scholarly journals Heat Flux and Thermal Characteristics of Electrically Heated Windows: A Case Study

2022 ◽  
Vol 14 (1) ◽  
pp. 481
Author(s):  
Ruda Lee ◽  
Eunho Kang ◽  
Hyomun Lee ◽  
Jongho Yoon
Keyword(s):  
Heat Flux ◽  
Operating Temperature ◽  
Winter Season ◽  
Measured Data ◽  
Building Envelope ◽  
Dew Point ◽  
Building Energy Efficiency ◽  
The South ◽  
Heat Gain ◽  
Point Distribution

Energy loss through windows can be high relatively compared to other opaque surfaces because insulation performance of fenestration parts is lower in the building envelope. Electrically heated window systems are used to improve the indoor environment, prevent condensation, and increase building energy efficiency. The purpose of this study is to analyze the thermal behaviors of a heated window under a field experiment condition. Experiments were conducted during the winter season (i.e., January and February) with the energy-efficient house that residents occupy. To collect measured data from the experimental house, temperature and heat flux meter sensors were used for the analysis of heat flow patterns. Such measured data were used to calculate heat gain ratios and compare temperature and dew point distribution profiles of heated windows with input power values under the changed condition in the operating temperature of the heated glazing. Results from this study indicated that the input average heat gain ratio was analyzed to be 75.2% in the south-facing and 83.8% in the north-facing at nighttime. Additionally, compared to January, reducing the operating temperature of the heated glazing by 3 °C decreased the input energy in February by 44% and 41% for the south-facing and north-facing windows, respectively. Through such field measurement study, various interesting results that could not be found in controlled laboratory chamber conditions were captured, indicating that the necessity of establishing various control strategies should be considered for the development and commercialization of heated windows.

Research and Simulation of Energy-Saving Hierarchical Design Model for Differentiate Architecture

2014 ◽  
Vol 986-987 ◽  
pp. 1026-1028
Author(s):  
Hai Qing Guo
Keyword(s):  
Energy Saving ◽  
Building Energy ◽  
Indicator System ◽  
Building Envelope ◽  
Design Model ◽  
Current Status ◽  
Building Energy Efficiency ◽  
Hierarchical Design ◽  
Evaluation Information

Energy-saving hierarchical design model is established for differentiate architecture. From current status of China's construction, exploration research is established on energy-saving hierarchical design model of differentiate architecture to evaluate indicator system of energy-saving building. Availability of evaluation information in index system is low, so it is difficult to play the role of evaluation of building energy-efficiency. EHTV difference method is used to calculate and evaluate energy-saving design of hierarchical building, including: heat transfer indicator of building envelope targets, air conditioning and heating consumption, basis of EHTV indicators.

scholarly journals The Impact of Aspect Ratio on External Heat Gain of Multi-storey Office Buildings in Jakarta

2018 ◽  
Vol 16 (1) ◽  
pp. 24-31
Author(s):  
Wasiska Iyati ◽  
◽  
Eryani Nurma Yulita ◽  
Jusuf Thojib ◽  
Heru Sufianto ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Building Design ◽  
Climatic Conditions ◽  
Building Envelope ◽  
External Heat ◽  
Office Buildings ◽  
Office Building ◽  
Cooling Load ◽  
Heat Gain ◽  
The Impact

The narrow land in big cities such as Jakarta, increases the amount of high rise building, especially multi-storey office building. Office building consumes much energy to provide air conditioning to meet the thermal comfort inside the building. On the other hand, the building shape, building envelope, and building orientation to the sun's position are the main factors in building design aspects that affect the amount of cooling load. This study aims to investigate the impact of the aspect ratio or the ratio of the longer dimension of an oblong plan to the shorter, on external heat gain of multi-storey office building. Variables examined include the transparent and solid area of building envelope, the total area of the surface of the building envelope in any orientation, and the volume of the building, as well as the influence of those proportion on the external heat gain. This study uses mathematical calculations to predict the cooling load of the building, particularly external heat gain through the walls, roof and glass, as well as comparative analysis of models studied. The study also aims to generate the design criteria of building form and proportion of multi-storey office buildings envelope with lower external heat gain. In Jakarta climatic conditions, the result on rectangular building plan with aspect ratio of 1 to 4 shows that the external heat gain did not differ significantly, and the smallest heat gain is found on the aspect ratio of 1.8. Results also showed that the greater aspect ratio, the greater reduction of external heat gain obtained by changing the orientation of the longest side facing east-west into the north-south, about 2.79% up to 42.14% on the aspect ratio of 1.1 to 4. In addition, it is known that in same building volume, changing the number of floors from 10 to 50 can improve the external heat gain almost twice.

scholarly journals Energy and thermal modeling of building façade integrated photovoltaics

2018 ◽  
Vol 22 (Suppl. 3) ◽  
pp. 921-932 ◽  
Author(s):  
Konstantinos Ordoumpozanis ◽  
Theodoros Theodosiou ◽  
Dimitrios Bouris ◽  
Katerina Tsikaloudaki
Keyword(s):  
Electricity Generation ◽  
Measured Data ◽  
Building Envelope ◽  
Zero Energy ◽  
Large Area ◽  
Finite Volume Model ◽  
Volume Model ◽  
Urban Buildings ◽  
Zero Energy Building ◽  
Integrated Performance

Electricity generation on site is a design challenge aiming at supporting the concept of energy-autonomous building. Many projects worldwide have promoted the installation of photovoltaic panels on urban buildings, aiming at utilizing a large area to produce electricity. In most cases, photovoltaics are considered strictly as electricity generators, neglecting their effect to the efficiency and to the thermal behaviour of the building envelope. The integrated performance of photovoltaic ventilated fa?ades, where the photovoltaics are regarded as part of a complicated envelope system, provides design challenges and problems that cannot be overlooked within the framework of the Nearly Zero Energy Building concept. In this study, a finite volume model for photovoltaic ventilated fa?ades is developed, experimentally validated and found to have a significant convergence to measured data.

scholarly journals Weakening of Cold Halocline Layer Exposes Sea Ice to Oceanic Heat in the Eastern Arctic Ocean

2020 ◽  
Vol 33 (18) ◽  
pp. 8107-8123 ◽  
Author(s):  
Igor V. Polyakov ◽  
Tom P. Rippeth ◽  
Ilker Fer ◽  
Matthew B. Alkire ◽  
Till M. Baumann ◽  
...  
Keyword(s):  
Heat Flux ◽  
Sea Ice ◽  
Arctic Ocean ◽  
Mixed Layer ◽  
Winter Season ◽  
Atlantic Water ◽  
The Arctic ◽  
Surface Mixed Layer ◽  
Winter Convection ◽  
Oceanic Heat Flux

AbstractA 15-yr duration record of mooring observations from the eastern (>70°E) Eurasian Basin (EB) of the Arctic Ocean is used to show and quantify the recently increased oceanic heat flux from intermediate-depth (~150–900 m) warm Atlantic Water (AW) to the surface mixed layer and sea ice. The upward release of AW heat is regulated by the stability of the overlying halocline, which we show has weakened substantially in recent years. Shoaling of the AW has also contributed, with observations in winter 2017–18 showing AW at only 80 m depth, just below the wintertime surface mixed layer, the shallowest in our mooring records. The weakening of the halocline for several months at this time implies that AW heat was linked to winter convection associated with brine rejection during sea ice formation. This resulted in a substantial increase of upward oceanic heat flux during the winter season, from an average of 3–4 W m−2 in 2007–08 to >10 W m−2 in 2016–18. This seasonal AW heat loss in the eastern EB is equivalent to a more than a twofold reduction of winter ice growth. These changes imply a positive feedback as reduced sea ice cover permits increased mixing, augmenting the summer-dominated ice-albedo feedback.

Flex House

2011 ◽  
Author(s):  
Stanley Russell ◽  
Mark Weston ◽  
Yogi Goswami ◽  
Matthew Doll
Keyword(s):  
Closed System ◽  
State Of The Art ◽  
Building Envelope ◽  
Passive Cooling ◽  
Optimum Level ◽  
Seasonal Temperature ◽  
Zero Energy ◽  
Humid Climate ◽  
Heat Gain ◽  
Hot Humid Climate

Flex House is a flexible, modular, pre-fabricated zero energy building that can be mass produced and adapted easily to a variety of site conditions and plan configurations. The key factor shaping the design is central Florida’s hot humid climate and intense solar radiation. Flex house combines the wisdom of vernacular Florida houses with state of the art Zero Energy House technologies (ZEH.) A combined system of photovoltaic panels and solar thermal concentrating panels take advantage of the region’s abundant insolation in providing clean renewable energy for the house. Conservation is achieved with state of the art mechanical systems and innovative liquid desiccant dehumidification technology along with highly efficient lighting and appliances. The hybrid nature of the Flex house allows for both an open and closed system to take advantage of the seasonal temperature variation. Central Florida buildings can conserve energy by allowing natural ventilation to take advantage of passive cooling in the mild months of the year and use a closed system to utilize mechanical cooling when temperatures are too high for passive cooling strategies. The building envelope works equally well throughout the year combining an optimum level of insulation, resistance to air infiltration, transparency for daylight, and flexibility that allows for opening and closing of the house. Flex House is designed with a strong connection between interior spaces and the outdoors with carefully placed fenestration and a movable wall system which enables the house to transform in response to the temperature variations throughout the year. The house also addresses the massive heat gain that occurs through the roof, which can generate temperatures in excess of 140 degrees. Flex House incorporates a parasol-like outer structure that shades the roof, walls and courtyard minimizing heat gain through the building envelope. To be implemented on a large scale, ZEH must be affordable for people earning a moderate income. Site built construction is time consuming and wasteful and results in higher costs. Building homes in a controlled environment can reduce material waste, and construction costs while increasing efficiency. Pre-fabricating Flex House minimizes preparation time, waste and safety concerns and maximizes economy, quality control, efficiency and safety during the construction process. This paper is an account of the design and construction of Flex House, a ZEH for central Florida’s hot humid climate.

A Reconfigureable Passive Solar Test Facility

2012 ◽  
Author(s):  
Brian S. Robinson ◽  
M. Keith Sharp
Keyword(s):  
Heat Pipe ◽  
Side Wall ◽  
Building Envelope ◽  
Test Facility ◽  
Weather Data ◽  
The South ◽  
Original Design ◽  
Pipe System ◽  
South Wall ◽  
Passive Solar

A 12′ by 24′ passive solar test building has been constructed on the campus of the University of Louisville. The building envelope is comprised of structural insulated panels (SIPs), 12″ thick, (R-value of 45 ft2F/Btu) for the floor and walls and 16″ (R-63) for the roof. The building is divided into two symmetrical rooms with a 12″ SIPs wall separating the rooms. All joints between panels are caulked to reduce infiltration. Each room contains one window (R-9) on the north side wall, and two windows (also R-9) facing south for ventilation and daylighting, but which will also provide some direct gain heating. The south wall of each room features an opening that will accommodate a passive solar heating system so that performance of two systems can be compared side-by-side. The overhang above the south openings is purposely left short to accommodate an awning to provide adjustable shading. The calculated loss coefficient (UA) for each room of the building is 6.07 W/K. Each room is also equipped with a data acquisition system consisting on an SCXI 1600 16 bit digitizer and an SCXI 1102B isolation amplifier with an SCXI 1303 thermocouple module. Pyranometers are placed on the south wall and the clerestory wall to measure insolation on the solar apertures. For initial tests, one room is equipped with an original heat pipe system previously tested in another building, while the other is equipped with a modified heat pipe system. Changes to the modified system include copper absorbers versus aluminum, an adiabatic section constructed of considerably less thermally-conductive DPM rubber than the copper used for the original design, and one of the five condenser sections of the heat pipes is exposed directly to the room air to provide early-morning heating. Experimental results will be compared to simulations with as-built building characteristics and actual weather data. Previous simulations with a load to collector ratio of 10 W/m2K, a defined room comfort temperature range between 65°F to 75°F, and TMY3 weather data for Louisville, KY, showed that the modified heat pipe wall design improves annual solar fraction by 16% relative to the original design.

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