Abstract Understanding the dynamic properties of a plate heat exchanger plays an essential role when developing smart control algorithms for modern energy-efficient district heating and cooling applications. In this work, the dynamic behaviour of a counterflow plate heat exchanger is studied in order to understand its transient responses due to inlet temperature disturbances at different fluid flow configurations. For this purpose, a suitable theoretical model has been proposed. The temperature transients are evaluated numerically by solving a lumped-parameter system representing the derived 1D model of the studied plate heat exchanger. The numerical results revealed that different fluid flow configurations considerably influence the transient temperature responses as well as the overall temperature drop and heat transfer rate when following the cold down process of a fluid travelling from the inlet to the outlet of the plate heat exchanger hot fluid side. The predicted transients are experimentally verified by conducting a series of systematic tests using infrared thermography technology. The analysis shows that the proposed model is in good agreement with the experiments. The results of the thermal imaging measurements also provide a more in-depth insight into the temperature distribution and its transient front propagation along the fluid flow channels. In future studies, such an experimental approach is valuable to identify the critical temperature zones when predicting the thermal fatigue life-time of brazed plate heat exchangers and as well to extend the proposed theoretical model to include the 2D local heat transfer coefficient distribution obtained by the IR thermography.

中文翻译：

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板式换热器的动态行为：温度扰动和流动配置的影响

摘要 在为现代节能区域供热和制冷应用开发智能控制算法时，了解板式换热器的动态特性起着至关重要的作用。在这项工作中，对逆流板式换热器的动态行为进行了研究，以了解其在不同流体流动配置下入口温度扰动引起的瞬态响应。为此，提出了合适的理论模型。通过求解代表所研究的板式换热器的派生一维模型的集总参数系统，对温度瞬变进行数值评估。数值结果表明，随着流体从板式换热器热流体侧的入口到出口的冷却过程，不同的流体流动配置显着影响瞬态温度响应以及整体温降和传热速率。 . 通过使用红外热成像技术进行一系列系统测试，对预测的瞬变进行了实验验证。分析表明，所提出的模型与实验吻合良好。热成像测量的结果还提供了对温度分布及其沿流体流动通道的瞬态前沿传播的更深入的了解。在未来的学习中，