Application of holographic optical elements in buildings for various purposes like daylighting, solar shading and photovoltaic power generation

Since four years the ILB is developing lightdirecting building components, using holographic optical elements (HOE). The holograms are produced on films, which are laminated between two panes of floatglass. By the physical effect of diffraction different forms of light manipulation are possible, comparable to those of mirrors, prisms, lenses and other optical elements. Laminated glass with lightdirecting holograms allows a great variety of applications in architecture for utilization of solar energy, improvement of room comfort as well as design of solar light- and colour effects.     

Load and energy requirements in residential buildings in Saudi Arabia: A comparative study

The load and energy requirements in residential buildings vary according to a number of factors. One of these factors is the geographical location in which the building is situated. Using a detached single-family house, the DOE2.1C load and energy analysis program was used to investigate the effect of the geographical location on the load and energy requirements. Four different cities, namely Dhahran, Riyadh, Jeddah and Khamis-Mushayt, representing four different climatic locations, are considered in this study. The analysis shows that the building parameters having the greatest impact on load are conduction through walls and roof, glazing area and infiltration level. The capacity requirements of the equipment and the total energy requirement for year-round air conditioning were calculated for a house in each city. A comparison shows that the city of Khamis-Mushayt has the lowest energy consumption and Jeddah has the highest energy consumption. The equivalent uniform annual cost (EUAC) method was also used to compare the economic performances of typical houses in the four cities. The comparison shows that the district of Khamis-Mushayt has the lowest EUAC, but the difference between the other cities is not significant. Furthermore, it shows that there is a significant difference between the government's and customers' EUACs.     

Comparison and analysis of energy consumption of energy-efficient office buildings in different climate regions in China: case studies

The purpose of this paper is to analyze the energy consumption (EC) and find out the determining factors of energy-efficient office building cases according to specific case studies in typical cities of different climate zones in China. The investigated building cases were located in four cities (Beijing, Ningbo, Nanjing and Shenzhen) of three architecture thermotechnical design zones (cold zone, hot summer and cold winter zone, hot summer and warm winter zone). The analysis indicates that the energy consumption index (ECI) of these four cases ranges from 41.06 to 74.23 kW·h/(m²·a). Besides, the outdoor climate can change the EC of air conditioning/heating systems, and further determine the monthly volatility of the total EC of the whole building.     

Solar seasonal thermal energy storage for space heating in residential buildings: Optimization and comparison with an air-source heat pump

ABSTRACT

This study evaluates the techno-economics of replacing an air-source heat pump (ASHP) system with a solar seasonal thermal energy storage (STES) system for space heating in Hangzhou, China. Three heating systems, solar STES, ASHP, and ASHP with short-term storage of solar energy, are developed using TRNSYS for a house with 240 m² of floor area. The ratio of tank volume to collector area (RVA) of the STES is optimized for the lowest equivalent annual cost over a lifespan of 20 y. The determined optimal RVA is 0.33 m³/m², although it depends on the system and electricity prices. The optimized STES reduces the electricity demand to 1,269 kWh (74% reduction). Despite the superior energy performance, the economic benefit is only possible with large STES systems, which enjoy low tank prices due to scale effects. The results suggest that policy support is needed for STES, where district scaling is not an option.     

Electric energy demands of Turkey in residential and industrial sectors

The main objective of the present study is to apply the artificial neural network (ANN) methodology, linear regression (LR) and nonlinear regression (NLR) models to estimate the electricity consumptions of the residential and industrial sectors in Turkey. Installed capacity, gross electricity generation, population and total subscribership were selected as independent variables. Two different scenarios (powerful and poor) were proposed for prediction of the future electricity consumption. Obtained results of the LR, NLR and ANN models were also compared with each other as well as the projection of the Ministry of Energy and Natural Resources (MENR) and the results in literature. Results of the comparison showed that the performance values of the ANN method are better than the performance values of the LR and NLR models. According to the poor scenario and ANN model, Turkey's residential and industrial sector electricity consumptions will increase to value of 140.64 TWh and 124.85 TWh by 2015, respectively.     

Implementation of energy efficiency standards of household refrigerator/freezer in China: Potential environmental and economic impacts

Due to the rapid economic development, living standards in China are improving fast. Chinese families are having more household electrical appliances, among which refrigerators are indispensable. Energy consumption of refrigerators is huge in China and causes environmental concerns. China has issued the national energy efficiency standards of household refrigerators, GB12021.2-2003 and GB12021.2-2008 to promote high-efficiency refrigerator production and use. This study evaluated the impacts of the standards on the environment, manufacturers and consumers over a long-term period of 2003–2023. It first evaluated the potential electricity conservation and GHG emission reduction resulting from energy efficiency improvements driven by the standards. Next, manufacturers’ technological and economic concerns about complying with the standards were discussed. Some efficiency improving design options were considered and the resulting increases in manufacturing cost and retail price were estimated. The return of consumers from invest in efficiency was analyzed based on lifecycle cost saving of the improved models. The economical viability of the standards was then evaluated by national consumer costs and benefits. Results showed that the considered efficiency standards will potentially save a cumulative total of 588–1180 TWh electricity, and reduce emission of 629–1260 million tons of CO₂, 4.00–8.04 million tons of SO_x and 2.37–4.76 million tons of NO_x by 2023, depending on sale share of models by efficiency. In a more environmentally optimal case (75% sale share of high-efficiency models), the national consumer benefits are 121 billion RMB (discounted), with the benefit/cost ratio of consumer’s expenditure being 1.45:1. However, the preference to high-efficiency models is substantial influenced by consumer’s expectation on return from the additional cost on efficiency.     

Pattern analysis and suggestion of energy efficiency retrofit for existing residential buildings in China's northern heating region

In China, Energy Efficiency Retrofit for Existing Residential Buildings (EERFERB) is faced with a fast development status. The Central Government decided to prompt the retrofit of 1.5×10⁸ m² existing residential buildings in China's northern heating region during the “11th Five-Years Plan”. But, at present, the relative incentive policies and measurements are very insufficient. Especially, on the aspect of the retrofit pattern about the organization, retrofit content, investing and financing mode, the policy and management and other factors, no existing successful one can be spreaded into the whole northern heating region. This research not only analyzed the foreign advanced methods, drew lessons from their retrofit in Germany and Poland, but contrasted and analyzed energy efficiency retrofit demonstrations from Harbin, Tianjin, Tangshan and Baotou in China to get our domestic successful patterns and experience. Finally, some recommended retrofit patterns are presented, which can be applied for the instruction and decision-making for the Chinese local governments.     

An economic analysis of energy requirements and input costs for tomato production in Turkey

The aim of this study was to examine direct and indirect input energy in per hectare in tomato (industrial type) production and compare it with production costs. The research also sought to analyse the effect of farm size. For this purpose, the data were collected from 95 tomato farmers by questionnaire method. The results indicated that tomato production consumed a total of 45.53 GJ ha⁻¹ of which diesel energy consumption was 34.82% followed by fertilizer and machinery energy. Output–input energy ratio and energy productivity were found to be 0.80 and 0.99 kg of tomato MJ⁻¹, respectively. Cost analysis revealed that the most important cost items were labour costs, machinery costs, land rent and pesticide costs. According to the benefit–cost ratio, large farms were more successful in energy use and economic performance. It was concluded that energy use management at farm level could be improved to give more efficient and economic use of energy.     

整体煤气化联合循环电站的模拟和经济性分析

用GTPRO软件模拟了整体煤气化联合循环（IGCC）和燃气轮机联合循环（GTCC）电站,并进行经济性分析.分析内容包括煤价、电价和贷款利率对IGCC电站经济性的影响;IGCC电站和GTCC电站的经济性对比,特别是对天然气价格在其中的影响进行了分析,得出了一些有重要参考价值的定量结果.     

The economic competitiveness of promising nuclear energy system: A closer look at the input uncertainties in LCOE analysis

In this study, we aimed to provide important information about the potential economic benefits and risks of nuclear electricity generation associated with existing and prevailing nuclear technologies and to examine the economic effects of nuclear fuel cycle strategies in Korea. An economic analysis model that evaluates the overall life‐cycle costs of nuclear energy systems coupled with multiple fuel cycle options was specially developed by using the levelized cost of electricity (LCOE) as the fundamental methodology. This model is capable of identifying a range of techno‐economic uncertainties underlying each individual nuclear energy system taking into account the state of the art in fuel cycle technologies. It can also quantify and incorporate the resulting impacts into a system‐wide LCOE distribution for each fuel cycle option based on Monte Carlo probabilistic simulation. We analyzed and discussed examples of the economic performance of 13 promising candidates for nuclear energy systems integrated with extensive fuel cycle technologies (including one direct disposal and 12 specific reprocessing and recycling fuel cycle options). We also conducted a sensitivity analysis to investigate the major sensitivity factors of the system component cost in each fuel cycle option and their impacts on individual economic performances. Furthermore, a closer look at the techno‐economic uncertainties of advanced fuel cycle technologies in a break‐even analysis offers evidence of the potential economic feasibility and cost‐reduction opportunities in the reprocessing and recycling options relative to the direct disposal of spent nuclear fuel.     

Parametric equations for energy and load estimations for buildings in India

Detailed simulations have been performed for a single zone building to calculate the maximum heating and cooling loads as well as specific annual energy consumption for a single zone building. Numerical results have been used to derive parametric equations as a function of the thickness of insulation as well as the surface to volume ratio (A/V) taking into account the effect of increasing height as well as increasing length and width. For un-insulated building, the energy consumption increases steeply with increasing height, whereas for an insulated building, the energy consumption decreases slightly. For increasing lengths and widths, the change in energy consumption is a mild positive slope. The optimum thickness of the insulation obtained in the paper corresponds to the recommended U-values of roof and the walls in the building code of India, U being the total heat transfer coefficient.     

Co-production of electricity and hydrogen from wind: A comprehensive scenario-based techno-economic analysis

The aim of this study is to investigate the economic prospects of producing electricity and hydrogen using wind energy under different scenarios. For this, the most essential criteria to investors including Levelized Cost of Wind-generated Electricity (LCOWE), Levelized Cost of Wind-based Hydrogen (LCOWH), payback period, and rate of return are examined. Technical and environmental impacts are factored into the LCOWE formulation to obtain comprehensive insight. Owing to the uncertain nature of future, five degradation rates concerned with wind turbine performance and five likely rates as to the future value of money are investigated under the scenarios of I) utilizing wind electricity to replace fuel oil electricity, II) to replace natural gas electricity and III) without considering environmental penalties. The results indicate that LCOWE would be in the range of 0.0325–0.0755 $/kWh, while the corresponding LCOWH being in the range of 1.375–1.59 $/kg. Moreover, payback period of the related LCOWE and LCOWH would be in the range of 2.55–9.48 yr during the lifetime of wind power plant and 3.91–8.41 yr during that of hydrogen production system, respectively. The corresponding rate of return pertinent to the above-mentioned ones would be respectively in the range of 14.15–23.54% and of 9.87–21.55%.     

Assessment of technical and economical viability for large-scale conversion of single family residential buildings into zero energy buildings in Brazil: Climatic and cultural considerations

This paper addresses the viability of converting single-family residential buildings in Brazil into zero energy buildings (ZEBs). The European Union and the United States aim ZEBs implementation to address ‘peak oil’ and environmental concerns. However, literature shows no agreement on a consensual definition of ZEB. Seeking a Brazilian ZEB definition, this paper addresses PassivHaus and thermal comfort standards for hot climates, source metrics for ZEB, Brazil′s energy mix, residential energy end uses and Brazilian legal framework for residential photovoltaic (PV) generation. Internal Rate of Return for PV systems in two Brazilian cities is calculated under various scenarios. It shows grid parity was reached from April 2012 to November 2012 assuming residential electric tariffs of that period and the financial conditions given by the Brazilian government for the construction of new dams in the Amazon and the lowest rates offered by Brazilian banks to private individuals. Governmental decision to lower electric residential tariffs in November 2012 reduced the scope of grid parity. Later revocation of a tax exemption in April 2013 ended grid parity in Brazil. It concludes, conversely to developed countries, it is the volatile Brazilian energy policy, instead of economical barriers, the main obstacle for ZEB viability in Brazil.     

不同朝向太阳辐射测试及应用对策分析

在太阳能建筑设计、建筑能耗模拟时,逐时的太阳辐射气象数据是最重要的基本参数。我国严寒和寒冷地区居住建筑节能设计标准规定,采暖期的计算需要准确的不同朝向的太阳辐射照度,但是,我国目前尚未广泛地进行不同朝向的太阳辐射观测工作。文章制定了一套不同朝向的太阳辐射测量方案,通过对数据进行处理分析,得出不同朝向的太阳辐射变化规律,验证了方案的可行性。基于分朝向的太阳辐射变化,提出了相应的建筑设计策略,为建筑节能提供更准确的理论依据。     

Life cycle cost analysis of a multi-storey residential Net Zero Energy Building in Denmark

It is well recognized that in the long run, the implementation of energy efficiency measures is a more cost-optimal solution in contrast to taking no action. However, the Net ZEB concept raises a new issue: how far should we go with energy efficiency measures and when should we start to apply renewable energy technologies? This analysis adopts the LCC methodology and uses a multi-family Net ZEB to find the answer to this question. Moreover, it looks at the issue from the building owner’s perspective, hence it should be seen as a private economy analysis. The study includes three levels of energy demand and three alternatives of energy supply systems: (1) photovoltaic installation with photovoltaic/solar thermal collectors and an ambient air/solar source heat pump; (2) photovoltaic installation with a ground-source heat pump; (3) photovoltaic installation with district heating grid. The results indicate that in order to build a cost-effective Net ZEB, the energy use should be reduced to a minimum leaving just a small amount of left energy use to be covered by renewable energy generation. Moreover, from the user perspective in the Danish context, the district heating grid is a more expensive source of heat than a heat pump for the Net ZEB.     

An economic and environmental assessment of transporting bulk energy from a grazing ocean thermal energy conversion facility

An ocean thermal energy conversion (OTEC) facility produces electrical power without generating carbon dioxide (CO₂) by using the temperature differential between the reservoir of cold water at greater depths and the shallow mixed layer on the ocean surface. As some of the best sites are located far from shore, one option is to ship a high-energy carrier by tanker from these open-ocean or “grazing” OTEC platforms. We evaluate the economics and environmental attributes of producing and transporting energy using ammonia (NH₃), liquid hydrogen (LH₂) and methanol (CH₃OH). For each carrier, we develop transportation pathways that include onboard production, transport via tanker, onshore conversion and delivery to market. We then calculate the difference between the market price and the variable cost for generating the product using the OTEC platform without and with a price on CO₂ emissions. Finally, we compare the difference in prices to the capital cost of the OTEC platform and onboard synthesis equipment. For all pathways, the variable cost is lower than the market price, although this difference is insufficient to recover the entire capital costs for a first of a kind OTEC platform. With an onboard synthesis efficiency of 75%, we recover 5%, 25% and 45% of the capital and fixed costs for LH₂, CH₃OH and NH₃, respectively. Improving the capital costs of the OTEC platform by up to 25% and adding present estimates for the damages from CO₂ do not alter these conclusions. The near-term potential for the grazing OTEC platform is limited in existing markets. In the longer term, lower capital costs combined with improvements in onboard synthesis costs and efficiency as well as increases in CO₂ damages may allow the products from OTEC platforms to enter into markets.     

The potential for integration of hydrogen for complete energy self-sufficiency in residential buildings with photovoltaic and battery storage systems

This paper presents an analysis of energy production in a pilot building located in Slovenia, which is a typical residential house with an installed photovoltaic (PV) system and pilot battery storage system. Energy management system gathers data from smart meters every 15 min. As the pilot building location is in central Europe, complete energy self-sufficiency cannot be provided. The most problematic period of energy production with photovoltaic systems is winter. Solar radiation during the winter is much lower than in the summer and sometimes snow covers photovoltaic panels and disables energy production. Energy production and energy consumption are analyzed for one year. This study shows that complete self-sufficiency can be achieved by supplementing photovoltaic systems with hydrogen fuel cells. The amount of hydrogen, which would suffice for complete self-sufficiency for the whole period, is calculated according to the analyzed data. A synergy between photovoltaic system and hydrogen fuel cells is a step forward to complete self-sufficiency with renewable energy sources. The share of self-sufficiency of a hybrid PV fuel cell system would be 62.13%, meaning that there is no possibility for complete self-sufficiency from the pilot system. The shortage of hydrogen is 144.24 kg for one year and for achieving complete energy self-sufficiency, PV system should be bigger. A hybrid system with photovoltaic system, battery storage system and hydrogen fuel cells can be a solution for complete self-sufficiency. From an economic point of view, such systems are accessible for commercial use. The initial investment is relatively high, because of the high cost of the hydrogen storage tank.     

Thermodynamic analysis of in-situ hydrogen from hot compressed water for heavy oil upgrading

Due to many benefits of heavy oil upgrading in the green medium of hot compressed water (HCW), the present study considers the thermodynamic analysis of in-situ hydrogen created by partial oxidation of light hydrocarbons (HC) in HCW. The aim is seeking the upgrading condition where light hydrocarbons create hydrogen (H₂) and carbon monoxide (CO) assisted by partial oxidation of light hydrocarbons. The formed CO collaborates in in-situ active hydrogen through water gas shift reaction (CO+H₂O↔H₂+CO₂) which is more effective than external hydrogen for hydrogenation of heavy oil in HCW. Applying the powerful capability of Aspen Plus®, i.e., sensitivity analysis, the effect of significant parameters, such as temperature, pressure (water density), water to oil ratio, and oxygen (O₂) to oil ratio are studied comprehensively in order to maximize the amount of active hydrogen. The results indicate that higher temperatures and the amount of water (H₂O/heavy oil) are two favorable factors to increase the contribution of active hydrogen, while the pressure is not a determinant factor at supercritical condition (P ≥ 25 MPa). The formation of methane is also decreased at high temperature which is desired for upgrading system. The higher amount of water implies more quantity of O₂ since partial oxidation affords the enthalpy of auto-thermal reforming of HO. Hence there should be a compromise in the selected ratios of H₂O/HC and O₂/HC in HCW upgrading system. A set of experiments are conducted in order to compare the simulation and experimental results. Although the experimental results are established on kinetic data which also reflect the physical effect of HCW during HO upgrading, however, the thermodynamic study provides valued information, in agreement with experiments, that improves our understanding of HO upgrading in HCW with less coke.     

Optimal working conditions of various city gate stations for power and hydrogen production based on energy and eco-exergy analysis

In this study, the feasibility of producing power and hydrogen from the waste heat of different City Gate Stations (CGSs) is investigated to select the optimal working conditions. A thermodynamic model is developed for a proposed system combined of the CGS station, the Rankin cycle and the extended hydrogen production cycle. Initially, six CGS stations are simulated based on energy, exergy-economic and environmental analysis and then a comparative study is conducted between different stations. The results of numerical modeling show that the Mashhad-old station with 5315 kW and 31.062 ton/year has the highest amount of power and hydrogen production among other stations, respectively. It is also observed that, it is more economic to increase the input gas pressure in order to increase the production rate. In addition, optimal working conditions are determined based on the two important optimization factors of the hydrogen production rate and SUCP (sum unit cost of the product) using genetic algorithm optimization technique. The results of multi-objective optimization indicate that Gonbad, Gorgan and Mashhad-old stations, where the inlet gas mass flow rate is in the range of 8–9 kg/s, are the optimum stations.     

Life-cycle analysis of energy use and greenhouse gas emissions of gas-to-liquid fuel pathway from steel mill off-gas in China by the LanzaTech process

The LanzaTech process can convert carbon monoxide-containing gases produced by industries, such as steel manufacturing, into valuable fuel products. The life-cycle analysis (LCA) of energy use and greenhouse gas emissions from the LanzaTech process has been developed for a Chinese setting using the original Tsinghua China Automotive LCA model along with a customized module developed principally for the process. The LCA results demonstrate that LanzaTech gas-to-liquid (GTL) processing in China’s steel manufacturing is favorable in terms of life-cycle fossil energy and can reduce greenhouse gas emissions by approximately 50% compared with the conventional petroleum gasoline. The LanzaTech process, therefore, shows advantages in both energy-savings and a reduction in greenhouse gas emissions when compared with most bio-ethanol production pathways in China.