Numerical study on the heat and mass transfer characteristics of the open-type cross-flow heat-source tower at low ambient temperature

• The heat-source tower heat pump (HTHP) has the advantage in preventing frosting and efficiently absorbing heat from the air in winter. Due to the low air humidity in low temperature environment (less than 0 °C), the latent heat exchange between the antifreeze solution and air is a key factor affecting the performance of HTHP. In this paper, a mathematical prediction model is established to investigate the heat and mass transfer characteristics of the heat-source tower (HST) in low temperature environment. It is found that the air temperature can be lower than the corresponding solution temperature in certain areas of HST when the inlet air-solution temperature difference is very small. Under the condition of the average heat transfer temperature difference of 5 °C, there is no significant reduction in the heat transfer when the ambient temperature drops from 0 °C to −15 °C, and the latent heat ratio is 25% and 50% at the ambient temperature of −15 °C and 0 °C respectively. The relationships between the optimum liquid-to-gas ratio of HST and the operation parameters of air and solution are also studied. The results show that air temperature, solution temperature and solution mass concentration have influences on the optimal liquid-to-gas ratio, whereas air relative humidity has no effect. This paper concludes that the latent heat has a significant impact on the heat transfer. A great amount of heat can be transferred from the air to the solution in HST by adjusting and optimizing the operation parameters in low temperature environment.

Ämnesord

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Klimatforskning (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Climate Research (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Samhällsbyggnadsteknik -- Annan samhällsbyggnadsteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Civil Engineering -- Other Civil Engineering (hsv//eng)

Nyckelord

Heat and mass transfer

HST

Low ambient temperature

Mathematical calculating model

Optimum liquid-to-gas ratio

Antifreeze solutions

Atmospheric temperature

Heat transfer

Latent heat

Calculating model

Corresponding solutions

Liquid-to-gas ratio

Low ambient temperatures

Low temperature environment

Mathematical prediction models

Temperature differences

Mass transfer

Strömnings- och klimatteori

Fluid and Climate Theory

Publikations- och innehållstyp

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