Hygrothermal Performance of Energy Retrofits in Buildings: An Assessment of the Residential Building Stock in the U.S.

Thesis (Ph.D.)--University of Washington, 2023Improving buildings’ energy efficiency has been widely recognized as one of the most versatile and effective means of reducing energy consumption in existing buildings. However, recent investigations of retrofits in residential buildings have raised concerns about unintended impacts correlated with negative effects on a building's life span, indoor environment, and occupant wellness. One of these unintended impacts is excess moisture in the building's envelope, potentially caused by inadequate air infiltration, lack of ventilation, and thermal insulation malfunction. The problem with damp building materials is that they can generate humidity that encourages the development of mold in the envelope’s cavity, affecting overall hygrothermal behavior (i.e., combined movement of heat, air, and moisture), and potentially degrading both the envelope and structure of the building. Hygrothermal behavior of buildings, in turn, is influenced by a range of building conditions (i.e., air and water permeability, thermal insulation, ventilation rates, occupant behavior, climate, and location). This dissertation examines the unintended effects arising from implementation of energy efficiency measures on wall assemblies, affecting the hygrothermal performance of building envelopes. The hygrothermal performance of an existing building envelope is assessed through dynamic transient simulations. Case studies for this assessment included three retrofit approaches defined by the location of the intervention (exterior, core, and interior). Since the implementation of energy retrofits in buildings is tied to local code policy, we drew on the International Energy Conservation Code (IECC) as an input in the design of the retrofit assemblies, applying its prescriptive component method. Moreover, since hygrothermal performance is sensitive to climate, we examined different climate zones, including hot and humid, marine, cool, cold, and arctic climates. Findings suggest that the implementation of energy retrofits can impact the hygrothermal performance of existing envelopes, and that those impacts are closely linked to the climate context. Specifically, EEMs installed in the exterior side of the thermal envelope led to the least hygrothermal consequences across six climate contexts studied. The use of strategies such as air layers in timber frame assemblies has been found to minimize undesired outcomes such as excess moisture, and mold growth. The study further indicates that the prescriptive framework provided by the current local codes for energy retrofits is inadequate in several climate zones studied, particularly in hot and humid regions

Systematic Review of Hygrothermal Computational Tools for New and Existing Buildings

The use of multiple design strategies seeking energy efficiency in buildings can offer a wide range of opportunities to improve energy and thermal performance. While thermal resistance is typically considered of high importance, to achieve energy efficiency and prolong the durability of buildings, hygrothermal conditions must also be taken into account. As new technology develops that is capable of measuring a given structure’s real-time data, the research community is increasingly relying on software and tools for hygrothermal assessments of buildings. As the tools vary widely in both extent and functionality, defining a method to identify the effectiveness and accuracy of hygrothermal tools for various project scopes presents a technical challenge. This paper presents a systematic review that organizes and summarizes a range of different software for hygrothermal assessment of new and existing buildings. This research review 11 hygrothermal models and tools based on three main characteristics: (1) interface and information transference, (2) hygrothermal assessment and scope, and (3) context and standards. This review seeks to offer a better understanding of technical tools for hygrothermal performance assessment to assist architects, engineers, and designers, promoting last-longing interventions, and improving assessments’ accuracy for energy-use estimations

Measurements and Verification (M&V) Guidelines for Weatherization Plus Health Program

Weatherization Plus Health (Wx+H), a pilot program introduced by the Washington State Department of Commerce, has proposed a new scope to improve the indoor environment quality (IEQ) for low-income housing residents—one that extends beyond energy benefits. Typical interventions include the distribution of green cleaning kits, walk-off mats, ventilation system upgrades, and resident education, among other elements. Wx+H experts are working to capture the long-term impact of these combined measures to assess the program’s potential. Although guidelines and best practices exist to measure and verify the impacts and influences of energy conservation, these indicators do not holistically incorporate occupant satisfaction and perceptions regarding health benefits in the context of low-income housing. This paper presents a preliminary literature review that summarizes measurements and verifications (M&V) schemes applicable to the residential sector from two major standards: ASHRAE Guideline 14 and the international performance measurement and verification protocol. Additionally, reports from the Washington State Commerce Department were analyzed to identify procedures and factors that might influence M&V schemes as applied by Washington State who are leading health and energy programs. Barriers, opportunities, and innovative M&V are discussed

Simple Tool to Evaluate Airtightness in Chilean Homes

Given the high impact that air leaks have on buildings' energy expenses, most developed countries have set out norms which regulate their presence in homes. Chile will soon begin this process; however, the airtightness revision strategy in envelopes has not been resolved as of yet. This article presents a tool to Assess Airtightness in Design, EHeD. The software will allow predicting the performance of homes under the regulations which will be set out, aiding designers, builders or owners to make decisions when making changes to improve airtightness. EHeD has been validated through pressurization tests in diverse homes across the country, with results that are in line with expectations, thus validating its calculation model. The methodology considers three stages: determining the main factors that have an impact on the airtightness in Chilean homes, preparing an airtightness database for each component (wall, windows and doors) and preparing a calculation model that is integrated in an IT interface

Resumos em andamento - Saúde Coletiva

Resumos em andamento - Saúde Coletiv

Resumos em andamento - Saúde Coletiva

Resumos em andamento - Saúde Coletiv