Influence analysis of building types and climate zones on energetic,economic and environmental performances of BCHP systems

The performance of building cooling heating and power (BCHP) system is obviously dependent upon the seasonal atmospheric conditions and the building types. This paper presents the energy flow analysis and the evaluation criteria of the redundant BCHP system and describes the optimal design method. The BCHP systems for four building categories (Hotel, Office, Hospital and School) in five climate zones (Severe Cold Zone, Cold Zone, Hot Summer and Cold Winter Zone, Mild Zone and Hot Summer and Warm Winter Zone) in China are compared and evaluated from energetic, economic and environmental aspects. The comparison results show that the BCHP system is generally suitable for the building, which operates for long time over the entire year, in the climate zone where buildings require more heat for space heating. Moreover, the influence analysis on BCHP capacity and operation strategy indicates that the capacity of power generation unit (PGU) is the most sensitive design parameter to influence the integrated performance of the BCHP system.     

Optimization design of BCHP system to maximize to save energy and reduce environmental impact

The energetic and environmental performances of building cooling heating and power (BCHP) system are closely dependent on its design and operation strategy. This paper analyzes the energy consumptions of a conventional separation production (SP) system and a BCHP system respectively and constructs their corresponding environmental impact models. Furthermore, three energy-related environmental issues, global warming, acid precipitation and stratospheric ozone depletion, are assessed in the proposed emission model. To maximize the benefits (energy-saving and emission-reducing) achieved by the BCHP system in comparison to the SP system, genetic algorithm (GA) is employed to optimize the capacity of BCHP system in consideration of its operation mode. A numerical case of BCHP system for a hotel building is applied to ascertain the effectiveness of the optimal method and demonstrate the performances of the optimal BCHP system.     

Sensitivity analysis of optimal model on building cooling heating and power system

The optimization of building cooling heating and power (BCHP) system is helpful to improve its comprehensive performance including energetic, economic and environmental aspects. However, the optimal results are closely dependent on the initial setting parameters. This paper deduces the energy consumption of BCHP system following the electrical load and presents the optimization problem of BCHP system that includes the decision variables, the objective function, the constraint conditions and the solution method. The influences of the initial parameters, which include the technical, economic and environmental parameters, the building loads and the optimization setting parameters, on the optimal decision variables and the performances of BCHP system are analyzed and compared. The contour curves of the performances of BCHP system in comparison to the conventional separation production (SP) system, and the sensitivity of the optimal decision variables to the initial parameters are obtained.     

Environmental impact analysis of BCHP system in different climate zones in China

The operation performance of building cooling, heating and power (BCHP) system is dependent on the seasonal atmospheric conditions. This paper presents the environmental impact models of separation production (SP) system and BCHP system respectively. Three most important energy-related environmental issues, global warming, acid precipitation and stratospheric ozone depletion, are considered to evaluate the environmental impact of BCHP system for a commercial building located in five climate zones, China. Because the global emissions of BCHP system are related to the central power plant that provides the additional electricity to building, the environmental impacts by coal-fired and gas-fired power plants are compared and discussed. The results indicate that the emission reduction potential of BCHP system over SP system in hot summer zone and mild zone is larger than in severe cold zone when the coal-fired power plant is used. Contrarily, BCHP system in severe cold zone reduces more emissions than in hot summer zone when the gas-fired power plant provides the additional electricity.     

Multi-objective optimization design and operation strategy analysis of BCHP system based on life cycle assessment

The promising energetic and environmental benefits of building cooling heating and power (BCHP) system are greatly dependent upon its design and operation strategy. In this paper, the energy and emission flows and different operation strategies of a BCHP system driven by gas engine are analyzed. Life cycle assessment (LCA) is employed to assess and compare the whole life energy saving potentials and pollutant emission reductions of BCHP system with the traditional energy system. Furthermore, energy consumption and three pollutant-related impacts, global warming, acid precipitation and respiratory effects, are selected as objective functions to optimize the gas engine capacity of BCHP system in different operation strategies. A numerical case of BCHP system for a commercial office building in Beijing, China is applied to obtain the optimum BCHP alternative in terms of the comprehensive energy and environment performance. The uncertainty of different evaluation criteria weights is also analyzed to show their influences on the optimal design and operation strategy. The results show that a reasonably sized BCHP system with an electric load-following strategy has the best performance under a wide interval of criteria weights, when the energetic and environmental benefits of producing excess electricity for nearby users are not considered.     

Cross-regional integrated energy system scheduling optimization model considering conditional value at risk

Integrated energy system is a very important way to improve energy efficiency. Based on the combined heating cooling and power system, combined with energy storage equipment, a cross-regional integrated energy system scheduling optimization problem is studied. An integrated energy system scheduling optimization model is established that meets the requirements of electrical, heating, and cooling load under a variety of energy sources while both considering the interaction of electrical, heating, and cooling load between regions, and complementation of them within one region. Meanwhile, the value at risk (VaR) theory is introduced and the operating constraints of equipment in the integrated energy system fully considered, the integrated energy system scheduling model with VaR is established. The example shows that the model can realize multi-type electrical, heating, and cooling load optimized by schedule across regions under the premise of satisfying the balance of energy supply and demand, which can reduce the system operation cost. The sensitivity analysis of the minimum expected cost and the influencing factors of conditional VaR is carried out to verify the validity and feasibility of the proposed model.

• An integrated energy system scheduling optimization model is established that meets the requirements of electrical, heating, and cooling load under a variety of energy sources while both considering the interaction of electrical, heating, and cooling load between regions, and complementation of them within one region.
• By using the conditional value at risk theory to consider various types of the integrated energy system complements and evaluates the operational risk of the system under optimal operating conditions of the system.
• The total cost of system scheduling operation is proportional to the storage capacity, which is inversely proportional to the heat storage capacity and inversely proportional to the pipeline capacity within a certain interval.

     

BCHP系统中余热锅炉结构参数的热经济学优化

本文建立以BCHP系统的产品平均（yong）成本为目标函数,以余热锅炉排烟温度、蒸发器和省煤器中螺旋翅片管排数、每排管数、管束横向节距和纵向节距为决策变量的余热锅炉优化模型。应用所建立的优化计算模型,对BCHP系统不同工况分别进行优化计算,结果表明,无论在何种工况下,余热锅炉参数优化后其效率比优化前有所提高,冷量分摊的成本、系统的产品平均(yong)成本比未优化时均有所降低。     

基于VMD的混合储能容量优化配置

针对光伏发电输出功率的波动性以及混合储能容量优化,以光储联合的发电系统为研究对象,提出一种基于变分模态分解(VMD)的混合储能容量优化配置策略.该策略采用VMD对光伏输出功率进行处理,利用欧氏距离方法将相关模态和非相关模态进行区分,利用滑动平均法提取非相关模态中的持续分量信号,将其与相关模态进行重构作为满足国家标准的并...     

Parametric analysis and optimization of a building cooling heating power system driven by solar energy based on organic working fluid

Building cooling heating power (BCHP) systems as a kind of distributed energy resource have shown a great potential in improving energy efficiency and meeting multiple energy demands in buildings. In this paper, we present a BCHP system driven by solar energy with flat‐plate solar collectors. A modified system efficiency is introduced to evaluate the whole day performance of the system more accurately. Based on the mathematical models and simulation platform established, we have investigated the influences of some key thermodynamic parameters, namely condensation temperature, turbine inlet temperature and turbine inlet pressure on the system performance. In order to find the optimum combination of these parameters that leads to the best performance, we have performed parametric optimization by means of the genetic algorithm. Results indicate that the best performance and the highest efficiency of the system are achieved when the working fluid reaches its saturated state and the corresponding efficiencies of the system operating in the combined heating power mode, the combined cooling power mode and the power production mode turn out to be 19.10%, 27.24% and 10.47%, respectively. Copyright © 2012 John Wiley & Sons, Ltd.     

Economical assessment of a wind–hydrogen energy system using WindHyGen software

This paper considers the problem of analyzing the economical feasibility of a wind–hydrogen energy storage and transformation system. Energy systems based on certain renewable sources as wind power, have the drawback of random input making them a non-reliable supplier of energy. Regulation of output energy requires the introduction of new equipment with the capacity to store it. We have chosen the hydrogen as an energy storage system due to its versatility. The advantage of these energy storage systems is that the energy can be used (sold) when the demand for energy rises, and needs (prices) therefore are higher. There are two disadvantages: (a) the cost of the new equipment and (b) energy loss due to inefficiencies in the transformation processes. In this research we develop a simulation model to aid in the economic assessment of this type of energy systems, which also integrates an optimization phase to simulate optimal management policies. Finally we analyze a wind–hydrogen farm in order to determine its economical viability compared to current wind farms.     

基于蚁狮算法的风电集群储能容量配置优化方法

随着风电渗透率提高,风电并网对电网安全稳定运行影响更加显著。风电配备储能可有效改善风电出力波动性和不确定性,增强可调度性。该文建立以风电集群联合储能系统售电收益最高为优化目标的模型,采用蚁狮算法算法进行求解,得到风电集群功率备用、储能功率和容量最优配置方案,对比蚁狮算法、遗传算法和粒子群算法优化结果,分析储能电池单位成本和寿命对优化结果影响。最后以中国东北某风电集群作为算例,验证了所提算法与模型的有效性。     

The review of thermal management technology for large-scale lithium-ion battery energy storage system

大容量锂离子电池储能系统对完善传统电网和高效利用新能源都具有非常重要的作用。为了实现大容量锂离子电池储能系统的高倍率化、长寿命化以及高安全性,高性能电池热管理系统的研发刻不容缓。本文总结了温度对锂离子电池性能的影响规律,综述了空冷、液冷、热管冷却、相变冷却这4种典型热管理技术的研究概况,分析了热管理技术在锂离子电池储能系统中的应用与研究状况。随着锂离子电池储能系统工作倍率的提高,产热量随之增大,对热管理系统的要求也越来越高。下一步的研究工作应围绕空冷系统优化、基于新型冷却介质的液冷系统、经济型热管及多目标优化设计这4方面展开。     

基于电池寿命损耗的火电一体化调频系统容量配置

电池储能系统具有快速、精确的功率响应能力,为传统火电机组配置适当容量的储能系统,不仅能够帮助电厂更好的跟踪自动发电控制指令,而且可以帮助电网更高效地完成AGC(自动发电控制指令)控制目标。以锂离子电池为基础,采用对机组补偿的控制策略,在保证AGC补偿收益最大情况下,基于储能电池寿命方程,建立储能系统寿命损耗成本最小的目标函数,然后对机组运行过程中实际需求的容量进行分析,综合得出最优的配置容量。对某发电厂实际运行的数据进行算例分析,进一步验证了所提方法可以有效提升机组的调频效果。     

楼宇冷热电联供系统的变工况及热力学分析

燃气轮机的楼宇冷热电联供系统是一种有前途的节能和环保的能源系统，该文对1个己运行了4年的系统进行了变工况和热力学分析计算，得出了该系统在夏季的设计负荷和变工况条件下能源效率和Yong效率的数据，并进行了讨论和给出了结论。     

Analysis of the problem of optimal placement and capacity of the hydrogen energy storage system in the power system

Nowadays the trend of increasing the generation units based on renewable energy sources in the electric power system can be observed. Obviously, this is due to the intensifying level of consumer load and demand for electricity. However, renewable generation is characterized by intermittent energy production, which can cause and potential imbalance between generation and demand, especially during off-peak periods. Therefore, in order to ensure a reliable power supply to consumers, it is necessary to use a maneuverable reserve of capacity, such as energy storage systems, in conjunction with the renewable energy source unit. Over the past 10 years, the energy storage market has grown by almost 50%: the installed capacity of energy storage system in the world is about 5 GW. Analysis of the literature on the subject determines the need to study the impact of these devices on the parameters of electric power systems and one of the primary tasks is to determine the optimal location and capacity of energy storage system in the power system. This paper presents the result of solving the task of determining the optimal parameters of a hydrogen energy storage system using the particle swarm optimization method for example a test scheme radial distribution system – 33 bus IEEE. The choice of the type of energy storage is based on such advantages of a hydrogen energy storage system as environmental friendliness, high energy capacity and the ability to store electricity for a long period of time. In addition, compared to lithium-ion batteries, hydrogen energy storage systems have a long life time of about 25 years, during this period of time there is no degradation and significant deterioration of its properties. All these advantages of hydrogen as an energy carrier allow to take into account not only the criterion of total value of active power losses and its maximum reduction respectively, but the possibility and economic efficiency of partial use of the stored hydrogen for other needs when determining the optimal scenario of their operation in the process of discharge.     

含复合储能的冷热电联供系统多目标运行优化研究

冷热电联供（combined cooling, heating and power, CCHP）系统是分布式能源系统发展的主流趋势,针对CCHP系统的能量调度问题,提出了储电、储热相结合的复合储能技术;为实现CCHP系统的运行优化控制,建立了CCHP系统拓扑架构、系统模型、多目标函数及约束条件,采用线性加权和法将多目标函数转化为单目标函数,利用遗传算法进行优化求解,并与不含复合储能的CCHP系统进行对比分析。结果表明：将复合储能引入CCHP系统,能有效降低系统运行成本和一次能源消耗量,提高系统节能率和削峰填谷能力,为CCHP系统的优化运行策略提供了较好的参考方法。     

Combined heat and power systems with dual power generation units and thermal storage

The objective of this paper is to study the performance of a combined heat and power (CHP) system that uses two power generation units (PGU). In addition, the effect of thermal energy storage is evaluated for the proposed dual‐PGU CHP configuration (D‐CHP). Two scenarios are evaluated in this paper. In the first scenario, one PGU operates at base‐loading condition, while the second PGU operates following the electric load. In the second scenario, one PGU operates at base‐loading condition, while the second PGU operates following the thermal load. The D‐CHP system is modeled for the same building in four different locations to account for variation of the electric and thermal loads due to weather data. The D‐CHP system results are compared with the reference building by using conventional technology to determine the benefits of this proposed system in terms of operational cost and carbon dioxide emissions. The D‐CHP system results, with and without thermal storage, are also compared with that of single‐PGU CHP systems operating following the electric load (FEL), following the thermal load (FTL), and base‐loaded (BL). Results indicate that the D‐CHP system operating either FEL or FTL in general provides better results than a single‐PGU CHP system operating FEL, FTL, or BL. The addition of thermal storage enhances the potential benefits from D‐CHP system operation in terms of operational cost savings and emissions savings. Copyright © 2013 John Wiley & Sons, Ltd.     

Performance enhancement of a subcooled cold storage air conditioning system

This article experimentally investigates the enhancement of thermal performance for an air conditioning system utilizing a cold storage unit as a subcooler. The cold storage unit is composed of an energy storage tank, liquid-side heat exchanger, suction-side heat exchanger and energy storage material (ESM), water. When the cooling load is lower than the nominal cooling capacity of the system, the cold storage unit can store extra cold energy of the system to subcool the condenser outlet refrigerant. Hence, both the cooling capacity and coefficient of performance (COP) of the system will be increased. This experiment tests the two operation modes: subcooled mode with energy storage and non-subcooled mode without energy storage. The results show that for fixed cooling loads at 3.05 kW, 3.5 kW and 3.95 kW, the COP of the subcooled mode are 16.0%, 15.6% and 14.1% higher than those of the non-subcooled mode, respectively. In the varied cooling load experiments, the COP of the subcooled cold storage air conditioning system is 15.3% higher than the conventional system.     

Optimization of capacity and operation for CCHP system by genetic algorithm

The technical, economical and environmental performances of combined cooling, heating and power (CCHP) system are closely dependent on its design and operation strategy. This paper analyzes the energy flow of CCHP system and deduces the primary energy consumption following the thermal demand of building. Three criteria, primary energy saving (PES), annual total cost saving (ATCS), and carbon dioxide emission reduction (CDER) are selected to evaluate the performance of CCHP system. Based on the energy flow of CCHP system, the capacity and operation of CCHP system are optimized by genetic algorithm (GA) so as to maximize the technical, economical and environmental benefits achieved by CCHP system in comparison to separation production system. A numerical example of gas CCHP system for a hotel building in Beijing is given to ascertain the effectiveness of the optimal method. Furthermore, a sensitivity analysis is presented in order to show how the optimal operation strategy would vary due to the changes of electricity price and gas price.     

冷热电三联供系统配置与运行策略的优化

对一个冷热电三联供系统的配置与运行策略进行了分析。该系统由燃气内燃机、吸附制冷机和电热泵组成。根据设备容量、数量、性能和分时段能源价格等，在满足应用场合冷热电负荷需求条件下，运用混合整型（0-1）多级目标规划方法，建立了联供系统的优化模型，得到了系统的最优配置和运行策略。该模型三级目标函数包括运行费用最低、各主要设备配置数量最少和实际运行负荷率最大化。应用该模型对一实例进行的分析取得了较好的经济效果。