District Heating Systems (DHS) are widely utilized for space heating in residential and commercial buildings. They offer economic benefits to consumers in terms of lower heating costs. The energy efficiency of DHS can be further improved by optimally controlling the operating parameters of the system. With this as a motivation, dynamic modeling and optimal operation strategies of DHS are explored in this thesis.; Two typical District Heating Systems namely Direct District Heating System (DDHS) and Indirect District Heating System (IDHS) are considered. Using typical system configurations the components of the DHS were sized. Dynamic models of the designed DHSS useful for control analysis were developed. Open loop tests subject to constant inputs and loads were conducted to evaluate the time response characteristics of DHS.; A methodology for computing optimal operating parameters of DHS is presented. These optimal parameters so computed are used as set points for PID controllers. The DHS by virtue of its long distribution network is subject to large transportation time delays. To compensate such time delays, a PID controller augmented with a Smith Predictor is developed. The designed controller is used to simulate closed loop operation of DHS under variable load conditions. Results show that the optimal set point strategy can save 10%–15% energy compared to conventional control strategies.
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机译:区域供热系统(DHS)被广泛用于住宅和商业建筑的空间供热。它们以较低的供暖成本为消费者提供了经济利益。通过优化控制系统的运行参数,可以进一步提高DHS的能源效率。以此为动力,本文探讨了国土安全部的动态建模和最优运行策略。考虑了两种典型的区域供热系统,即直接区域供热系统(DDHS)和间接区域供热系统(IDHS)。使用典型的系统配置来确定DHS的组件大小。开发了可用于控制分析的设计的DHSS的动态模型。在恒定输入和负载下进行开环测试,以评估DHS的时间响应特性。提出了一种计算DHS最佳运行参数的方法。这样计算出的这些最佳参数将用作PID控制器的设定值。国土安全部由于其漫长的分销网络而遭受较大的运输时间延迟。为了补偿这种时间延迟,开发了带有Smith Smith Predictor的PID控制器。设计的控制器用于模拟DHS在可变负载条件下的闭环运行。结果表明,与常规控制策略相比,最佳设定点策略可以节省10%至15%的能量。
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