关于空调水系统节能的探讨

以空调冷冻水系统的节能为例 ,探讨空调系统节能的途径、存在的问题及解决办法     

空调冷冻水系统的微机控制

本文通过分析空调耗能量与自然环境的关系,应用控制原理,提出了一种用微机来控制冷冻水系统的方法。最后,以某办公大楼空调冷冻水系统为例,进行了微机控制系统的分析。     

高层建筑空调节能设计的探讨

指出了空调系统耗能的两个方面，介绍了空调系统设计的几个节能措施，如合理降低室内温度湿度标准、控制与正确利用室外新风量等。     

住宅的采暖空调设计

在设计北京高层高级住宅时，从提高住宅的舒适性考虑，一定要设计采暖空调系统，从系统的经济、节能乃至于今后的运行方面考虑一定要进行优化计算，为此，我们做了如下两方面的工作。（1）了解住宅用各种采暖空调设备的所有性能及适用条件。（2）对各种采暖空调方案进行经济、节能、环境乃至今后运行的比较，确定最优方案。     

减阻技术在集中供热与空调水输配系统中的应用

集中供热与空调系统在我国已经成为耗能大户 ,其中大量能耗消耗在水泵上用来输送热水或冷冻水、冷却水。减阻技术在集中供热及空调水输配系统的应用可以极大地降低泵耗 ,从而具有广阔的节能前景。本文介绍了可用来降低泵耗的粘性减阻技术的减阻机理、减阻方法 ,并介绍了国、内外减阻技术在暖通空调领域的应用研究情况。     

某铸造厂综合空调系统节能设计

从某铸造工厂综合空调系统的实际工程出发,在综合空调系统设计和控制系统设计的基础上,分别从自然冷却、冷冻水的能量能级利用、岗位空调技术、变频控制等方面论述该空调系统的节能措施。     

大温差空调冷冻水系统的节能分析

以单位冷量空调总能耗为目标函数,对大温差空调冷冻水系统方案进行了优化计算,得出了空调冷冻水系统最佳供回水温差为7.2℃,探讨了大温差空调水系统方案的适用场合.     

化纤厂暖通空调节能探讨

根据化纤厂暖通空调是能耗大户的特点，从热力系统、制冷系统、水系统、空调系统等方面进行分析，总结出耗能原因，并提出相应的节能措施。     

大温差水系统运用于数据中心空调节能性分析

对大温差空调水系统应用于数据中心项目进行了节能性分析,基于假定的系统模型对不同冷冻水供回水温差条件下系统的制冷主机能耗、冷冻水泵能耗以及末端精密空调设备能耗进行了计算。计算结果表明,增大供回水温差对于数据中心空调系统能效提升具有积极意义。     

某综合楼空调通风节能设计

探讨移动通信综合楼的空调通风形式，着重阐述选用冷冻水型机房专用空调器的优点、应该注意的问题及本工程所采取的措施，并介绍了中央空调冷源、水系统、空调末端装置、通风防排烟系统及自控等的设置情况，以及空调系统节能设计的重要性。     

集中式循环冷却水系统能量分析

针对火电厂、石化等大型及特大型企业的冷却水用水量消耗巨大的问题,分析了集中式循环冷却水系统的能量。为提高循环冷却水系统内的能量利用效率,在现阶段循环冷却水系统流行的两种设计方法即按水泵扬程最小化和按基建投资最优的基础上,提出了利用水动风机冷却塔和生态小水电两种冗余能量回收改造法;为便于直观比较各设计方法的节能效果,提出了冗余能量系数λ,提供了一种工业循环冷却水系统设计方法的选择标准。     

Evaluation of energy saving of CCHP systems using an active energy storage regulation method

节能性是评价冷热电联供系统的重要指标之一.阐述了分布式冷热电联供系统中主动储能调控方法的原理.基于用户侧负荷特性和燃气轮机变工况运行规律的分析,采用相对节能率作为评价联供系统节能性的指标,以夏季冷电并供时的饭店类型建筑典型负荷为案例,探讨主动储能调控在分布式冷热电联供系统中的节能效果及影响因素.结果表明,与常规分产系统相比,无主动储能的相对节能率为11.8%,主动储能调控的联供系统相对节能率为21.6%.相对节能率的大小受到电压缩制冷系统性能系数和用户负荷冷电比的影响,电压缩制冷系统性能系数越高则联供系统相对节能率越低,用户负荷冷电比越高,联供系统相对节能率越高.     

A methodology to assess suitability of a site for small scale wet and dry CSP systems

This study presents a methodology to assess suitability of a site for small scale concentrated solar power (CSP) systems for its energy conversion efficiency and make‐up water requirement. Energy conversion efficiency of CSPs relies not only on the level of direct solar radiation but also on the performance of the cooling system. Regions with high solar potential have to deal with heat rejection at elevated temperatures which causes reduced energy conversion efficiencies due to high condenser temperatures. It is desirable to utilize wet cooling systems as they can achieve temperatures lower than the dry bulb temperature by evaporative cooling. On the other hand, such regions usually lack water resources which deteriorate the sustainable nature of CSP applications. This study combines various available models for both solar resource estimation and cooling systems' performance considering (i) the influence of ambient temperatures, and (ii) the influence of humidity levels. These models are integrated together to analyze the use of dry or wet cooling systems in terms of overall energy output and water consumption at a selected site in northern Cyprus. The model inputs consist of only annual hourly surface weather data and the location of the site of interest. The results show that dry cooling unit at northern Cyprus is capable of saving water about 18.7 ton/MWh while it produces 27% less energy compared to the wet cooling alternative for the representative annual weather data. Copyright © 2015 John Wiley & Sons, Ltd.     

Modeling and daily operation optimization of a distributed energy system considering economic and energy aspects

This paper presents a distributed energy system (DES) for a local district and formulates a constrained nonlinear multiobjective optimization model for the daily operation of the system. The main objective of the study is to increase the efficiency by minimizing energy cost, energy consumption, and energy losses. It is implemented through the integration and complementation of renewable energies and fossil fuels as well as the recycling utilization of waste heat in the DES. The consideration of network topology and energy losses of water heating network could also contribute to the improvement of energy efficiency. To solve the optimization problem, a novel Whale Optimization Algorithm is employed. Furthermore, the economic and energy performance of the DES are evaluated and compared with that of conventional centralized energy systems, ie, the EG and MG energy‐supply modes. After simulation studies, the hourly optimal energy (both natural gas and electricity) purchasing schedule as well as the hourly optimal set points of mass water flow rates and supply/return water temperatures could be determined. The results show that the DES saves more than 50% of energy costs/energy consumption than the MG mode and over 22% than the EG mode for a whole day, verifying the competitive advantage and great potential of both energy saving and cost reduction of the DES.     

A study of the potential of using the Earth to air heat exchanger for cooling and heating of residential buildings in Iraq

The Earth to air heat exchanger (EAHE) is an effective passive cooling and heating system for buildings. This paper studied numerically the potential for reduction in energy consumption for cooling and heating loads for a residence equipped with an EAHE system in the climate of Nasiriya city, which is located in southern Iraq and at 31.7°N and 45.8°E, latitude and longitude, respectively. Also, this paper presents a study about the thermal performance of three types of EAHE systems, system 1, consisting of one layer of EAHE and buried at an available area of house garden with 3‐m depth, system 2, at the same site of system 1, but with two layers of EAHE at two depths, 3 and 4 m, and finally, system 3, buried along the area of the house at a depth of 3 m. First, the built numerical model was validated against experimental results, and the results of the comparison showed good agreement. The electricity consumption for cooling and heating of the house is calculated with and without the EAHE system. The results showed that with using EAHE, there is a considerable saving in energy and saving in the cost of electricity consumption, which reached 376 329 IQD ($301.11) over 1 year for system 2.     

冷热组合型超市系统的设计与经济性分析

设计了冷热组合型超市系统,利用CO2跨临界循环对空间夏季供冷和冬季供热,采用R290/CO2复叠式制冷循环对食品冷冻冷藏,同时回收CO2跨临界循环高温气体散发的热量和R290/CO2复叠式制冷循环R290高温循环气体的冷凝热,实现夏季空间供冷、食品制冷的同时供应生活热水,冬季空间供暖、食品制冷的同时供应生活热水,及春秋季节食品制冷同时供应生活热水。并与供冷、供暖、食品制冷和供应生活热水分别进行的常规R404A超市系统的能效相比较,得出冷热组合型超市系统的能耗大大降低,能效明显增加,不仅节约能源,而且保护环境,是很有发展前景的绿色环保系统。     

供冷系统能耗评价模型及应用

随着人民生活水平提高,供冷系统日益普及。受全球气候变暖和能源资源短缺问题影响,供冷系统能耗控制日益受到广泛关注。为科学表征供冷系统能源消耗状况,将供冷系统划分为六个子系统,从总能系统层次上给出了适合于各类供冷系统的广义化的能耗评价一般模型。在此基础之上,结合单耗分析方法,提出了供冷系统能耗的定量计算方法。采用了热力学第一定律、热力学第二定律分析,对供冷过程的热力学本质、冷量?、供冷能力等方面展开研究,系统阐述了供冷系统的理论节能极限及理论最低能耗,并立足总能系统对供冷过程的理论极限－可逆供冷作出了说明。在北京市目前设计标准下,供冷系统理论最低燃料单耗为0.82kg/GJ,当前供冷系统能耗水平（25.27 kg/GJ）与之相比,节能潜力甚大。为验证所构建的供冷系统能耗评价一般化模型,结合北京市通州区供冷系统的实施方案,对分散电制冷、集中电制冷、分散热制冷、集中热制冷四个基本类型的供冷模式进行了实例计算分析,并与四种模式的?分析计算结果进行了比较,结果显示：所提能耗模型与?分析结果一致,电制冷燃料单耗低于热制冷,分散制冷燃料单耗低于集中制冷,集中热制冷能耗较高,应慎重发展。所提出的能耗分析评估模型为各种类型供冷系统的一般化对比评估提供了理论分析方法,同时可为城市供冷系统的规划设计提供参考。     

Optimization model analysis of centralized groundwater source heat pump system in heating season

The ground-water heat-pump system (GWHP) provides a high efficient way for heating and cooling while consuming a little electrical energy. Due to the lack of scientific guidance for operating control strategy, the coefficient of performance (COP) of the system and units are still very low. In this paper, the running strategy of GWHP was studied. First, the groundwater thermal transfer calculation under slow heat transfixion and transient heat transfixion was established by calculating the heat transfer simulation software Flow Heat and using correction factor. Next, heating parameters were calculated based on the building heat load and the terminal equipment characteristic equation. Then, the energy consumption calculation model for units and pumps were established, based on which the optimization method and constraints were established. Finally, a field test on a GWHP system in Beijing was conducted and the model was applied. The new system operation optimization idea for taking every part of the GWHP into account that put forward in this paper has an important guiding significance to the actual operation of underground water source heat pump.     

多冷却塔循环水系统的能耗优化

建立了电耗为目标函数的多冷却塔循环水系统数学模型,先用计算软件MATLAB确定循环水最佳出塔温度,然后用商业软件GAMS求解出电耗最小时的分配系数,并给出了最优结构;文章最后部分给出了详细的案例分析,将优化前后风机和水泵的电耗,总电耗加以比较;结果表明,优化后风机和水泵的电耗均有所降低,总电耗降低多达20%左右,节能效果明显。     

Water usage and energy penalty of different hybrid cooling system configurations for a natural gas combined cycle power plant—Effect of carbon capture unit integration

Electric power generation from thermoelectric power plants is associated with a negative impact on water availability, referenced as the water‐energy nexus, which is aggravated by climate change. In the present study, the effect of four different hybrid cooling system configurations on water usage and power penalty of a natural gas combined cycle has been investigated. The hybrid cooling system with a parallel connected indirect dry cooling system and wet cooling system is the most conventional studied hybrid cooling system in the literature, while the other studied hybrid configurations in the present study are novel regarding their effect on water requirement and power penalty. Simulations were conducted using the COCO 3.3 software and have been validated using data sets from a reference natural gas combined cycle plant, both with and without carbon capture unit, which is available in the literature. Four hybrid cooling system configurations were explored to evaluate their water requirements and power penalty. Other conventional cooling systems such as closed cooling, once‐through, and direct and indirect dry cooling methods were simulated with and without postcombustion carbon capture (PCCC) integration for comparison. It was found that the hybrid configuration, including indirect air‐cooled condenser and natural draft wet cooling tower, has the best performance as compared to the other conventional and hybrid cooling systems, amounting to 2.038 (gal/min)/MW_net, 1.573 (gal/min)/MW_net, and 12.29 MW for water withdrawal, consumption, and energy penalty, respectively, for the case of a unit without PCCC unit and 3.9 (gal/min)/MW_net, 2.928 (gal/min)/MW_net, and 15.177 MW for water withdrawal, consumption, and energy penalty, respectively, for a unit with carbon capture unit. It was confirmed that the PCCC integration approximately doubles the water withdrawal and consumption for all cooling systems. In addition, the indirect air‐cooled condenser and wet cooling tower is still the best performing cooling system with PCCC integration.