While the visible plume from a cooling tower is not a pollutant, it can affect the surrounding environment. Moreover, the accompanied evaporation loss has a great potential for wastewater recovery. In the present study, a novel coupling technology for water conservation and plume abatement was proposed, and its feasibility was verified by using thermodynamic analysis. A surface-type heat exchanger was designed and a thermodynamic calculation model was established. Next, based on the principle of “no plume,” the effect of the number of heat exchanger units (N) and the circulating water volume (G) on the water conservation and plume abatement was evaluated under design condition. Results showed that the optimized parameters for the operation of the cooling towers were N = 8 and G < 3000 m3/h, which have a good effect on water conservation and plume abatement. Furthermore, as per the condensation calculation model, the average water conservation amount was 1.105 kg/s and the annual water conservation amount reached 2.8641 × 107 kg.

Magnesium hydride (MH) is one of the most promising hydrogen storage materials. Under the hydrogen storage process, it will emit a large amount of heat, which limits the efficiency of the hydrogen storage reaction. In this paper, the hydrogen storage performance of the magnesium hydrogen storage reactor (MHSR) and the effect of structural parameters were studied by numerical simulation. The effect of different operating conditions on the hydrogen storage performance of the MHSR is analyzed. The volume energy storage rate (VESR) was taken as the comprehensive evaluation index (CEI). The results show that fins and heat exchange tubes can improve the heat transfer performance of the MHSR. Increasing fin thickness can reduce hydrogen storage time, but increasing fin spacing is the opposite. With the increase of fin thickness and fin spacing, VESR increases first and then decreases. With the increase of inlet temperature, the hydrogen storage time decreases first and then increases. When the inlet velocity is more than 5 m/s, the hydrogen storage time basically stays at 900 s. By optimizing the operating conditions, the hydrogen storage time can be shortened by 57.8%.

Cooling towers are widely used in many fields, but the generation of visible plumes has a serious impact on the environment. Moreover, the evaporation losses also cause a great waste of water. In this paper, a vapor-condensing plume abatement system was designed for a mechanical-draft cooling tower based on the mechanism of vapor plume generation. An effective method to achieve water-saving and eliminate the water fog generated in the cooling tower was proposed, and its feasibility was verified by using thermodynamic analysis. Next, the vapor-condensing plume abatement device was designed and used for both the confined space cooling tower (CSCT) and the free space cooling tower (FSCT). The surface type heat exchanger was adopted to design the vapor-condensing plume abatement device. Then a basic calculation flow and method were proposed to obtain thermodynamic operating parameters. According to the comparison between the results of theoretical calculation and practical engineering application, it was found that the designed vapor-condensing plume abatement system obviously benefits the water-saving of a mechanical-draft cooling tower and considerable economic benefits can be obtained. The contents presented provide the theoretical basis and technical support for the upgrade of the cooling tower and the design of the new cooling tower.