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In this paper we have investigated the differences between the prices of different commercial oils of the Persian Gulf region. The prices of 7 different crude oils from Iran, Kuwait, Saudi Arabia, Oman, Abu Dhabi and Dubai were compared with the benchmark light oil of Saudi Arabia over the period January 2000–April 2010. A neural network is introduced to forecast the price of any commercial oil in...
The aim of the present paper is to describe a general methodology suitable for analysing any intermediate configuration considered in staged vapour compression refrigeration cycles. This general methodology only depends on two basic parameters related to the subcooling and desuperheating obtained in the inter-stage system. A COP expression based on the two basic parameters was obtained from the general...
District heating is an efficient way to provide heat to residential, tertiary and industrial users. Heat is often produced by CHP (combined heat and power) plants, usually designed to provide the base thermal load (40–50% of the maximum load) while the rest is provided by boilers. The use of storage tanks would permit to increase the annual operating hours of CHP: heat can be produced when the request...
Identifying the building parameters that significantly impact energy performance is an important step for enabling the reduction of the heating and cooling energy loads of apartment buildings in the design stage. Implementing passive design techniques for these buildings is not a simple task in most dense cities; their energy performance usually depends on uncertainties in the local climate and many...
This study experimentally examined a cylindrical multi-hole premixed burner for its potential use for a condensing gas boiler, which produces less NO x emissions and performs better. In this study, the hole diameters and the arrangement of a multi-hole burner were investigated using a flat burner model. The combustion characteristics for the flame stability as well as the NO x and...
Coffee cut-stems (CCS) represent a promising candidate for fuel ethanol production in tropical countries because of their high availability and high biomass yield per hectare. In this work, pretreatment of this agricultural residue with dilute sulfuric acid and liquid hot water (LHW) was integrated in the simulation and economic assessment of the process for fuel ethanol production. High reducing...
Energy efficiency of agriculture needs improvement to reduce the dependency on non-renewable energy sources. We estimated the energy flows of a wheat–maize–soybean–maize rotation of three different cropping systems: (i) low-input integrated farming (LI), (ii) integrated farming following European Regulations (IFS), and (iii) conventional farming (CONV). Balancing N fertilization with actual crop requirements...
Steam injection technique is one of the most important methods for enhancing the heavy oil production. Evaluating the reliability of steam injection projects requires the investigation of the heat transfer in the wellbore and the surrounding formation. In this study, a new formation heat-transfer model taking into account the wellbore heat capacity was developed and a novel analytical transient heat-conduction...
Large district heating (DH) system accounts for 70% of urban building heating in China. In North China, this proportion is even higher (The North China is the north of the Huai River and Qinling Mountains). Many cities in North China can exploit various kinds of low-grade renewable energy. This paper presents a new heating method to realize renewable energy recovery by absorption heat pumps associated...
Significant energy efficiency gains in zones with concentrated activity from energy intensive industries can often be achieved by recovering and reusing waste heat between processing plants. We present a systematic approach to target waste heat recovery potentials and design optimal reuse options across plants in industrial zones. The approach first establishes available waste heat qualities and reuse...
In this paper, the performance of wind energy system is assessed thermodynamically, from resource and technology perspectives. The thermodynamic characteristics of wind through energy and exergy analyses are considered and both energetic and exergetic efficiencies are studied. Wind speed is affected by air temperature and pressure and has a subsequent effect on wind turbine performance based on wind...
In this paper we deepen the study of a thermodynamical model, based on the extended irreversible thermodynamics with internal variables, for a semiconductor doped by impurities of n type, where we take into consideration the density of holes coming from the intrinsic base of the semiconductor and its flux. Furthermore, taking into account a geometric model developed for n and p type semiconductors...
Based on the model of a typical alkaline fuel cell (AFC) with circulating potassium hydroxide (KOH) solution as electrolyte and oxygen as oxidant and the experimental data available in the current literature, thermodynamic–electrochemical analyses on the performance of the AFC are carried out, in which multi-irreversibilities such as charger-transfer, concentration and ohmic overpotentials are taken...
The paper presents the research results pertaining to the renewable biomass charcoal–diesel slurries and their use as alternative fuels for combustion in diesel generating plants. The utilization of charcoal slurry fuel aims to reduce diesel oil consumption and would decrease fossil green house emissions into the atmosphere. The paper investigates the formulation, emulsification, sprays, combustion,...
Thermoelectric power generation due to solar heating is a current interest in green energy research. One of the applications of the thermoelectric power generator is involved with the topping cycle, in which the thermoelectric generators were placed on the heat collector elements of a conventional solar concentration power plant. Although the topping cycle is practical and easy to operate, the efficiency...
Exergoeconomic formulations and procedure including exergy flows and cost formation and allocation within a high temperature steam electrolysis (HTSE) system are developed, and applied at three environmental temperatures. The cost accounting procedure is based on the specific exergy costing (SPECO) methodology. Exergy based cost-balance equations are obtained by fuel and product approach. Cost allocations...
The production of ethanol via entrained flow gasification of biomass and subsequent catalytic synthesis is economically assessed by considering current and future scenarios. In the current scenarios, the process plants proposed only make use of available technologies and state-of-the-art mixed alcohol catalysts (Rh–Mn/SiO 2 and KCoMoS 2 catalysts). In the future scenarios, the effects...
This paper investigated the empirical relationship between economy development and energy consumption by material production, nonmaterial production and household. Empirical models accounting for the key influential factors were constructed. Ordinary Least Square Regression (OLS) analysis of the official data of China for the year 1985–2007 permitted the relationship between individual energy consumption...
Theoretical and experimental investigation on the application of flat plate solar water heater coupled with air humidifier for regeneration of liquid desiccant has been presented in this work. The heated water from the storage tank of the solar heating system is circulated in a finned tube air heater. Hot air from the air heater is blown through a packing of a honeycomb type for the purpose of regeneration...
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