Primary Energy Use Research Articles

Analysis of the Environmental Impact in the Life Cycle of a Single-Family House in Poland

Buildings consume energy, which is a major contributor to greenhouse gas emissions. In order to reduce their environmental impact, it is important to choose suitable building materials and energy source. The paper presents the results of a multi-variant analysis of five environmental impact categories (global warming potential, acidification, eutrophication, ozone layer depletion, and total use of primary energy) for a single-family house located in Poland in a 25-year life cycle. The tests were carried out for two different types of building structures (brick and wooden), two variants of external partition insulation, and four heat sources. The following computer programs were used for the calculations: OpenStudio and EnergyPlus, and One Click LCA. The analysis took into account the erection of the building in its shell and the energy consumption for heating in a 25-year life cycle. Studies have shown that when an electric heat source is used, the use stage has the greatest environmental impact, accounting for up to 80% of the total emissions over the life cycle. This ratio can be reduced by half in the case of a house with thicker external wall insulation and an eco-biomass boiler.

Study on Air-to-Water Heat Pumps Seasonal Performances for Heating in Greece

Air-to-water heat pumps (AWHPs) is a very good option for efficient heating in the residential and commercial building sectors. Their performance and therefore the use of primary energy and CO2 gas emissions are affected by various factors. The aim of this paper is to present a study on the seasonal coefficient of performance in heating (SCOP) of AWHPs, which are available in the Greek market. The sample consists of 100 models in total, offered by 12 manufacturers, in a range of heat pump’s thermal capacity up to 50 kW. The calculation of SCOP values was performed according to the methodology proposed by the EN14825 standard. The results indicate how the heating capacity, the local climate, the supply water temperature, the compressor’s technology, and the control system affect the seasonal performance of the various AWHP models examined. Setting the SCOP ≥ 3 value as a criterion, the analysis that was carried out in four climatic zones A, B, C, and D of Greece, shows that there are many models that meet this criterion, and, in fact, their number increases from the coldest to warmer climates, in combination with lower water supply temperatures to the heating system and a control system with weather compensation.

Formation of geopolymeric materials properties depending on the molar modules of SiO2/Al2O3 and SiO2/Na2O

The construction sector is responsible for around 37% of global emissions of the carbon dioxide to the atmosphere. Therefore, reducing gas emissions, in this construction sector, is particularly important ,given the progressing climate change. For this reason, limiting its emissions and limiting the emission of other greenhouse gases in this sector, is of particular importance in view of the progress of climate change. It is important that new construction products have less impact on the environment during their entire life cycle, and their production has been decoupled from the use of primary energy. In this work, selected properties of geopolymeric materials were examined. Geopolymers are inorganic aluminosilicate polymers with an amorphous microstructure, which may be an alternative in certain applications, for products based on Portland cement. Here, the properties of geopolymer mortars, i.e. porosity, microstructure and mechanical strength, were compared. The influence of the composition of reaction mixture on these properties, defined by the appropriate SiO2/Al2O3 and SiO2/Na2O molar ratios, was also defined. The results show that increasing the content of SiO2 in relation to Al2O3 in the composition of the reaction mixture, reduces porosity. Thus, leading to a more compact microstructure and higher mechanical strength. A similar effect occurs when a higher NaOH solution concentration is used, in comparison to the sodium silicate [Na2SiO3] solution.

Energy and economic sustainability in the renewal of centralized heating systems using hybrid heat pump systems

In the context of the energy transition policies desired by the EU, the objectives set by 2030 include the reduction of greenhouse gas emissions, the achievement of greater energy savings and the increase in the use of renewable energy. This study, after an analysis concerning the Italian building stock, aims to highlight a possible first step towards achieving these objectives: the renewal of centralized heating systems in multi-dwelling buildings. In fact, on the national scenario there are about 430,000 condominiums with centralized heating system built before 1990 and, therefore, possibly liable to energy efficiency. In this research a case study building was simulated using the software EnergyPlus in which a renovation of the existing heating system was modelled in the Matlab/Simulink environment with an innovative hybrid generator consisting of an air/water heat pump and a condensing boiler. The analysis of this solution, carried out for three different Italian climatic zones, highlights how significant reductions in CO2 emissions can be achieved, high energy savings in terms of primary energy use and savings regarding usage costs, thus achieving greater comfort and sustainability. In addition, an economic analysis was carried out comparing different combinations of systems with the aim of identifying the best solution for each application.

Development of a 1 kW Micro-Polygeneration System Fueled by Natural Gas for Single-Family Users

The use of primary energy saving techniques and renewable energy systems has become mandatory to tackle the effects of global temperature rise. As a result, a transition is taking place from centralized energy generation to distributed energy generation. Starting from the experience concerning a 15 kW micro-CHP plant previously designed at DII, this paper addresses the development of a 1 kW micro-CHP system fueled by natural gas for single-family users. Specifically, the paper presents a wide experimental investigation aimed at optimizing performance and emissions of a small scale two-stroke spark ignition gasoline engine properly modified to be fueled with natural gas to make the engine more suitable for cogeneration purposes. The described activity was carried out at the DII of the University of Naples Federico II. Rigorous laboratory tests were conducted with the engine in order to characterize both gasoline and CNG operation in terms of brake mechanical power, overall efficiency and exhaust gas emissions in different operating regimes. Furthermore, several physical quantities associated with the engine operation were measured through several sensors in order to optimize performance and emissions achieved when the engine is fueled with CNG. In particular, dynamic pressure variations inside the cylinder were measured and analyzed to evaluate the effect of the adopted fuel on the optimum ignition-timing angle and cyclic dispersion.

An Active Voltage Coordinate Control Strategy of DFIG-Based Wind Farm with Hybrid Energy Storage System

In a power system with wind farms, the point of common coupling (PCC) usually suffers from voltage instability under large wind speed variations and the load impact. Using the internal converter of a doubly fed induction generator (DFIG)-based wind turbine to provide voltage support auxiliary service is an effective scheme to suppress the voltage fluctuation at PCC. To satisfy the reactive power demand of the connected grid, an active voltage coordinate control strategy with the hybrid energy storage system of the wind farm is proposed. The dynamic reactive power balance model is established to show the interaction between the reactive power limitation of the wind farm and the reactive power compensation demand of the grid. This indicates the initial conditions of the active voltage coordinate control strategy. According to the critical operating point and the operation state of the DFIG, the active and reactive power coordinate control strategy composed of active ω-β coordinate control and active β control is proposed to enhance the reactive power support capability and stabilize the grid voltage. To compensate the active power shortage, an auxiliary control strategy based on the hybrid energy storage system is introduced. The simulation results show that the proposed strategy can suppress the voltage fluctuation effectively and make full use of primary energy.

Influence of climate change on the energy performance assessment of NZEB houses

The Energy Performance of Buildings (EPB) regulations aim to reduce primary energy use and carbon dioxide emissions of buildings, which are the result of creating a comfortable and healthy indoor environment. In this study, the influence of climate change on the regulatory EPB calculation results is analysed for the Flanders region in Belgium. The results of the analysis may be used by authorities to better define nearly zero energy building (NZEB) requirements today. Meteonorm has been used to simulate future climate change based on IPCC scenarios and urban heat island effect. These future climates have been implemented in a Revit-and Excel-based tool that calculates the stochastic variation of energy performance for six different dwelling typologies, based on the semi-steady state energy use calculation method applied in the regional rating method. Four different packages of measures to achieve NZEB performance (thermal insulation, energy efficient ventilation, renewable energy technologies,…) have been considered. The results for primary energy use, overheating indicator and net energy use for heating and cooling have been analysed. As may be expected, climate change is found to lead to an increase in overheating risk, an increase in cooling energy use, and a decrease in heating energy use in the analysed dwellings. Since in most cases the decrease in heating energy use outweighs the increase in cooling energy use, the total primary energy use decreases in most cases for the 2050 future climate.

Examining the dynamics of ecological footprint in China with spectral Granger causality and quantile-on-quantile approaches

ABSTRACT With 2.5 global hectares (gha) per capita against 2.7 gha per capita, China’s ecological footprint is desirably below the world’s average ecological footprint per capita. Undesirably, the country’s per person ecological footprint outweighs the world’s average biocapacity per person of 1.7 gha, thus signifying an enormous pressure on the country’s ecological capacity. This reason accounts for the motivation to explore the dynamics of ecological footprint for China over the period 1971–2016 by employing a series of empirical techniques that include quantile-on-quantile regression (QQR), spectral Granger causality (SGC), and quantile regression. Indicatively, the empirical findings are in folds. First, from the QQR, economic growth exerts a positive effect on (i) ecological footprint especially in the middle quantile (0.4–0.7) and (ii) all quantiles (0.01–0.95) of economic growth. Second, both fossil fuel and primary energy utilization exert a positive impact on (i) all quantiles (0.01–0.95) of ecological footprint and (ii) all quantiles (0.01–0.95) of the two energy profiles. Third, it is surprising to see renewable energy utilization exerting a positive effect on ecological footprint at the lower tail (0.1–0.40) and on renewable energy use at the higher tail (0.70–0.95). Additionally, the SGC result revealed Granger causality from primary energy use and economic growth to the ecological footprint in the long-run without reverse. Additionally, without reverse, there is a Granger causality from renewable energy use to the ecological footprint in the short-, medium-, and long-term. Importantly, the overall policy implication suggests a more drastic decoupling of the country’s growth from the supply side (ecological pressure and environmental deprivation).

The implications of ambitious decarbonisation of heat and road transport for Britain’s net zero carbon energy systems

Decarbonisation of heating and road transport are regarded as necessary but very challenging steps on the pathway to net zero carbon emissions. Assessing the most efficient routes to decarbonise these sectors requires an integrated view of energy and road transport systems. Here we describe how a national gas and electricity transmission network model was extended to represent multiple local energy systems and coupled with a national energy demand and road transport model. The integrated models were applied to assess a range of technologies and policies for heating and transport where the UK’s 2050 net zero carbon emissions target is met. Overall, annual primary energy use is projected to reduce by between 25% and 50% by 2050 compared to 2015, due to ambitious efficiency improvements within homes and vehicles. However, both annual and peak electricity demands in 2050 are more than double compared with 2015. Managed electric vehicle charging could save 14TWh/year in gas-fired power generation at peak times, and associated emissions, whilst vehicle-to-grid services could provide 10GW of electricity supply during peak hours. Together, managed vehicle charging, and vehicle-to-grid supplies could result in a 16% reduction in total annual energy costs. The provision of fast public charging facilities could reduce peak electricity demand by 17GW and save an estimated £650 million annually. Although using hydrogen for heating and transport spreads the hydrogen network costs between homeowners and motorists, it is still estimated to be more costly overall compared to an all-electric scenario. Bio-energy electricity generation plants with carbon capture and storage are required to drive overall energy system emissions to net zero, utilisation of which is lowest when heating is electrified, and road transport consists of a mix of electric and hydrogen fuel-cell vehicles. The analysis demonstrates the need for an integrated systems approach to energy and transport policies and for coordination between national and local governments.

Sizing and control optimization of thermal energy storage in a solar district heating system

Solar district heating systems have shown significant promise to facilitate the large scale adoption of solar energy technologies and thus substantially reduce greenhouse gas emissions. Given the mismatch between solar energy and district heating demand, energy storage devices play a critical role given their capacity to stockpile solar energy in both the short-term (hours to days) and long-term (months). However, the integration, sizing and control of energy storage technologies is far from simple. This paper investigates sizing and controlling thermal energy storage from the perspective of its performance within a district heating system, highlighting the close link between design and control. A 52-house Canadian solar district heating system, the Drake Landing Solar Community (DLSC), was used as a case study. This system uses solar collectors as main energy supply, borehole thermal energy storage (BTES) for seasonal storage and two 120-m3 water tanks for short-term thermal storage (STTS).The effect of (a) storage sizing (STTS volume) and (b) storage control (rate at which energy is either injected or extracted from the BTES) was evaluated. A control-oriented model, calibrated and validated with operational data at 10-min intervals, was used along with an optimal rule-based control to gauge system primary energy use. Different scenarios were tested, with STTS volumes ranging from 120 m3 to 480 m3, and BTES loop nominal flow rates between 2.5 and 4.5 L/s. An optimization routine was developed to calculate the optimum parameters of the rule-based control strategy. Results show that, in comparison with the design and control in place, primary energy savings of 13%–30% (with BTES flow rates of 2.5–4.5 L/s) could have been obtained with the proposed rule-based control strategy. By decreasing the STTS volume to 120-m3, energy savings up to 6% could still be achieved; savings could reach 27%–36% by increasing the STTS size to 360-m3.

Comfort-based control for mixed-mode buildings

International thermal comfort standards are applicable for the design and operation of either mechanically cooled or naturally cooled buildings and limited guidance is given for mixed-mode buildings. In this study, a control framework for mixed-mode buildings was defined based on the adaptive comfort model and PMV-PPD method. The proposed framework was tested using a simulation-based analysis of a central module of an office building. The results were compared with a mechanically cooled building. The objective was to characterize how to control mixed-mode buildings optimally, regarding both energy use and thermal comfort. Five locations were considered: Copenhagen - DK, Edinburgh - UK, Palermo - IT, Tokyo - JPN, and Zurich - CH. The mixed-mode control strategy had a primary energy use between 12 and 51 % lower than the mechanically cooled case. In this context, using the upper limit of the adaptive comfort zone as cooling set point rather than the upper limit of the PMV-based comfort zone showed nearly 20 % more energy savings and fewer switchovers between operation modes. Night cooling led to lower operative temperatures and fewer switchovers between operation modes as well as additional energy savings of 10 % only in Palermo. The results show that a mixed-mode building operated based on the adaptive comfort criteria can have a large reduction of energy use without compromising thermal comfort or indoor air quality, compared to a mechanically cooled building.

Optimal design and operation of distributed energy resources systems for residential neighbourhoods

Different designs of distributed energy resources (DER) systems could lead to different performance in reducing cost, environmental impact or use of primary energy in residential networks. Hence, optimal design and management are important tasks to promote diffusion against the centralised grid. However, current operational models for such systems do not adequately analyse their complexity. This paper presents the results of a mixed-integer linear programming (MILP) model of distributed energy systems in the residential sector which builds up on previous work in this field. A superstructure optimisation model for design and operation of DER systems is obtained, providing a more holistic overview of such systems by including the following novel elements: a) Design and utilisation of a network with integrated heating/cooling pipelines and microgrid connections between neighbourhoods; b) Exploration of use of feed-in tariffs (FITs), renewable heat incentives (RHIs) and the ability to buy/sell from/to the national grid. It is shown that the (DER network mitigates around 30–40% of the CO2 emissions per household, compared with “traditional generation”. Money from FITs, RHIs and sales to the grid, as well as reduced grid purchases, make DER networks far more economical, and even profitable, compared to the traditional energy consumption.

Targeting net climate benefits by wood utilization in Finland: Participatory backcasting combined with quantitative scenario exploration

To obtain net climate benefits from intensified forest utilization in the short-term, the substitution impact of wood harvesting and increased carbon stocks of wood-based products should be higher than the forest carbon stock loss. However, the product specific substitution impacts change dynamically over time along with technological development, and long-term climate change mitigation strategies need to consider this, as well as the market forces. We identified future pathways enabling globally market viable environments for wood utilization scenarios in Finland resulting in net climate benefits in 2050. We I) indicated substitution impacts in 2050 applying future-oriented parameter modification based on LCA, and developed quantitative target scenarios by altering wood-based product portfolios to achieve required substitution, and II) identified pathways enabling scenarios by applying participatory backcasting. In the scenarios, a major shift from primary energy use to high added-value products including textiles, chemicals, composites and advanced biofuels, or long-lifetime construction products was needed and more lifecycles for wood products by recycling were required. The actions enabling market viable environment focused on the global level policies and consumer perceptions, while actions locally were limited and current production technology development oriented. We recommend multi-target backcasting together with LCA to analyse more synergies and trade-offs.

Primary Energy Use and Environmental Effects of Electric Vehicles

The global market of electric vehicles has become one of the prime growth industries of the 21st century fueled by marketing efforts, which frequently assert that electric vehicles are “very efficient” and “produce no pollution.” This article uses thermodynamic analysis to determine the primary energy needs for the propulsion of electric vehicles and applies the energy/exergy trade-offs between hydrocarbons and electricity propulsion of road vehicles. The well-to-wheels efficiency of electric vehicles is comparable to that of vehicles with internal combustion engines. Heat transfer to or from the cabin of the vehicle is calculated to determine the additional energy for heating and air-conditioning needs, which must be supplied by the battery, and the reduction of the range of the vehicle. The article also determines the advantages of using fleets of electric vehicles to offset the problems of the “duck curve” that are caused by the higher utilization of wind and solar energy sources. The effects of the substitution of internal combustion road vehicles with electric vehicles on carbon dioxide emission avoidance are also examined for several national electricity grids. It is determined that grids, which use a high fraction of coal as their primary energy source, will actually increase the carbon dioxide emissions; while grids that use a high fraction of renewables and nuclear energy will significantly decrease their carbon dioxide emissions. Globally, the carbon dioxide emissions will decrease by approximately 16% with the introduction of electric vehicles.

Investigating techno-economic effects and environmental impacts of energy renovation of residential building clusters on a district heating system

Studying energy renovation of older residential building stocks together with the surrounding district heating (DH) system is essential to fully understand implications from a reduced district heat demand and for involved actors. This study reveals the benefit of integrating the simulation and optimization tools OPERA-MILP, IDA ICE, and MODEST to investigate thoroughly the effect of energy renovation strategies on heat load supply, building and DH system-based life cycle costs (LCCs), primary energy use, and total of direct and indirect CO2 emissions. Energy renovation considered different cluster combinations of slab and tower blocks of a stock of 343 apartment buildings in two Swedish municipalities and strategies for lowest LCC and code compliance. Applied tools were thoroughly validated and verified including heat demand and load duration curves and numerical accuracy. Results with all aggregated clusters and renovation strategy for code compliance showed a reduced combined heat and power production with 35.7 GWh/a (heat) and 6.5 GWh/a (electricity), deceased primary energy use with 36.2 GWh/a and reduction of marginal CO2 emissions with 8.4 kton/a mainly from released biofuels substituting for fossil fuels in power plants, increased CO2 emissions of 0.5 kton/a with electricity production mix, and financial deficit for building owners, energy companies, and industries of respective 44, 33.9, and 2.2 M€/50a.

RETRACTED: Design, Development and Performance Testing of a Novel Utility Solar Cooker with Highlighting Its Significance in Current Scenario

Abstract In most developing worlds, cooking with heat has been a technically feasible replacement for fuelwood in food production as the need of the hour. Cooking energy accounts for 36% of India's gross primary energy use. Non-commercial oils are used mainly by the rural and urban populations to fulfil their energy requirements. Solar cooking is one potential alternative, but it has been met with some resistance due to some obstacles. Simple box-type solar cookers are an easy way to cook food utilizing solar energy throughout the day, but cooking is not feasible all across the night-time. In this research, a box-type solar cooker with energy storage is developed, and a performance study is conducted to enable food to be cooked at odd hours. Thermal energy has been stored using phase change content (PCM). The amount of energy retained, the amount of heat lost during the charging and discharging period, and the amount of PCM needed are all calculated. Experiments were carried out with two continuous loads in a cooker with a 0.5 m2 aperture region and PCM (Erythritol). While the performance of the PCM cooker is comparable to that of a simple box-type cooker, cooking during off-sunshine hours is not feasible with the simple box-type cooker, according to the report. However, by utilizing the specially built and manufactured PCM cooker, cooking can be done at any time of day. As a result, this paper aims to summarise the research on solar cooking systems that incorporate phase shift materials (PCMs).

A lifecycle comparison of natural resource use and climate impact of biofuel and electric cars

Here we compare the biomass feedstock use, primary energy use, net CO2 emission, and cumulative radiative forcing of passenger cars powered by different energy pathways. We consider the full lifecycle of the vehicles, including manufacture and operation. We analyze battery electric vehicles (BEVs) powered by standalone electricity generation using woody biomass, with and without CCS, and with integration of wind electricity. We analyze internal combustion vehicles (ICVs) powered by fossil gasoline and by biomethanol derived from woody biomass, with and without carbon capture and sequestration (CCS). Our system boundaries include all fossil and biogenic emissions from technical systems, and the avoided decay emissions from harvest residue left in the forest. We find that the pathways using electricity to power BEVs have strongly lower climate impacts, compared to the liquid-fueled ICV pathways using biomethanol and gasoline. The pathways using bioelectricity with CCS result in negative emissions leading to global cooling. The pathways using gasoline and biomethanol have substantial climate impact, even with CCS. Regardless of energy pathway, smaller cars have consistently lower climate impact than larger cars. These findings suggest that accelerating the current trend toward vehicle electrification, together with scaling up renewable electricity generation, is a wise strategy for climate-adapted passenger car transport.

Environmental payback periods of reusable alternatives to single-use plastic kitchenware products

Many consumers are transitioning away from single-use plastic products and turning to reusable alternatives. Oftentimes, this change is being made with the assumption that these alternatives have fewer environmental impacts; however, reusable products are frequently made from more environmentally intensive materials and have use phase impacts. This study used LCA to examine the GWP, water consumption, and primary nonrenewable energy use associated with reusable alternatives for single-use plastic kitchenware products and determined environmental payback periods. The environmental impacts for each reusable alternative are calculated on the functional units of 1 use, 1 year (5 uses/week), and 5 years (5 uses/week). Payback periods are calculated for each reusable alternative and defined as the number of times a consumer must reuse an alternative in order for the environmental impact per use to be equivalent to the environmental impact for the single-use product. The research explored the sensitivity of the results to different consumer washing and reuse behaviors, as well as local conditions such as overall transportation distances and the carbon intensity of different electricity grids. Product types studied included straws (4 reusable, 2 single-use), sandwich storage (2 reusable, 3 single-use), coffee cups (3 reusable, 2 single-use), and forks (1 single-use, 3 reusable). Environmental impacts associated with the reusable alternatives were highly dependent on the use phase due to dishwashing, making payback period sensitive to washing frequency and method, and for GWP, carbon intensity of the energy grid (used for water heating). For single-use products, the material/manufacturing phase was the largest contributor to overall impacts. It was found that nine of the twelve reusable alternatives were able to breakeven in all three environmental indicators. The coffee cup product type was the only product type to have one reusable alternative, the ceramic mug, and have the shortest payback period for all three impact categories. Both the bamboo straw and beeswax wrap were unable to breakeven in any scenario due to high use phase impacts from manual washing. The research found that reusable alternatives can payback the environmental impacts of GWP, water consumption, and energy use associated with their more resource intensive materials, but it is dependent on number of uses, consumer behavior, and for GWP, carbon intensity of the energy grid. A key takeaway is that consumer behavior and use patterns influence the ultimate environmental impact of reusable kitchenware products. Some recommendations for consumers looking to reduce the overall impact of kitchenware products include the following:

ANALYSIS OF THE CONVERSION OF PRIMARY ENERGY INTO HEAT FOCUSED ON A HEAT PUMP WITH A WORKING SUBSTANCE (REFRIGERANT) CO2

The need for research in the field of energy efficiency and the ecological aspects of primary energy use is currently receiving considerable attention in the framework of European Union policy as well as in the Slovak Republic. It is necessary to deal with this issue not only for the needs of normal operations, but especially in the current situation, when due to the threat of the COVID-19 virus, the requirements for thermal energy are increased. A suitable way to achieve this is the use of renewable resources, in Slovakia mainly biomass, solar, wind, water and geothermal energy. Ambient air, ground heat, heat contained in groundwater and various other waste heat from technological processes represent a huge potential for the use of low-potential energy. The article is focused on solving the problem of conversion of primary energy into heat using thermodynamic cycles and compressor circulation with working substance (refrigerant) CO2.

DOES DOMESTIC PRIVATE INVESTMENT INDUCE ENVIRONMENTAL DAMAGE IN TURKEY? EVIDENCE FROM FOURIER-BASED METHODS

Although many aspects of domestic private investment (DPRI) have been empirically studied in the literature, evidence regarding the effect of DPRI on environmental sustainability is rather nascent. This research attempts to fill this gap by investigating how DPRI in Turkey affected environmental degradation (namely ecological and carbon footprints) for the 1975-2017 period by employing Fourier-based approaches. The findings in this research indicate that employed variables (environmental degradation, income, energy use, and DPRI) have a long-run association in both proposed models. Furthermore, the dynamic relationship captured by the autoregressive distributed lag (ARDL) method shows that DPRI and primary energy use induce ecological and carbon footprints in the long-run, while income intensifies both environmental degradation indicators in the short-run. These results clearly indicate that DPRI threatens Turkey’s long-term environmental sustainability.