Energy efficiency performance of multi-energy district heating and hot water supply system

A district heating and hot water supply system is presented which synthetically utilizes geothermal energy,solar thermal energy and natural gas thermal energy.The multi-energy utilization system has been set at the new campus of Tianjin Polytechnic University(TPU),A couple of deep geothermal wells which are 2 300 m in depth were dug,Deep geothermal energy cascade utilization is achieved by two stages of plate heat exchangers(PHE) and two stages of water source heat pumps(WSHP).Shallow geothermal energy is used in assistant heating by two ground coupled heat pumps(GCHPs) with 580 vertical ground wells which are 120 m in depth.Solar thermal energy collected by vacuum tube arrays(VTAs) and geothermal energy are complementarily utilized to make domestic hot water.Superfluous solar energy can be stored in shallow soil for the GCHP utilization.The system can use fossil fuel thermal energy by two natural gas boilers(NGB) to assist in heating and making hot water.The heating energy efficiency was measured in the winter of 2010-2011.The coefficients of performance(COP) under different heating conditions are discussed.The performance of hot water production is tested in a local typical winter day and the solar thermal energy utilization factor is presented.The rusults show that the average system COP is 5.75 or 4.96 under different working conditions,and the typical solar energy utilization factor is 0.324.

Value analysis of district heating system with gas-fired peak load boiler in secondary network

In district heating(DH) system with gas-fired peak load regulating boiler in the secondary network,by prolonging run time of base load plants under rated condition,the mean energy efficiency could be increased. The fuels of the system,including coal and gas,would cause different environmental impacts. Meanwhile,the reliability of the heating networks would be changed because the peak load regulating boiler could work as a standby heat source. A model for assessment of heating system was established by value analysis to optimize this kind of system. Energy consumption,greenhouse gas emission,pollution emission and system reliability were selected as functional assessment indexes in the model. Weights of each function were determined by analytical hierarchy process (AHP) and experts consultation. Life cycle cost was used as the cost in the model. A real case as an example was discussed to obtain the optimal base load ratio. The result shows that the optimal base load ratio of the case is 0.77.

The Preliminary Research of Sea Water District Heating and Cooling for Tallinn Coastal Area

This paper describes possibilities to utilize sea water for district heating and cooling purposes in Tallinn costal area. The sea water temperature profiles and suitability of heating and cooling generation are studied for continental climatic conditions. The district network study bases on 21 buildings located near to the Gulf of Finland. Industrial reversible heat pump technology is selected to cover heating and cooling loads for the new buildings. Combination of existing district heating and heat pump technology is considered for existing buildings. The results show possibilities, threats and need for further research of the sea water based heat pump district network implementation.

A Neuro-Fuzzy Based Adaptive Set-Point Heat Exchanger Control Scheme in District Heating System

The control of heat exchange stations in district heating system is critical for the overall energy efficiency and can be very difficult due to high level of complexity. A conventional method is to control the equipment such that the temperature of hot water supply is maintained at a set-point that may be a fixed value or be compensated against the external temperature. This paper presents a novel scheme that can determine the optimal set-point of hot water supply that maximizes the energy efficiency whilst providing sufficient heating capacity to the load. This scheme is based on Adaptive Neuro-Fuzzy Inferential System. The aim of this study is to improve the overall performance of district heating systems.

Polish District Heating Systems--Development Perspectives

The most economical and rational means of heat supply for city inhabitants are district heating systems. Heat generated in power plants and large heat sources is cheaper than heat from individual sources. The reason for that is the amount of the generated heat and the used fuel （coal for most heat sources）. District heating, a very important energy sub-sector for the Polish economy, provides heat supply to centralised heating systems, which, on average, satisfy 72% of the demand for heat in Polish cities. Therefore, several million Polish citizens use heat from district heating systems that produce heat in professional, industrial and municipal power plants. In Europe, over 100 million citizens use district heating systems. The present situation of the Polish district heating sector is a result of Poland＇s transformation that took place at the beginning of the 1990s. The reform put the obligation of heat supply on the local authorities, on the municipality, instead of the state. Along with the transformation, district heating also made huge technological and technical progress. Increasing expectations of recipients posed new challenges for the branch, however.

Wireless Sensor Networks for Optimisation of District Heating

The upgrading of the DH （district heating） system through installing WSN （wireless sensor networks）--a technology by which to monitor and control quality operation of the DH system will lead to more effective use of thermal energy, enabling also the provision of quality customer services, as the data concerning the status of the existing networks is available in a timely manner, and in the stated amounts. Over the last decades, the use of WSN systems in enabling quality monitoring of heat production and supply process has been widely discussed among various researchers and industry experts, but has been little deployed in practice. These researchers and industry experts have analysed the advantages and constraints related to the use of the WSN in district heating. A pilot project conducted by Riga Heat （the main heating supplier in Riga, Latvia） has allowed to gain a real life experience as to the use of the WSN system in district in-house heating substations, and is deemed to be a major step towards future development of WSN technologies.

Solid Particle Emission Abatement from Biomass-Fired Boilers at District Heating Plants

The district heating company ＂Rigas siltums＂ operates biomass fuelled boiler in Riga city. Three systems consisting ofbiomass boilers having a comparatively similar heat capacity and particle abatement units like multicyclons, electrostatic precipitators and flue gas condensers are compared. The main goal of the study is to evaluate the boiler plant as a system where solid particles are both emitted and caught. The results show that, the particulate matter can be efficiently trapped from flue gases by the particle abatement technologies, and the electrostatic precipitator with sufficiently large collection surfaces is able to provide appropriate flue gas treatment of the particulate matter in the biomass boilers also without pre-cleaning of the flue gas in multieyelons.

基于ANFIS的太阳能-空气源热泵供暖系统温度控制研究

针对太阳能-空气源热泵供暖系统运行环境复杂多变,模糊控制器的设计高度依赖人工经验的问题,提出一种基于自适应神经模糊推理系统(ANFIS)改进的模糊控制方法。该方法利用ANFIS在复杂系统建模中的优势,结合供暖系统温度响应特性和实际运行数据,建立联合供暖系统变工况ANFIS模型,生成与系统性能适配的模糊规则库并传递给模糊控制器执行。Matlab/Simulink仿真对比试验表明,与单一的模糊控制相比,该方法的控制精度提高了17.65%,调节时间缩短了36.4%,具有更高的控制精度和响应速度。

小样本情形集中供热系统元件失效率估计方法研究

对国内3个典型城市集中供热系统失效事件进行了调查统计,并对元件失效率进行了估计。针对直接估计模型存在的限制,引入了Bayes(贝叶斯)理论,融合历史信息,提出了一般Bayes模型和分层Bayes模型。比较了3种模型的精度,管道、阀门和补偿器3类元件的分层Bayes模型精度分别为0.31、0.32、0.29,在3种模型中精度最高;最终通过改变样本量,得出3种模型精度随样本量增加均呈现上升趋势,且相互差距逐渐缩小,验证了Bayes模型在小样本情形的适用性。

利用数据中心余热供热的系统设计与分析

数据中心余热供热是提高数据中心能源利用效率和实现冬季清洁供暖的重要途径。本文提出了一种适用于数据中心的长距离供热系统,在热源和热汇处设置多级热泵以增大供热管网供回水温差,并使用储热装置保障数据中心和供热系统的安全性,提高数据中心余热利用率。以张家口某数据中心为例进行了分析,该系统初投资为50.21元/m^(2),运行费用为26.37元/GJ,投资回收期约为5.31 a,具有较好的经济性和节能减排效果。

基于数据增广的区域供热系统热力站负荷预测模型准确率提升方法研究

开展了热力站数据生成模型研究,基于生成对抗网络和去噪扩散概率模型建立了数据生成模型,通过学习气象、室温、热力站运行数据的联合分布,对原始训练数据进行增广,为预测模型训练提供充足的数据支撑,从而提高预测模型的准确率。在北京市某热力站进行了验证和实际测试,结果表明:该方法可以将热力站一次侧电动调节阀开度和二次网供水温度的预测误差分别降低约7%和11%;同时,应用准确率提升后的负荷预测值进行供热量调节得到的预计室温与室温目标值之间的偏差可进一步降低5.44%。基于生成对抗网络的生成模型能够扩展预测模型的预测范围,基于去噪扩散概率模型的生成模型能够在原预测范围内提高预测模型的准确率。本文研究可为进一步提高区域供热系统热力站负荷预测能力与按需精准调控水平提供支撑。

电-热-氢综合能源系统鲁棒区间优化调度

储能技术与风电相结合实现电能的时空平移是解决系统运行稳定性问题的有效手段。氢储能具有储存容量大、可实现电热联产联供的优点,具有很大的发展潜能。然而由于风电存在不确定性,氢储能系统在频繁切换工作模式时面临着不确定的热能需求。因此,文中综合考虑氢储能在间歇模式下的热能需求,首先,介绍了氢储能系统接入的电-热综合能源系统基本结构,将风电场与氢储能相结合构成风-氢混合系统;然后,提出考虑风-氢混合系统热平衡需求不确定性的电-热综合能源系统鲁棒区间优化调度模型;最后,基于对偶理论,对所提出的模型转化求解,通过算例对比分析各类情况优化结果,验证了氢储能在促进风电消纳、提高系统能源综合利用率方面的有效性,并证明了考虑电解槽和燃料电池工作温度能提高系统的工作效率并提高风电场并网功率。

区域能源与数据中心融合项目应用实例分析

本文以南京市某区域能源与数据中心融合项目为例,对融合前后冷热源系统设计方案进行对比,阐述了融合系统方案设计要点,并简要分析了融合项目的经济性,提出区域能源与数据中心融合模式可以实现“1+1>2”的效果,应积极推广使用。

基于数据挖掘算法的DHC系统负荷时序预测方法

区域供冷供热系统(DHC)负荷预测的精准度是实现系统设计合理和运行节能的关键因素。以某区域能源站实测数据为基础,采用多元线性回归(MLR)、分类与回归树(CART)和随机森林(RF)三种数据挖掘算法,分别建立了系统负荷时序预测模型,并对比了三种模型在不同时序变量影响下的负荷预测结果以及预测效率。结果表明:在不同时序变量影响组合下,随机森林模型的预测效果最好;在仅考虑预测精度的情况下,负荷的时序变量组合维度越复杂,预测结果精度越高,而预测效率越低;在同时考虑预测精度和预测效率的情况下,当时序变量采用室外干球温度、室外相对湿度、负荷(t-1)和负荷(t-2)的组合2时,随机森林模型的综合性能最好。

集中供热系统能耗异常数据识别及修复方法研究

在集中供热系统中,精确的能耗预测是实现高效系统管理的重要前提。为有效处理监测系统采集数据中的异常样本,进而提高能耗预测效果,本文以实际工程的运行数据为基础,采用基于箱线图与孤立森林算法的异常数据识别方法和MissForest填补法,对数据集进行预处理工作。设置对比实验,利用LightGBM算法构建能耗预测模型验证本文所提数据预处理方法对能耗预测效果提升的有效性。实验结果表明:本文提出的数据预处理方法可有效且准确地识别并修复异常数据,对预测模型的优化效果显著。

东京新宿地区的集中供热供冷（DHC）装置

本文介绍了东京新宿地区的区域供热供冷系统，其容量一期工程为１８万ｋＷ，二期为２１万ｋＷ，是世界上规模最大的集中供冷工程，采用热电联产方式后节约能源达３３．５％。

再生水热泵供暖系统发展分析

介绍了郑州再生水资源概况,根据再生水规划和利用现状,结合再生水热泵供暖系统的特点,研究在郑州市发展再生水热泵供暖技术的适用性。结果表明,郑州市的再生水供水量及温度满足再生水热泵系统的需求,利用再生水热泵技术对建筑物进行供热,具有显著的经济效益和环保效益。

区域多热源联合供热系统热平衡及运行参数分析

以太原市供热现状为基础,分析多热源联合供热现状,探讨二次网分布式调峰锅炉与集中供热系统串、并联两种运行方式下的系统性能,建立热平衡方程和调节公式,并对相关运行参数进行求解。计算结果表明,相比串联连接,并联连接能耗更低。研究结果对区域多热源联合供热系统的设计及优化运行具有一定的指导价值。

蓄能中央空调系统在区域供热供冷(DHC)中的应用

介绍了常州金禧园大型住宅小区冰蓄冷中央空调系统、电锅炉蓄热采暖系统和电锅炉蓄热生活热水系统的设计方案和特点,与其他空调方式进行了初投资和运行费用的比较,简单介绍了冷热量计费系统;指出蓄能技术应用于区域供热供冷系统具有经济、环保的优点,值得应用和推广。

武汉某国际商务区暖通空调冷热源工程设计

武汉某国际商务区江水源能源站项目被评为湖北省2019年建筑节能示范工程,本文对该项目的暖通空调冷热源工程设计进行了介绍,阐述了采用可再生能源——江水为冷、热源、利用热泵技术为商务区提供空调用冷、热水的方案,介绍了冬季供冷的四管制设计思路,同时对空调水系统进行了设计,阐述了采用二次泵+一次泵变流量设计的合理性等;设计内容可为大规模商务区集中供冷供热的暖通空调冷热源系统设计提供参考。