Search NASA⌕ Search

Engineering topics

Curcija, Charlie

Publications and source records attributed to Curcija, Charlie.

13 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

PyDynamicWindow v1

This software is developed for researchers to evaluate the energy performance of of dynamic windows in the world-wide climate, and this first version focuses on thermochromic windows. We bring new indicators (necessity level and recommendation index) to the evaluation system for thermochromic windows. We estimate the majority users of this software tool will be non-commercial academic researchers. But commercial companies can also use it to optimize their products and estimate where their product has the most promising market.

Gao, Yuan↗
DOE OSTI2021

Parametric study of solid-solid translucent phase change materials in building windows

Thermal energy storage and solar radiation management are crucial to improve the sustainability and energy efficiency of buildings. Compared with the implementation of phase change materials (PCMs) in opaque components, the energy saving potential of incorporating PCMs in transparent glazing windows is much less studied and not well understood. Here we present a comprehensive parametric study of novel PCM windows for building energy saving with a focus on optimizing and quantitatively distinguishing the contributions from the optical and thermal properties of the PCM, which is particularly useful for the design of solid-solid PCM windows. We investigate a reference commercial office building using EnergyPlus by developing an equivalent model of our PCM window that is compatible with EnergyPlus's modeling capabilities. Compared with a clear-clear double-pane window, the integration of 3 mm solid-solid PCMs with optimal properties in warm, mixed, and cold climates can respectively save up to 17.2%, 14.0%, and 5.8% energy for the HVAC (heating, ventilation, and air conditioning) system, and 9.4%, 6.7%, and 3.2% energy for the whole building. We also demonstrate that these energy savings are most sensitive to the solar absorptance of PCMs for all three climates. The optimal transition temperature varies with climate and is related to the climate and solar radiation heat gain. Other issues are also briefly discussed, such as hysteresis, window orientations, and the effect of interior lighting. Finally, although the optimal PCM windows show energy saving performance comparable with low-emissivity windows, the PCM windows provide a unique advantage in terms of shifting HVAC loads which can provide benefits to the electrical grid.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2021

Evaluation of Interior Cellular Shades in a Residential Building

Windows are major contributors to energy demand in residential homes because of their inferior thermal resistance compared with the opaque envelope and sometimes from unwanted solar heat gain. Window attachments can help to mitigate this demand by controlling the solar heat gains and enhancing the thermal resistance of the windows. In this study, the energy savings potential of cellular shades in residential homes is studied using experimental testing and energy simulations. The energy performance of the shading devices was experimentally tested during the heating season from December 2019 to May 2020 with a focus on cellular shades. Five shading devices—three single and two double cellular/cell-in-cell shades—were used to compare the performance with generic horizontal (venetian) blinds using two nearly identical sideby-side rooms in a residential building with their exterior window facing east. Another objective of the experimental testing was to evaluate any impact of the side-channel of the shading device on energy savings. To observe the impact of the side-channels on energy savings, from shades in two of the test cases, cellular shades with side-channels were used. From the experimental testing, daily energy savings in the range of 9% to 23% were observed by considering data from 6 p.m. until 6 a.m. of the next day.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2019

New Rating Opening Windows to a World of Comfort, Opportunity, and Cost-Effective Savings

Window attachments offer a huge, cost-effective energy-saving opportunity that remains largely untapped. The newly launched window attachment energy rating and certification program, through the Attachments Energy Rating Council (AERC), is altering the way people think about residential and commercial window attachments by providing reliable, easy-to-understand energy performance information to consumers. Window attachments, such as blinds, shades, shutters, awnings, and low-emissivity (low-e) storm windows, represent an enormous existing market. With 64% of U.S. homes having single- or double-pane clear (non-low-e) less-efficient windows, the savings opportunity is significant. Studies of model homes show energy savings of 10% or more after installing more efficient storm window and cellular shades technologies (AERC 2016). In a study conducted by Efficiency Vermont, 68% of respondents had concerns with their existing windows and could benefit from an upgrade (Efficiency Vermont 2016). Through AERC, window attachment products are rated based on their Energy Performance (EP). The EP metric is an easy-to-understand comparative metric created for consumers. This rating not only allows consumers to make more informed decisions when buying attachments products, but also creates a new energy savings measure for utilities and efficiency programs to incentivize energy efficient window attachment products. Here, this paper will outline the savings potential of window attachments, introduce the AERC rating program, detail the methodology behind the Energy Performance ratings, and explain the AERCalc tool that generates the ratings.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2019

Berkeley Lab WINDOW Calc Engine (CalcEngine) v2

Calculation of thermal and optical properties of glass, windows, and shades. Calculational code only, no GUI. The software hosted at this repository is one out of five repositories that make up this entire project. The others can be found at the following DOIs: 10.11578/dc.20190522.2, 10.11578/dc.20190522.4, 10.11578/dc.20190522.5, and 10.11578/dc.20190524.1.

Kohler, Christian↗
DOE OSTI2019

Berkeley Lab WINDOW Calc Engine (CalcEngine) v2

Calculation of thermal and optical properties of glass, windows, and shades. Calculational code only, no GUI. The software hosted at this repository is one out of five repositories that make up this entire project. The others can be found at the following DOIs: 10.11578/dc.20190522.1, 10.11578/dc.20190522.4, 10.11578/dc.20190522.5, and 10.11578/dc.20190524.1.

Kohler, Christian↗
DOE OSTI2019

Berkeley Lab WINDOW Calc Engine (CalcEngine) v2

Calculation of thermal and optical properties of glass, windows, and shades. Calculational code only, no GUI. The software hosted at this repository is one out of five repositories that make up this entire project. The others can be found at the following DOIs: 10.11578/dc.20190522.1, 10.11578/dc.20190522.2, 10.11578/dc.20190522.5, and 10.11578/dc.20190524.1.

Kohler, Christian↗
DOE OSTI2019

Thermal performance and potential annual energy impact of retrofit thin-glass triple-pane glazing in US residential buildings

Heat transfer through the building envelope and associated air leakage comprise the largest HVAC loads in most climates, and windows, which are known as the weakest link in the thermal envelope, are responsible for about 5 Quads, or approximately 10%, of building energy use. Therefore, windows offer a significant opportunity for building energy savings. High performance windows, such as triple glazing, though comprised of less than 2% of all US window sales in 2016 and has remained stagnant because they typically require a full and expensive redesign of the typical window sash and frame. One potential low incremental cost solution to kick start the market is upgrading the glazing with a thin-glass triple-pane design that does not require modifications to existing frame and sash. Here in this work, we first define the characteristics and performance of current “typical” residential windows through an examination of the National Fenestration Rating Council (NFRC) Certified Products Directory (CPD). With knowledge of the typical window, we determine the potential thermal performance impact of replacing typical glazing with thin-glass triple-pane glazing. Finally, with an understanding of the potential improvements to traditional performance metrics, such as U-factor, we show the energy savings potential of the thin-triple glazing in place of typical low-e windows in residential buildings is 16% in heating dominated climates such as Minneapolis, MN, 12% in mixed climates such as Washington DC, and 7% in cooling dominated climates such as Houston, TX.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2018

New Rating Opening Windows to a World of Comfort, Opportunity, and Cost-Effective Savings

Window attachments offer a huge, cost-effective energy-saving opportunity that remains largely untapped. The newly launched window attachment energy rating and certification program, through the Attachments Energy Rating Council (AERC), is altering the way people think about residential and commercial window attachments by providing reliable, easy-to-understand energy performance information to consumers. Window attachments, such as blinds, shades, shutters, awnings, and low-emissivity (low-e) storm windows, represent an enormous existing market. With 64% of U.S. homes having single- or double-pane clear (non-low-e) less-efficient windows, the savings opportunity is significant. Studies of model homes show energy savings of 10% or more after installing more efficient storm window and cellular shades technologies (AERC 2016).In a study conducted by Efficiency Vermont, 68% of respondents had concerns with their existing windows and could benefit from an upgrade (Efficiency Vermont 2016).Through AERC, window attachment products are rated based on their Energy Performance (EP). The EP metric is an easy-to-understand comparative metric created for consumers. This rating not only allows consumers to make more informed decisions when buying attachments products, but also creates a new energy savings measure for utilities and efficiency programs to incentivize energy efficient window attachment products. This paper will outline the savings potential of window attachments, introduce the AERC rating program, detail the methodology behind the Energy Performance ratings, and explain the AERCalc tool that generates the ratings.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2018

Breaking the 20 Year Logjam to Better Insulating Windows

Windows account for about 4 Quads of US energy consumption or 12% of building energy use. After 20 years of public/private investment (from 1980 to 2000) in technology R&D, coupled with new rating and labeling organizations (NFRC) and with subsequent voluntary ENERGY STAR programs and tighter codes and standards, windows using low-E/argon gas fill (~R3) gained a dominant market share and now account for >86% of all annual sales. However, this remarkable transformation of prior markets has stagnated, with triple glazing (~R5-R7) comprising less than 2% of all window sales in 2016. U.S. Department of Energy (DOE) estimates the national technical potential savings using R5-R7 windows at ~ 2Q annually, but manufacturers claim they would have to redesign their entire sash/frame inventory to accommodate the thicker and heavier insulating glass units (IGUs) in conventional triple glazed window designs. This paper outlines the initial findings from the first phase of a new collaborative effort, now underway with industry partners, to transform window markets to the R5-R7 insulating levels by introducing a novel packaging of existing technology elements, implemented as a “drop-in replacement” for current IGUs. The program involves working with supply chain partners to ensure component availability, with leading window manufacturers to integrate the key technology elements and initially deploy the new designs, and with market pull partners to speed adoptions rates. Market pull partners include building code officials, utility rebate/incentive programs and ENERGY STAR, along with early adopters such as builders targeting net zero and passive house designers.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2015

Control algorithms for dynamic windows for residential buildings

This study analyzes the influence of control algorithms for dynamic windows on energy consumption, number of hours of retracted shades during daylight and shade operations. Five different control algorithms - heating/cooling, simple rules, perfect citizen, heat flow and predictive weather were developed and compared. The performance of a typical residential building was modeled with EnergyPlus. The program Widow was used to generate a Bi-Directional Distribution Function (BSDF) for two window configurations. The BSDF was exported to EnergyPlus using the IDF file format. The EMS feature in EnergyPlus was used to develop custom control algorithms. The calculations were made for four locations with diverse climate. The results showed that: (a) use of automated shading with proposed control algorithms can reduce the site energy in the range of 11.6-13.0%; in regard to source (primary) energy in the range of 20.1-21.6%, (b) the differences between algorithms in regard to energy savings are not high, (c) the differences between algorithms in regard to number of hours of retracted shades are visible, (e) the control algorithms have a strong influence on shade operation and oscillation of shade can occur, (d) additional energy consumption caused by motor, sensors and a small microprocessor in the analyzed case is very small.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2011

Research Needs: Glass Solar Reflectance and Vinyl Siding

The subject of glass solar reflectance and its contribution to permanent vinyl siding distortion has not been extensively studied, and some phenomena are not yet well understood. This white paper presents what is known regarding the issue and identifies where more research is needed. Three primary topics are discussed: environmental factors that control the transfer of heat to and from the siding surface; vinyl siding properties that may affect heat build-up and permanent distortion; and factors that determine the properties of reflected solar radiation from glass surfaces, including insulating window glass. Further research is needed to fully characterize the conditions associated with siding distortion, the scope of the problem, physical properties of vinyl siding, insulating window glass reflection characteristics, and possible mitigation or prevention strategies.

14 SOLAR ENERGY↗