value as the HAM Toolkit. We've used it to develop examples for our education programs and it serves us well with simple self explanatory straight forward graphics.

	Figure 9. Adapted screen shots from the Heat, Air and Moisture Tool Kit:outputs are simple self explanatory and straight forward.
	NRC-IRC hygIRC-1-D: helps design community choose optimal building envelope components and systems We purchased this program several years ago and though it is easy to use, it does take some time to learn the navigation through the various screens. The tool comes with a weather database with 30 to 40 years of hourly weather data for 25 North American cities and a material database containing the hygrothermal properties of 80 common construction materials. It does both steady state and transient analysis and has been tested against various benchmarks for its accuracy. As noted by NRC, "Situations involving air leakage, water leaks, and gravity are, however, still best handled using the two-dimensional version of hygIRC." Great information guys but where can we obtain the 2-D version online? The 1-D version verdict: a very good tool, lots of research papers available on its use but not free like the WUFI program.

	Figure 10. Screen shot from the NRC-IRC hygIRC-1-D tool. Relatively easy to use for steady state and transient analysis.
	WUFI-ORNL/IBP: Educational PC-Program for calculating the coupled heat and moisture transfer in building components This is a "go to tool" for many building scientist and one of the few that has formal training offered through such noted experts from Building Science Corporation. Like the NRC-IRC hygIRC-1-D tool it takes some time to learn the navigation but once you get it figured it out it is relatively easy to use...and the best part is it's price of free for a special "light" version. For the pro version you'll have to open up the wallet.


	Figure 11. Screen shot of the WUFI program, relatively easy to use and offered in a free light version.
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