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[Display omitted] • A building model was developed and 22 EPC were determined and analysed. • Different heating technologies were compared to determine final and primary energy. • Pollutant emissions resulting from the building's energy needs was calculated. • An analysis of the relationship between emissions and energy demand was indicated. • Critical review of the methodology for determining EPC were presented. The assessment of energy efficiency and the environmental impact of building operation, in energy terms, determine to a large extent the energy intensity of the housing sector as a whole and the planning of energy transition measures. In order for these measures to be properly targeted and the building assessment to be reliable, it is necessary to accurately determine the energy demand of the building. The calculation model presented in the article allows for a multivariate assessment of a building's energy demand using static methods. The methodology presented in the article for the determination of energy performance certificates for buildings is complemented by an interpretation regarding the efficiency of the energy systems in the building and the environmental emissions. A model of the existing single-family building was evaluated for this purpose, and subjected to a multivariate analysis depending on the configuration of the heating system. Final and primary energy values, fuel consumption and emissions of pollutants to the environment were determined for each of total twenty-two variants. The analysis carried out and the results obtained show that there is no logical relationship between the primary energy indicator, used for the energy assessment of buildings, and the energy intensity of the building and its environmental impact. [ABSTRACT FROM AUTHOR]

Fuel cells are considered one of the key technologies to reach the ambitious European goal of a low carbon economy, by reducing CO 2 emissions and limiting the production of other pollutants. The manuscript presents an assessment of the life cycle energy and environmental performances of a solid oxide fuel cell system for household applications using primary data from the manufacturing phase and experimental data for the start-up and operation phases. The Life Cycle Assessment methodology is applied, based on a functional unit of 1 MJ of exergy and includes the life cycle steps from the raw materials extraction to the maintenance. The results show a particular relevance of the operation stage on the impacts (about 98% of cumulative energy demand and more than 63% of about half of the examined environmental impacts), mainly due to the fuel supply and, focusing on climate change, to the CO 2 emissions during the conversion of chemical energy into electricity. Manufacturing step is the main responsible of the remaining half of the impacts, with a contribution higher than 38%, mainly imputable to the stacks production. For almost half of the examined impact, a contribution of 20–30% is caused by the maintenance step, with a relevant contribution of the stacks and DC/DC booster substitutions. The analysis highlights that eco-design solutions of the assessed system can be traced in the improvement of the energy system efficiency and reduction of emissions during the operation, and in the increase of the durability of the system components, thus reducing the number of their substitutions. The results of a sensitivity analysis on the selection of the functional unit also clarified the importance of the recovery of the thermal energy generated by the fuel cells, in order to avoid concurrent energy generation from conventional sources. Unlabelled Image • The LCA of a solid oxide fuel cell system for household application is presented • Operation is responsible of more than 63% of about half on the impacts • The contribution of the manufacturing is higher than 38% for half of the impacts • Improvement of efficiency can allow for reducing the impacts of fuel cells • Extending the useful life of the system components is a valid eco-design solution [ABSTRACT FROM AUTHOR]

Abstract This analysis uses empirical data for 20 single-family homes from a smart grid demonstration project in Austin, Texas to create intra-day natural gas and electricity use profiles on one-minute intervals based on cooling and heating degree days. Combining these intra-day energy use profiles with emissions factors and a linear programming model, temporal energy use profiles were evaluated to quantify primary energy consumption, CO 2 emissions, and peak electric load for a house with a residential fuel cell used as on-site power generation versus being connected to the electric grid. Results showed that natural gas use primarily peaked in the morning, while electricity use peaked in the afternoon. For fuel cell capacities of 0–3.0 kW e and efficiency of 40%, total CO 2 emissions, including the fuel cell for the cooling day, were 1.7–1.9 times higher than the heating day. For a fuel cell capacity of 1.0 kW e and efficiency of 40%, peak electric load decreased during on-peak hours (14:00–20:00) for the cooling and heating days by 60% and 44%, respectively. Effects of fuel cell capacity and efficiency on total primary energy consumption and CO 2 emissions showed that as the fuel cell capacity and efficiency increased, primary energy consumption and CO 2 emissions were reduced from the baseline values that represent conventional homes' patterns. These results show that the use of residential fuel cells can offer environmental benefits from reducing primary energy consumption and CO 2 emissions, and grid reliability benefits by reducing peak electric load. [ABSTRACT FROM AUTHOR]

Hybrid chiller systems that combine electric and absorption chillers can play critical roles in performances of a combined cooling, heating, and power (CCHP) or trigeneration system. The objective of the present study is to investigate a new strategy for hybrid chiller-based CCHP systems that can optimize electric power production while achieving zero-excess electricity generation for a given building. Using this operation strategy, energy and environmental performances were examined for two U.S. Department of Energy reference buildings (large office and hospital) located in two climates (San Francisco, CA and Long Island, NY). The results show that the hybrid chiller-based CCHP systems can save the primary energy consumption up to 5.8 GWh/y for the large office building and 13.6 GWh/y for the hospital compared to the conventional reference system that utilizes a central grid. More significant energy savings are realized for the hospital than the large office mainly due to high electric and thermal loads throughout the year. Carbon dioxide emission associated with a CCHP system highly varies with the emission factor of a local grid. In case of using the hybrid chiller system in Long Island, NY, the carbon dioxide emission is 0.2–1.5 kton/y lower than the reference system, whereas it is 1.1–1.5 kton/y higher in San Francisco. However, compared to traditional CCHP systems that utilize only absorption chillers, the hybrid chiller-based CCHP systems can reduce carbon dioxide emission by 0.7 kton/y for the large office and 3.5 kton/y for the hospital. When comparing the effects of building types and local climates, building types have more significant effects on the energy performance, while local grid conditions have larger impacts on carbon dioxide emission of a hybrid chiller-based CCHP system. Overall, the study results suggest that the hybrid chiller-based CCHP systems can reduce more energy and carbon dioxide emission for commercial buildings or districts with high thermal and electric loads during the cooling season. [ABSTRACT FROM AUTHOR]

Abstract The introduction of a heat source water network system using heat from hot spring and drainage water for hot water supply in accommodation facilities in hot spring areas is expected to contribute to increased energy efficiency. In this study, the relationship between the temperature of the heat source water and the energy efficiency of heat pump water heaters introduced in hot spring facilities connected to a single-loop heat source water network was analyzed. The primary energy consumption of the heat source water network system was compared with that of a centralized heat supply system by conducting a dynamic simulation using Modelica in the Dymola environment. The yearly average coefficients of performance of the proposed heat source water network and centralized heat supply systems were estimated to be is 4.56 and 3.24, respectively. The seasonal performance of the proposed system was also investigated based on measurement data. In December, it was estimated that the heat source water network system would achieve a 17.6% reduction in primary energy consumption in comparison with the centralized heat supply system. However, in August, it was estimated that the primary energy consumption of the heat source water network system would be 8.9% higher than that of the centralized system. [ABSTRACT FROM AUTHOR]

The analysis of energy performance certificates is one method of better understanding the current constructive reality of the building stock and of generating knowledge that is applicable to energy planning in the residential sector. The objective of this study is to develop a correction algorithm for energy performance certificates to assess the residential building stock of a country by region. The selected case study of the Autonomous Community of Aragón aims to advance the energy and environmental assessment of the residential building stock of climate zones with temperate and cold winters in Spain. The results reveal that 49.71% of the energy performance certificates in Aragón contain incorrect information. Additionally, the average primary energy consumption varies between 203.9 kWh/m 2 ·year and 282.0 kWh/m 2 ·year based on the climate zone, and the associated emissions vary between 44.1 kg CO 2 /m 2 ·year and 63.6 kg CO 2 /m 2 ·year. In addition to highlighting the differences between urban and rural areas, the obtained results are compared to published results of similar studies in other Autonomous Communities. This study serves as a basis for outlining optimal future energy and environmental scenarios, wherein public administrations can promote measures for energy rehabilitation and improve energy savings and efficiency. [ABSTRACT FROM AUTHOR]

Energy planning is fundamental for energy planners to accurately plan for the future and to utilize the sustainable and renewable energy resources to a larger extent. But how well are we able to project the future? In this paper, past projections of global and regional energy consumption are compared to real data. The conclusions found that when comparing energy consumption projections with real registered data projections in 1977 substantially overestimated energy demand in the future, while later projections in the 80 s and 90 s were closer to reality, slightly underestimating real growth in demand. Although projections made in these two decades for total demand were typically slightly underestimated, per capita projections were still overestimating real trends. Considering the building sector, residential and commercial, energy consumption was underestimated in WEO 1982 and WEO 1994; and again, when per capita values are considered, higher values than reality were projected. [ABSTRACT FROM AUTHOR]

Among other things, the European Union climate and energy legislation package seeks to achieve a renewable energy contribution of 20% to total energy consumption by the year 2020. In addition, it also seeks to improve energy efficiency and to reduce the 2005 total primary energy consumption by 20% in that same year. In 2013, the residential sector of Spain consumed 15.0 Mtoe of final energy, representing 19% of total energy consumption. This sector has great potential for savings and energetic improvement due to the multitude of possible actions that can be taken to improve it. This paper presents a methodology for evaluating the final energy consumption, primary energy consumption, and contribution by renewable energy of the residential sector decomposed by energy source in any Autonomous Community and in Spain as a whole. The method is applied to the Autonomous Community of La Rioja and to Spain between 1991 and 2013. The results show a complete energy analysis of the Riojan and Spanish residential sectors, ultimately obtaining the key energy indicators to demonstrate the advances toward compliance with European goals for 2020, adapted to the residential sector. The results themselves serve as a control tool for energy planning. [ABSTRACT FROM AUTHOR]

Integrating thermal energy storage (TES) with building cogeneration system is an effective way to improve part load efficiency and save primary energy consumption. In this paper, a novel analytical method is put forward to evaluate the energy saving potential of cogeneration system with TES equipment under following thermal load operation strategy. Moreover, the load fluctuation factor is defined, based on the maximal and average load amount, and its relationship with primary energy consumption and system exergy losses are established. The results show that the primary energy consumption is mainly influenced by three factors: (1) no-load fuel consumption ratio and rated efficiency of gas turbine; (2) heating load fluctuation factor; (3) ratio of heat to electricity load. Furthermore, with increasing gas turbine efficiency and heating load fluctuation factor, the primary energy saving ratio grows whereas system exergy loss declines. The illustrative example in Beijing indicates that the primary energy consumption decreases by 16% and 23% for the hotel and office building respectively in one typical winter day. This work can provide guidance for practical design cogeneration system with TES equipment. [ABSTRACT FROM AUTHOR]

The augmented energy-growth nexus with globalization is analyzed for a panel of 43 countries between 1971 to 2013, by using an autoregressive distributed lag (ARDL) approach. The impacts of economic, political and social globalization on energy-growth nexus are explored. The results are consistent with the presence of cointegration. Evidences of the traditional feedback hypothesis on the energy-growth nexus was found. Economic, political and social globalization have heterogenous impacts on the nexus. In general, globalization is a long-run driver of both energy consumption and economic growth. Accordingly, globalization should be promoted. In addition, restrictive energy policies should be avoided or carefully designed to no hamper economic growth. [ABSTRACT FROM AUTHOR]

Due to the economic development and occupancy requests, building thermal comfort reached higher levels during the last years. Energy consumption rates have become excessive and engendered an increasing reliance on fossil-fuel reserves. Hence, the conception of energy-efficient buildings as well as applying solar cooling techniques has become a promising solution. In this context, the current work dealt with the appraisal of a solar system that drives the cooling process in an office building located in the Center of Researches and Energy Technologies in Tunisia. The solar system consisting of linear parabolic trough solar collectors' field coupled to a 16 kW double effect Lithium Bromide absorption chiller, supplies chilled water to a set of fan coils installed in the 126 m 2 laboratory building. A dynamic model that couples the solar cooling system with the building was developed using the TRNSYS tool and several simulations were performed to assess the case study and improve its performance. The model results were compared to the data collected during the experimental campaign conducted in summer 2015 and showed that the collectors efficiency was at the range of 26–35%, the COP ranged between 0.65 and 1.29, the daily maximum solar COP was approximately at 35%. However, the solar system was unable to cover 32.3% of the cooling requirements, the absorption chiller was switched on only during 53.8% of its total operating time. An improved system configuration was then studied; the integration of an auxiliary heater prior to the chiller as well as the increase of the aperture area guaranteed high driving temperatures and more suitable conditions to the absorption chiller. As a result, the chiller operating time increased to 75.8%, the cooling power increased by 75.6%, the solar COP reaches 57% and the solar fraction averaged 87%. The summer season performances predict that the improved system configuration achieves primary energy savings that reach 82.3% compared to a classic air conditioning system producing the same cooling power, the yearly avoided CO 2 emissions are estimated to 2947 kg. [ABSTRACT FROM AUTHOR]

Aiming for improvement of the cooling performance, the hybrid desiccant cooling system ( HDCS ) is investigated and compared with a reference desiccant cooling system ( RDCS ). By replacing a sensible wheel of the RDCS with a heat pump, the HDCS is expected to increase the energy efficiency as well as to improve the system compactness. The cooling cycle is simulated and its results are compared with those of the RDCS . The analysis showed that specific cooling power of the HDCS increases from that of RDCS , promising the miniaturization of the system. Also, COP of HDCS was found to overtake the COP of RDCS in a particular range of heat pump capacity. For analysis of total energy consumption, a new parameter, R v , the ratio of the primary energy factor of electrical energy to the primary energy factor of thermal energy was introduced. In the range of R v (=5–10) such as from the CHP plants, the optimal heat pump capacity was estimated when the heat pump occupies 30–40% of the total cooling output of the HDCS . With the optimal configuration, the total energy consumption of HDCS reduces by 20–30% and the cooling capacity of HDCS increases by 40–60%, compared to RDCS . [ABSTRACT FROM AUTHOR]

The building construction sector is responsible for more than 30% of the world's total energy consumption and almost 30% of its CO 2 emissions. European directives addressing energy performance have opened up a number of possibilities for action as they have evolved from obligatory measures to opportunities for advancement. Energy certifications for buildings and dwellings can illuminate many of the realities of construction, improve the efficiency of existing buildings and endow residential sector planning with a more realistic vision. This study examines the Autonomous Community of La Rioja – a Spanish region in which cold winter climate zones predominate – and analyzes how energy performance certificates can be used as a planning tool by calculating and verifying the average primary energy consumption and the corresponding CO 2 emissions per square meter and per year for the residential sector. In addition, the differences between rural and urban areas are presented. The average primary energy consumption varied between 229.4 kWh/m 2 ·year and 309.4 kWh/m 2 ·year, depending on the climate zone, and the associated emissions varied from 51.7 kg CO 2 /m 2 ·year to 72.0 kg CO 2 /m 2 ·year. This study is an initial benchmark to develop all that concerns the residential sector in La Rioja's 2015–2025 Energy Plan. The data obtained will enable different energy rehabilitation scenarios to be sketched out. Based on this information, government agencies can determine appropriate policies to be implemented in the future. Therefore, this study is the first step in defining the actual energy consumption conditions for the residential sector in a southern European region. [ABSTRACT FROM AUTHOR]

A combined forecast of Grey forecasting method and neural network back propagation model, which is called Grey Neural Network and Input-Output Combined Forecasting Model (GNF-IO model), is proposed. A real case of energy consumption forecast is used to validate the effectiveness of the proposed model. The GNF-IO model predicts coal, crude oil, natural gas, renewable and nuclear primary energy consumption volumes by Spain's 36 sub-sectors from 2010 to 2015 according to three different GDP growth scenarios (optimistic, baseline and pessimistic). Model test shows that the proposed model has higher simulation and forecasting accuracy on energy consumption than Grey models separately and other combination methods. The forecasts indicate that the primary energies as coal, crude oil and natural gas will represent on average the 83.6% percent of the total of primary energy consumption, raising concerns about security of supply and energy cost and adding risk for some industrial production processes. Thus, Spanish industry must speed up its transition to an energy-efficiency economy, achieving a cost reduction and increase in the level of self-supply. [ABSTRACT FROM AUTHOR]

The energy consumption and CO 2 emissions of heat pump systems can be reduced effectively by adopting an appropriate alternative refrigerant. However, investigation on alternative refrigerants for ground-source heat pump (GSHP) and solar-assisted ground-source heat pump (SGSHP) systems is limited although these systems still use conventional refrigerants. In this study, the life cycle climate performance (LCCP) and primary energy consumption (PEC) for GSHP and SGSHP systems using conventional and alternative refrigerants are compared to those for conventional boiler systems. Experiments are conducted to investigate the heating performance of selected refrigerants. For regions with low CO 2 emission conversion factor for electricity (μ C O 2. e l e c ), GSHP systems using R1234yf are the most suitable considering the LCCP, owing to its low GWP and high performance. However, SGSHP systems using R134a with a large system size are preferred in regions with high μ C O 2. e l e c , because system efficiency takes the priority in reducing the LCCP. For PEC, SGSHP systems using R134a are recommended owing to its high efficiency. However, in regions where oil or natural gas is used dominantly, either the system size of SGSHPs should be increased or the primary energy conversion factor of electricity should be reduced to guarantee the benefits of PEC reduction of SGSHP systems. • Life cycle climate performance and primary energy consumption are evaluated. • Boiler, ground-source, and solar-assisted ground-source heat pumps are considered. • R134a and R1234yf are suitable for energy and climate performance, respectively. • Increasing system size is beneficial in climate performance only in Berlin. • Primary energy consumption of electricity should be reduced in Bern and Berlin. [ABSTRACT FROM AUTHOR]

A new bi-directional systematic methodology was developed to minimize the building thermal load and energy consumption using cooling-to-heating load ratio and system efficiency to select optimal sets of building design factors and HVAC systems. On the basis of simulations conducted on a total of 384 combinations of HVAC system and alternative building models, the correlation between building cooling-to-heating load ratio and HVAC system energy consumption was analyzed. The diverse and total cooling and heating system efficiency of HVAC systems was derived. It was found that the ratio of the efficiencies of heating and cooling systems affected the optimum building design, hence the active and passive parts of a building should be considered simultaneously in a coupled way for the optimum design for the energy-efficient buildings. Energy consumption tends to vary radically with the type of HVAC system, even under identical building load conditions. That is, with different cooling-to-heating load ratio but a similar total energy, the total primary energy consumption and the cooling-to-heating energy ratio are predicted to change depending on the selected HVAC system. It is expected that a design plan formulated using the method and system efficiency enable a bi-directional energy optimization process conducive to providing feedback and prove to be of great use in building design factors, HVAC system solution, and decision-making at the initial design stage that considers building thermal load characteristics. [ABSTRACT FROM AUTHOR]

Wood biomass is considered a renewable raw product, but the supply chain of wood biomass involves non-renewable energy inputs, and thus possibly entailing environmental impacts. The objective of this study was to analyze different environmental impacts (GHG emissions, without biogenic CO 2 ; primary energy consumption, non-renewable; particulate matter) caused by the provision of forest biomass for the four main tree species in Bavaria using Life Cycle Assessment (LCA) techniques. Based on forest growth simulations, a set of realistic forest biomass supply chains for Bavarian forestry conditions were modeled for the raw wood product system from site preparation to forest road and to plant/farm gate, respectively, analyzing the four different process groups: [A1] site preparation, [A2] site tending, [A3] biomass harvesting and [T] transport of biomass to plant/farm gate. Total GHG emissions of about 383,000 t CO 2 -eq ∗ year − 1 (18.95 kg CO 2 -eq ∗ m − 3 ) are estimated for the Bavarian forestry sector (from site preparation to plant/farm gate) in the reference year 2013 indicating a share of 0.41% in the total GHG emissions of Bavaria. 0.035 MJ of non-renewable energy has to be invested in order to provide 1 MJ of woody biomass to plant/farm gate (267 MJ ∗ m − 3 ). One hundred and sixty six tons of particulate matter emissions per year are calculated for the Bavarian forestry sector in 2013 (0.008 kg PM 2.5 -eq ∗ m − 3 ). Our LCA results reveal that there is no single GHG emission value for raw wood but a broad range of possible GHG emissions for the Bavarian forestry. Most decisive parameters are forest road maintenance, biomass harvesting, forwarding and biomass transport, and GHG emissions are also notably influenced by tree species, age class, wood assortment and site quality. We recommend that environmental impact calculations should be implemented, for example in wood certification procedures as they are important key indicators for sustainable forest management. [ABSTRACT FROM AUTHOR]

The energy and environmental merits of three types of internal-combustion-engine primed trigeneration (ICEPT) systems were investigated when compared with a conventional chilled water system powered by the grid electricity for use in a high-rise office building in Hong Kong. With the employment of the ICEPT systems, the year-round total electricity demand from the building was reduced by at most 10.4% for the natural-gas-fueled one. However, the saving in the total primary energy consumption ( PEC ) only ranged from 1.7% to 6.8% with the diesel-oil-fueled system being the best although for all the three types of ICEPT systems more than 70% of the energy from the fuel had been utilized. The huge difference in the coefficient of performance ( COP ) between the absorption chiller and the vapor-compression chiller was the main cause which impaired the benefit of recovering the waste heat to provide space cooling. The total carbon dioxide emission ( CDE ) varied widely with the types of fuels adopted with a maximum of 26.7% for the natural-gas-fueled system which was due to the lower carbon dioxide emission index of natural gas as compared to other fuel types. The overall ranking of the ICEPT systems depended on the weighing between energy and environmental merits. [ABSTRACT FROM AUTHOR]

Integrating thermal energy storage (TES) device with building cooling heating and power (BCHP) system proves to be an effective way to improve the performance of the whole system. In this paper, the applicability of TES-BCHP system is investigated according to the relationship between user load demands and system energy supply. Based on the supplied thermal power ratio of the prime mover and the required one of users, a new parameter, the degree of mismatch (DM), is defined. Moreover, the relationship between primary energy saving ratio (PESR) of TES-BCHP system and DM is established, under following thermal load (FTL) and following electrical load (FEL) respectively for three different working conditions. The preliminary results show that the more DM approaches to unity, the higher PESR of TES-BCHP will be. It also indicates that TES-BCHP is more applicable for those where the heating demand is dominant. [ABSTRACT FROM AUTHOR]

This work has the aim to carry on a techno-economic analysis to verify the performance of PEMFC and SOFC based micro combined heat and power systems, analyzing the seasonal performance of the device on the basis of the thermal and electrical 1-minute-averaged user load profiles. A Matlab ® program has been written to build the annual profiles and to perform the energy evaluation of the system, considering the fuel cell production and the user demand and including a thermal and electrical storage. Four kinds of operation have been considered in order to evaluate the system behavior with different modulation strategies. Because the fuel cell needs a certain time to adapt its output power to steep load changes, a sensitivity analysis on the ramp rate has been made, in order to consider the impact of the speed of the cell in following the load requests. The calculation has been implemented both for the electrical led and thermal led operations, for single-family buildings. The economic analysis (based on the current prices of the technologies involved) has the aim to analyze different support schemes aimed at facilitating the technology competitiveness in the market, giving a general view of the possible technology applications in the near future. [ABSTRACT FROM AUTHOR]

This study measures energy consumption in existing educational buildings. The study provides an overall picture of energy consumption and assesses the factors that are used in evaluating measured energy. The studied buildings are day care centres, schools and university buildings located in southern Finland. The energy efficiency requirements in Finnish building regulations have become significantly stricter in recent years. This study shows that in different educational building type, the newer buildings consume less heating. However, such a clear correlation not found for electricity consumption. In the day care centres and school buildings studied, the primary heating consumption as a function of the age of the buildings has a decreasing trend. In turn, the primary electricity consumption has a slightly rising trend. However, in different building types, the primary heating and electricity consumption varied significantly between the buildings e.g. in day care centres variation was 83%, in schools 84% and in university buildings 76%. This study shows that even though Finnish climate is cold the primary electricity consumption is higher than primary heating in educational buildings constructed in the 2000s. This means that in the design phase, there is a need to find ways to influence the electricity consumption in particular. [ABSTRACT FROM AUTHOR]

Natural gas-driven Building Cooling Heating and Power (BCHP) system shows high energy efficiency and low emission. Nevertheless non-synchronized and fluctuating thermal and electrical demands lead to part load working conditions of the energy supply devices (prime mover and absorption chiller), resulting in low energy efficiency of the whole system. Integrating Thermal Energy Storage (TES) equipment to BCHP proves to be an effective way to improve the system performance. The location of the TES device in BCHP has a great impact on the performance of the whole system. In this paper, a simplified model of BCHP with TES system composed by a Gas Turbine (GT), an Absorption Chiller (AC) and a TES device of different heat exchange effectiveness is presented. Aiming to minimize primary energy consumption, the performances of BCHP systems with different TES locations (upstream and downstream the AC) are compared and analyzed. The preliminary results indicate that it is better for improving efficiency and reducing installed capacities of energy supply devices, to place TES close to users. Moreover, it is shown that the Relative Energy Saving Ratio (RESR) of BCHP with TES system is influenced by whether the co-generated power is merchantable to the power grids. This work is of great significance in further understanding the energy saving mechanism between TES and BCHP and guiding the design of practical BCHP with TES systems. [ABSTRACT FROM AUTHOR]

This paper analyze the benefits of the use of bioenergy, solar thermal and wind energy in a flexible energy system to increase the share of renewable sources (RES) in primary energy supply, reduce primary energy consumption (PEC) and ensure power supply security in Inland Norway, and Norway at large. Firstly, the Inland reference energy system was built and validated using the EnergyPLAN system analysis tool based on the year 2009. Two alternative systems (scenarios), mainly of bio-heat and heat pumps in individual and district heating systems were then constructed and compared with the reference system using EnergyPLAN. The quality of a given energy system can be best described by its PEC, RES, emission levels and socio-economic costs. The result shows that it is plausible to improve the quality of the Inland energy system by optimal resource assortment in the energy mix. Integrated use of bio-heat and heat pumps in individual and district heating systems, as a replacement for direct electric heaters would reduce PEC and socio-economic costs considerably more than intensive bio-heating deployment alone, thereby increasing total domestic green electricity generation. The ability to integrate wind power and its value in the Inland energy system is more reflected by reducing imports of electricity during peak demand periods in winter, as wind power availability in the region is significant as opposed to the low precipitation during these periods. In addition, increasing wind energy penetration helps to limit biomass consumption in a district heating system built on heat pumps and bio-heat boilers. [ABSTRACT FROM AUTHOR]

The gas turbine capacity and operating strategy selection of Building Cooling, Heating and Power (BCHP) systems play an important role in the system operating performance, leading to different primary energy consumption for the same building load. However, the optimal design problems of those two factors have not been solved very well. This paper presents a new simple method to determine the optimal gas turbine capacity and operating strategy. The gas turbine electricity efficiency, the Coefficient of Performance ( COP ) of absorption heat pumps, and the demand heat/power ratio are found to be the key factors. There exists two values of the critical gas turbine efficiency. More primary energy will be consumed when the selected gas turbine electricity efficiency is below the smaller critical value compared with the separated generation. When the selected gas turbine electricity efficiency is between the two critical values, the hourly optimal operating strategy and the gas turbine capacity can be determined by Following the Thermal Load (FTL). Otherwise, the optimal gas turbine capacity should be sized by Following the Electricity Load (FEL) with the consideration of the actual given conditions. Based on this method, some typical cases with or without TES are analyzed. The results agree well with the conclusions drawn in the current published papers. This method gives a new aspect to understand BCHP analytical design, and can be applied in the engineering area. [ABSTRACT FROM AUTHOR]

Abstract: Modeling and forecasting of the primary energy consumption (PEC) play a vital role for policy makers and related organizations in developing countries such as Turkey. In this study, Turkey׳s PEC is modeled by regression analysis (RA) based on population (CP) and gross domestic product (GDP). The derived model is validated by various statistical approaches such as the determination coefficient, t-test, F-test, and residual analysis. Additionally, the performance of the derived model is assessed using mean absolute percentage error (MAPE), root mean square error (RMSE) and means absolute error (MAE). Three scenarios are used for forecasting Turkey׳s PEC in the years 2010–2025. For each scenario, various assumptions are made considering different growth rate for CP and GDP. Using the proposed model, Turkey׳ PEC is forecasted under different scenarios. The results show that the proposed model can be affectively used for forecasting of Turkey׳s PEC. The scenarios also show that the future energy consumption of Turkey would vary between 174.65 and 203.13Mtoe in 2025. [Copyright &y& Elsevier]

Highlights: [•] We propose an optimal design method for the HVAC system in apartment house using a genetic algorithm. [•] By a modified genetic algorithm called multi-island genetic algorithm, the optimal running pattern of HVAC systems is decided to minimize the energy consumption. [•] The proposed method is significantly capable of determining optimal system design for saving energy in apartment house. [Copyright &y& Elsevier]

Highlights: [•] Modelling of both the micro-CHP based building level and the network level. [•] Estimation of the total primary energy consumption of the entire system. [•] Economics- and total energy consumption- based optimisation strategies compared. [•] A detailed case study carried out on the UK residential energy supply. [Copyright &y& Elsevier]

Abstract: In this study biomass-based energy production was introduced to an urban city area of Helsinki, Finland. The study compared two cases in integration with a municipality: (1) biomass fuelled small-scale CHP (combined heat and power)-plant and (2) a biorefinery. The comparison was made according to primary energy consumption, primary energy factors, CO2 (carbon dioxide) emissions and the price of produced biowax. It was also studied how results are influenced by different assumptions. The results showed that the primary energy consumption and CO2 emissions were higher in the biorefinery case in absolute amounts as more products i.e. biowax was produced. The results indicated the primary energy factors were almost the same for both cases. Additionally, the primary energy use was very low for district heat and electricity produced in the biorefinery, when the primary energy use of the biorefinery was allocated only to the biowax. The sensitivity analysis of biowax pricing showed that a biorefinery is a competitive alternative for a CHP-plant if the prices of biomass and market electricity are low and the price of CO2 allowance is high. In terms of overall energy efficiency comparison, the comparison cannot be properly completed, because of the different end-products of the plants. [Copyright &y& Elsevier]

Abstract: In this paper, the greenhouse gas and energy balances of the production and use for space heating of substitute natural gas from biomass (bio-SNG) for space heat are analysed. These balances are compared to the use of natural gas and solid biomass as wood chips to provide the same service. The reduction of the greenhouse gas emissions (CO2-eq.) – carbon dioxide, methane and nitrous oxide – and of the fossil primary energy use is investigated in a life cycle assessment (LCA). This assessment was performed for nine systems for bio-SNG; three types of gasification technologies (O2-blown entrained flow, O2-blown circulating fluidised bed and air–steam indirect gasification) with three different types of feedstock (forest residues, miscanthus and short rotation forestry). The greenhouse gas analysis shows that forest residues using the air–steam indirect gasification technology result in the lowest greenhouse gas emissions (in CO2-eq. 32 kg MWh−1 of heat output). This combination results in 80% reduction of greenhouse gas emissions when compared to natural gas and a 29% reduction of greenhouse gases if the forest residues were converted to wood chips and combusted. The gasification technologies O2-blown entrained flow and O2-blown circulating fluidised bed gasification have higher greenhouse gas emissions that range between in CO2-eq. 41 to 75 kg MWh−1 of heat output depending on the feedstock. When comparing feedstocks in the bio-SNG systems, miscanthus had the highest greenhouse gas emissions bio-SNG systems producing in CO2-eq. 57–75 kg MWh−1 of heat output. Energy analysis shows that the total primary energy use is higher for bio-SNG systems (1.59–2.13 MWh MWh−1 of heat output) than for the reference systems (in 1.37–1.51 MWh MWh−1 of heat output). However, with bio-SNG the fossil primary energy consumption is reduced compared to natural gas. For example, fossil primary energy use is reduced by 92% when air–steam indirect gasification technology and forest residues is compared to natural gas. There is no significant difference of the fossil primary energy consumption between the use of solid biomass (0.13–0.15 MWh MWh−1 of heat output) and the bio-SNG systems (0.12–0.18 MWh MWh−1 of heat output). [Copyright &y& Elsevier]

Abstract: The China TIMES model system, integrated with China energy service demand projection model (ESDPM) and TIMES model (the integrated MARKAL-EFOM system), is built to study China''s future sustainable energy and environment development strategy, based on energy demand projection with scenario analysis. On the basis of reasonable assumptions on the future economic growth and social development, the model system is employed to project China''s energy demand from 2010 to 2050. The result shows that China''s energy demand is expected to maintain a sustained and rapid growth before 2020, and then slow down gradually, reaching 6.6 and 6.2 billion tce in 2050 in reference scenario and policy scenario respectively. [Copyright &y& Elsevier]

Abstract: Optimization of combined cooling, heating, and power (CCHP) systems operation commonly focuses only on energy cost. Different algorithms have been developed to attain optimal utilization of CCHP units by minimizing the energy cost in CCHP systems operation. However, other outcomes resulting from CCHP operation such as primary energy consumption and emission of pollutants should also be considered during CCHP systems evaluation as one would expect these outcomes can be subject to regulation. This paper presents an optimization of the operation of CCHP systems for different climate conditions based on operational cost, primary energy consumption (PEC), and carbon dioxide emissions (CDE) using an optimal energy dispatch algorithm. The results for the selected cities demonstrate that in general there is not a common trend among the three optimization modes presented in this paper since optimizing one parameter may reduce or increase the other two parameters. The only cities that show reduction of PEC while also reducing the CDE are Columbus, MS; Minneapolis, MN; and Miami, FL. For these cities the operational cost always increases when compared to the reference case consisting of using a vapor/compression cycle for cooling and natural gas for heating. On the other hand, for San Francisco and Boston, CCHP systems increase the CDE. In general, if CCHP systems increase the cost of operation, as long as energy savings and reduction of emissions are guaranteed, the implementation of these systems should be considered. [Copyright &y& Elsevier]

Abstract: Feasibility of cooling, heating, and power systems frequently is based on economic considerations such as energy prices. However, a most adequate feasibility of CHP systems must be based on energy consumption followed by economic considerations. CHP systems designs must yield economical savings, but more importantly must yield real energy savings based on the best energy performance. For CHP systems, energy savings is related to primary energy and not to site energy. This paper presents a mathematical analysis demonstrating that CHP systems increase the site energy consumption (SEC). Increasing the SEC could yield misleading results in the economic feasibility of CHP systems. Three different operation modes are evaluated: (a) cooling, heating, and power; (b) heating and power; and (c) cooling and power, to represent the operation of the system throughout the year. Results show that CHP systems increase site energy consumption; therefore primary energy consumption (PEC) should be used instead of SEC when designing CHP systems. [Copyright &y& Elsevier]

Abstract: The objective of the present study is to estimate the potentialities of hydrogen production in Algeria. Particular attention is paid to the clean and sustainable hydrogen production, i.e., production from renewable energy. First, the present overall energy situation in Algeria is reviewed. Trend in energy demand is analysed taking into account major parameters such as population growth, urbanization, improvement in quality of life and export opportunities. The resources available for hydrogen production are then presented. Finally, the estimation of hydrogen production potential using solar sources, the most important renewable energy sources in Algeria, is presented. This study indicates that the shift to hydrogen economy shows a promising prospect. Not only, it can meet the evergrowing local needs but it will also allow Algeria to keep its share of the energy market. Indeed, as is now the case for natural gas, hydrogen could be delivered to Western Europe through pipelines. [Copyright &y& Elsevier]

Abstract: Since the beginning of the last century the world is experiencing an important demographic transition, which will probably impact on economic growth. Many demographers and social scientists are trying to understand the key drivers of such transition as well as its profound implications. A correct understanding will help to predict other important trends of the world primary energy demand and the carbon emission to the atmosphere, which may be leading to an important climate change. This paper proposes a set of coupled differential equations to describe the changes of population, gross domestic product, primary energy consumption and carbon emissions, modeled as competing species as in Lotka–Volterra prey–predator relations. The predator–prey model is well known in the biological, ecological and environmental literature and has also been applied successfully in other fields. This model proposes a new and simple conceptual explanation of the interactions and feedbacks among the principal driving forces leading to the present transition. The estimated results for the temporal evolution of world population, gross domestic product, primary energy consumption and carbon emissions are calculated from year 1850 to year 2150. The calculated scenarios are in good agreement with common world data and projections for the next 100 years. [Copyright &y& Elsevier]

Abstract: With life cycle assessment (LCA) methodology, a life cycle model of coal-based dimethyl ether (CBDME) as a vehicle fuel is established for China. Its life cycle from well to wheel are divided into three phases. They are feedstock extraction, fuel production and fuel consumption in vehicle. The primary energy consumption (PEC) and global warming potential (GWP) of CBDME pathway are analyzed and compared with coal-based diesel (CBD) as a latent rival to replace conventional petroleum-based diesel (CPBD). This study demonstrates that the LCA methodology is very suitable and effective for the choice of vehicle fuels. One result is that the greenhouse gases (GHGs) emission of coal-based vehicle fuel pathways is usually concentrated on fuel production stage. The percentages of CBDME and CBD pathways both exceed 60%. The application of carbon capture and storage (CCS) is helpful for coal-based vehicle fuel pathways to improve their global warming effect dramatically. Compared with CBD pathway, CBDME pathway consumes less PEC and emits less GHGs emission as well. Even though the CCS and CH4-fired generation are used, the advantages of CBDME are still kept. For saving petroleum energy and reducing global warming effect, CBDME has greater potential than CBD to substitute CPBD under current fuel synthesis technologies. If the hurdles such as the maturity of engine and vehicle technologies, corresponding regulations and standards and infrastructures are reliably solved, CBDME will have better prospect in China. [Copyright &y& Elsevier]

A comprehensive case study life cycle assessment (LCA) was conducted of a 7300 m2, six-story building with a projected 75 year life span, located on the University of Michigan campus. The bottom three floors and basement are used as classrooms and open-plan offices; the top three floors are used as hotel rooms. An inventory of all installed materials and material replacements was conducted covering the building structure, envelope, interior structure and finishes, as well as the utility and sanitary systems. Computer modeling was used to determine primary energy consumption for heating, cooling, ventilation, lighting, hot water and sanitary water consumption. Demolition and other end-of-life burdens were also inventoried.The primary energy intensity over the building’s life cycle is estimated to be 2.3×106 GJ, or 316 GJ/m2. Production of building materials, their transportation to the site as well as the construction of the building accounts for 2.2% of life cycle primary energy consumption. HVAC and electricity account for 94.4% of life cycle primary energy consumption. Water services account for 3.3% of life cycle primary energy consumption, with water heating being the major factor, due to the presence of hotel rooms in this building. Building demolition and transportation of waste, accounts for only 0.2% of life cycle primary energy consumption.All impact categories measured (global warming potential, ozone depletion potential, acidification potential, nutrification potential and solid waste generation) correlate closely with primary energy demand.The challenges in developing a life cycle model of a complex dynamic system with a long service life are explored and the implications for future designs are discussed. [Copyright &y& Elsevier]

A paint booth is the dominant energy consumer in a manufacturing plant. Large amount of conditioned air with accurate temperature and humidity is required in the spray-paint booth to guarantee constant product quality, which implies huge energy consumption for air-conditioning. However, there has been limited research on energy-saving design for air-conditioning systems applied in the spray-paint booth. In this study, a novel segmented liquid desiccant air-conditioning system is proposed for energy conservation in the spray-paint booths of a bus manufacturing plant. A mathematical model is built to simulate the performance of the proposed system during the cooling season. The advantages of the proposed system can be summarized in terms of the following two aspects: first, the segmented and cascaded configuration of the proposed system helps to reduce the cooling load from 2844.4 to 1078.0 kW under basic conditions when compared with the separated configuration; second, the adoption of the liquid desiccant dehumidifier helps to avoid reheating, and a reheating capacity of 630.8 kW in the current operating system could be saved by operating the proposed system under basic conditions. When operating the proposed system, a yearly primary energy saving rate of 40.7% can be achieved, while a yearly running cost saving rate of 35.6% can be achieved in this plant as compared to the current operating system. This study would provide valuable reference for energy-efficient air-conditioning system design for applications in spray-paint booths. • A liquid desiccant air-conditioning system is proposed for bus spray-paint booths. • The proposed configuration of the system can save the cooling load by 62.1%. • The adoption of the liquid desiccant dehumidifier helps to avoid reheating. • A primary energy saving rate of 40.7% can be achieved by the proposed system. [ABSTRACT FROM AUTHOR]

As the result of the growing problems of energy shortage and environmental pollution, the world needs more energy-saving and low-emissions vehicles. Although most future vehicles claim to have good performance, their real effects on sustainability in the life cycle under complex scenarios still need careful evaluation. In this study, a comprehensive and state-of-the-art life cycle assessment of the fuel cell vehicle, electric vehicle and internal combustion engine vehicle in China is conducted to compare their sustainability under different hydrogen production methods and driving mileages. The results show that primary energy consumption and greenhouse gas emissions of electric vehicles in the vehicle life cycle is significantly higher than that of the other two vehicles caused by the high energy consumption and emissions of battery production. In the total life cycle, fuel cell vehicles using hydrogen from electrolysis by abandoned hydropower and coke oven gas have the best performance among all scenarios when the driving mileage reaches around 75,000 km, and their advantage will become more obvious with increasing the driving mileage. In summary, it is necessary to select proper vehicle and fuel scenario based on the driving mileage to achieve good sustainability impact. • A life cycle assessment of FCV, EV and ICEV on sustainability in China is conducted. • Six hydrogen production methods and different driving mileages are considered. • FCVs using hydrogen from abandoned hydropower and COG have good prospects. • FCVs with suitable hydrogen productions are better than EVs on sustainability. [ABSTRACT FROM AUTHOR]