Better Use Of Energy Research Articles

A Financial Analysis of Several Air Conditioning Systems with Different Habitable Area in Typical Cities

Air conditioning is widely used nowadays. It brings comfortable life to us while gives some problems. Regional shortage of power supply has a great deal to do with the extensive use of air conditioner for long time. Against the background of low carbon economy, this paper choose 3 room types of 4 typical cities which have different habitable area and carry out a financial analysis of 4 types of air conditioning system(northern city has 5 types). So we’ll have a comprehensive and intuitive understand of economy of typical air conditioning system. It could help the selection of air conditioning system of different area and make good use of energy.

The Time is Right to Replace Steam Systems with Hot Water Systems

ABSTRACT Thousands of steam boilers are in operation to make steam that is converted to domestic hot water or hot water used for space heating. Is this the best use of energy? Is there a better way? Does steam-to-hot water conversion sometimes make sense? These and other questions are relevant as building owners contemplate replacement of 30-, 40-, or 50+-year-old steam boilers. Many building owners think they have no alternative but to keep replacing energy-hungry steam boilers. There are many factors to consider when making an informed decision.

Políticas públicas para la promoción de la cogeneración eléctrica en México

Se ha buscado el desarrollo de la cogeneración en el mundo mediante la promoción en los diferentes sectores con capacidad para implantarla. Esta labor fue impulsada desde los gobiernos y apoyada por organizaciones públicas gubernamentales y académicas, además de asociaciones privadas comerciales y fabricantes de equipos. Ello con la finalidad de dinamizar este proceso, aprovechar los potenciales, desarrollar este mercado, ampliar y robustecer el sector eléctrico, utilizar mejor la energía, mitigar los efectos contaminantes e intensificar el impulso a tecnologías más eficientes. En el caso de México ha sido menos exitoso, a juzgar por los resultados obtenidos desde 1992 hasta la fecha.

Modeling wireless sensor networks using random graph theory

A critical issue in wireless sensor networks (WSNs) is represented by limited availability of energy within network nodes. Therefore, making good use of energy is necessary in modeling sensor networks. In this paper we proposed a new model of WSNs on a two-dimensional plane using site percolation model, a kind of random graph in which edges are formed only between neighbouring nodes. Then we investigated WSNs connectivity and energy consumption at percolation threshold when a so-called phase transition phenomena happen. Furthermore, we proposed an algorithm to improve the model; as a result the lifetime of networks is prolonged. We analyzed the energy consumption with Markov process and applied these results to simulation.

Maximizing system lifetime in wireless sensor networks

One of the most critical issues in wireless sensor networks is represented by the limited availability of energy on network nodes; thus, making good use of energy is necessary to increase network lifetime. In this paper, we define network lifetime as the time spanning from the instant when the network starts functioning properly, i.e., satisfying the target level of coverage of the area of interest, until the same level of coverage cannot be guaranteed any more due to lack of energy in sensors. To maximize system lifetime, we propose to exploit sensor spatial redundancy by defining subsets of sensors active in different time periods, to allow sensors to save energy when inactive. Two approaches are presented to maximize network lifetime: the first one, based on column generation, must run in a centralized way, whereas the second one is based on a heuristic algorithm aiming at a distributed implementation. To assess their performance and provide guidance to network design, the two approaches are compared by varying several network parameters. The column generation based approach typically yields better solutions, but it may be difficult to implement in practice. Nevertheless it provides both a good benchmark against which heuristics may be compared and a modeling framework which can be extended to deal with additional features, such as reliability.

An Energy-Efficient Method for Nodes Assignment in Cluster-Based Ad Hoc Networks

One of the most critical issues in wireless ad hoc networks is represented by the limited availability of energy within network nodes. Thus, making good use of energy is a must in ad hoc networks. In this paper, we define as network lifetime the time period from the instant when the network starts functioning to the instant when the first network node runs out of energy. Our objective is to devise techniques to maximize the network lifetime in the case of cluster-based systems, which represent a significant sub-set of ad hoc networks. Cluster-based ad hoc networks comprise two types of nodes: cluster-heads and ordinary nodes. Cluster-heads coordinate all transmissions from/to ordinary nodes and forward all traffic in a cluster, either to other nodes in the cluster or to other cluster-heads. In this case, to prolong the network lifetime we must maximize the lifetime of the cluster-heads because they are the critical network element from the energy viewpoint. We propose an original approach to maximize the network lifetime by determining the optimal assignment of nodes to cluster-heads. Given the number of cluster-heads, the complexity of the proposed solution grows linearly with the number of network nodes. The network topology is assumed to be either static or slowly changing. Two working scenarios are considered. In the former, the optimal network configuration from the energy viewpoint is computed only once; in the latter, the network configuration can be periodically updated to adapt to the evolution of the cluster-heads energy status. In both scenarios, the presented solution greatly outperforms the standard assignment of nodes to cluster-heads, based on the minimum transmission power criterion.

Sustainable agriculture: the role of plant pathology

A sustainable system of crop production is one that may be used continuously for many years, is soundly based on the potential and within the limitations of a particular region, and does not unduly deplete its resources or degrade its environment, makes best use of energy and materials, ensures good and reliable yields, and benefits the health and wealth of the local population at competitive costs. Plant pathology can and should contribute in each of these respects--by assessing the immediate and potential dangers to crops from diseases, by forecasting their incidence and severity, by deploying the best methods of control in the short and longer term, by evaluating the risks particularly by integrated use of the methods, by exploiting the potential for disease control in new systems of crop production, by recognizing the critical importance of extension and training in getting farmers to adopt the best practices, and by research at the highest levels on pathogens and diseases to provide the scientific base upon which major improvements in the technology of disease control will depend.

Improving the Quality of Life Through Better Use of Energy and Resources

Improving the Quality of Life Through Better Use of Energy and Resources