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A model of space heating and cooling system, in which a surface water pond with an insulating cover serves as the heat source in the winter and heat sink in the summer, is presented. Based on the heat load of the building, the vapor compression heat pump cycle and the seasonal energy storage of the water pond, the performance of the system is obtained. The total compressor work year round, as well...
The purposes of this study were to determine energy consumption of input and output used in sugar beet production, and to make a cost analysis in Tokat, Turkey. Data were collected from 146 sugar beet farms in Tokat, Turkey by using a face-to-face questionnaire performed in January and February 2005. Farms were selected based on random sampling method. The results revealed that total energy consumption...
China's carbon dioxide emissions from fossil fuel combustion had increased with an annual growth rate of 4.36% since 1980, hitting 1GtC in 2003. The global climate change issue is becoming more and more important and hence to be the fourth challenge for China's future energy development, following energy supply shortages, energy security, and local environmental protection. This paper used three MARKAL...
The energy consumption and greenhouse gas emissions of all private and transit vehicles from the Lower Fraser Valley, British Columbia, Canada are analysed for the year 2000. The energy figures are then compared with the Province's renewable energy potential. Results indicate that electric trolley buses and the automated rapid transit SkyTrain were eight times as energy efficient as private vehicles...
In order to obtain reliable irradiation data for the design, operation and economic assessment of solar power stations, eight widely used standard models predicting diffuse irradiation values are tested. A statistical analysis of hourly, daily and monthly correlations is carried out, using a 5yr data archive (1999–2003) of hourly global and diffuse solar irradiances obtained at five selected meteorological...
Nine different concepts for natural gas fired power plants with CO 2 capture have been investigated, and a comparison is made based on net plant efficiency and emission of CO 2 . The cycles are one post-combustion, six oxy-fuel and two pre-combustion capture concepts. A 400MW combined cycle plant is applied as a reference case. A common basis for the comparison of all concepts is defined...
This paper summarizes the results from an exploratory analysis of residential customer response to a critical peak pricing (CPP) experiment in California, in which 15 times per year participating customers received high price signals dispatched by a local electricity distribution company. The high prices were about three times the on-peak price for the otherwise applicable time-of-use rate. Using...
This paper evaluates possible synergies with industry, such as heat and oxygen recovery from the hydrogen production. The hydrogen production technology used in this paper is electrolysis and the calculations include the cost and energy savings for integrated hydrogen production. Electrolysis with heat recovery leads to both cost reduction and higher total energy efficiencies of the hydrogen production...
As electricity markets deregulate and energy tariffs increasingly expose customers to commodity price volatility, it is difficult for energy consumers to assess the economic value of investments in technologies that manage electricity demand in response to changing energy prices. The key uncertainties in evaluating the economics of demand–response technologies are the level and volatility of future...
In this paper an attempt has been made to determine the factors that influence individual's decision to choose a particular energy carrier, viz., firewood, LPG, kerosene, and electricity. From the economic perspective, an individual's propensity to choose a particular energy carrier is determined by his/her economic status, carrier availability and prices, household size and other regional and demographic...
A typical commercial building was selected for a detailed study of energy use by mechanical ventilation and air-conditioning (MVAC) systems. Data from preliminary building energy auditing were analyzed and compared with the energy use of other similar buildings. Correlation relationships between the building envelope heat gain and the electrical energy use for MVAC system with key parameters were...
Generally, it is very difficult to assess the true operating cost of an electrical power unit in the countries where there is little or no operational experience. Since Turkey has no experience on operating a nuclear unit, operating costs of a nuclear unit is uncertain for use in generation expansion planning (GEP). Furthermore, there is a disagreement of whether it is cheap or not. In this study,...
In order to increase the efficiency of waste utilization in thermal conversion processes, pre-treatment is advantageous. With the Herhof Stabilat ® process, residual domestic waste is upgraded to waste-derived fuel by means of biological drying and mechanical separation of inerts and metals. The dried and homogenized waste-derived Stabilat ® fuel has a relatively high calorific value...
When a system produces two or more products, cumulative exergy (CEx) should be allocated to each product. Separation process is a common operating unit, which is characterized by multiple products. Based on the minimum separation work (MSW) theory, a novel allocation parameter of CEx, the minimum separation power of product (MSPP), is proposed in this article. The natural causality between the MSPP...
World wind energy resources are substantial, and in many areas, such as the US and northern Europe, could in theory supply all of the electricity demand. However, the remote or challenging location (i.e. offshore) and especially the intermittent character of the wind resources present formidable barriers to utilization on the scale required by a modern industrial economy. All of these technical challenges...
A solar deep-freezing process has been designed. It aims at cooling down a cold box to about −20°C, using simple flat plate solar collectors operating at 70°C. This original process involves two cascaded thermochemical systems based on the BaCl 2 /ammonia reaction. Its working mode is discontinuous as it alternates between a regeneration mode during daytime and a cold production mode during...
Monthly average daily global radiation on surfaces tilted towards the equator and also inclined at various azimuth angels are estimated for three locations in the Southern African region from reported global and diffuse radiation on a horizontal surface. The anisotropic model suggested by Hay is used in obtaining daily radiation at various slopes and orientations. Total annual radiation data are also...
The trend toward the energy efficiency improvement for transcritical carbon dioxide refrigeration cycles has led to the development of the two-stage compression process. Three different variations of transcritical carbon dioxide two-stage compression cycles with expanders are investigated by using thermodynamics analysis. They are the two-stage compression at optimal intermediate pressure (TCOP) cycle,...
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