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排序方式: 共有508条查询结果,搜索用时 15 毫秒
1.
受中国电信委托、原邮电部经济技术发展研究中心在全国进行一次农村电信市场调查,以了解当前农村通信市场发展潜力,本文公布了此次调查的结果,从经济能力、资费和潜在市场等方面提出了发展农话的建议 。 相似文献
2.
Effect of electricity tariff on the optimum insulation-thickness in building walls as determined by a dynamic heat-transfer model 总被引:5,自引:0,他引:5
Thermal insulation is one of the most effective energy-conservation measures in buildings. Despite the widespread use of insulation materials in recent years, little is known regarding their optimum thickness under dynamic thermal conditions. Insulated concrete blocks are among the units most commonly used in the construction of building walls in Saudi Arabia. Typically, the insulation layer thickness is fixed at a value in the range 2.5–7.5 cm, regardless of the climatic conditions, type and cost of insulation material, and other economic parameters. In the present study, a numerical model based on a finite-volume, time-dependent implicit procedure, which has been previously validated, is used to compute the yearly cooling and heating transmission loads under steady periodic conditions through a typical building wall, for different insulation thicknesses. The transmission loads, calculated by using the climatic conditions of Riyadh for a west-facing wall, are fed into an economic model in order to determine the optimum thickness of insulation (Lopt). The latter corresponds to the minimum total cost, which includes the cost of insulation material and its installation plus the present value of energy consumption cost over the lifetime of the building. The optimum insulation thickness depends on the electricity tariff as well as the cost of insulation material, lifetime of the building, inflation and discount rates, and coefficient of performance of the air-conditioning equipment. In the present study, the effect of electricity tariff on the computed optimum insulation thickness is investigated. Different average electricity tariffs are considered; namely, 0.05, 0.1, 0.2, 0.3 and 0.4 SR/kWh (designated as Cases 1–5, respectively; 1 US$ = 3.75 Saudi Riyals). Results using moulded polystyrene as an insulating material show that the values of Lopt are: 4.8, 7.2, 10.9, 13.7 and 16.0 cm for Cases 1–5. Under the conditions of optimal insulation thickness for each electricity tariff, Case 1 gives the lowest total cost of 17.4 SR/m2, while Case 5 gives the highest total cost of 53.1 SR/m2. Corresponding thermal performance characteristics in terms of yearly total and peak transmission loads, R-value, time lag and decrement factor are presented. 相似文献
3.
Marielle Montginoul 《Water Resources Management》2007,21(5):861-871
This paper presents the results of a 2003 national survey of urban water pricing structure implemented by 429 district level
water utilities. After providing some background elements on the diversity of existing water pricing structures, the paper
shows how each structure can be used to achieve different management objectives (water allocation efficiency, costs recovery,
and equity). It then describes the structures adopted by French water utilities, showing that flat rate are rarely adopted;
declining blocks frequently used; and increasing blocks pricing which should be used to promote water use efficiency remain
extremely rare. A statistical clustering is then conducted and a typology of situations elaborated. The paper concludes with
highlighting that current pricing structures are influenced by past practices and that the dominant objective of water utilities
is to cover costs. 相似文献
4.
《The Electricity Journal》2022,35(10):107219
Given the steady growth in the use of electric vehicles in India, and the need to locate charging stations in various places to fulfill the corresponding demand, this paper focuses on an applicable Electricity Tariff Policy Framework in the context of power supply to Electric Vehicle Charging Stations(EVCSs). The framework is conceptualized by a theoretical foundation, an operational/functional foundation, and a transactional foundation. The theoretical foundation incorporates justice risk across the Energy Lifecycle stages by classifying the relevant international, regional, and national issues within the legal layers of Energy Law while examining the core ideas of the 'Energy Trilemma'. The paper identifies two basic dimensions, (a) the target sets of end-users, and (b) EVCSs settings and the applicable tariff schemes, as the foundation of the framework. The operational/functional foundation consists of techno-economic and social criteria, and the transactional foundation involves the consideration of different target sets of end-users. The proposed framework will benefit policymakers in general and those, especially in India. Adaptation and use of the framework in other countries should consider their basic economic, geographic and political structures. 相似文献
5.
为实现跨境物流服务供应链完全协调,运用Stackelberg博弈理论,构建由一个跨境物流服务供应商与一个物流服务集成商组成的二级供应链。采用因子分析法测度通关水平,分析通关水平对跨境物流服务供应链最优决策及协调运作的影响,设计可供跨境物流服务供应链完美协调的契约机制。研究表明,考虑通关水平使跨境物流服务供应链成员及供应链整体利润均得到提升;集中决策下跨境物流服务供应链整体利润总是高于分散决策;收益共享契约可实现跨境物流服务供应商及供应链整体决策的帕累托优化,但不能达到供应链的完全协调,而Nash协商改进的二部定价契约模型可实现供应链的完全协调。 相似文献
6.
在高供高计的用电企业中,变压器空载时的无功损耗往往由电网供给,影响电网输送能力,另外造成企业用电功率因数偏低,产生高额的力调电费。该文采用低压自动空载补偿的方法,减少变压器空载时从电网中消耗的无功功率,从而提高功率因数,节约企业生产成本。 相似文献
7.
利用价格杠杆调节北京地区夏季高峰负荷 总被引:2,自引:0,他引:2
针对北京地区的新电价方案.简要介绍了调整电价结构的必要性和具体内容,调节高峰负荷的预计效果以及各用电单位充分利用价格杠杆调荷节电、减少电费支出的应对措施。 相似文献
8.
黄健 《安徽电气工程职业技术学院学报》2003,8(1):40-43
电费计算工作政策性很强 ,本文依据现行电价制度及有关电费电价的政策法规精神 ,对不同的客户在不同用电方式下的电费计算问题 ,进行了归类总结。 相似文献
9.
刘占清 《小型微型计算机系统》1998,19(6):72-76
本文介绍程控交换机计费系统的设计,并结合改进某进口程控交换机计费系统的实践,提出设计中确保计费准确性的若干关键环节。 相似文献
10.