The economic geography of fuel choice: The spatial nexus of consumer economics and carbon emissions is fundamental to effective decarbonization policy-making

Many state and local governments are considering ways to decarbonize their building sectors. This study evaluates domestic heat pumps’ relative advantage over comparable natural gas-burning systems in terms of consumer economics and carbon impacts in 48 states, accounting for disparities in physical and market conditions that determine system’s use and costs. The results show that decarbonization policies are more likely to succeed in states where potential carbon benefits coincide with favorable consumer economics.     

高效蓄能互联热泵系统技术及应用

在目前国家大气污染治理工作背景下,针对我国严寒地区及寒冷地区无法使用水地源热泵或地埋管热泵问题,以及使用空气源热泵存在能效比低、故障率高等问题,提出蓄能互联热泵系统清洁采暖方案,通过综合技术创新突破单一技术运用的客观限制,打造"不打井、不做地埋管"的水-水热泵系统,使得常规空气源热泵的使用边界扩大、稳定性增强、投资减少、故障率降低,并且能够在暖气片供暖系统改造中稳定提供60℃热水。以国网兰州建西变电站家属楼暖气片改造项目为例,进行了方案设计、设备选型和运行效果分析,验证了蓄联热泵系统的可靠性、经济性。     

计及建筑蓄能的综合能源系统优化调度

针对传统用户侧综合能源系统在优化调度过程中未充分利用建筑蓄能特性的问题,建立了以燃气轮机为主体的冷热电三联供系统,并将太阳辐射、围护结构传热过程以及室内空气蓄热等因素考虑进去对建筑进行建模,通过设置温度舒适区间使建筑蓄能参与到优化调度过程中.利用该模型,以最低运行成本为目标对四种典型场景进行对比分析,计算得出四种场景运行成本分别为187.01$、316.52$、191.55$、319.13$.结果 表明,围护结构不仅能够隔热而且具有蓄热特性,它与室内空气共同构成建筑蓄能环节,能够根据热量需求以及电价变化参与到系统调度过程中,完成热电解耦或制冷需求调节;充分利用建筑蓄能特性能够有效降低运行成本.     

Energy Conservation in Urban Areas

This article outlines the energy conservation measures in the civilian sector from a few different viewpoint regarding energy conservation in cities. First, the energy consumption trends in the business and residential sectors are discussed, focusing the importance of energy conservation measures in applications such as home heating, water heating and specific power demand. Second, as a measure to reduce energy demand itself, energy conservation by way of applying heat insulating materials to buildings and changing the life style of residents is considered. And from the viewpoint of improving the energy system efficiency, additionally discussed here are the measures to improve the efficiency of each energy equipment such as air‐conditioners and co‐generation equipment, and the characteristics of District heating and cooling systems such as the local energy infrastructures. Lastly, from the knowledge obtained through model analyses by the authors, a scheme is recommended that would be one of the most efficient city‐energy schemes where the energy systems including heat pumps, co‐generators or equipment using solar power are utilized for their best‐suited applications for business and residential customers. Copyright © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Estimation of low-potential heat recuperation efficiency of smoke fumes in a condensation heat utilizer under various operation conditions of a boiler and a heating system

For enhancement of the natural gas utilization efficiency in boilers, condensation heat utilizers of low-potential heat, which are constructed based on a contact heat exchanger, can be applied. A schematic of the contact heat exchanger with a humidifier for preheating and humidifying of air supplied in the boiler for combustion is given. Additional low-potential heat in this scheme is utilized for heating of the return delivery water supplied from a heating system. Preheating and humidifying of air supplied for combustion make it possible to use the condensation utilizer for heating of a heat-transfer agent to temperature exceeding the dewpoint temperature of water vapors contained in combustion products. The decision to mount the condensation heat utilizer on the boiler was taken based on the preliminary estimation of the additionally obtained heat. The operation efficiency of the condensation heat utilizer is determined by its structure and operation conditions of the boiler and the heating system. The software was developed for the thermal design of the condensation heat utilizer equipped by the humidifier. Computation investigations of its operation are carried out as a function of various operation parameters of the boiler and the heating system (temperature of the return delivery water and smoke fumes, air excess, air temperature at the inlet and outlet of the condensation heat utilizer, heating and humidifying of air in the humidifier, and portion of the circulating water). The heat recuperation efficiency is estimated for various operation conditions of the boiler and the condensation heat utilizer. Recommendations on the most effective application of the condensation heat utilizer are developed.     

Investigation of failures in operation of heat networks of large heat supply systems

The effect of deviations in heat network parameters on operation of heating system and hot-water supply systems in buildings is examined. The consequences of a decrease in the water temperature in a heat network under extreme weather conditions in a range below the design ambient air temperature, the efficiency of disconnection of a hot water supply system (HWSS) heater in this period, and deviations in the normal heat supply in the transition period at relatively high outdoor temperatures are considered. The specific and scope of failures depend on the design-heating load to design hot water supply load ratio for the heat network. A mathematical model was developed, and numerical investigation was performed of modern schemes of heat points which are designed primarily for covering the hot water supply load and recovering the heating system heat output in case of low or no hot water consumption in HWSS. The performed calculations demonstrate that the heating system has no time to restore its heat output, thereby considerably reducing air temperature in the heated premises. The lower the ambient air temperature and the lower the ratio of the design loads for hot water supply and heating, the greater is this decrease. At the same time, in case of a sudden decrease in the outdoor temperature and an accident in the heat supply system, the heating system must be the priority consumer, since a heating failure not only decreases the thermal comfort of consumers but can cause emergency situations in local utility systems, such as a cold water supply system. Correction of failures in a heat supply system requires calculation of operating conditions of heat networks.     

Startup of air-cooled condensers and dry cooling towers at low temperatures of the cooling air

The problems of startup and performance of air-cooled condensers (ACC) and dry cooling towers (DCT) at low cooling air temperatures are considered. Effects of the startup of the ACC at sub-zero temperatures are described. Different options of the ACC heating up are analyzed, and examples of existing technologies are presented (electric heating, heating up with hot air or steam, and internal and external heating). The use of additional heat exchanging sections, steam tracers, in the DCT design is described. The need for high power in cases of electric heating and heating up with hot air is noted. An experimental stand for research and testing of the ACC startup at low temperatures is described. The design of the three-pass ACC unit is given, and its advantages over classical single-pass design at low temperatures are listed. The formation of ice plugs inside the heat exchanging tubes during the start-up of ACC and DCT at low cooling air temperatures is analyzed. Experimental data on the effect of the steam flow rate, steam nozzle distance from the heat-exchange surface, and their orientation in space on the metal temperature were collected, and test results are analyzed. It is noted that the surface temperature at the end of the heat up is almost independent from its initial temperature. Recommendations for the safe start-up of ACCs and DCTs are given. The heating flow necessary to sufficiently heat up heat-exchange surfaces of ACCs and DCTs for the safe startup is estimated. The technology and the process of the heat up of the ACC with the heating steam external supply are described by the example of the startup of the full-scale section of the ACC at sub-zero temperatures of the cooling air, and the advantages of the proposed start-up technology are confirmed.     

考虑配电网容量约束和建筑热惰性的城市换热站电制热补热优化配置方法

北方地区市政供暖普遍存在热源、热网缺口和化石燃料依赖度高的问题,增量建筑的末端供热效果难以保障,而依靠传统配电网增容的方式一定程度上造成了社会资源的浪费。设计了一种面向城市换热站的电制热补热系统,提出了一种配电网“免增容”的城市换热站电制热补热优化配置方法。首先,阐述了电制热补热系统的设计结构,建立了制热设备和蓄热设备的模型与建筑热惰性模型。然后,通过两阶段优化方法,考虑设备投资与运行成本,以经济性为目标,建立了电制热补热优化配置模型。最后,以北京市石景山某居民区为研究对象通过Matlab进行仿真计算,研究结果表明,电制热补热优化配置方法可有效降低配电网负荷峰谷差,保障末端供热效果,并且具有较好的经济性,可为电采暖规划提供参考。     

In this issue

Global research shows that urgent and unprecedented actions are needed to combat climate change, but the development of clean-energy technologies means that solutions are at hand. What we need now to decarbonize the economy – affordably, quickly, and reliably – is to make it possible for these technologies to deploy and operate as cost-effectively and efficiently as possible. The articles in this special issue further explore ways we can optimize energy use, making the power system both more efficient and more flexible.     

基于模型预测控制的智能楼宇用能灵活性调控策略

提出一种基于模型预测控制的智能楼宇用能灵活性调控策略。首先,根据楼宇蓄热特性,构建考虑楼宇内部不同制热区域的智能楼宇能耗预测模型,并将楼宇系统作为灵活可控单元集成到配电网中;然后基于模型预测控制方法,通过楼宇内部暖通空调系统在温度舒适度范围内对室温进行优化调节,实现楼宇系统的能耗灵活管理,降低楼宇运行成本;最后,在冬季制热场景下,对不同暖通空调控制方法下的楼宇集群进行优化调度分析,并对比分析了楼宇集群优化调度对于配电网运行状态的影响。结果表明,所提方法在保证温度舒适度的前提下可充分发掘智能楼宇的需求响应潜力,降低楼宇运行成本,同时可有效解决由可再生能源出力预测数据误差而导致的楼宇日前调控方案与实际运行场景偏差较大的问题,在预测不确定性环境下具有较强的鲁棒性。     

基于暖通负荷集群响应能力的电力系统频率控制策略

为提升系统频率稳定水平,提出了一种基于暖通空调负荷集群响应能力的电力系统频率控制策略,采用建筑采暖热泵作为可控负荷参与系统调频服务.首先,通过构建等值热力学参数模型来描述热泵的控制温度动态过程.进而根据用户温度舒适范围确定单体热泵的调频可控域,判断热泵是否可参与调频响应,保障热泵工作过程中的控制温度满足用户需求.同时,...     

北京市建筑节能及地源热泵的推广前景

北京作为首都,可持续发展的目标是要建设成为一座宜居城市,供暖空调采用环保技术是大势所趋。电力作为二次能源,没有任何本地污染,非常适合北京地区使用;在各级政府机关及能源界各行业的共同努力下,国内建筑节能市场日趋成熟,供暖空调技术呈现出多元化发展的景况,面对巨大的国内建筑节能市场,应当加大推动电驱动热泵技术的力度,扩大电力在建筑节能领域内的市场份额。     

Estimation of efficiency of the heat supply system based on a boiler house and a wind turbine in the northern environment

This article describes a methodological approach to defining indoor air temperature in buildings heated by a power supply unit consisting of a boiler house and a wind-driven power plant (WDPP). We discuss a heating option for a residential building in the windy conditions of Murmansk city. We proved that, during the periods of strong wind, a WDPP can partially or fully satisfy the heat demand and sometimes even create a surplus of energy. During low wind weather, almost all loads are handled by the boiler house. We considered a possibility to accumulate the surplus energy obtained from a WDPP during strong wind by increasing the temperature in the whole building up to 25°C and further using the accumulated heat during the lowwind period when indoor air temperature may fall below 20°C. This allows saving organic fuel in the boiler house. We demonstrated how indoor air temperature in the building may change throughout the year when using the surplus energy from the WDPP due to thermal storage capacitance of the building. We also provided the results of study, showing favorable energy-related effects of using a WDPP along with the boiler house. It was determined that engaging a WDPP in fulfilling the diagram of heating loads promotes the decrease in the boiler house’s contribution to heat supply by 30 to 50%, and using the surplus energy from the WDPP and thermal storage capacitance of the building allows reducing the contribution of the boiler house by 5–15% more in certain months.     

考虑建筑热平衡与柔性舒适度的乡村微能源网电热联合调度

针对乡村高渗透率新能源消纳和清洁供暖问题,提出了一种考虑建筑热平衡与用户柔性舒适度约束的微能源网电热联合调度方法。首先,提出了基于乡村地区人员作息规律的柔性舒适度约束,并建立了考虑围护结构特性、门窗渗透、冷风侵入、内热源散热等因素的热平衡模型;其次,构建了含户级电热分散供应和村级集中光伏接入的乡村微能源网基本架构,发展了空气源热泵等微能源网元件的效能描述模型;再次,考虑光伏消纳经济性,构建了以系统整体效益最优为目标、用户舒适性为约束的乡村微能源网电热联合日前调度的数学模型,提出了基于遗传算法的求解方法;最后,通过算例验证了所提模型和方法的有效性与实用性。     

Converting excess low-price electricity into high-temperature stored heat for industry and high-value electricity production

The large-scale deployment of wind or solar energy results in electricity prices below the price of fossil fuels at times of high wind or solar output. Price collapse can be limited by using low-price electricity to heat firebrick to high temperatures, store the heat in firebrick, and provide hot air as needed to industrial furnaces, kilns, power plants and gas turbines. This sets a minimum price on electricity near that of fossil fuels.     

Emissions reduction potential from electric heat pumps in California homes

Electric heat pumps offer a promising opportunity to help achieve deep decarbonization of the building sector. However, since electric generators serve load in real time with varying emissions, comparing the emissions impact of heat pumps to their natural gas heating alternatives requires considering time of use. We analyze the temporal load shapes of heat pump water heaters and air-source heat pumps in the context of temporal grid-level emissions data. We find that switching from natural gas to electricity could reduce the annual emissions of a California household by 50–70% and 46–54% for water and space heating, respectively. These findings support the adoption of electric heat pumps as a strategy for deep decarbonization.     

空调冰箱热水三用机研发生产可行性论证

中国是全球家电生产量和需求量最大的国家,市场竞争、产能过剩已成了不争的事实。空调冰箱热水三用机在节能上有一定的突破,每年可为每户3～5人家庭节约上千元的电费,同时也减轻了夏季居民社区的热岛效应和周边环境的热污染;本项目产品具有空调器、冰箱、热水器三种产品的综合功能,其优点是空调、冰箱制冷排放的热量用于制热水,使得夏季供生活热水O消费,春秋冬季供热水比电热水器节电75％以上。该产品最大的特点就是冰箱系统为全天候双向使用,其产品以性价比高、节能能力强的优势,必将受到消费者的青睐。     

Energy Interactions of Electric Clothes Dryers and Heat Pump Water Heaters with Building Equipment Systems

The way in which an appliance is used or where the appliance is located affects its energy usage. The building equipment system which usually is most affected by the efficiency and/or the manner of operation of other building equipment systems (appliances) is the house heating and cooling (HVAC) system. Two cases of energy interactions between appliances and the house HVAC are discussed, and measured operating data are used to calculate the appliance energy usage including the HVAC interaction. The first study involves the interaction between a heat pump water heater (HPWH) and the house HVAC. Since an HIPWH extracts energy from the air in its surroundings and adds it to the water it is heating, the load on the house HVAC will be changed if the HPWH is located in a conditioned space. The second study concerns the increased amount of infiltration air brought into a house caused by venting a clothes dryer to the outside. All the increased infiltration air must be conditioned by the house HVAC if the dryer is located in a conditioned space. Graphs and tables based on measured data are presented which show the estimated interaction of the house HVAC with an HPWH and a vented electric clothes dryer.     

基于ZigBee技术的建筑中央空调节能监控网络节点研究

针对暖通空调耗能多、节能潜力大的现状,研发了一种基于Zig Bee技术的建筑中央空调节能监控网络,可实现对大型公共建筑或建筑群中央空调系统的实时监测与控制。网络节点根据IEEE 802.15.4/Zig Bee协议组成自组织无线传感网络,采用无线温度、湿度等传感器,对建筑环境温度、湿度,动力中心板式换热器二次侧供水、回水温度等参数进行实时采集。通过GPRS网络将现场运行参数传至监控中心上位机,实现了上位机对整个系统运行的节能管理与优化控制。     

热泵空调器节能技术及使用方法的研究

从解决热泵空调器在实际使用过程中出现的制冷量与制热量需求的矛盾,在低温度环境下使用时制热能力和能效比（性能系数）衰减严重及出“冷风”等问题为突破口,以实际实验数据和理论计算为依据,证实热泵空调器通过系统配机和改进使用方法是可以得到广泛应用的。