Detrimental Effects of Air Leakage on Building Enclosure Performance: Energy Consumption, Occupant Comfort, and Moisture Accumulation

This study examines the impact of energy management and productivity-enhancing measures, implemented as part of LEED Existing Buildings Operations and Management (EBOM) certification, on source energy use intensity and rental premiums of office spaces using data on four major US markets. Energy management practices, comprised of commissioning and advanced metering, may reduce energy usage. Conversely, improving air quality and occupant comfort in an effort to increase worker productivity may in turn lead to higher overall energy consumption. The willingness to pay for these features in rental office buildings is hypothesised to depend not only on the extent to which productivity gains enhance the profits of a commercial tenant but also on the lease arrangements for passing any energy savings to the tenant. We apply a difference-in-differences method at a LEED EBOM certification group level and a multi-level modelling approach with a panel data structure. The results indicate that energy management and indoor environment practices have the expected effect on energy consumption as described above. However, the magnitude of the achieved rental premiums appears to be independent of the lease type.

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Durability of traditional clamped joints in the vapour barrier layer: experimental and numerical analysis

Canadian Journal of Civil Engineering ◽

10.1139/cjce-2018-0593 ◽

2019 ◽

Vol 46 (11) ◽

pp. 996-1000 ◽

Cited By ~ 1

Author(s):

Lars Gullbrekken ◽

Klodian Gradeci ◽

Øyvind Norvik ◽

Petra Rüther ◽

Stig Geving

Keyword(s):

Climate Change ◽

Energy Consumption ◽

Climatic Conditions ◽

The Other ◽

Use Of Self ◽

Air Leakage ◽

Building Envelopes ◽

Frame Buildings ◽

Wood Frame ◽

Numerical Estimations

Clamped joints of wood frame buildings are a traditional way in Norway to attain airtight joints for the air and vapour barrier. There are numerous defects registered in the SINTEF Building Defects Archive related to air leakage through the vapour barrier, on one hand, and stricter requirements for reduced energy consumption, on the other hand, question today’s efficacy of these type of joints. This study investigates the durability of clamped joints by studying how the airtightness is affected by several drying and wetting cycles. Experimental work is carried out to measure air leakage rates, which in turn, are used to evaluate their impact on the airtightness of two different constructions by numerical estimations. Results show that the air leakage rates are increased significantly due to transient climatic conditions. Clamped joints may no longer provide airtight building envelopes given the stricter requirements for energy consumption and implications of climate change. A more promising and robust alternative is the use of self-adhesive tapes.

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Inverse Modelling of Climate Adaptive Building Shells. System Dynamics Approach

Environmental and Climate Technologies ◽

10.2478/rtuect-2020-0064 ◽

2020 ◽

Vol 24 (2) ◽

pp. 170-177

Author(s):

Toms Mols ◽

Andra Blumberga

Keyword(s):

Energy Consumption ◽

Ghg Emissions ◽

Climatic Conditions ◽

Comfort Level ◽

Inverse Modelling ◽

Climate Conditions ◽

Building Enclosure ◽

Energy Consumption Reduction ◽

Model Research ◽

Computer Based

AbstractThe paper describes the development of a computer-based inverse model for climate adaptive building shell which is in the cold climatic conditions of Latvia to determine changes in energy consumption. Types, principles of operation and classification of climate adaptive building shells (CABS) were reviewed and CABS most fitting to Latvia’s climate conditions were chosen for application in the model. Research implies that building modelling tools play an important role in the design phase. The results indicate that hourly facade adjustment can have a significant impact on GHG emissions and energy consumption reduction without compromising the comfort level. Optimization is proven to be an essential part of the inverse modelling phase, which provides the best possible option defined by the user for the characteristics that distinguish climate adaptive building shells. Inverse modelling approach allowed to determine necessary building enclosure parameters that need to be met to provide best performance.

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Development and Testing of an Automated Building Commissioning Analysis Tool (ABCAT)

ASME 2010 4th International Conference on Energy Sustainability, Volume 1 ◽

10.1115/es2010-90389 ◽

2010 ◽

Cited By ~ 1

Author(s):

John D. Bynum ◽

David E. Claridge ◽

Jonathan M. Curtin

Keyword(s):

Energy Consumption ◽

Large Scale ◽

Weather Conditions ◽

The United States ◽

Commercial Buildings ◽

Test Case ◽

Analysis Tool ◽

Component Level ◽

Building Commissioning ◽

Occupant Comfort

Experience has shown that buildings on average may consume 20% more energy than required for occupant comfort which by one estimate leads to $18 billion wasted annually on energy costs in commercial buildings in the United States. Experience and large scale studies of the benefits of commissioning have shown the effectiveness of these services in improving the energy efficiency of commercial buildings. While commissioning services do help reduce energy consumption and improve performance of buildings, the benefits of the commissioning tend to degrade over time. In order to prolong the benefits of commissioning, a prototype fault detection and diagnostic (FDD) tool intended to aid in reducing excess energy consumption known as an Automated Building Commissioning Analysis Tool (ABCAT) has been developed. ABCAT is a first principles based whole building level top down FDD tool which does not require the level of expertise and money often associated with more detailed component level methods. The model based ABCAT tool uses the ASHRAE Simplified Energy Analysis Procedure (SEAP) which requires a smaller number of inputs than more sophisticated simulation methods such as EnergyPlus or DOE-2. ABCAT utilizes a calibrated mathematical model, white box method, to predict energy consumption for given weather conditions. A detailed description of the methodology is presented along with test application results from more than 20 building years worth of retrospective applications and greater than five building years worth of live test case applications. In this testing, the ABCAT tool was used to successfully identify 24 significant energy consumption deviations in five retrospective applications and five significant energy consumption deviations in four live applications.

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Occupant Comfort Management Based on Energy Optimization Using an Environment Prediction Model in Smart Homes

Sustainability ◽

10.3390/su11040997 ◽

2019 ◽

Vol 11 (4) ◽

pp. 997 ◽

Cited By ~ 5

Author(s):

Wenquan Jin ◽

Israr Ullah ◽

Shabir Ahmad ◽

Dohyeun Kim

Keyword(s):

Energy Consumption ◽

Power Consumption ◽

Prediction Model ◽

Optimization Model ◽

Indoor Environment ◽

Energy Optimization ◽

Comfort Index ◽

Optimal Power ◽

Temperature And Humidity ◽

Occupant Comfort

Occupant comfort management is an important feature of a smart home, which requires achieving a high occupant comfort level as well as minimum energy consumption. Based on a large amount of data, learning models enable us to predict factors of a mathematical model for deriving the optimal result without expensive experiments. Comfort management supports high-level comfort to the occupant in the individual indoor environment, using the optimal power consumption to run home appliances. In this paper, we propose occupant comfort management based on energy optimization, using an environment prediction model. The proposed energy optimization model provides optimal power consumption based on the proposed objective function, which requires temperature and comfort index data as the input parameters. For the input requirement, temperature prediction model and humidity prediction model are presented based on a recurrent neural network with a pre-collected dataset, including indoor and outdoor temperature and humidity sensing data. Using the predicted temperature and humidity data, the comfort index model derives the predicted mean vote value to be used in the energy optimization model with the predicted temperature data. The experimental results present an 8.43% reduction of the optimized power consumption compared to the actual power consumption using mean absolute percentage error to calculate. Moreover, the emulation of an indoor environment using optimal energy consumption presents as approximately similar to the actual data.

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A digital twin framework for improving energy efficiency and occupant comfort in public and commercial buildings

Energy Informatics ◽

10.1186/s42162-021-00153-9 ◽

2021 ◽

Vol 4 (S2) ◽

Author(s):

Anders Clausen ◽

Krzysztof Arendt ◽

Aslak Johansen ◽

Fisayo Caleb Sangogboye ◽

Mikkel Baun Kjærgaard ◽

...

Keyword(s):

Energy Efficiency ◽

Energy Consumption ◽

Model Predictive Control ◽

Predictive Control ◽

Controlled Environment ◽

Building Automation ◽

Digital Twin ◽

Digital Twins ◽

Occupant Comfort

AbstractModel Predictive Control (MPC) can be used in the context of building automation to improve energy efficiency and occupant comfort.Ideally, the MPC algorithm should consider current- and planned usage of the controlled environment along with initial state and weather forecast to plan for optimal comfort and energy efficiency.This implies the need for an MPC application which 1) considers multiple objectives, 2) can draw on multiple data sources, and 3) provides an approach to effectively integrate against heterogeneous building automation systems to make the approach reusable across different installations.To this end, this paper presents a design and implementation of a framework for digital twins for buildings in which the controlled environments are represented as digital entities. In this framework, digital twins constitute parametrized models which are integrated into a generic control algorithm that uses data on weather forecasts, current- and planned occupancy as well as the current state of the controlled environment to perform MPC. This data is accessed through a generic data layer to enable uniform data access. This enables the framework to switch seamlessly between simulation and real-life applications and reduces the barrier towards reusing the application in a different control environment.We demonstrate an application of the digital twin framework on a case study at the University of Southern Denmark where a digital twin has been used to control heating and ventilation.From the case study, we observe that we can switch from rule-based control to model predictive control with no immediate adverse effects towards comfort or energy consumption. We also identify the potential for an increase in energy efficiency, as well as introduce the possibility of planning energy consumption against local electricity production or market conditions, while maintaining occupant comfort.

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Vapour Diffusion Open Arctic Wall: A Comparison of Moisture Accumulation Potential Versus Other Cellulose Superinsulation Strategies

10.32920/ryerson.14653413 ◽

2021 ◽

Author(s):

Cory Brun

Keyword(s):

Energy Efficient ◽

Potential Versus ◽

Experimental Simulation ◽

The Arctic ◽

Air Leakage ◽

Energy Retrofit ◽

Building Enclosure ◽

Vapour Diffusion ◽

Heating Load ◽

Open Materials

Superinsulation is becoming increasingly attractive in the construction of energy efficient new homes or energy retrofit projects. By increasing the thermal insulation inside walls, new possible unforeseen building durability issues arise that were otherwise not present during standard 2”x6” construction, as there is less potential for drying. The reduced drying is often attributed to using low permeance materials in the building enclosure. One method to combat the reduced drying potential is to use the highest permeable vapour diffusion open materials for all building enclosure components such as the “Arctic Wall”. The purpose of this study is to determine how the Arctic Wall performs in Fairbanks, Alaska in addition to other climates, and how it also compares with other common vapour diffusion open methods. The results of experimental simulation using WUFI 5.2 hygrothermal software have shown that all vapour diffusion open walls have a potential for condensation that is most dominated by the heating load across the climates that were tested. The Arctic Wall was found to be safe to use in all climates using the tested methods, but still poses a potential risk due to potential condensation due to air leakage. The results of this study have shown that the Arctic Wall performed on par with other vapour diffusion open strategies.

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Field Evaluation of Hotel/Motel Through-the-Wall HVAC Systems Supervisory Controller

Advanced Energy Systems ◽

10.1115/imece2002-33340 ◽

2002 ◽

Author(s):

Evelyn Baskin

Keyword(s):

Energy Consumption ◽

Potential Energy ◽

Energy Savings ◽

Field Evaluation ◽

Test Period ◽

Lodging Industry ◽

Study Objective ◽

Supervisory Controller ◽

Occupant Comfort ◽

Air Conditioning Systems

Several potential energy-savings devices are available for through-the-wall HVAC (heating, ventilation, and air-conditioning) systems but independent test data quantifying their savings are sparse. This field evaluation and demonstration study quantifies the potential energy savings and assesses the impacts on occupants and staff of using a supervisory HVAC controller in the lodging industry. The supervisory controller operates according to the occupancy status of each room in a hotel or motel. The controller is a plug-in device installed between a wall outlet and the room HVAC unit. Preliminary tests in laboratory simulated environmental conditions suggest that energy savings ranging from 50% to 80% are possible in unoccupied lodging rooms employing the controller (Fisher, 1999). The field study objective was to quantify and verify these estimates and to identify impacts on occupant comfort. The controller was developed as a tool for reducing energy consumption and lowering operating costs in the lodging industry. This paper describes results from a field evaluation of the performance of a supervisory HVAC controller. During the test period, the uncontrolled rooms HVAC energy consumption averaged 2632.2 kWh monthly while the controlled rooms HVACs consume an averaged 1684.6 kWh, which equates to the uncontrolled rooms HVAC consuming an averaged of 947.6 kWh (56.3%) more energy than the units in the controlled room monthly. Due to intermittent inoperability of the controllers and other energy loads (controllers controlled approximately 50% of the hotel’s conditioned space), comparison analysis of the energy cost over a three-year period for the entire hotel does not reveal any discrete savings during the test period over prior years.

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Effect of Airtightness on Thermal Loads in Legacy Low-Income Housing

Energies ◽

10.3390/en12091677 ◽

2019 ◽

Vol 12 (9) ◽

pp. 1677 ◽

Cited By ~ 3

Author(s):

Samuel Domínguez-Amarillo ◽

Jesica Fernández-Agüera ◽

Miguel Ángel Campano ◽

Ignacio Acosta

Keyword(s):

Energy Consumption ◽

Low Income ◽

Social Housing ◽

Building Envelopes ◽

Comfort Levels ◽

Occupant Comfort ◽

Reduce Energy Consumption ◽

Indoor Comfort ◽

The Impact ◽

Death Count

Spain’s high winter weather-associated death count, the second largest in Europe, can be attributed primarily to the low construction standards of its social housing, particularly the stock built prior to the entry into effect of the earliest statutory provisions on envelope quality. Hence, improving building envelopes to both reduce energy consumption and raise occupant comfort levels is important. Air leakage is one of the factors with the greatest impact on indoor comfort and domestic energy consumption. This study explores the sensitivity of energy consumption to that parameter in a series of types of social housing built between 1950 and 1979 in five Mediterranean climate zones. Demand in a total of 53 housing units located in 21 developments was simulated to that end. The findings show that air permeability has a significant effect on wintertime demand in the sample studied. Although the impact is greater in the more severe climates where it is estimated to be over 10 kWh/m2, it may also affect energy consumption in mild climates.

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