Transient Hygrothermal Simulation for Unfinished Buildings

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Solution Overview

Problem

Existing hygrothermal simulation tools inaccurately predict the transient behavior of building components in unfinished buildings without a functioning HVAC system, as they assume a constant interior temperature and humidity, leading to potential moisture damage and health risks due to mold growth.

Innovation Solution

A method using commercially available transient hygrothermal simulation software to create a software model that accounts for varying exterior and interior climatic factors, non-climatic factors, and performance characteristics, predicting the transient hygrothermal behavior of building components over time, especially in unfinished buildings where interior conditions are affected by exterior environments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If existing hygrothermal simulation tools use constant interior temperature and humidity assumptions, then the simulation process is simplified and faster, but the prediction accuracy of transient hygrothermal behavior deteriorates

Engineering Contradiction:

Improvesimulation speedVSAvoidprediction accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The patent applies dynamics by transitioning from static constant interior environment assumptions to dynamic time-varying interior temperature and humidity profiles. The simulation model now incorporates transient interior conditions that change over time, allowing accurate prediction of hygrothermal behavior in unfinished buildings where interior conditions are not controlled by HVAC systems.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameters of the interior environment from constant values to time-dependent varying values. By modifying the interior temperature and humidity from fixed parameters to dynamic parameters that evolve over time, the simulation accurately reflects real-world conditions in unfinished buildings while maintaining computational feasibility.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If existing simulation tools assume controlled HVAC environments, then the model complexity is reduced, but the applicability to unfinished buildings deteriorates

Engineering Contradiction:

Improvemodel complexityVSAvoidapplicability to unfinished buildings

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent enhances universality by developing a simulation model that functions for both finished buildings with HVAC control and unfinished buildings without HVAC control. The model adapts to different building types by incorporating time-varying interior environment parameters, making it applicable to a broader range of building conditions including residential construction scenarios.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Productivity

If transient hygrothermal behavior is not accurately predicted, then the construction process continues without delays, but moisture damage and mold growth risks increase

Engineering Contradiction:

Improveconstruction speedVSAvoidmoisture damage and mold risk

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by using the improved transient hygrothermal simulation model to predict future moisture conditions before construction activities proceed. This allows stakeholders to determine optimal timing for enclosure and sealing operations in advance, preventing moisture damage and mold growth before they occur while maintaining construction efficiency.

Inventive Principle:

Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach provides accurate predictions of transient hygrothermal behavior, helping to prevent moisture-related issues and ensure the safe enclosure of building components by determining when installed materials reach equilibrium moisture content, thus avoiding adverse effects on performance and health risks.

Implementation Method 1

the thermal properties and hygric behavior of building components and the mutual interdependence of the thermal properties and hygric behavior of building components can be determined

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

the hygric behavior of building components should also be considered in connection with building construction

Methodology Applied

Scientific EffectMoisture transport: Diffusion

Implementation Method 3

increased moisture content favors heat losses and thermal conditions affect moisture transport

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 4

permanently increased moisture content in an installed building component may result in moisture damage

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentUS7899655B2Method of predicting and communicating the performance of an installed building component based on the transient hygrothermal behavior of the component

Publication Date: 2011.03.01 JOHNS MANVILLE CORP

AI summary

A method of predicting and communicating transient hygrothermal behavior of an installed building component in a building wherein an interior environment of the building is materially affected by an environment exterior of the building, includes: defining a performance characteristic of the building component that is affected by transient hygrothermal behavior of the building component; defining exterior and interior climatic factors that affect the defined performance characteristic wherein the interior climatic factors are a function of the exterior climatic factors; and defining one or more non-climatic factors that affect the defined performance characteristic. Inputting these factors into a transient hygrothermal simulation software program to create a software model for performing simulations which predict changes in the defined performance characteristic, as a function of time, that are compared with a threshold performance characteristic value, to provide a user guide.