Integrated energy system for industrial complexes. Part I: A linear programming approach

A personal-computer based model of an Integrated Energy System for Industrial Estates (IESIE) has been developed as a pre-feasibility tool: it addresses the total energy concept by combining a set of CHP plant(s), boilers, vapor-compression and absorption chillers, national grid and utility transportation system. The core of the general model is the linear programming (LP) model which takes into account the changing demand-pattern of various loads and their tariffs, standby charge of electricity, unit fuel price, equipment costs, land cost, depreciation, O & M expenses, interest rate, taxes, etc. The output of the LP model yields the minimum total operating cost, optimal sizes of the equipment and their respective operational schedules. The hot utility and cold utility transportation model estimates the economic-minimum pipe size, considering installation cost, heat loss/gain cost and pumping cost. The heat balance model finds the thermal cycle equipment sizes as well as the variation of the heat-to-power ratio with load. Finally the economic model does the cash-flow analysis to determing whether the project will yield a required rate-of-return to be economically viable. Simulations have been done using the model considering a number of sample load patterns with the prevailing cost factors in India. An after tax IRR of 20% was found for sites having load factors greater than 0·6, and up to 10 km utility transportation distance.

Integrated energy system for industrial complexes. Part II. A case study using the LP model

In Part I of the paper, a model of an integrated energy system for an industrial estate (IESIE) was introduced. In this part the model is applied to assess the potential of an integrated energy system in an existing industrial estate in India which has time varying electrical, heating and cooling loads. Results indicate that an after-tax IRR of 11·2% can be obtained from a coal-fired combined heat and power (CHP) plant under the prevailing conditions of loads and costs and a utility transportation distance of 10 km. Considering a 4% statutory return of the Indian public utilities, the rate of return for this system seems substantial. There is a net annual energy saving of 72 million t of coal (calorific value of 5000 kcal/kg) with the associated reductions in environmental pollution.

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Not AvailableThis study was carried out for three successive years during 1999–2001 to evaluate growth and yield performance of fish, prawn and paddy under rice–fish integration system in rainfed medium land ecosystem. Irrespective of stocking density, faster growth rate was recorded for Catla catla followed by Cyprinus carpio, Cirrhinus mrigala, Labeo rohita and Macrobrachium rosenbergii. C. carpio and C. mrigala performed better growth rate against that of L. rohita probably due to the fact that being bottom dwellers, C. carpio and C. mrigala are more tolerant to fluctuation of oxygen concentration. Productivity of fish and prawn was, however, higher ( p < 0.05) in refuges with 10-cm weir height plots, irrespective of stocking density, while overall yield performance was good at stocking density of 25,000 ha 1. It was observed that, even with supplemental feeding, with increase in stocking density, biomass yield increased up to an optimum and then decreased. An average minimum and maximum yield of 906.6–1282.3 kg ha 1 of fish and prawn has been achieved, which was much higher than the earlier recorded productivity in a season under rice–fish integration system. Highest grain yield was recorded at 15-cm weir height plot (3629 kg ha 1), probably contributed by higher number of panicles per square meter (235.5) and number of filled grains per panicle (121.7). Percentage increase in rice yield under rice–fish integration system was 7.9–8.6% against control, where paddy was cultivated without integration of fish and prawn probably due to better aeration of water, greater tillering effect and additional supply of fertilizer in form of leftover feed and fish excreta. Irrespective of stocking density, the overall rice equivalent yield (REY) of the system was high (4.22–4.55 tons ha 1) at 12.5-cm weir height plots-cum-refuge, without using any pesticide, herbicide, etc.Not Availabl

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Not AvailablePerformance of a rehabilitated and turned over flow based minor irrigation project with respect to irrigation, agriculture and institutional aspects was assessed. The irrigation system was found performing better. However, inadequacy of irrigation water availability in dry season and spatial inequity of water distribution, even after rehabilitation and irrigation management transfer were the couple of shortcomings which have been observed. In order to augment the water resource of the system, the feasibility of introducing secondary storage reservoir in each outlet command was conceptualized and field tested. Keeping in view the area required for providing secondary reservoirs, the existing water bodies in the command of the study system were surveyed. The utility and functioning of the secondary reservoir was field demonstrated. Utilization of the harvested water in the secondary reservoir for irrigating dry season crop in addition to the irrigation water from the main reservoir have resulted in increasing the yield of sunflower, tomato, brinjal and groundnut by 14.29, 14.95, 16.95 and 20%, respectively. Among the cropping patterns considered, rice–tomato cropping pattern resulted in highest net return (Rs. 29,457 per ha) followed by rice–brinjal cropping pattern (Rs. 22,430 per ha). Highest benefit–cost ratio of 2.09 was obtained for rice–sunflower cropping system. The low input-based scientific fish culture in the secondary storage reservoir has enhanced the fish yield by three fold over traditional practice.Not Availabl

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Not AvailableQuantitative techniques such as simulation modelling and optimization play a vital role in the management of complex groundwater systems. This study demonstrates the combined use of groundwater-flow and resource optimization models to scientifically address the water scarcity problem in well-based command areas through a case study in eastern India. A transient simulation-optimization model was developed for the study area using Visual MODFLOW (groundwater-flow simulation tool) and the response-matrix technique to maximize pumping from the existing tubewells. The optimized maximum pumping rates obtained from the integrated simulation-optimization model were further used in linear programming-based optimization models to determine optimal cropping patterns for the wet, normal and dry scenarios. The net annual income from the optimal cropping patterns for the wet, normal and dry scenarios were estimated at Rs. 81.8 million, Rs. 76.4 million and Rs. 71.6 million, respectively. The results of simulation-optimization modelling indicated that if the suggested optimal cropping patterns are adopted in the study area, the net annual irrigation water requirements will be reduced by 28, 35 and 40%, and net annual income will be increased by 28, 23 and 17% during wet, normal and dry scenarios, respectively.Not Availabl

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Not AvailableA two-stage rainwater conservation technique was intervened in the farmers field of rainfed shallow low land, in which, part of the rainwater is conserved in rice field up to the weir crest level and the remaining in a refuge for rearing of fish (Catla catla, Labeo rohita, Cirrhinus mrigala and Cyprinus carpio). The conserved rainwater in the refuge is also used for giving supplemental irrigation to rice crop during rainy season and growing a light duty crop in winter season. On-farm experiment was conducted in the farmer’s field for three consecutive years to study the scope and feasibility of this technique in enhancing productivity and cropping intensity. Three different weir heights (15, 20 and 25 cm) were considered as treatments with two replications each. Refuge occupying areas of 5–8 % of the rice field with a depth of 1.75 m were constructed at the downstream side of each plot. As a result of this intervention, the mono-cropped area could be gradually brought under double cropping. The rice yield increased from 1.8 to 5.3 t/ha. Fish yield of as high as 1,693 kg/ha was obtained for a fish rearing period of about 6 months. The net water productivity increased from 3.76 to 7.38 Rs./m3 . The highest net return of Rs. 63,572 was recorded in 20 cm weir height plots with a benefit cost ratio of 2.60. The system generated employment opportunity, increased income for farmers and provided nutritional security.Not Availabl

Secondary storage reservoir: a potential option for rainwater harvesting in irrigated command for improved irrigation and agricultural performance

Present study recommends an option to overcome the limited water availability in surface irrigation system through provision of secondary reservoirs in the command. The harvested water can be utilized for irrigation in the dry season, short duration fish culture, etc. Approximately 10% of the command area is required for the secondary reservoir with assumption of 50% capacity of the main reservoir will be available for irrigating dry season crops. The demonstration of use of water from the secondary reservoir in addition to the water from main reservoir has resulted in substantial crop and fish yield. The gross and net returns from various cropping patterns considered using irrigation water from main reservoir (MR) and from main and secondary reservoir (MR+SR). Among the cropping patterns considered, rice-tomato cropping pattern resulted in highest net return of INR 29,457/ha followed by rice-brinjal cropping pattern (INR 22,430/ha) with benefit cost ratio of 2.07 and 1.79, respectively. Highest benefit-cost ratio of 2.09 was obtained for rice-sunflower cropping system due to relatively lower cost of cultivation of sunflower. The highest incremental value of net returns of 3710 `/ha was obtained with rice-tomato cropping system. The low input-based scientific fish culture in the secondary reservoir has enhanced the fish yield by three fold over traditional practice increasing the gross return from the system. The economic analysis also revealed that the intervention is economically viable

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Not AvailableIn an integrated aquaculture and aquatic crop cultivation system, comparative growth analysis of aquatic crop, water chestnut (Trapa bispinosa Roxb.) and waterhyacinth [Eichhornia crassipes (Mart.) Solmes], a weed in waterlogged areas, was carried out to understand the extent of interference of waterhyacinth on growth and fruit yield of water chestnut and associated yield of fish. Growth of water chestnut was faster during the first 2 months after planting, and thereafter the growth rate of waterhyacinth was faster and suppressed growth of water chestnut. Fast-growing waterhyacinth restricted leaf area development and affected crop growth rate of water chestnut. Flowering frequency of the water chestnut plants, which had an influence on fruit initiation and yield, was also severely reduced in the presence of waterhyacinth vegetation. Fruits were smaller, with pale- colored peels. The coexistence of waterhyacinth caused 93% decrease in the yield of water chestnut from 3.96 t ha-1 to 0.25 t ha-1 . Survival rate of walking catfish [Clarias batrachus (Magur)] was highest (68%) in plots with water chestnut followed by waterhyacinth-infested plots (44%). The highest fish yield (1.8 t ha-1 ) with higher mean body weight (360 g) was noted in plots with water chestnut compared to fish yield of 0.79 t ha-1 , with average mean body weight of 224.5 g in plots with both water chestnut and waterhyacinth. Gut contents analysis showed 25 to 30% natural food from the ambient ecosystem when fish was reared with water chestnut. Infestation of waterhyacinth not only suppressed growth and yield of water chestnut, but also significantly reduced the growth and yield of fish, probably due to competition for space and nutrients, very low primary productivity, and low-intensity light penetration. However, walking catfish and water chestnut could be grown together, as fish with water chestnut recorded the highest production size index (648), performance index (194.9), and apparent feed conversion ratio (1.39). Therefore, a fish þ water chestnut system provided better aquatic environment than a fish + water- hyacinth system, and a reduction of supplemental fish feed of 25 to 30% by this fish + water chestnut coproduction system increases productivity of the system.Not Availabl