Annual Carbon Dioxide Emissions Research Articles

Energy, exergy, exergoeconomic, economic, and environmental analyses and multi-objective optimization of a novel combined cooling and power system with dual-pressure Kalina cycle-absorption refrigeration

A novel combined cooling and power system, the dual-pressure Kalina cycle-absorption refrigeration (DPKC-AR-CCP), is proposed for the cascade utilization of waste heat from high-temperature flue gas and jacket water from internal combustion engines. A pneumatic booster pump unit is employed to increase the inlet pressure of the low-pressure expander, with heat generated during the compression process utilized for preheating the ammonia/water mixture, and exhaust gas from the low-pressure expander is combined with driving gas for absorption refrigeration. By integrating the first and second laws of thermodynamics with the SPECO Methodology, models for energy, exergy, exergoeconomy, economy, and environment of the DPKC-AR-CCP system are developed. A multi-objective optimization model is formulated with maximum exergy efficiency, minimum total exergy cost rate, and maximum annual equivalent carbon dioxide (CO2) emission reduction as objective functions. MATLAB software (combined with REFPROP software) is utilized for simulation and multi-objective optimization. The performance of each component under specific conditions is assessed, and a comparison with the simple absorption refrigeration/Kalina cogeneration system (AR/KC) highlights the advantages of the DPKC-AR-CCP system; an investigation into the effects of different operating parameters on performance is conducted. The results indicate that, under identical operational parameters, the DPKC-AR-CCP system exhibits a substantial increase in net output power (230.2 %), cooling capacity (98.7 %), and exergy efficiency (148.8 %) compared to the simple AR/KC system; payback period is reduced by 64.8 %; and annual equivalent CO2 emissions are decreased by 202.2 %. However, there is an increase in the total exergy cost rate by 90.5 %. The optimal concentration of ammonia/water is determined to be 0.816/0.184, with a heat exchanger outlet temperature of 341.07 K, driving pressure of 0.654 MPa, and low-pressure expander inlet pressure of 5.064 MPa. Correspondingly, the optimal exergy efficiency is 87.2 %, the annual reduction in CO2 emissions is 5.53 × 107 kg, and the total exergy cost rate is 288.48$/h.

Influences of carbonate weathering and hyporheic exchange on carbon fluxes in Pearl River Basin, China

Deciphering riverine dissolved carbon dynamics is pivotal for a comprehensive picture of the global carbon cycle. Through rigorous in-situ sampling across the Pearl River Basin (PRB), our investigation reveals the Pearl River networks function as a significant carbon source, with the annual carbon dioxide (CO2) emission of 2.57 ± 1.94 Tg C, which offsets 10 ± 8 % of the forest carbon sequestration or 65 ± 49 % carbon sink via chemical weathering in the PRB. Based on the mass balance of 222Rn, we initially reveal that the contributions of water flux from the hyporheic zone increased with the river orders (Hack Order) across both dry and wet seasons. Conversely, the evasion rates of dissolved CO2 (CO2*) and dissolved inorganic carbon (DIC) from the hyporheic zone into river channels exhibited a decline with the increasing river orders. The hyporheic exchange contributes 4 – 11 % of the lateral and vertical DIC losses, thereby is a key mechanism in the riverine carbon cycle. Furthermore, CO2* derived from the hyporheic zone was ∼4 times of riverine CO2 emissions and this CO2* flux from the hyporheic zone was buffered into carbonates/bicarbonates in river channels, due to the high riverine pH resulted from carbonate weathering in the basin. These results not only highlight the substantial role of carbonates and hyporheic processes in modulating riverine carbon fluxes but also signify their broader implications on understanding riverine carbon dynamics at both regional and global scales.

Performance analysis of residential hybrid cooling and heating system operating under low solar radiation

Renewable energy sources are becoming increasingly important due to rising energy consumption and environmental pollution caused by greenhouse gases. In the study, a system was designed to provide year-round air conditioning in a residential located in regions with low solar radiation. This design consists of a single-stage absorption cooling system to meet the cooling need in summer and a solar energy-supported natural gas combi boiler heating system to meet the heating need in winter. The designed system was subjected to a comprehensive analysis, taking into account the integration of four different collector types: flat plate collector, evacuated tube collector, compound parabolic collector and parabolic trough collector. A thermal energy storage unit is integrated into the system to increase its efficiency. In the study, the feasibility and efficiency of the solar energy system recommended for residences in low-radiation regions were investigated. Appropriate system conditions were determined by evaluating economic and environmental aspects. In the study, a maximum net present value (NPV) of 3.941.49 US$ and 4 % exercise efficiency were calculated for the system designed using ETC collectors at 80°C generator and 6°C evaporator temperature. At the same time, the hybrid system can prevent annual carbon dioxide emissions of 800.28 kg compared to coal-fired systems and 62.42 kg annually compared to natural gas systems. These results show that the designed system is economically feasible and contributes positively to environmental sustainability.

Multi-objective optimization and evaluation of hybrid combined cooling, heating and power system considering thermal energy storage

Introducing thermal energy storage (TES) and solar energy effectively reduces fossil fuel consumption and greenhouse gas emissions in combined cooling, heating, and power (CCHP) systems. This study establishes a two-layer optimization framework to obtain the optimal configuration of the CCHP system coupling solar and thermal energy storage. The outer layer uses component sizes as decision variables to optimize the system's annual economic economy, annual carbon dioxide emissions, and annual primary energy consumption; the inner layer uses equipment output as decision variables to optimize the operation and maintenance costs. Firstly, the representative typical scenes were obtained using the k-means algorithm to reduce the computational complexity. Then, the multi-objective chaos optimization (MOCGO) algorithm is combined with mixed-integer linear programming (MILP) to obtain the established optimization model's configuration scheme and optimal operating strategy. TOPSIS is to rank the best Pareto solutions. Finally, a large hotel is a case study. The optimization results indicate that the proposed two-layer optimization model can achieve the optimal configuration scheme and scheduling strategy for hybrid CCHP. Compared to the rule-based multi-objective one-layer optimization model, the proposed two-layer optimization model can achieve maximum improvements of 30.63 %, 37.94 %, and 38.16 % in economic, energy, and environmental performance. Compared with the rule-based single-objective one-layer optimization model, the proposed two-layer optimization model can achieve maximum improvements of 34.95 %, 35.81 %, and 37.55 % in economic, energy, and environmental performance, respectively. In addition, TES can substantially increase the optimal performance of the two-layer optimization model.

Effects of natural light on improving the lighting and energy efficiency of buildings: toward low energy consumption and CO2 emission

Abstract Visual information acquisition is essential for our daily lives, with vision relying on the presence of light. Lighting systems serve the fundamental purpose of enabling vision. This study aims to contribute to sustainable architectural design by emphasizing the efficient utilization of natural daylight. Specifically, the design of skylights or light wells in low–lateral-area, deep-depth structures is of significant importance. While current design criteria consider skylight dimensions and the skylight-to-building height ratio, these factors alone may not suffice for optimal skylight design. To achieve an appropriate lighting and architectural design for such structures, it is essential to evaluate the factors influencing the required amount of daylight on different floors. This study aims to investigate the impact of skylights and light wells on the energy consumption and CO2 emissions of a four-storey building located in Hail, Kingdom of Saudi Arabia. The physical parameters of skylights and light wells were analyzed, taking into account various aspects that affect the amount of light reaching different levels. The findings highlight the significant influence of skylight size on the light reaching the building’s floors. For square skylights, reducing the well index (increasing skylight size) exponentially increases the daylight factor. Furthermore, this study evaluates the annual energy consumption and carbon dioxide emissions of the building, considering the daylighting factor. The results demonstrate that skylights contribute to increased solar heat gain, thermal conductance, and artificial lighting efficiency. Notably, as the lighting factor of the building increases from 3% to 6%, there is an annual decrease of 3% in CO2 emissions.

Prediction of Atmospheric Carbon Dioxide Radiative Transfer Model based on Machine Learning

Global warming is caused by the increasing amount of greenhouse gases in the atmosphere. The Kyoto Protocol to the United Nations Framework Convention on Climate Change defines carbon dioxide (CO), methane (CH:), nitrous oxide (N0) fluorocarbons (HFC), holocarbon (PFC), and sulfur hexafluoride (SF.) Six gases are divided into the main greenhouse gases, of which CO, the largest proportion of emissions, is an important man-made greenhouse gas." As the main gas affecting the global greenhouse effect (75%), the amount of CO in the atmosphere has increased from 315 ppm in 1958 to 417 ppm in 2022, and global annual CO emissions have increased from 27 Pg to 49 Pg% over the past 40 years. Therefore, under the background of deep reinforcement learning, it is a problem that all countries pay more attention to predict the concentration emission of carbon dioxide to cope with the severe situation of climate warming. In order to obtain the radiative forcing value under the influence of carbon dioxide concentration, a simplified net radiative flux model is established. Based on the radiative transfer equation, this model can calculate the net radiative flux and radiative forcing of each layer of the atmosphere due to changes in carbon dioxide concentration. The results are compared with the RRTMG-LW long-wave radiative transfer model of American Center for Atmospheric and Environmental Research (AER) under the same factor, and the error is less than 1%.

Advancing Applications for Artificial-Intelligence-Supported Ambient Control in the Built Environment

Ambient intelligence (AmI) relying on electronic devices employing information and communication technology (ICT) and artificial intelligence (AI) embedded in the network connecting these devices tends today to be insufficiently used. This deficiency implies that spaces are uncomfortable and considerable energy dissipates due to distribution losses, excessive or unnecessary climate control of little- and unoccupied spaces, etc. Building operations are responsible for ±27% of annual carbon dioxide (CO2) emissions, and infrastructure materials and construction are responsible for an additional ±13% annually; both need to be addressed integratively to meet sustainability goals. 1,2 This paper addresses this in three AI-supported AmI test simulations of applications focusing on illumination and ventilation systems embedded in the built environment.

Thermal insulation performance of buildings with phase-change energy-storage wall structures

Considering that improving the energy efficiency of buildings is crucial to achieving China's carbon neutrality goal, the application of phase-change energy-storage (PCES) technology could be considered a practical and feasible approach. Currently, the heat transfer characteristics of PCES walls and their influence mechanisms on the indoor building environment are the key issues to be solved in this field. Based on gypsum-based phase-change materials (PCMs), outdoor, indoor and central PCES walls are designed in this study. Unsteady heat transfer experiments, finite element numerical simulations and energy consumption analyses were used to study the thermal behaviour of PCES walls, and the thermal insulation performance of the buildings utilizing these wall structures were assessed. The results show that the maximum temperature of inner surface of wall with PCMs applying at the interior side is reduced by 0.6 °C, and the maximum temperature lag is reduced by 0.8 h. The results also prove that buildings employing this PCES walls as envelope have a reduction of annual cooling energy consumption about 7.6%, and a reduction of annual carbon dioxide emissions by about 2%, comparing with conventional buildings. Thus, these results suggest that the use of PCES walls can effectively enhance the thermal insulation performance of buildings in summer. This research could provide an innovative idea for the design of PCES walls, which is of significance for the application of PCES walls in severe cold regions.

Improved estimates of carbon dioxide emissions from drained peatlands support a reduction in emission factor

Under the United Nations Framework Convention on Climate Change, Annex 1 countries must report annual carbon dioxide (CO2) emissions from peatlands drained for extraction. However, the Tier 1 emission factor (EF) provided in the IPCC 2014 Wetland Supplement is based mainly on warm season data from a limited number of sites. Here we evaluate the current IPCC EF and revise it with newly published data. The updated EF is 2.46 ± 0.25 t C ha−1 yr−1, a 12% reduction and a threefold decrease in the confidence interval compared to the current IPCC (2014) EF. We generate a Tier 3 EF, 1.4 ± 0.25 t C ha−1 yr−1 for a typical extraction site in eastern Canada using numerical CoupModel that explicitly considers seasonality and interannual climatic variability, and suggest how to account for seasonality for the previously published EFs. This reduction has implications for comparing alternatives to peat-based growing substrates, the assessment of offsets, and possible punitive carbon taxes or cap-and-trade schemes.

A Study on Time-Varying Synergy of Energy Consumption, Economic Growth, and CO2 Emissions in China

Since its reform and opening, the Chinese economy has witnessed unprecedented development. This long-term high-speed development has significantly impacted the environment. In the process of energy development and consumption, the environment has been severely polluted, and greenhouse emissions have increased. This has resulted in environmental imbalances such as global climate change, rising sea levels, and extreme weather. Using annual energy consumption (EC), economic growth (GDP), and carbon dioxide (CO2) emissions in China from 1981 to 2021, this study employed the maximum likelihood estimation method to estimate the parameters of the nonlinear MS-VAR model. Cointegration tests, regimes analysis methods, and impulse response function analysis methods were adopted to explore the differences or similarities in the dynamics of the three under various regimes. The research results are as following. (i) The cointegration test findings demonstrate a long-term equilibrium relationship among EC, economic growth, and CO2 emissions. (ii) Regime analyses exhibit that there are three regimes: “low-level regime,” “medium-level regime,” and “high-level regime.” The three regimes have a mutual transfer transmission mechanism that exhibits nonlinear properties. (iii) Impulse response function analyses show that external EC and GDP shocks favorably impact the other two variables in all three regimes. EC in all three regimes is negatively impacted by external CO2 shocks. Moreover, in the “low-level regime,” the relationship between CO2 and GDP has an inverted U-curve, whereas in the other two regimes, the relationship has a negative association. This study can help China formulate reasonable and effective CO2 emissions reduction and energy policies and successfully achieve the emissions reduction goal of the 14th Five Year Plan as well as dual carbon goals.

Evaluation of small hydropower turbines installed downstream of Nile River branches (Egypt)

The current study proposes a new strategy for using small hydroelectric turbines in downstream river branches with the least amount of construction and the lowest cost by comparing two different methods of installing the turbines, the first by installing the turbines at the river's bottom and the second by installing the turbines on floating boats. The methodology of this article is based on predicting the distribution of velocities through the watercourse using experimental data collected at various points in the river's depth, and then predicting the resulting electrical power for different sizes of turbines, as well as estimating the number of turbines for each row and the number of rows along the river. Therefore, Investigate the proposed systems. The proposed small hydropower system's economic viability and environmental impact are investigated in this article. According to the nature of the waterway, the best diameter of a turbine that can be used is 1.5 m based on water velocities and river depths. The proposed power plant generated 25.8 kW per single turbine row, with an estimated cost of produced power (0.035 USD/kWh) of approximately 20 turbines installed per row. Compared to other renewable energy sources, the proposed hydropower system is cost-effective and environmentally friendly, as generating electricity with the proposed small hydropower plant could reduce annual carbon dioxide emissions by 368 tones of CO2 per single turbine row.

Life Cycle Carbon Dioxide Emissions and Sensitivity Analysis of Elevators

With the intensification of climate warming, the carbon dioxide emissions from high-energy-consuming elevators have attracted increasing societal attention. The assessment of carbon dioxide emissions, particularly the boundaries and strategies of carbon dioxide emissions accounting, lacks systematic research. However, an efficient evaluation of elevator carbon dioxide emissions is beneficial for improving elevator energy utilization. A carbon dioxide emissions accounting method and inventory analysis of a life cycle for an elevator is proposed to measure the carbon dioxide emissions from production to disposal. In addition, a new assessment indicator, namely, annual carbon dioxide emissions per ton·kilometer, is proposed to evaluate the carbon dioxide emissions for different types of elevators. The lifetime carbon dioxide emissions of the elevator and its sensitivity to influencing factors were assessed. The results indicate that the carbon dioxide emissions in the four stages of manufacturing, installation, operation and maintenance, and demolition and scraping contributed 41.31%, 0.92%, 57.32% and 0.44%, respectively. The annual carbon dioxide emissions of the elevator were about 27.18 kgCO2/t·km. The four primary factors affecting CO2 emissions were electricity consumption, printed circuit boards, low-alloy steel and chrome steel in descending order. Their probability distribution characteristics all obeyed triangular or uniform distributions. The median of their 95% confidence intervals was about 73,800. Their coefficients of variation were all below 2.1%. The effective strategies for energy conservation and carbon reduction were suggested by the life cycle impactor assessment. They also provide guidance for sustainable elevators.

Potential of prospective plans in MENA countries for green hydrogen generation driven by solar and wind power sources

This study is focused on exploring the potential of green hydrogen production in distinctive geographical locations in the Middle East and North Africa (MENA) by leveraging solar and wind energies. Those locations include Egypt, Morocco, and the Gulf region, as prospective hydrogen hubs. The current mathematical model has been developed using Matlab/Simulink and validated with the respective literature. Using realistic meteorological data of those cities, the hourly hydrogen yield, energetic and exergetic efficiencies have been predicted. A levelized cost of hydrogen and carbon dioxide mitigation has been examined. Besides, a holistic map of hydrogen cost depending on a widespread spectrum of solar radiation and wind speed has been developed. The results demonstrate that hydrogen production rates using solar energy are staggering compared to those using wind energy, specifically for the economic zone of Ain Sokhna in Egypt. The results reveal that Hurghada has a significant hydrogen cost of 4.4 $/kg, notably by exploiting wind energy. Using solar energy, Aswan and Salalah have a distinguished hydrogen cost of 5 $/kg, while NEOM, Hurghada, Al Maktoum, and Duqm have a hydrogen cost of 5.1 $/kg. Based on environmental perspectives, exploiting solar energy can alleviate 47.6 tons/year in Aswan, while harnessing wind resources in Hurghada mitigates 77.9 tons of annual carbon dioxide emissions.

Proposal and analysis for effective implementation of new measures to reduce the operational carbon intensity of ships

The Carbon Intensity Indicator (CII) requirements for international shipping regulate total annual carbon dioxide emissions (by transport work proxy using the ship's Deadweight Tonnage (DWT) instead of the actual cargo carried). It limits the accurate calculation of operational efficiency and causes an overestimation of the operational energy efficiency of international shipping. Due to lack of research on the International Maritime Organization's (IMO) CII requirements (energy efficiency based on actual cargo), the effects of CII requirements were investigated by contrasting the CII values based on DWT and actual cargo carried from data provided by the European Union Monitoring, Reporting and Verification. Results demonstrated that the CII calculated using actual cargo carried differed from that calculated using DWT by an average of 30%. Thus, future data collection must be based on actual cargo volume to apply IMO CII criteria more precisely, intuitively, and consistently.

Thermodynamic evaluation and optimization of supercritical CO2 Brayton cycle considering recuperator types and designs

The recompression supercritical carbon dioxide Brayton cycle (SCO2-BC) has great potential for bottoming cycles among future energy conversion systems with comparatively high thermal efficiency. However, the recuperator type selections and optimal designs are a long-standing bottleneck of realizing maximum cycle efficiency and minimum cost. Reasonable collocation of recuperator types remains challenging. In this study, the thermodynamic–economic evaluation and optimization of recompression cycle were performed considering different recuperator types and designs. Printed circuit recuperator channel types include straight, zigzag, S-shaped, and airfoil fins. The design parameters include recuperator enthalpy efficiency and recompression fraction. The results indicate that low-temperature recuperator (LTR) with zigzag channel and high-temperature recuperator (HTR) with zigzag channel exhibit the best comprehensive cycle performance. The cycle thermal efficiency is more sensitive to the HTR enthalpy efficiency compared with the LTR. There is a local inflection point of the recompression fraction where the cycle efficiency is maximum and the exergy loss is minimum. The optimal solution of three-objective optimization considering efficiency, total cost, and exergy loss is more comprehensive than that of the two-objective optimization considering efficiency and cost. In the application of concentrated solar power, the annual carbon dioxide emission can be directly reduced by 0.43 Gt through this optimization improvement. The results of the current study offer a promising route to high-efficiency and low-cost applications of SCO2-BC by rational selection of recuperator types and designs.

Resource scheduling and performance analysis of hybrid renewable energy systems with carbon neutrality consideration: A scenario-based multi-agent approach

Given the increasing global consensus on carbon neutrality for sustainable development, a key related challenge is to build a hybrid renewable energy system that simultaneously ensures stable power supply and carbon neutrality. This paper proposes a complete framework for designing, scheduling optimization, evaluation and analysis of hybrid renewable energy systems at the village scale. The framework integrates zero-carbon system design based on agent-based modeling, comprehensive evaluation of scheduling schemes under a multi-index system, and analysis of the impact of policy parameters, implemented through programming on the AnyLogic platform. The proposed framework was applied to a simulated region in Zhoushan, China. The results show that among the seven scheduling schemes, the photovoltaic/wind turbine/battery/diesel system is the best resource scheduling scheme in the region, with renewable energy power supply accounting for 98.5% of the total supply, the net present cost of $42,108.174, the cost of energy of $0.072/kWh, and the annual carbon dioxide emission of 5,064.346 kg. Installing carbon capture, utilization, and storage equipment can achieve carbon neutrality without significantly affecting system costs, with only an additional net present cost of $1,200. Among all meteorological factors, wind speed has the greatest impact on system performance and should be given priority in wind power generation. In terms of micro-behavioral management, discrete gear setting for diesel engines is better than continuous gear setting and more helpful in reducing system economic costs.

A two-stage planning method for design and dispatch of distributed energy networks considering multiple energy trading

Distributed energy network integrated by distributed energy system has significant performance advantages due to energy sources sharing. However, the incorporation of multiple distributed energy systems also complicates design and operation. This study constructs a two-stage optimization framework to plan the distributed energy network, which is driven by solar energy, geothermal energy and natural gas. First, the scale and operation status of energy equipment are optimized based on the economic, energy and environment performance of the energy network, and then the energy trading prices are optimized to enhance the economic performance of the energy system. In addition, two scheduling modes are constructed according to the dispatching strategy of storage unit and transfer unit. Finally, NSGA-II+ARSBX and TOPSIS are utilized to determine the optimal solution. The case analysis indicates that the best dispatching strategy is to first consider energy transfer units, and the annual cost, primary energy and carbon dioxide emissions are reduced by 1.30%, 10.82% and 14.56%. As for energy exchange, multiple energy sources are traded at very low prices or free from 10 pm and 6 am, while those are traded at relatively high prices between 6 am and 10 pm.

Sensitivity analysis of energy, exergy, and environmental models for a combined cooling, heating, and power system at different operating conditions of proton exchange membrane fuel cell

AbstractIn this research article, for recovering the waste heat of the proton exchange membrane (PEM) fuel cell, a combined cooling heating and power (CCHP) system with a new arrangement is proposed. The main system components are a PEM, an absorption chiller, an auxiliary boiler, and hydrogen and heat storage tanks. The electrochemical model of PEM is presented for evaluating the power and heat of the fuel cell. Also, energy and exergy efficiencies and fuel energy saving ratio of the CCHP system are evaluated by the steady‐state thermodynamic model, and for the first time, the impacts of critical operating parameters of PEM such as current density, operating pressure, and temperature on the annual carbon dioxide (CO2) emission reduction and annual CO2 tax reduction as well as fuel saving are studied. The results show that the proposed CCHP system's energy efficiency is evaluated at about 66%. With the increase in temperature of PEM, the exergy efficiency reaches 37%. In addition, using this system can reduce CO2 emissions by 191 ton per year. Also, this system can reduce the tax cost of carbon dioxide emissions by about $ 5700 per year.

Optimization of biomass gasification combined cooling, heating and power system integrated with solar energy

The integration of solar energy with biomass gasification combined cooling, heating and power (BGCCHP) system is performed. The solar-assisted hybrid BGCCHP (SAHB) system following electricity load (FEL) and following thermal load (FTL) is optimized to maximize its energetic, economic and environmental benefits in comparison with typical separated production (TSP) system. Based on a hotel building in Beijing, the optimal configuration and performance of the SAHB system fueled by corn straw (CS), rice straw (RS), wood pellet (WP) and wheat straw (WS) are obtained. Results show that the annual primary energy consumption saving ratio (APECSR), annual total cost saving ratio (ATCSR), annual carbon dioxide emission reduction ratio (ACDERR) and comprehensive saving ratio (CSR) are from 92.60% to 123.57%, from 29.39% to 52.75%, from 92.15% to 132.37% and from 72.49% to 102.90%, respectively, which indicates that the SAHB system performs better in energetic, economic, environmental and comprehensive aspects compared with TSP system. The area of photovoltaic panel (PVP) is recommended to be 880.40 m2, i.e., the available roof area, which means that PVP is more conducive to improving the system performance compared with solar thermal collector (STC). The SAHB system operating under FTL is superior to that operating under FEL because more electricity is sold back to the electricity grid when the SAHB system operates under FTL. Among the biomass materials, CS yields the best energetic, economic, environmental and comprehensive performance. Under FEL, the CSR of CS is 3.28%, 0.90% and 2.84% larger than that of RS, WS and WP, respectively. Under FTL, the CSR of CS is 4.25%, 1.17% and 3.18% larger than that of RS, WS and WP, respectively. Sensitivity analysis shows that biomass price and gasification efficiency have the most significant impact on the system performance under FEL and FTL, respectively. When the biomass price of CS increases by 10.00%, the CSR under FEL decreases by 1.28%. On the contrary, the CSR under FTL increases by 1.88% when the gasification efficiency of CS increases by 10.00%.

Optimizing the operation strategy of a combined cooling, heating and power system based on energy storage technology

Energy storage technology is the key to achieving a carbon emission policy. The purpose of the paper is to improve the overall performance of the combined cooling, heating and power-ground source heat pump (CCHP-GSHP) system by the battery. A new operation strategy (the two-point operation) is proposed by controlling the power generation unit work. The power generation unit has two operation modes of non-operation and rated efficiency operation by the storage electricity battery. The new operation strategy is compared with the traditional CCHP-GSHP that without a battery. The optimization goals include the primary energy saving ratio, the reduction ratio of carbon dioxide emissions, and the annual total cost saving ratio. The independent GSHP system is used as a reference system. Multipopulation genetic algorithms are selected to achieve the problem of optimization. A hotel building is selected for a case study. The optimal configuration of the coupling system is computed following the electric load strategy. Finally, the results show that the CCHP-GSHP system has a better performance under the new operation strategy compared with the traditional CCHP-GSHP (the primary energy saving ratio increases by 5.5%; the annual carbon dioxide emission reduction ratio increases by 1%; the annual total cost reduction ratio increases by 5.1%). This paper provides reference and suggestions for the integration and operation strategy of CCHP-GSHP in the future.