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Proceedings of BSO Conference 2018: Fourth Conference of IBPSA-England

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The Effect of Nanofluid to Vertical Single U-tube Ground Heat Exchanger

Yuanling Peng, Yong Wang, Ruiqing Du

Abstract: A small amount of scholars began to pay attention to the use of nanofluids instead of the traditional fluids (water, ethylene glycol solution, etc.) of the ground heat exchanger (GHE). However, there is a lack of long-term heat transfer studies on the GHE using nanofluids. In this study, based on the principle of thermal similarity, a vertical GHE thermal similarity model experimental system and a three-dimensional numerical model were established. Through the similar numerical model, the effects of six sets of 𝐶𝑢–water nanofluids with different nanoparticle sizes and volume fractions as heat transfer fluids of the ground heat exchangers (GHEs) were investigated. Maintaining the same fluid pressure drop and thermal power, compared with pure water, it proved that the difference in outlet temperature of the GHE between nanofluid and pure water conditions ∆T was up to 0.074 °C (summer)/0.083°C (winter) when 𝑑𝑛 is 50 nm, 𝜑𝑛 is 1.5% and the thermal power of GHEs is 30W/m., which generally reached a stable value in 24h operating time (equivalent to the actual operating time of 64 days). The energy saving potential of nanofluids for GHEs is small. The method will provide reference for further study of the effects of nanofluids on the long-term heat transfer of the GHEs.
Pages: 350 - 357
Paper:
bso2018_4A-1