Heat transfer in a borehole heat exchanger: Frequency domain modeling

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• 作者：Griet Monteyne ; Saqib Javed ; Gerd V ; ersteen
• 关键词：Heat transfer ; Modeling ; Borehole heat exchanger ; Frequency domain ; Modeling ; Ground Source Heat Pump
• 刊名：International Journal of Heat and Mass Transfer
• 出版年：February, 2014
• 年：2014
• 卷：69
• 期：Complete
• 页码：129-139
• 全文大小：1465 K

文摘

This paper proposes a new frequency domain method to model the heat transfer between the injected/extracted heat and the temperature of the fluid exiting a borehole heat exchanger. The method is based on in situ measurements and focuses particularly on the short-term borehole heat transfer. It uses a rational function of the Warburg variable in the Laplace domain to model the borehole heat transfer. The rational model is transformed to a time domain model using inverse Laplace transformation. This time domain model makes it possible to calculate the temperature response on a random heat variation signal. The paper also demonstrates a new way to perform the classical thermal response test. Instead of injecting a constant amount of heat, the experiments have been performed using multiple short-duration heat injections. In this way, the obtained rational heat transfer model contains information about both the short- and the long-term heat transfer. The results obtained using the proposed modeling method are compared with those obtained from a state-of-the-art analytical method. The time domain model can be used to design a controller to optimize the performance of a Ground Source Heat Pump system, the efficiency of which depends strongly on the temperature of the fluid exiting the borehole.