Total Annual Energy Consumption Research Articles

Impact of Window Films on the Overall Energy Consumption of Existing UK Hotel Buildings

Recently, considerable attention has justifiably been directed towards energy savings in buildings as they account for up to 20–40% of total energy consumption in developed countries. In the United Kingdom, studies have revealed that buildings’ CO2 emissions for account for at least 43% of total emissions. Window panels are a major component of the building fabric with considerable influence on the façade energy performance and are accountable for up to 60% of a building’s overall energy loss. Therefore, the thermal performance of glazing materials is an important issue within the built environment. This work evaluates the impact of solar window films on the overall energy consumption of an existing commercial building via the use of a case study U.K. hotel and TAS dynamic simulation software. The study results demonstrated that the impact of window films on the overall energy consumption of the case study hotel is approximately 2%. However, an evaluation of various overall energy consumption components showed that the window films reduce the annual total cooling energy consumption by up to 35% along with a marginal 2% increase in the annual total heating energy consumption. They can also provide overall cost and CO2 emissions savings of up to 3%.

Energy consumption in buildings: A correlation for the influence of window to wall ratio and window orientation in Tripoli, Libya

This study has been conducted to investigate the influence of window to wall ratio (WWR) and window orientation (WO) on cooling, heating and total energy consumption. The study aims to provide architects with a simple correlation for proper design of facades for office buildings from an energy consumption point of view. The work includes a case study, in which an external wall of a small office space located in the city of Tripoli, Libya was analyzed. Walls with WWR between 0 and 0.9, and with orientation varied in steps of 45° (i.e., facing all eight cardinal and intercardinal directions) were considered. EnergyPlus software was used for energy simulation with “OpenStudio plugin for SketchUp” as an interface. Results indicate that increasing WWR produces an increase in cooling energy consumption and a decrease in heating energy consumption. Cooling energy consumption is found to be substantially higher than heating energy consumption, however, when adding windows to southern walls, cooling consumption drastically increases, while heating energy consumption decreases to zero due to passive solar heating. In general, the effect of adding windows to facade results in an increase in annual total energy consumption by 6–181% for the cases explored in this study. Finally, a correlation representing the relation between total energy consumption, WWR and WO has been established in this paper.

Effect of geometric factors on the energy performance of high-rise office towers in Tianjin, China

To improve energy efficiency of office buildings in Tianjin, we select a prototypical high-rise office tower as an example and focus on the effect of geometric factors on building energy performance. These factors include the orientation, plane shape, floor area, plane shape factor (the ratio of the plane length to the plane width, only as regards to a rectangle-shaped plane), floor height, floor number and window-to-wall ratio. The simulation is performed in DesignBuilder, which integrates artificial lighting with instantaneous daylight during the energy simulation process. The geometric factors of the defined prototype are examined in both single-parameter and multi-parameter evaluations. As to the multi-parameter results, the energy saving rate can vary by up to 18.9%, and reducing the floor height is observed to be the most effective means of reducing annual total end-use energy consumption, followed by increasing the plane shape factor and reducing the floor area. The results can serve as a reference for passive design strategies related to geometric factors in the early design stage.

Traditional energy resources in India (coal, crude oil, natural gas): A review

ABSTRACTIndia is a developing country with a growing population and economy. For sustainable growth, it will need to secure its supply of energy minerals. In 2013, India ranked 5th in terms of coal reserves, 21st in crude oil reserves, and 23rd in natural gas. At the same time, India was the 3rd largest producer of bituminous and lignite, 22nd largest producer of crude oil, and the 25th largest producer of natural gas. In addition, India was also the 4th largest energy consumer in the world. The total primary usage in India is dominated by coal followed by oil and natural gas. In the period from 2000–2013, the total annual energy consumption doubled to 595.0 million tons oil equivalent. Coal increased its share from 49 to 54% and oil decreased its share from 36 to 30% of the total. The share of the natural gas remains at the same value of 8%.

Reduction of the Carbon Footprint in Agricultural Greenhouses

Climate change in the planet is currently creating many environmental, economic and social problems which are probably going to multiply in the near future. Reduction of greenhouse gases emitted from fossil fuels could result in the mitigation of greenhouse effect and the climate change. Agricultural greenhouses consume large amounts of energy mainly derived from fossil fuels, for the cultivation of various crops. Reduction of their carbon footprint is of primary importance to day. In order to investigate the possibilities of reducing their carbon footprint, the energy consumption during their operation has been estimated and the sustainable energy technologies which could be used for substitution of fossil fuels used have been analyzed. It has been found that a modern greenhouse located in Mediterranean region with a covered area of 1,000 m2 and a total annual energy consumption of 200 KWh/m2 emits 76,900 kg CO2 per year. Total elimination of their CO2 emissions could be achieved with the investment of 44,000 € in renewable energy technologies, including solid biomass for heating and solar-PV for power generation and resulting in lower energy cost during their operation. The payback time of the abovementioned investments has been estimated at 4.84 years.

The importance of integrally simulating the building, HVAC and control systems, and occupants’ impact for energy predictions of buildings including temperature and humidity control: validated case study museum Hermitage Amsterdam

For buildings including temperature and humidity control, this study compares the energy prediction accuracy of a ZABES-model (Zone Air Building Energy Simulation) to an IBES-model (Integral Building Energy Simulation), which additionally includes models of the air handling unit (AHU) and controllers. Museum Hermitage Amsterdam served as a case study. For one year, measurements were performed in the main exhibition hall and its AHU. The ZABES-model was developed using heat air and moisture model for building and systems evaluation (implemented in MATLAB). The IBES-model was developed in Simulink and consists of the ZABES-model and models of AHU-components and controllers. Both models have been validated in detail. The IBES-model’s energy prediction errors are well within 10%. However, the ZABES-model underestimated the total annual energy consumption by 84%. Moreover, including occupants’ heat and moisture gains leads to realistic results using the IBES-model, but leads to unrealistic results using the ZABES-model. In conclusion, IBES-models are essential for reliable energy predictions of buildings including humidity control.

실측데이터를 이용한 에너지제로주택의 연간 에너지성능평가

Purpose: In this study, we evaluate the annual energy performance of the detached house which was designed with the aim of zero energy. Method: The experimental house which was constructed in Gonju Chungnam in 2013, is the single family detached house of light weight wood frame with <TEX>$100m^2$</TEX> of heating area. Thermal transmittance of roof (by ISO 10211) and building external walls are designed as <TEX>$0.10W/m^2K$</TEX> and <TEX>$0.14W/m^2$</TEX> respectively and low-e coating vacuum window glazing with PVC frame was installed. Also grid connected PV system and natural-circulation solar water heater was applied and 6kWp capacity of photovoltaic module was installed in pitched roof and <TEX>$5m^2$</TEX> of solar collector in vertical wall facing the south. We analyzed the 2014 annual data of the detached house in which residents were actually living, measured though web-based remote monitoring system. Result: First, as a result, total annual energy consumption and energy production (PV generation and solar hot water) are 7,919kWh and 7,689kWh respectively and the rate of energy independence is 97.1% which is almost close to the zero energy. Second, plug load and hot water of energy consumption by category showed the highest numbers each with 33% and 31%, with following space heating 24%, electric cooker 8%, lighting 3% in order. Hot water supply is relatively higher than space heating because high insulation makes it decreased.

Toward residential building energy conservation through the Trombe wall and ammonia ground source heat pump retrofit options, applying eQuest model

The aim of this research is to apply the eQuest model to investigate the energy conservation in a multifamily building located in Dayton, Ohio by using a Trombe wall and an ammonia ground source heat pump (R-717 GSHP). Integration of the Trombe wall into the building is the first retrofitting measure in this study. Trombe wall as a passive solar system, has a simple structure which may reduce the heating demand of buildings significantly. Utilization of ground source heat pump is an effective approach where conventional air source heat pump doesn't have an efficient performance, especially in cold climates. Furthermore, the type of refrigerant in the heat pumps has a substantial effect on energy efficiency. Natural refrigerant, ammonia (R-717), which has a high performance and no negative impacts on the environment, could be the best choice for using in heat pumps. After implementing the eQUEST model in the said multifamily building, the total annual energy consumption with a conventional R-717 air-source-heat-pump (ASHP) system was estimated as the baseline model. The baseline model results were compared to those of the following scenarios: using R-717 GSHP, R410a GSHP and integration of the Trombe wall into the building. The Results specified that, compared to the baseline model, applying the R-717 GSHP and Trombe wall, led to 20% and 9% of energy conservation in the building, respectively. In addition, it was noticed that by using R-410a instead of R-717 in the GSHP, the energy demand increased by 14%.

A novel approach for the simulation-based optimization of the buildings energy consumption using NSGA-II: Case study in Iran

This paper provides a novel and efficient approach for the simulation-based multi-criteria optimization of the building energy performance. In the current investigation, a multi-objective non-dominated sorting genetic algorithm (NSGA-II) is coupled with EnergyPlus building energy simulation program to obtain optimal solutions leads to increase the building energy performance. The main aim of this work is to explore the effect of some architectural parameters, including the building orientation, the window size and the overhang specifications on the building energy consumption in four major climatic regions of Iran, e.g. cold, mild, warm-dry, and warm-humid. In the optimization section, mono-criterion and bi-criteria optimization analyses of the annual cooling and lighting building energy demands are studied with the purpose of understanding the interactions between these objective functions. The results point out that the bi-criteria optimization of the test case model brings down the annual cooling energy consumption 55.8–76.4% in various climates. However, the annual lighting electricity demand increases 1–4.8%. As a result, the final optimum configuration leads to 23.8–42.2% decrease in the annual total building energy consumption. The results depict that the climate and the appropriate selection of the architectural parameters are very important and critical in reducing the building energy consumption. The proposed optimization methodology is a powerful and useful tool to achieve this goal and to facilitate decision-making in early phases of a building design in order to enhance its energy efficiency.

Modeling methodology of the heating energy consumption and the potential reductions due to thermal improvements of staggered block buildings

Understanding of the buildings energy performance at the city level is necessary in order to form a city energy planning policy and make a strategic decision on which buildings should be thermally improved. Energy modeling of the building sector is methodology that estimates energy consumption in buildings and simulates the effects of energy efficiency improvements of building envelopes and systems. In this paper engineering bottom-up method was used for modeling the heating energy consumption of a multi-family residential building sector built before 2012 in the city of Kragujevac in Serbia. The first part of methodology presents the criteria based on which a multi-family residential building sector of the city was described and building types were defined. The second part of methodology investigates the selection of the real buildings, their modeling and heating energy consumption simulation. The modeling method was performed on staggered block buildings constructed between 1981 and 1990, and estimated heating energy consumption was compared to measured consumption. After the simulation of different thickness of polystyrene thermal insulation additions to external walls and simulation of the new windows installation, the reductions of the total annual heating energy consumption were obtained.

Energy positive curtain wall configurations for a cold climate using the Analysis of Variance (ANOVA) approach

Curtain walls are believed to be “energy sinks” because of their relatively low thermal performance; however, the integration of energy generating technologies such as photovoltaic (PV) panels may enable converting these systems to “energy positive” curtain walls. A methodology using the Analysis of Variance (ANOVA) approach is developed and implemented to identify configurations of energy positive curtain walls by accounting for the complex interacting effect of facade design parameters. The “energy positive” curtain wall in this paper is defined as the energy generated by the curtain wall facade on an annual basis exceeds the energy consumption of a perimeter zone office enclosed by this curtain wall facade. Ten design parameters are studied, including glazing U-value, solar heat gain coefficient (SHGC), and visible transmittance (Tv); U-value of the spandrel panel; U-value of the mullion; window wall ratio (WWR); infiltration rate; depth and inclination of overhang; and efficiency of PV modules. The significance of individual design parameters on the energy performance is ranked for four cardinal orientations based on the total sensitivity index. The WWR, U-glazing, and infiltration rate are the three most significant parameters influencing the total annual energy consumption of the office unit simulated, while the WWR, PV efficiency, and U-glazing are the most significant design parameters for achieving energy positive curtain walls. The methodology presented in this paper helps facilitate the design process to resolve the issues with conflicting effects of design parameters.

Do energy efficiency measures really reduce household energy consumption? A difference-in-difference analysis

This study investigates the impact of energy efficiency measures installed through the Carbon Emission Reduction Target (CERT) and the Community Energy Saving Programme (CESP) on domestic gas and total energy consumptions. The recently released National Energy Efficiency Data-Framework (NEED) database is used to examine the changes in domestic gas and total energy consumptions for the dwellings in the sample relative to the changes in gas and total energy consumptions for a comparable control group in the year after installation. The results obtained from this difference-in-difference analysis confirm that observed energy consumption decreases significantly in dwellings following upgrades such as cavity wall insulation, loft insulation and a new efficient boiler. The single most effective energy efficiency measure when installed alone is found to be cavity wall insulation, reducing annual gas consumption by 10.5 % and annual total energy consumption by 8.0 % in the year following installation. Comparing bundles of different energy efficiency measures, we find that dwellings retrofitted with both cavity wall insulation and a new efficient boiler experience the largest reductions in annual gas and total energy consumptions of 13.3 and 13.5 %, respectively. This is followed by a mean annual reduction of 11.9 and 10.5 % in gas and total energy consumptions for dwellings with all three energy efficiency measures installed in the same year. Contrary to expectations, installing cavity wall insulation on its own is found to be more effective in reducing measured energy consumption than combining loft insulation and a new efficient boiler.

Global progress in green energies development and the environment

Globally, buildings are responsible for approximately 40% of the total world annual energy consumption. Most of this energy is for the provision of lighting, heating, cooling, and air conditioning. Increasing awareness of the environmental impact of CO2, NOx and CFCs emissions triggered a renewed interest in environmentally friendly cooling, and heating technologies. Under the 1997 Montreal Protocol, governments agreed to phase out chemicals used as refrigerants that have the potential to destroy stratospheric ozone. It was therefore considered desirable to reduce energy consumption and decrease the rate of depletion of world energy reserves and pollution of the environment. This article discusses a comprehensive review of energy sources, environment and sustainable development. This includes all the renewable energy technologies, energy efficiency systems, energy conservation scenarios, energy savings and other mitigation measures necessary to reduce climate change.

Situations and challenges of household energy consumption in Chinese small towns

A large scale survey of household energy consumption in Chinese small towns was conducted to obtain the fundamental data and analyze the key problems. Based on the survey results, the total annual household energy consumption in Chinese small towns is around 156 million tons of coal equivalence (tce) (4.6×109GJ). The breakdowns include 74 million tons of raw coal (1.5×109GJ), 11 million tons of firewood (0.2×109GJ), 38 million tons of straw (0.6×109GJ), 5.7 million tons of liquefied petroleum gas (LPG) (0.3×109GJ), 8478 million m3 natural gas (NG) (0.3×109GJ), 1.5 million tons of charcoal (0.5×108GJ) and 160 billion kWh electricity. Space heating accounts for the most proportion of household energy consumption in northern small towns in whole country. Coal is widely used for space heating. There will be a big challenge on energy and environment with a large number of migration from rural areas to small towns during the urbanization. To avoid significant increase of energy and pollutant emissions, making full use of biomass energy for household space heating in small towns is proposed based on the analysis of supply and demand of biomass resources. The results obtained from this study could also provide references to guide the development in small towns in other countries, particularly the developing world during the process of rapid urbanization.

A quasi-transient model of a transcritical carbon dioxide direct-expansion ground source heat pump for space and water heating

In this study, a theoretical quasi-transient model is developed for detailed simulations of a carbon dioxide (CO2) direct-expansion ground source heat pump (DX-GSHP). This model combines a transient analytical model for the ground, steady-state numerical models for the borehole and the gas cooler, as well as several thermodynamic models for the remaining components of a conventional heat pump, organized in interacting subroutines to form a powerful simulation tool. Extensive validation combining experimental data and CFD-generated results was performed for the borehole before the tool was used to simulate a practical application case.Performance is investigated for a system satisfying both space heating and domestic hot water requirements of a typical single family detached home in a cold climate region. The variation of different system parameters is also evaluated in this study. It is shown that CO2 DX-GSHPs can offer relatively efficient and stable performance for integrated water and space heating applications. Furthermore, the importance of an accurate geothermal borehole sizing is highlighted for the DX-CO2 heat pump systems. It is shown that, due to changes in the system working conditions, the total borehole length is not linearly correlated with the heat pump energy consumption and other parameters such as heat pump coefficient of performance and pressure drop in ground heat exchangers. Results showed that increasing the total borehole length of an optimum design (reference case study) by 25% decreases the total annual energy consumption by only 6%. However, reducing total borehole length of the reference case by 25% increases the total annual energy consumption by 10%.

Techno-economic Impacts Analysis of a Hybrid Grid Connected Energy System Applied for a Cattle Farm

Abstract Increase in energy demand has made the renewable resources more attractive. Representing the largest sources of renewable energy, Solar and wind systems are expanding due to the rapid depletion of fossil fuel resources and the growing evidence of the global warming phenomena. This study aims to investigate the techno-economic impacts of a hybrid grid connected PV/wind energy system applied for a medium cattle farm in the north part of Algerian desert. The target location is a medium farm of 20 dairy cows in Ghardaia city, with the total annual electrical energy consumption of 6.716kWh, and a peak demand of about 7.7 kW. The system is optimized using the National Renewable Energy Laboratory's (NREL) HOMER software according to the net present cost (NPC) value. Furthermore, three scenarios are proposed to assess the system configuration according to its impact on both technical and economic balance of the farm. It is found that under the specific climatic conditions of the studied location, the three optimized systems satisfy the typical farm load of 18kWh per day. The second scenario optimized system meets the requirement of paying back the total costs of system investment during the system's lifetime and the third scenario optimized system enhances the grid reliability by decreasing the power grid peak load by 70 kW and feeding to the grid 119MWh annually.

Reduce Household Energy Consumption Using Passive Methods

Recent researches and studies demonstrate that the need for sustainable buildings which do less impact on the environment is rising in the worldwide [1], [2]. Not only the energy generator from energy supply side needs to be considered to build a sustainable building, but also the novel construction methods and materials from demand side will contribute to the energy saving. The aim of this study is to carry out an investigation of a property's energy consumption from the view of passive energy saving, and then use the results to determine the best energy saving plan. A field audit and the Design Builder software simulation of a detached house were carried out during this study. The results indicate that the simulation energy consumption (9.66MWh) is matching well with the actual energy usage (9.76MWh) and the property consumes less energy than national average (16.90MWh). From the study, it is found that the annual total household energy consumption reduced for about 33% than traditional construction materials and technology by using passive energy saving methods.

Applications of dividing wall column technology to industrial-scale cumene production

Recent advances in dividing wall column (DWC) have led to renewed interest in the design or redesign of many industrial processes. For the distillation system of cumene production, the existing design alternatives have the potentials of energy savings and consequently the reduction of total annual cost (TAC) and energy consumption. In this paper, cumene production based on the real industrial process is simulated in a conventional process using commercial process simulator Aspen Plus, and two DWC distillation processes are introduced. Then optimization study for the proposed DWC distillation processes is performed based on the TAC calculation with sensitivity analysis to investigate the effects of operating parameters. The results indicate that the optimum DWC distillation process works well for the production of cumene, and the corresponding TAC is reduced significantly accompanied by substantial energy savings.

Evaluating Energy and Exergy Efficiencies in Transportation Sector of Iran

Considering the increasing energy demands, energy has gained an important role in planning and policies of many countries. This study presented the status of overall energy consumption in the transportation sector of Iran. According to most of the recently issued statistics, the annual transportation energy consumption of Iran is more than 296×106 barrels of oil equivalent, which is about 25% of Iran’s total annual energy consumption. So, it is logical to analyze energy consumption in transportation sector for the purpose of better planning. Statistics of energy consumption in Iran’s transportation sector was presented for a period of 24 years (1988 to 2011) in this paper. Different transportation sub-sectors (highways, airways, railways, and waterways) and different energy forms were considered separately in the presented statistics. Using these data, energy and exergy efficiencies of the transportation sector were derived. Analyzing the efficiency values in the mentioned 24 year period resulted in concluding some considerable points, which could be used in Iran’s transportation principle policies in the future.

Energy and environment in Chinese rural buildings: Situations, challenges, and intervention strategies

A large-scale national survey of energy consumption and indoor environmental quality of rural housing was conducted in China. Its purpose was to obtain fundamental data and to analyze key problems related to the homes of approximately 600 million rural people. The survey results indicate that the total annual household energy consumption in rural China reached 317 million tons of standard coal equivalent (tce) (9.3 × 109 GJ), in the forms of 192 million tons of raw coal (4.0 × 109 GJ), 5.9 million tons of liquefied petroleum gas (LPG) (0.3 × 109 MJ), 132 billion kWh of electricity (1.4 × 109 GJ), and 219 million tons of raw biomass (3.6 × 109 GJ). There is an upward trend in the use of coal for space heating and cooking, which is a significant source of air pollution. The pilot study of a program to provide passive energy savings in northern rural China was also conducted. Based on the results of actual demonstration projects, feasible intervention strategies for sustainable development in rural China are proposed, with the goal of achieving “zero coal villages”. Projections show that achieving “zero coal villages” nationwide could provide huge and permanent benefits both to China and to the rest of the world. The results obtained from this study could also provide guidance for development of rural housing in other countries, particularly in the developing world.