Date of Award

Spring 1-1-2011

Document Type

Thesis

Degree Name

Master of Science (MS)

First Advisor

Moncef Krarti

Second Advisor

Marcus Bianchi

Third Advisor

John Zhai

Abstract

Infiltration is a major contributor to the energy consumption of buildings, particularly in homes where it accounts for one-third of the heating and cooling loads. Traditionally, infiltration is calculated independent of the building envelope performance, however, research has found a coupling exists between the infiltration and conduction heat transfer of the building envelope. This effect is known as infiltration heat recovery (IHR). Experiments have shown infiltration heat recovery can reduce the infiltration load by ten to twenty percent.

Currently, energy simulation tools do not account for infiltration heat recovery. Over the years, five steady-state IHR models have been developed to account for the interaction between infiltration and the building envelope. The effects of each model have been quantified against traditional calculations but a lack of testing has been found in literature. In this study, inter-model and experimental comparisons are done to assess the models' performance. This is a beneficial and necessary step to accurately model IHR. Sensitivity analysis will help determine which model parameters impact IHR the most. Using a sample case study of homes in Colorado, an evaluation of measured infiltration heat recovery is compared to the IHR models. In addition, results from the EnergyPlus simulation engine implemented with infiltration heat recovery are compared.

Comparative model analysis verifies each model provides the same solution when using a reference method. The models deviate in their results once their parameters are considered. A sensitivity study of IHR models reveals the most important consideration to characterize infiltration heat recovery is diffuse air fraction and wall participation factor. Experimental comparison of the IHR models reveal the models predict within 2% in a 1D flow case with the use of a wall participation factor, but within 10% and greater when comparing to 2D flow cases. When applying IHR to EnergyPlus simulation, a significant reduction in heating consumption is found for the case study of homes in Boulder, ranging from 5-40%, but minimum of 5-14% reduction. The Claridge IHR model is found to provide the best comparison to the sample data set in this study.

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