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How to convert from CTF to HAMT

asked 2026-05-29 10:42:37 -0500

AnaeGrant's avatar

I am working on a university research project on the hygrothermal and energy performance of bio-based insulation materials in building envelopes. I am still learning EnergyPlus, and I want to use it to compare the energy consumption of assemblies using bio-based versus conventional insulation materials.

I have an existing EnergyPlus model that uses the default CTF algorithm, and I want to switch it to HAMT to enable moisture transport modelling alongside the energy comparison.

What I have tried: I read the EnergyPlus Engineering Reference section on HAMT and the relevant IDD entries (HeatBalanceAlgorithm, MaterialProperty, HeatAndMoistureTransfer). I understand that HAMT requires additional material properties (moisture diffusivity, liquid transport coefficients, sorption isotherm) that CTF does not use.

My question: Is converting an existing CTF model to HAMT as straightforward as changing the HeatBalanceAlgorithm object and adding the hygric material properties ? Or are there additional model-level changes to expect?

Any experience or pitfalls to flag would be very helpful.

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answered 2026-07-14 06:47:44 -0500

To learn more about the Heat and Moisture Transfer options in EnergyPlus, you can see the InputOutputReference for

  • HeatBalanceAlgorithm Timestep
  • SurfaceProperty:HeatTransferAlgorithm
  • SurfaceProperty:HeatTransferAlgorithm:MultipleSurface
  • SurfaceProperty:HeatTransferAlgorithm:Construction
  • SurfaceProperty:HeatTransferAlgorithm:SurfaceList
  • SurfaceProperties:VaporCoefficients
  • MaterialProperty:HeatAndMoistureTransfer:Settings
  • MaterialProperty:HeatAndMoistureTransfer:SorptionIsotherm
  • MaterialProperty:HeatAndMoistureTransfer:Suction
  • MaterialProperty:HeatAndMoistureTransfer:Redistribution
  • MaterialProperty:HeatAndMoistureTransfer:Diffusion
  • MaterialProperty:HeatAndMoistureTransfer:ThermalConductivity

These are all available in the PDF or online.

You should definitely read the Engineering Reference on the Combined Heat and Moisture Transfer (HAMT) Model either the PDF or online.

There are also three example files (see the ExampleFiles directory) that use these objects:

  • 1ZoneUncontrolledFourAlgorithms.idf
  • HAMT_DailyProfileReport.idf
  • HAMT_HourlyProfileReport.idf

As far as your original question, I have not tried to convert a file from CTF to HAMT but I think if you can gather all the required inputs and specify the HAMT algorithm, I think that is all you need.

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Asked: 2026-05-29 10:42:37 -0500

Seen: 236 times

Last updated: Jul 14