Integration of Low-level Waste Heat Recovery and Liquefied Nature Gas Cold Energy Utilization

Two novel thermal cycles based on Brayton cycle and Rankine cycle are proposed, respectively, which integrate the recovery of low-level waste heat and Liquefied Nature Gas （LNG） cold energy utilization for power generation. Cascade utilization of energy is realized in the two thermal cycles, where low-level waste heat,low-temperature exergy and pressure exergy of LNG are utilized efficiently through the system synthesis. The simulations are carried out using the commercial Aspen Plus 10.2, and the results are analyzed. Compared with the conventional Brayton cycle and Rankine cycle, the two novel cycles bring 60.94% and 60% in exergy efficiency, respectively and 53.08% and 52.31% in thermal efficiency, respectively.

Effects of sustained cold and heat stress on energy intake, growth and mitochondrial function of broiler chickens

To study the correlation of broiler chickens with energy intake, growth and mitochondrial function which exposed to sustained cold and heat stress and to find out the comfortable temperature, 288 broiler chickens（21-day with（748±26） g, 144 males and 144 females） were divided randomly into six temperature-controlled chambers. Each chamber contained six cages including eight AA broilers per cage, each cage as a repeat. After acclimation for one week（temperature, 21℃; relative humidity, 60%）, the temperature of each chamber was adjusted（finished within 1 h） respectively to 10, 14, 18, 22, 26, or 30℃（RH, 60%） for a 14-day experimental period. After treatment, gross energy intake（GEI）, metabolizable energy intake（MEI）, the ratio of MEI/BW, metabolizability, average daily gain（ADG）, the concentration of liver mitochondria protein and cytochrome c oxidase（CCO） were measured respectively. Our results confirmed that when the temperature over 26℃ for 14 days, GEI, MEI and CCO activities were decreased significantly（P〈0.05）, but the concentration of liver mitochondria protein was increased and metabolizability of broilers was not influenced（P〉0.05）. Compared with treatment for 14 days, the ratio of MEI/body weight（BW） were also decreased when the temperature over 26℃ after temperature stress for 7 days（P〈0.05）, meanwhile mitochondrial protein concentration was increased at 10℃ and CCO activity was not affected（P〉0.05）. Additionally at 22℃, the ADG reached the maximal value. When kept in uncomfortable temperatures for a long time, the ADG and CCO activities of broiler were reduced, which was accompanied by mitochondrial hyperplasia. In summary, our study focused on the performance of broilers during sustained cold and heat environmental temperatures ranging from 10 to 30℃. From the point of view of energy utilization, moreover, 22 to 26℃ is comfortable for 28–42 day s broilers. And these could provide the theoretical basis on the high efficient production.

Numerical Analysis of Doublet Wells for Cold Energy Storage on Heat Damage Treatment in Deep Mines

Deep mining is an inevitable tendency in the development of coal industry. There are many heat damage problems with the increase of mining depth. The technology of using doublet wells, together with Heat Exchange Machine Systems （HEMSs）, to store cold energy is a key to solve the heat damage problems in deep mines. Based on the geological conditions, thermodynamic and hydraulic parameters of Jiahe Mine, the isotherms in the period of cold energy storage and refrigeration and the volumes of cold water within different temperature ranges of the cold energy storage well were numerically analyzed. The results show that 1） with the same pumped and injected water volumes, the lower the temperature of injected water is, the larger the volume.of cold water in the cold energy storage well is. With the larger volume, the effect of cold energy storage is better. 2） the larger the volumes of pumped and reinjected water frigeration is better. And 3） without disturbance, the volume and temperature of cold water in the cold energy storage well can keep unchanged or have only a little change for a long time. Therefore the technology of doublet wells for cold energy storage is feasible and the cold energy storage aquifers can meet the requirement of the technology.

Recent Development and Application of Geothermal Heat Pump Systems in Cold-Climate Regions of the US: A Further Investigation

A Geothermal Heat Pump (GHP) system is known to have enormous potential for building energy savings and the reduction of associated greenhouse gas emissions, due to its high Coefficient Of Performance (COP). The use of a GHP system in cold-climate regions is more attractive owing to its higher COP for heating compared to conventional heating devices, such as furnaces or boilers. Many factors, however, determine the operational performance of an existing GHP system, such as control strategy, part/full-load efficiency, the age of the system, defective parts, and whether or not regular maintenance services are provided. The omitting of any of these factors in design and operation stages could have significant impacts on the normal operation of GHP systems. Therefore, the objectives of this paper are to further investigate and study the existing GHP systems currently used in buildings located in cold-climate regions of the US, in terms of system operational performance, potential energy and energy cost savings, system cost information, the reasons for installing geothermal systems, current operating difficulties, and owner satisfaction to date. After the comprehensive investigation and in-depth analysis of 24 buildings, the results indicate that for these buildings, about 75% of the building owners are very satisfied with their GHP systems in terms of noise, cost, and indoor comfort. About 71% of the investigated GHP systems have not had serious operating difficulties, and about 85% of the respondents (building owners) would suggest this type of system to other people. Compared to the national median of energy use and energy cost of typical buildings of the same type nationwide, the overall performance of the actual GHP systems used in the cold-climate regions is slightly better, i.e. about 7.2% energy savings and 6.1% energy cost savings on average.

Design and Analysis of a Small Sewage Source Heat Pump Triple Supply System

Based on the characteristics of sewage from beauty salons,a simulation model of a small sewage source heat pump triple supply system that can be applied to such places is established to optimize the operating conditions of the system.The results show that with the increase of sewage temperature and flow,the performance of the system also increases.In summer conditions,the system provides cooling,recovers waste heat and condensed heat from sewage,with a COP value of 8.97;in winter conditions,the system heats and produces hot water,with a COP value of 2.44;in transitional seasons,only hot water is produced.The COP value is 2.75.Compared with the traditional systems which refers to the air source heat pump and hot water boiler system currently used in beauty salons,this system can save energy by 50.9%.

Energy-efficient intermittent liquid heating of lithium-ion batteries in extreme cold using phase change materials

The electrochemical performance of lithium-ion batteries significantly deteriorates in extreme cold.Thus,to ensure battery safety under various conditions,various heating and insulation strategies are implemented.The present study proposes a hybrid heating approach combining active heating with passive insulation.Conceptual experiments were conducted to investigate the effects of phase change materials(PCMs),inlet water temperature,and intermittent pump startup strategies on battery performance.The obtained experimental results demonstrate that low temperatures lead to increased electrochemical impedance and reduced charge–discharge capacity in batteries.Notably,charge transfer resistance of 162 mΩwas observed at-30℃.Herein,the developed PCM-based battery heating system effectively extended the operational capacity of batteries in cold driving conditions and maintained battery warmth by leveraging the superior heat storage capability of the PCM.Additionally,after the switch off of the heating system,the charge capacity of the battery exceeded 80%owing to latent heat.The use of an intermittent heating strategy not only allowed to conserve energy but also maintained adequate heat storage within the battery module.At-30℃,this strategy enhanced the power efficiency of the cooling system by 35.94%with a reduction in capacity of only 0.8%compared to the continuous strategy.

Development of Submersible Corrugated Pipe Sewage Heat Exchanger

Based on the characteristics of heat transfer for corrugated pipe,a method of calculating and design on the submersible corrugated pipe sewage heat exchanger was put forward theoretically and experimentally.The actual movement parameters of air-conditioning system used in this heat exchanger were measured.The experimental result shows that the quantity of heat transfer of the corrugated pipe sewage heat exchanger can satisfy the building's load with the average coefficient of performance 4.55.At the same time,the quantity of heat transfer of the corrugated pipe sewage heat exchanger was compared with that of the other nonmetallic sewage heat exchangers(i.e.,the plastic-Al pipe sewage heat exchanger and PP-R pipe sewage heat exchanger)experimentally.It is found out that the effect of heat transfer for submersible corrugated pipe sewage heat exchanger is superior to those of the plastic-Al pipe and the PP-R pipe.The quantity of heat transfer per mile of corrugated pipe sewage heat exchanger is 5.2 times as much as that of the plastic-Al pipe,and it is 8.1 times as much as that of PP-R pipe.

Applicability of sewage heat pump air-conditioning system

A sewage heat pump system and its application based on a project in Chongqing,China,were discussed. Based on the sewage conditions,a feasibility analysis of the sewage heat pump air conditioning system was conducted. The theoretical and quantitative calculations indicate that sewage flux in the city sewage main pipe in the project can satisfy heat exchange requirements,and taking water from the pipes has relatively small influence on the pipe net in summer and winter. The sewage heat pump air-conditioning system can save 21.5% operating cost in one year,which is energy efficient and environmentally friendly.

High-Superelasticity NiTi Shape Memory Alloy by Directed Energy Deposition-Arc and Solution Heat Treatment

Directed energy deposition-arc(DED-Arc)technology has the advantages of simple equipment,low manufacturing cost and high deposition rate,while the use of DED-Arc has problems of microstructure inhomogeneity,position dependence of macroscopic mechanical properties and anisotropy.Therefore,it is necessary to carry out a subsequent heat treatment to improve its microstructure uniformity,mechanical properties and superelasticity.In this investigation,the DED-Arc 15-layer NiTi alloy thin-walled parts with the solution treatment at different process parameters were studied to analyze the effects of solution heat treatment on microstructure,phase composition,phase transformation,microhardness,tensile and superelasticity.The temperature range of solution treatment is 800-1050℃,and the treatment time range is 1-5.5 h.The results show that after solution treatment at 800℃/1 h,the content of precipitated phase decreases,the grain is refined,the microhardness increases,and the mechanical properties in the 0°direction are improved.The strain recovery rate after 10 tensile cycles has increased from 37.13%(as-built)to 49.25%(solid solution treatment).This research provides an effective post treatment method for high-performance DED-Arc NiTi shape memory alloys.

某油田联合站污水余热利用研究

原油集输系统中的热化学沉降脱水,需要将原油温度升高,这一过程将消耗大量能源,其燃料主要为天然气,加热产生大量的CO_(2)。文中通过对某油田联合站生产流程研究分析,同时结合站内用热情况,确定采用压缩式热泵替代现有燃气加热炉技术路线,用于冬季采暖和一段原油加热。项目实施后,每年可节能源8932×10^(4) MJ,折合标煤减少3481.8 t,减少CO_(2)排放2024.5 t,每年可节省能源消耗费用651.8万元,节能减排效果显著,该研究对油田联合站清洁能源替代,减少CO_(2)排放具有重要意义。

寒冷地区农村居住建筑供暖能耗计算方法研究

分析了主要文献对多智能体的定义及其特征,对建筑环境与能源控制领域的多智能体控制系统应用的标准、常用框架和语言进行了综述和介绍,并对多智能体控制系统的不同系统架构、协调机制、优化算法进行了对比分析。针对建筑设备系统优化控制、单体建筑能源与环境优化控制、建筑与外部能源网络交互优化控制、建筑群与外部能源网络优化控制等不同层次的多智能体控制应用研究进行了综述,并对多智能体控制系统在建筑能源和环境领域应用中存在的时间序列优化、在线学习、计算不确定性、稳定性与收敛性等重要问题进行了讨论。

严寒地区农村住宅围护结构现状分析与优化研究

我国严寒地区气候寒冷且供暖季漫长,农村住宅采暖能耗问题突出,多数住宅采用自建形式,围护结构的热工性能普遍不理想。本研究从严寒地区农村住宅围护结构实际情况出发,对本溪农村地区200余户现有住宅进行调研。结果显示,本溪现有农宅基本未设置外墙保温,虽部分住宅屋顶设置保温,但保温材料均已超过使用年限,保温效果较差。有86.95%的农宅室内温度基本维持在18℃以下,农户满意度仅24.2%。实地测量3户典型农宅的室内环境温度。采用EnergyPlus模拟得到农宅围护结构的传热系数相比居住建筑节能设计标准规定限值超出300%~400%。根据实测数据和模拟数据对外墙、屋顶、外窗进行热工性能改造。对比单一围护结构改造前后的供暖季热负荷,得出外墙的改造效果最好。

严寒地区空气源热泵耦合电磁能系统模拟运行研究

目的 为了促进空气源热泵耦合电磁能供热系统在严寒地区住宅建筑中的应用,研究该系统的运行性能和稳定性。方法 以沈阳地区某住宅建筑为例,应用Trnsys软件建立了空气源热泵耦合电磁能供热系统仿真模型,并用实测值对模型进行了验证;深入探讨空气源热泵耦合电磁能供热系统在供热期的运行特点,并与空气源热泵和电磁能供热系统分别进行比较。结果 空气源热泵耦合电磁能供热系统模型可靠,相对误差可以控制在15%以内;在供热期,室内平均温度可保持在17.97~21.84℃;空气源热泵耦合电磁能供热系统比电磁能供热系统的COP提高了59.17%,空气源热泵耦合电磁能供热系统CO_(2)减排量比空气源热泵和电磁能供热系统分别提高1.47%和59.50%。结论 空气源热泵耦合电磁能供热系统运行和COP变化更为稳定,系统环境效益更佳,室内热舒适性更高。

考虑变掺氧富氧燃烧与利用LNG冷能的LAES的综合能源系统低碳经济调度

为促进风电消纳,减少火电机组的碳排放,解决综合能源系统(Integrated Energy System,IES)低碳经济运行问题,文中引入变掺氧富氧燃烧技术对燃气机组进行改造,并结合利用液化天然气(Liquefied Natural Gas,LNG)冷能的液化空气储能(Liquid Air Energy Storage,LAES),提出了一种电热气冷IES低碳经济优化策略。首先,构建含变掺氧富氧燃烧燃气机组、利用LNG冷能的LAES、电转气(Power To Gas,P2G)设备、中央空调和溴化锂制冷机的IES架构,并建立各设备的数学模型;其次,引入阶梯式碳交易机制,建立了以系统运行成本最小为目标的电热气冷IES低碳经济调度模型;最后,采用MATLAB调用GUROBI求解器对多个场景进行求解,验证了文中提出的低碳经济优化调度策略可以提高系统的风电消纳、有效降低系统运行成本,实现碳减排。

基于个人舒适系统杭州住宅冬季热舒适与能耗

为揭示该地区个人舒适系统(PCS)作用下的居民冬季热舒适特征和供暖能耗需求,以杭州市为对象,采用问卷调研和入户现场实测的方式得出冬季住宅开窗、遮阳、使用空调和PCS等典型热环境组合调节模式以及典型供暖模式和居民活动状态组合下的热舒适特征;在此基础上模拟得到冬季室内热舒适和供暖能耗特征。结果表明,冬季“无设备+静坐”、“空调+静坐”、“PCS+静坐”、“无设备+家务劳动”、“空调+家务劳动”、“PCS+家务劳动”等6种工况下的冬季中性温度分别是17.3、18.8、16.4、15.7、15.7、13.9℃,舒适温度区间分别是14.3~20.3℃、17.1~20.5℃、14.4~18.4℃、13.7~17.8℃、13.3~18.1℃、11.0~16.9℃。冬季室内热舒适水平受热环境调节模式影响较大,客厅在室舒适时间占比在43.74%~80.21%之间,卧室在室舒适时间占比均为70%以上。使用空调与PCS供暖时,典型建筑在冬初冬末的供暖能耗强度是1.28 kWh·m^(-2),在严冬的供暖能耗强度是13.06 kWh·m^(-2)。

基于某商务区多源耦合供热系统运行研究

为了实现“双碳”目标,提高可再生能源的利用率,减少碳排放量,对沈阳某商务区进行规划,充分发挥区域内地热能、污水能等可再生能源灵活供热的特点,以地源热泵+污水源热泵+电锅炉3种热源耦合进行供热,为区域综合能源多能互补、灵活调度提供参考。利用DeST模拟软件建立区域建筑模型,模拟出区域建筑供暖季逐时热负荷;通过TRNSYS软件建立区域综合能源系统模型,以某典型设计为例,分别讨论了在5种工况下该耦合供热系统峰谷电时段的运行策略,并采用费用年值法对系统经济性进行分析。结果显示:该区域内办公类建筑热负荷最大;系统不蓄热时初投资最小,由于在电高峰时段增加了电锅炉运行时长,导致系统运行费用增加,系统整体经济性变差;在蓄热率为100%时,该耦合供热系统初投资较大,但运行费用较低,系统费用年值最小,经济性最优,体现了蓄热方案下降低运行费用的优势。

Regulatory effects of Poria on substance and energy metabolism in cold-deficiency syndrome compared with heat-deficiency syndrome in rats

Recent studies have revealed that the property of drug is mainly associated with the body's substance and energy metabolism. The present study aimed to evaluate the drug property of Poria, called Fuling(FL) in traditional Chinese medicine(TCM), in terms of its effects on the substance and energy metabolism in rat models of cold-deficiency and heat-deficiency syndromes, compared with Aconiti Lateralis Radix Praeparaia, called Fuzi(FZ) in TCM, with hot property, and Anemarrhenae Rhizoma, called Zhimu(ZM) in TCM, with cold property, as reference drugs, respectively. The appearance score, toe and rectal temperatures of the animals treated were assessed at different time points. Several indices in vivo correlated with substance and energy metabolism(glucokinas, phosphoglycerate kinase, cytochrome c reductase, cytochrome c oxydase, and Na^+-K^+-ATPase), endocrine system(triiodothyronine, thyroxine, and 17-hydroxycorticosteroid), nervous system(acetylcholin esterase), and cyclic nucleotide system were determined. The changes in appearance score and indices in vivo suggested the successful establishment of cold-deficiency and heat-deficiency syndrome models. FZ reversed the decreased levels of indices(substance and energy metabolism and endocrine system) and alleviated the syndrome of cold-deficiency model, and ZM showed obviously therapeutic effect on heat-deficiency syndrome(appearance score, substance and energy metabolism, and endocrine system). FL could alleviate cold-deficiency syndrome and raise the decreased levels of glucokinas, phosphoglycerate kinase, cytochrome c reductase and triiodothyronine in cold-deficiency model, but had no significant effect on heat-deficiency syndrome. Drug property of FL was inferred as trending to "flat and warm", which still need further study. It was advisable to adopt both cold-deficiency and heat-deficiency models to study the drugs with "flat" property.

基于正常大鼠物质能量代谢的栀子不同炮制品寒热药性研究

目的通过检测栀子不同炮制品对正常大鼠物质代谢与能量代谢水平的影响,以期阐明炒制引起栀子寒热药性变化的科学内涵。方法雄性SD大鼠随机分为对照组、生栀子组、炒栀子组及焦栀子组。对照组大鼠灌胃蒸馏水(1 mL·100 g^(-1)),生栀子组、炒栀子组及焦栀子组大鼠分别灌胃给予等体积的相应炮制品水提取物,连续给药9天。记录各组大鼠给药期间体质量、肛温变化。酶联免疫吸附(ELISA)法检测大鼠肝脏组织中物质能量代谢相关指标GCK、PFK、PK、Acetyl-CoA、PDH、CS、ICD、α-KGDHC、PYGL、GSK-3、ATGL、CCR、COX、ATPs、ADK、Na^(+)-K^(+)-ATP酶、ATP、ADP、NAD及NADH的含量。免疫组化法(Immunohistochemistry,IHC)检测AMPK/mTOR信号通路关键蛋白的表达。结果与对照组相比,生栀子极显著性降低大鼠体质量、肛温、PK、PDH、Acetyl-CoA、CS、ICD、PYGL、GSK-3、ATGL、CCR、ATPs、ADK、Na^(+)-K^(+)-ATP酶、ATP、NAD^(+)、NADH、AMPK(P<0.01),显著性降低大鼠GCK、PFK、α-KGDHC、COX、ADP水平(P<0.05),极显著升高大鼠mTOR水平(P<0.01);炒栀子极显著性降低大鼠体质量、肛温、PK、PDH、Acetyl-CoA、CS、ICD、PYGL、ATGL、ATPs、ADK、Na^(+)-K^(+)-ATP酶、ATP、NAD^(+)、NADH水平(P<0.01),显著性降低大鼠PFK、α-KGDHC、GSK-3、COX、ADP及AMPK水平(P<0.05),极显著升高大鼠mTOR水平(P<0.01);焦栀子极显著性降低大鼠肛温、PK、Acetyl-CoA、CS、ICD、PYGL、ATGL、ATPs、ADK、NAD^(+)水平(P<0.01),显著降低大鼠体质量、PDH、Na^(+)-K^(+)-ATP酶、ATP及NADH(P<0.05),极显著升高大鼠mTOR水平(P<0.01)。与生栀子组相比,炒栀子极显著性升高大鼠PK、PDH、Acetyl-CoA、ICD、ADK及NADH水平(P<0.01),显著性升高大鼠PDH水平(P<0.05);焦栀子极显著性升高大鼠PK、PDH、Acetyl-CoA、CS、ICD、ADK、Na^(+)-K^(+)-ATP酶、NAD^(+)及NADH水平(P<0.01),显著性升高大鼠GSK-3、ATPs及AMPK水平(P<0.05)。与炒栀子组相比,焦栀子可极显著性升高大鼠Na^(+)-K^(+)-ATP酶及NADH水平(P<0.01)。结论生栀子组、炒栀子组及焦栀子组均能显著降低正常大鼠物质能量代谢水平,说明三者均属于寒性,这与《中国药典》记载的生栀子、炒栀子、焦栀子均属寒性一致。就大鼠物质能量代谢而言,焦栀子组高于炒栀子组,炒栀子组高于生栀子组,说明焦栀子寒性弱于炒栀子,炒栀子寒性弱于生栀子。

中深层地热地埋管管群换热性能模拟和布置优化

在中深层地热地埋管(DBHE)供热技术应用中,主要使用多个地埋管构成管群为建筑供暖。为了研究中深层同轴地埋管管群换热性能,本文基于西安市西咸新区典型地质分布,构建了中深层同轴地埋管管群数值模型,研究了不同间距、不同分布下各地埋管换热器间热交互作用以及长期取热期水温衰减规律。结果表明,多井集群供暖过程中周围岩土所形成的“冷堆积”现象是导致地埋管集群供暖能力逐年下降的主要原因;当地埋管间距从5m增至25m,平均出口水温和取热功率分别提升3.86%和11.5%;在西咸新区典型地质条件分布下,地埋管间间距应保持在15m以上;本文提出的四种管群分布中,地埋管呈直线分布时各地埋管出口水温和取热功率衰减最小,其中心地埋管出口水温仅衰减5.74%。在工程设计中,中深层地埋管管群应尽可能直线排布,避免重叠排布。

严寒地区被动房室内环境与供暖能耗后评估

对严寒地区某被动房示范项目的室内环境和供暖能耗进行了后评估,并与位于同一小区的普通住宅进行了对比分析。结果表明:被动房高性能的围护结构可有效提高室内操作温度,且由于设置了机械通风系统,可有效稀释室内CO_(2)浓度;被动房供暖季室内PM2.5浓度超标,新风系统对细颗粒物的过滤效率不满足要求;被动房供暖实际运行能耗高于超低能耗建筑年供暖耗热量指标,偏差达到33.6%。