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Abstract The absorption refrigeration system driven by low grade heat sources, especially the waste heat sources, becomes more and more attractive in recent decades. However, most traditional absorption systems cannot achieve a high utilization rate of the waste heat with limited heat capacity. These systems are usually designed to obtain heat in the generator, which means that the waste heat sources cannot be utilized to the temperature lower than the generator temperature. This paper proposed a new structure heated by heat conduction oil in the generator and electric heating rings around the stripping section. This structure can simulate the temperature-distributed heat sources when the electric heating rings work. It can also simulate a traditional generator when the electric heating rings do not work. Influences of different heat distributions are analyzed in detail in this paper. The results show that the heat sources utilization rate will increase with the increase of the heat in the stripping section, while the coefficient of performance will be negatively affected by the increasing heat in the stripping section. By optimizing the heating structure, the coefficient of performance can be similar to that of a traditional system when the heat is just added in the middle and lower part of stripping section. The optimum utilization rate of heat sources in this test model can reach 1.8 times to that of a traditional system. Under this heating model, the lowest temperature required in the heating section is 82 °C when the heat conduction oil inlet temperature is 169 °C. It is much lower than the temperature inside the generator, which is 137.3 °C.

Abstract Large amounts of heat is wasted through air coolers and water coolers for cooling low temperature ( H ) recovered in the evaporator were 8.0–8.6 MW for ORC using i-pentane as working fluid and 8.2–8.3 MW for Kalina cycle, respectively. Efficiency (η) of selected systems obtained at the highest power generated (W T ) was 10.0% (W T = 862 kW) for ORC and 10.57% (W T = 996 kW) for Kalina cycle within the design boundaries. Calculated carbon dioxide (CO 2 ) emission reduction potential was 2260 t/y for ORC and 2600 t/y for Kalina system, respectively, at advantageous process conditions. Results showed that Kalina cycle provided higher efficiency and power generation ability on expense of higher system pressure (29 bar–7 bar). Economic calculations showed that the payback time is about 5.0 year for both systems.

Abstract This paper gives an experimental investigation of the effect of climatic conditions on the performance and degradation of crystalline silicon photovoltaic modules under Saharan environment in Adrar region in the south of Algeria. The first part of this study is focused on the analysis and assessment of UDTS 50 PV modules degradation after a long term outdoor exposure to these conditions (more than 12 years). The visual inspection of 62 PV modules has allowed to observe and determine the degradation modes such as, EVA discoloration, delamination, busbar corrosion, cracking of solar cell, glass breakage, AR coating and solder bond. The degradation evaluation of three modules with different defects was also performed, using (I-V/P-V) characteristics and the degradation rates of the parameters (Pmax, Imp, Vmp, Isc, Voc, FF) at Standard test conditions (STC) in order to compare with the nominal data delivered by the manufacturer of photovoltaic panels. Finally, the combination of the partial shading effect and the presence of EVA browning defect was examined to assess the changes in I-V and P-V curves caused by the drop in electrical parameters.

Abstract After reviewing 16 recent studies, we 1. (i) identify the general approaches used to estimate customer outage costs, 2. (ii) ascertain the relative merits of each approach, and 3. (iii) determine the extent to which existing studies can provide accurate and meaningful estimates. We present cost estimates on a common denominator, explain variations in the results, and suggest areas for future research.

Abstract Demand response aims to change the energy consumption patterns of normal customers in response to changes in price rate or incentive offers. This process reduces peak loads and in turn potentially lowers the energy cost for customers. In this study, we propose a new demand response scheme on the basis of an adaptive consumption level pricing scheme. On the one hand, this strategy encourages customers to manage their energy consumption and consequently lower their energy bill. On the other hand, it allows utilities to manage the aggregate consumption and predict load requirement. Unlike other pricing schemes, such as block tariff and time-of-use, the proposed pricing scheme can lower the energy bill of about 73% of customers, assuming that the total utility revenue is the same for all pricing schemes. On the basis of the currently available schemes in the literature, we find that the proposed method has significant advantages over other schemes in terms of fairness in charging customers.

The Asia-Pacific region has the most rapidly growing energy demand in the world and will continue to have an increasing impact on world energy demand. Given the heterogeneity of economies in the region, any regional demand analysis has to be constructed country by country. In undertaking the demand forecasts provided in this study, scenarios were developed for high, low, and base cases that take into account variations in economic performance, prices, and fuel substitution in individual nations and in the region as a whole. China is included in the aggregate regional data provided in this article. Data from the countries of the former Soviet Union are not included in the regional totals in this article and are discussed separately in article 4.

Abstract We will consider cumulative socioeconomic impacts in environmental impact assessment and mitigation processes. Cumulative impacts from several simultaneous projects are greater than aggregate impacts for projects built in isolation. Impacts of energy facilities provide a baseline for potential cumulative impacts in a number of regions. Case studies illustrate the importance of cumulative impacts, as well as their uneven treatment in the environmental impact statement (EIS) process. Important institutional, legal, and practical considerations associated with cumulative impacts are analyzed, and descriptions are offered of how cumulative impact assessments can be used as tools in decision-making.

In this paper, we have proposed a gas turbine combined cycle with the integration of low-temperature thermal energy and methanol decomposition, and also investigated a principle of the cascade utilization of chemical exergy of fuel. Here, the combustion of methanol fuel is divided up into two steps: the methanol is decomposed into the syngas with hydrogen and carbon monoxide through recovering the low-temperature thermal energy from an intercooler of a gas turbine, and then the syngas is combusted with air, namely, the indirect combustion of methanol. As a result, the exergy destruction in the combustion of syngas is expected to be decreased by 7.5 percentage points of the input energy of cycle; at the same time, the low-temperature thermal energy is upgraded to the chemical energy of fuel, and the thermal efficiency of this gas turbine cycle is expected to be about 6 percent points higher than that of a conventionally combined cycle with intercooling at the turbine inlet temperature of 1300 °C and at a given overall pressure ratio of 15. The promising results obtained here indicated that this gas turbine combined cycle could simultaneously accomplish the decrease of exergy destruction in combustion and the upgrade of low-temperature thermal energy levels, leading to the effective utilization of clean syngas fuel and the recovery of low-temperature thermal energy in power system.

Abstract In this paper, the concept of well array operating enhanced geothermal system (EGS) is proposed in response to the existing challenges in EGS commercialization. A well array operating EGS is characterized by well sharing, which substantially reduces drilling cost and maximizes mass flow rate. Following a thorough discussion of conditions for representing an EGS by a 2D model, the life time performance of a well array operating EGS is investigated based on 2D finite element modeling. The accuracy of the presented numerical results is quantified by systematic tests of mesh, element order and time step dependence, and by direct comparison with an analytical solution for 2D porous flow, which is derived in the paper as well. This paper demonstrates that 2D modeling is not only capable of accurately solving a wide range of EGS problems at low computational cost, but also a powerful tool for quantitatively estimating 3D numerical modeling errors, which are usually not adequately addressed in previous studies. The modeling results of the well array operating EGS presented in this paper may serve as a benchmark for testing future EGS models.

Abstract A net energy analysis (NEA) of three different residential solar pond scenarios is performed. A single home, a complex of twenty homes and a community system with district heating are considered. The designs considered, Rabl-Nielsen and Krass-LaViale, are studied for locations in Columbus, Ohio and in Northampton, Massachusetts. The analysis reveals that economies of scale and design considerations influence the net energy ratio (NER).