scholarly journals Potential energy savings with exterior shades in large office buildings and the impact of discomfort glare

2015 ◽  
Author(s):  
Sabine Hoffmann ◽  
Eleanor Lee
Keyword(s):  
Potential Energy ◽  
Energy Savings ◽  
Office Buildings ◽  
Discomfort Glare ◽  
The Impact

Analysis of Daylighting Benefits for Office Buildings in Egypt

Solar Energy ◽  
2004 ◽  
Author(s):  
Mostafa Abd El Mohimen ◽  
George Hanna ◽  
Moncef Krarti
Keyword(s):  
Energy Savings ◽  
Simulation Analysis ◽  
Window Size ◽  
Electrical Energy ◽  
Office Buildings ◽  
Wall Area ◽  
Electricity Use ◽  
Daylighting Control ◽  
The Impact ◽  
Geographical Locations

This paper summarizes the results of a simulation analysis to determine the effectiveness of daylighting in reducing electrical energy consumption for office buildings in Egypt. Specifically, the impact on daylighting performance is investigated of window size, building size, daylighting control, and glazing type for three geographical locations in Egypt. It was determined that a window to wall area ratio of 0.20 minimizes the total annual electricity use for office buildings in three Egyptian locations, Cairo, Alexandria, and Aswan. A simplified analysis method is developed based on the analysis results to estimate the annual electrical energy savings attributed to daylighting.

scholarly journals Attaining sustainable high-rise office buildings in warm-summer-cold-winter climates: a case study on Frankfurt

2019 ◽  
Vol 14 (4) ◽  
pp. 533-542
Author(s):  
Yuanda Hong ◽  
Wu Deng ◽  
Collins I Ezeh ◽  
Zhen Peng
Keyword(s):  
Energy Savings ◽  
Building Energy ◽  
Energy Performance ◽  
Major Elements ◽  
Office Buildings ◽  
Cold Winter ◽  
Winter Climate ◽  
High Rise ◽  
Warm Summer ◽  
The Impact

Abstract Attaining sustainability in high-rise office buildings necessitates determining the major elements and their associating impacts on the energy performance of this building typology. This study investigates the impact of architectural and engineering features on the energy performance of high-rise office buildings within a warm-summer-cold-winter climate. A rectangular building plan form with a 1:1.44 plan ratio, vertical split core position and central atrium presented the best building performance. The plan form, core position and atrium effect accounted for 59, 30 and 11%, respectively, of an estimated 20.6% building energy savings. Furthermore, exploiting passive strategies founded on the climate and building features as defined by `PassivHaus’ standards further reduced the building energy usage.

Investigation of Potential Benefits of Using Bricks of High Thermal Capacity and Conductivity in a Rotating Calcining Kiln

2008 ◽  
Author(s):  
Lei Zhao ◽  
Ting Wang
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Capacity ◽  
Potential Energy ◽  
Thermal Energy ◽  
Energy Savings ◽  
Thermal Capacity ◽  
K Value ◽  
Hot Gas ◽  
The Impact

Petroleum coke is processed into calcined coke in a rotary kiln, where the temperature profiles of flue gas and coke bed are highly nonuniform due to different flow and combustion mechanisms. Motivated by saving energy costs, the effect of refractory brick’s thermal properties on potential energy savings is investigated. This study focuses on investigating potential energy savings by replacing inner one third of existing bricks with higher thermal capacity (Cp) and/or higher thermal conductivity (k) bricks. This investigation is motivated by postulating that the bricks with higher thermal capacity can store more thermal energy during the period of contacting with the hot gas and release more heat to the cock bed when the bricks rotate to below and in contact with the coke bed. A rotational, transient marching conduction numerical simulation is conducted using the commercial software FLUENT. The impact of brick heat capacity and thermal conductivity on transporting thermal energy to the coke bed is analyzed. The results show: (a) Increasing the heat capacity of brick layer reduces brick temperature which helps increase the heat transfer between the hot gas and brick, in other words it does help brick store more heat from the hot gas, but, heat transfer between brick and coke is reduced, which is opposite to the original postulation. (b) Higher brick thermal conductivity decreases brick temperature thus increases heat transfer between hot gas and the brick layer. The heat transfer from brick to coke bed is also increased, but not significantly. (c) Usually a brick with a higher Cp value also has a higher k-value. Simulation of a brick layer with both four times higher Cp and k values actually show appreciable heat is transported from the brick to the coke bed for one rotation for both lower and higher Cp and k bricks. The difference is not significant.

Analysis of Daylighting Benefits for Office Buildings in Egypt

2004 ◽  
Vol 127 (3) ◽  
pp. 366-370 ◽  
Author(s):  
Mostafa Abd El Mohimen ◽  
George Hanna ◽  
Moncef Krarti
Keyword(s):  
Energy Savings ◽  
Simulation Analysis ◽  
Window Size ◽  
Electrical Energy ◽  
Office Buildings ◽  
Wall Area ◽  
Electricity Use ◽  
Daylighting Control ◽  
The Impact ◽  
Geographical Locations

This paper summarizes the results of a simulation analysis to determine the effectiveness of daylighting in reducing electrical energy consumption for office buildings in Egypt. Specifically, the impact on daylighting performance is investigated of window size, building size, daylighting control, and glazing type for three geographical locations in Egypt. It was determined that a window to wall area ratio of 0.20 minimizes the total annual electricity use for office buildings in three Egyptian locations, Cairo, Alexandria, and Aswan. A simplified analysis method is developed based on the analysis results to estimate the annual electrical energy savings attributed to daylighting.

Optimal Supply Water Temperature Control of Water Source Heat Pump

Solar Energy ◽  
2005 ◽  
Author(s):  
M. Palahanska-Mavrov ◽  
G. Wang ◽  
M. Liu
Keyword(s):  
Potential Energy ◽  
Water Temperature ◽  
Heat Pump ◽  
Temperature Control ◽  
Energy Cost ◽  
Energy Savings ◽  
Water Source ◽  
Theoretical Models ◽  
The Impact ◽  
Supply Water

The water loop supply water temperature is the most critical control parameter for operating energy cost in water source heat pump systems. In this paper, the impact of the water loop temperature on operating energy cost is investigated for different types of buildings under different loads using theoretical models. The theoretical models and approaches are also applied to an 80,000 square feet office building to determine the building heating and cooling load, optimal supply water temperature, and potential energy cost savings based on measured supply water temperature and loop heat gain. It is concluded that the optimal supply water temperature control can significantly reduce the annual energy costs associated with compressor power and boiler energy. The potential energy savings is determined to be 24% in the application building.

Investigation of Potential Benefits of Using Bricks of High Thermal Capacity and Conductivity in a Rotating Calcining Kiln

2009 ◽  
Vol 1 (1) ◽  
Author(s):  
Lei Zhao ◽  
Ting Wang
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Capacity ◽  
Potential Energy ◽  
Thermal Energy ◽  
Energy Savings ◽  
Thermal Capacity ◽  
K Value ◽  
Hot Gas ◽  
The Impact

Petroleum coke is processed into calcined coke in a rotary kiln, where the temperature profiles of flue gas and coke bed are highly nonuniform due to different flow and combustion mechanisms. Motivated by saving energy costs, the effect of refractory brick’s thermal properties on potential energy savings is investigated. This study focuses on investigating potential energy savings by replacing inner one-third of existing bricks with higher thermal capacity (Cp) and/or higher thermal-conductivity (k) bricks. This paper investigates the postulation: the bricks with higher thermal capacity could store more thermal energy during the period in contact with the hot gas and would release more heat to the cock bed when the bricks rotate to the position in contact with the coke bed. A rotational transient marching conduction numerical simulation is conducted using the commercial software FLUENT. The impact of brick heat capacity and thermal conductivity on transporting thermal energy to the coke bed is analyzed. The results show the following: (a) Increasing the heat capacity of brick layer reduces brick temperature, which helps increase the heat transfer between the hot gas and brick. In other words, it does help brick to store more heat from the hot gas, but heat transfer between brick and coke is reduced, which is opposite to the original postulation. (b) Higher brick thermal conductivity decreases brick temperature, thus increases heat transfer between hot gas and the brick layer. The heat transfer from brick to coke bed is also increased but not significantly. (c) Since usually a brick with a higher Cp value also has a higher k-value, simulation of a brick layer with both four times higher Cp and k-values actually shows a reduction in the brick temperature, and hence a degradation of the heat transfer between the brick and coke bed. Therefore, replacing the existing brick layer with a high Cp- and/or high k-value brick is not recommended.

scholarly journals A Comprehensive Analysis of Energy and Daylighting Impact of Window Shading Systems and Control Strategies on Commercial Buildings in the United States

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2401
Author(s):  
Niraj Kunwar ◽  
Mahabir Bhandari
Keyword(s):  
United States ◽  
Energy Demand ◽  
Energy Savings ◽  
Control Strategies ◽  
The United States ◽  
Commercial Buildings ◽  
Office Buildings ◽  
Increase Energy Efficiency ◽  
Occupant Comfort ◽  
The Impact

Commercial buildings consume approximately 1.9 EJ of energy in the United States, 50% of which is for heating, cooling, and lighting applications. It is estimated that windows contribute up to 34% of the energy used for heating and cooling. However, window retrofits are not often undertaken to increase energy efficiency because of the high cost and disruptive nature of window installation. Highly efficient window technologies would also need shading devices for glare prevention and visual comfort. An automated window shading system with an appropriate control strategy is a technology that can reduce energy demand, maintain occupant comfort, and enhance the aesthetics and privacy of the built environment. However, the benefits of the automated shades currently used by the shading industry are not well studied. The topic merits an analysis that will help building owners, designers and engineers, and utilities make informed decisions using knowledge of the impact of this technology on energy consumption, peak demand, daylighting, and occupant comfort. This study uses integrated daylight and whole-building energy simulation to evaluate the performance of various control strategies that the shading industry uses in commercial office buildings. The analysis was performed for three different vintages of medium office buildings at six different locations in United States. The results obtained show the control strategies enabled cooling energy savings of up to 40% using exterior shading, and lighting energy savings of up to 25%. The control strategies described can help building engineers and researchers explore different control methods used to control shading in actual buildings but rarely discussed in the literature. This information will give researchers the opportunity to investigate potential improvements in current technologies and their performance.

scholarly journals Examining the Impact of Daylighting and the Corresponding Lighting Controls to the Users of Office Buildings

Energies ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 4024
Author(s):  
Lambros T. Doulos ◽  
Aris Tsangrassoulis ◽  
Evangelos-Nikolaos Madias ◽  
Spyros Niavis ◽  
Antonios Kontadakis ◽  
...  
Keyword(s):  
Energy Savings ◽  
Luminous Flux ◽  
Office Buildings ◽  
Proper Function ◽  
Post Occupancy Evaluation ◽  
Closed Loop Systems ◽  
Harvesting Technique ◽  
Harvesting Systems ◽  
The Impact ◽  
Daylight Harvesting

Daylight utilization significantly contributes to energy savings in office buildings. However, daylight integration requires careful design so as to include variations in daylight availability and maintain a balance between factors such as lighting quality and heat gain or loss. Designers with proper planning can not only improve the visual environment and create higher-quality spaces, but simultaneously minimize energy costs for buildings. The utilization of photosensors can exploit the benefits of daylighting by dimming the lighting system, so that no excessive luminous flux is produced, thus leading to energy savings as well as visual contentment. However, the human factor is crucial for the proper function of a lighting control system. Without its acceptance from the users, energy savings can be minimized or even negligible. The objective of this paper is to present a post-occupancy evaluation regarding occupant satisfaction and acceptance in relation to daylighting in offices equipped with automated daylight controls. In addition, the response of the users was compared with lighting measurements that were performed during the post-occupancy evaluation. Three case studies of office buildings with installed daylight-harvesting systems were examined. The age of the occupants was a crucial factor concerning their satisfaction in relation to the lighting levels. Aged users were more comfortable with lighting levels over 500lx, while young users were satisfied with 300lx. The impact of different control algorithms was outlined, with the integral reset algorithm performing poorly. The acceptance of the users for the closed loop systems maintained the expected energy savings of the daylight harvesting technique. Most of the occupants preferred to use daylight as a light source combined with artificial light but having the control to either override or switch it on and off at will. The results shown that a post-occupancy survey along with lighting measurements are significant for making an office environment a humancentric one.

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