چكيده به لاتين
Due to rising energy prices and environmental pollution, the use of CCHP systems has received much attention, today. In this thesis, we aim to modeling and optimizing the CCHP system for a hospital and compare the two strategies of priority of providing electricity and priority of providing heat. First, we introduce the CCHP system and the energy required by the hospital. Then, performed here to select the nominal capacities of gas engines by combination of optimization algorithm and maximum rectangle method (MRM). Determining the amount of prime mover nominal power in CCHP systems is very important because it strongly affects equipment cost, overall system efficiency, energy use (fuel and electricity) and environmental emissions. Modeling and optimizing of the CCHP system by introducing Relative Annual Benefit (RAB) as the objective function and choosing other system equipment (heat capacity of the backup boiler and the energy storage tank, and cooling capacity of the absorption and electrical chillers) from the market. We then introduce the design parameters and obtain their optimal values by maximizing the objective function (RAB). The optimization will be done by a genetic algorithm. In the following, we will examine the amount of energy consumed in a hospital. The optimization results show that two gas engines with nominal power of 1880 and 2030 kW in the priority of providing electricity strategy and two gas engines with nominal power of 5450 and 5470 kW in the priority of providing heat strategy presented the maximum value of the objective function (RAB). Due to the fact that the amount of heat required by the hospital is more than the required electricity, after gas engines with high capacity, we use the priority of providing heat strategy, which increases energy consumption and carbon dioxide emissions. The capacity of the electrical chiller is the same for both strategies, but in the priority of providing electricity strategy, we use the absorption chiller with more capacity. In the priority of providing electricity strategy, we use the boiler to supply the hospital, but in the priority of providing heat strategy, the boiler is not needed. Heat wasted in the priority of providing heat strategy is much more than the providing electricity strategy which is a weakness. The organic Rankine cycle was used to recover lost heat from the priority of providing heat strategy. The results show that starting an organic Rankine cycle is very expensive, but due to the high heat dissipation, more electricity can be sold to the grid. The amount of electricity sold to the national grid and the Relative Annual Benefit (RAB) in the priority of providing heat strategy (2.957e+006) is more than the priority of providing electricity strategy (2.137e+006). As a result, if the selling price of electricity to the grid increases, we must use the heat supply priority strategy.
