Sharif Digital Repository

Sensor networks have a wide range of potential and practical application. A sensor network consists of a large number of tiny, low power and short-living sensors. Some sensor network applications require k-coverage to ensure the quality of surveillance. Meanwhile, energy is another primary concern for sensor networks. In this dissertation, an algorithm proposed which groups sensors in to disjoint subsets. Every subset cans k-cover the whole area. The subsets are scheduled to work successively. Therefore, the network lifetime is prolonged. Furthermore, sensing range is fixed. Also another algorithm, proposed which constructs some non-disjoint subsets, and in each active subset, each sensor... 

A literature review on the studies and applications of heat pipe heat exchanger in air conditioning systems in recent years is conducted. The related papers were grouped into two main categories and a summary of experimental and theoretical studies is presented. Based on this investigation, the application of a heat pipe heat exchanger or a thermosyphon heat exchanger in the conventional air conditioning systems is recommended as an efficient means for energy savings and dehumidification enhancement to maintain acceptable room conditions. This review shows that the literature on the application of heat pipe heat exchangers in air conditioning systems is very limited. Therefore, much more... 

This article is focused on developing an Energy Service Company (ESCO) risk assessment model for use by energy savings certificates (ESC) market regulators. This model enables market regulators to determine the appropriate point in time for ESCOs to sell their certificates with the aim of minimizing risk as well as maximizing economic gain yet remain motivated for reducing the cost of energy efficiency technologies. To this end, the interactions between an ESCO and other parties (such as suppliers) in the market in addition to the principles of the energy efficiency performance contract are taken into consideration. Then, appropriate probability distributions have been fitted to the... 

This paper presents a comprehensive educational model considering share resources among several departments bounded to educational limitations for optimizing energy consumption. The thermal model calculates the load based on the ambient temperature to minimize the user's knowledge of the building's thermal model. It determines the percentage reduction of the building's heating load in case of a change in room temperature, a term's start date, and sharing classes compared to standard curricula. It employs linear Boolean optimization. Class planning is carried out concerning minimizing energy use, students' preferences, charts, educational constraints, professors' schedules, classes' numbers,... 

In drilling industry, energy consumption counts from 20 to 40 percent of total costs. Enhanced water-based mud (WBM) drilling fluids with nanoparticles can save energy in drilling processes. An in-house Taylor-Couette flow system (TCS) was developed at Australian University (AU) to study WBM enhanced by Al2O3, SiO2, and TiO2 nanoparticles. The TCS is really a practical tool to help well drillers with a rough idea of viscosity when nanoparticles are added. The TCS for sure cannot substitute advanced rheometry. The goal of the present experiment is to produce a rough estimate in field operation. Experimental results were examined with several rheology models in our previous publications. In... 

Most modern multi-core edge devices work in outdoor situations with limited power supplies like energy harvester and batteries. Therefore, energy consumption is a fundamental issue in which the memory subsystem has a significant role. Scratchpad memories (SPM) can provide a broad potential for energy saving. Still, due to the insufficient SPM capacity in such edge devices, a rigorous SPM data allocation scheme is necessary to reduce the energy consumption of the memory subsystem. Emerging non-volatile memories (NVMs) are very useful to reduce the energy consumption of the memory subsystem. Compared with SRAM, NVMs have lower leakage power and higher density, but the read and write latencies... 

According to one survey on energy consumption in Iran, commercial and building sector consume more energy than any other economic sectors. For example, about 38% of total energy that consumed in year 2001 has been used for space heating. Insulation in external walls of buildings has an important role to reduce the environmental effects on indoor space condition. Therefore, always using insulation is an alternative to avoid from the energy loss. In this paper, the effects of the using of a proper insulation on the energy saving in Iranian buildings are studied. For this purpose, an integrative modelling is used for simulation of the energy consumption in buildings. It is shown that energy... 

The growing worldwide demand for less polluting shapes of energy have led to a renewed interest in the use of Micro Combined Heat and Power (Micro CHP) technologies in the residential sector. Micro CHP have been introduced around Iran recently, and expected to diffuse more and more.In this paper, technical and economic studies for the use of Micro CHP in the different climate zones of Iran are executed. These zones are categorized in to five; Tehran, Rasht, Bandar Abbas, Ardebil and Yazd, based on weather conditions. Later on using an economic model, both annual energy savings and percentage of system profitability in each zone are calculated as well as reduction in annual emissions. It... 

Wireless Sensor Networks (WSNs) have developed in recent years and are used in many different applications such as fire detection, military operations, and healthcare. Sensor nodes have the ability to sense an environment, sending and receiving information and forwarding packets from source nodes to a sink. These tasks consume large amounts of energy. In many WSN applications, delay and reliability of data delivery and the energy consumption of nodes are important design metrics. Network protocols such as medium access control (MAC) and routing should be designed to improve these metrics. In this article, we propose a new cross layer algorithm that improves the performance of WSN networks... 

University (Educational) buildings comprise a considerable contribution of commercial buildings energy consumption. Optimizing operational measures are widely suggested for energy saving in university buildings. Hence, in this study, a bi-level energy-efficient occupancy profile optimization method using a metaheuristic algorithm, integrated with a demand-driven control strategy adjusted with dynamic set-point temperature is proposed to optimize the energy consumption within in a university departmental building. To proceed with the proposed energy saving strategies; first, building's thermal behavior and AHU system performance are identified and modeled through Artificial Neural Networks... 

One of the most effective measures for building energy conservation is the implementation of energy codes. The building energy codes introduction in Iran started two decades after the first oil crisis in the early 1970s by establishing the building energy conservation regulation called Issue 19. Nowadays, due to some financial and executive barriers, the implementation of Issue 19 is faced with some difficulties. The most critical obstacle is the low price of energy carriers, which lead to high subsidies of energy and the reluctance of the building owners to implement the regulation. The main goal of this paper is the introduction of an innovative financial and executive mechanism for... 

Energy developments plays a crucial role in the political power, economic growth, social development and environmental degradation of developing countries. Energy consumption in residential sector is an essential issue for providing a large variety of services that are necessary for social life tasks such as heating, cooling, and lighting. Therefore, there is a need for depiction of energy outlook and selection of appropriate strategies as the main pillars of economic and political stability in each society. The main objective of this research is to design and apply a methodology that helps decision makers for simulation, optimization and analysis of the residential sector energy system. The... 

In this paper, advantages of energy-efficient motors over standard-motors in terms of electrical energy saving and demand reduction in a tire-rubber factory are thoroughly evaluated. Energy-efficient motors reduce losses because of their better design, materials, and manufacturing. These motors are 2 to 8% more efficient than standard ones. Lengthening the core and using lower-electrical-loss steel, thinner stator laminations, and more copper in the windings reduce electrical losses. Because a motor consumes energy worth 4 to 10 times its own cost each year, energy-efficient motors often make economic sense in a wide variety of applications. At the end of this study, the amount of energy... 

Catalytic reduction of nitrobenzene is the leading technological step in aniline production. The hydrogen required for this stage, is dominantly produced from fossil fuels through reforming processes, which take much energy and emit large amounts of CO2. Biomass-derived glycerol steam reforming is an attractive alternative to traditional reforming to reduce the dependence on hydrocarbon resources and mitigate climate change. This research aims to analyze a mass- and heat-integrated multi-tubular membrane reactor, containing nitrobenzene hydrogenation (exothermic-side) and glycerol steam reforming (endothermic-side) for co-production of aniline and syngas. In this process, hydrogenation... 

The present study tries to use the methanol-silver nanofluid filled thermosyphon heat exchanger and compares the effectiveness as well as energy saving with pure methanol. Experimental results show that using methanol-silver nanofluid, leads to energy saving around 8.8-31.5% for cooling and 18-100% for reheating the supply air stream in an air conditioning system  

This study presents a cost-benefit analysis of energy saving strategies for the commercial sector inTehran City. The article includes a discussion of the estimated energy demand for various energy saving scenarios. The cost-benefit analysis was performed separately for seven energy-saving scenarios based on the energy demand and supply forecasting model. According to which, energy demand of the commercial sector was considered as final consumption, which is a function of different parameters such as number of commercial units, number of electric vehicles, volume of commercial activities, labor force, etc. The research findings indicated that all of the proposed scenarios are economically... 

Significant energy subsidies are believed to be the main factor that has resulted in high energy intensities of Iranian industries. The Subsidy Reform Act of 2010 was directed at modifying energy consumption pattern and fostering energy efficiency enhancement. This study aims at analyzing the effect of energy subsidy reform on promoting energy efficiency in six energy intensive industries of Iran. In order to do so, the energy efficiency practices that have not been adopted after the implementation of the first phase of energy subsidy reform are investigated. Data analysis reveals that if financially interesting investments are determined as those with payback periods less than three years,... 

This paper presents a fault tolerant and energy efficient write-back set-associative cache, which has a heterogeneous structure. The cache architecture is based on partitioning the ways of each set into two different parts. In each set, one cache way uses SECDED code and maintains dirty blocks while the other ways employ parity bit and keep clean blocks. To evaluate the set-associative cache, SIMPLESCALAR tool and CACTI analytical model are used. The experimental results show that as the feature size decreases and the associativity increases, the energy saving of the proposed cache increases. The experimental results express that for an 8-way setassociative cache in 32nm, about 7% area and... 

Basically, charge recovery logic styles have been devised for low-power purposes. However, they have some other characteristics such as inherent pipelining mechanism, low data-dependent power consumption, and low electromagnetic radiations which are usually neglected by researchers. These properties can be useful in other application areas such as side channel attack resistant cryptographic hardware. This paper addresses these properties of charge recovery logics and examines a common one, called 2N-2N2P, as a side channel attack countermeasure by information theoretic evaluation metrics. The observed results show that the usage of this logic style leads to improve DPA-resistance as well as... 

Write-through caches potentially have higher reliability than write-back caches. However, write-back caches are more energy efficient. This paper provides a comparison between the write-back and write-through policies based on the combination of reliability and energy consumption criteria. In the experiments, SIMPLESCALAR tool and CACTI model are used to evaluate the characteristics of the caches. The results show that a write-through cache with one parity bit per word is as reliable as a write-back cache with SEC-DED code per word. Furthermore, the results show that the energy saving of the write-through cache over the write-back cache increases if any of the following changes happens: i) a...