Yang Luwei

Research of pulse tube refrigerator with high and low temperature double-inlet

Through analyzing phase relation between pressures and flow characteristics of double-inlet and multi-bypass, mechanism of double-inlet to lower the temperature of pulse tube refrigerator is proposed. Then another proposal is put forward to replace the low temperature multi-bypass valve, which is another double-inlet valve at room temperature and a small tube prolonging to the low temperature part of pulse tube. Through experiment, this multi-double-inlet version proves effective to lower the refrigeration temperature. Test acquires a lowest temperature of 37 K with two double inlet valves and 50 K with one double inlet valve. The concept of low temperature double-inlet is proposed here for the first time.

Performance analysis of liquid air energy storage utilizing LNG cold energy

As the high energy density and can be stored in a long period, the liquid air is regarded as the potential energy storage medium. In the liquid air energy storage (LAES) system, liquid air is produced in the liquefaction processes by using the renewable energy or off-peak energy. The compressor is used to supply and recycle the air in liquefaction processes. In this paper, a LAES model is established, and the impact of compressor on LAES system is analysed theoretically. Liquid air energy storage (LAES) system utilizing LNG cold energy is also described. The results show that the round trip energy efficiency is enhanced and the utilizing has promising application prospect for large scale energy storage.

Operation characteristic of a heat pump of mechanical vapor recompression propelled by fans and its performance analysis applied to waste-water treatment

In this paper, a set of heat pump (called as Mechanical Vapor Recompression, MVR) propelled by a centrifugal fan is tested and it shows some special characteristic when it works together with a falling film evaporator. Firstly, an analysis of the fan’s suction and discharge parameters at stable state, such as its pressure and temperature, indicates that a phenomenon of wet compression is probably to appear during vapor compression. As a result, superheat after saturated vapor is compressed is eliminated, which reduces discharge temperature of the system. It is because drops boil away and absorb the super heat into their latent heat during vapor compression. Meanwhile, drops in the suction vapor add to the compressed vapor, which increase the given heat of the MVR heat pump. Next, assistant electric heat could adjust and keep steady of the operating pressure and temperature of an MVR heat pump. With the evaporation temperature up to be high, heat balance is broken and supplement heat needs to increase. Thirdly, the performance of an MVR heat pump is affect by the balance of falling film and evaporation that has an effect on heat transfer. Then, two parameters standing for the performance are measured as it runs in practical condition. The two important parameters are consumptive electricity power and productive water capacity. According to theoretical work in ideal condition by calculation and fan’s input power by measure as running, adiabatic efficiency (ηad) of a centrifugal fan is calculated when it is applied in a heat pump of MVR. Following, based on ηad, practical SMER and COP of an MVR heat pump are discovered to be correlative with it. Finally, in dependence on productive water in theory and in practice, displacement efficiency (ηv) of centrifugal fans is obtained when compressing vapor, and so provide some references of matching a fan for an MVR heat pump. On the other hand, it is helpful to research and develop MVR heat pumps, and also to check electricity power consumption while operating practically in light of electric motor efficiency (ηe) and ηad.In this paper, a set of heat pump (called as Mechanical Vapor Recompression, MVR) propelled by a centrifugal fan is tested and it shows some special characteristic when it works together with a falling film evaporator. Firstly, an analysis of the fan’s suction and discharge parameters at stable state, such as its pressure and temperature, indicates that a phenomenon of wet compression is probably to appear during vapor compression. As a result, superheat after saturated vapor is compressed is eliminated, which reduces discharge temperature of the system. It is because drops boil away and absorb the super heat into their latent heat during vapor compression. Meanwhile, drops in the suction vapor add to the compressed vapor, which increase the given heat of the MVR heat pump. Next, assistant electric heat could adjust and keep steady of the operating pressure and temperature of an MVR heat pump. With the evaporation temperature up to be high, heat balance is broken and supplement heat needs to increase. Thi...

Performance analysis of a single-stage scroll compressor used in a drying heat pump over a wide condensing temperature range (30–80°C)

This study presents the performance of a new single-stage scroll compressor used for the heat pump drying of thermally sensitive materials over a wide temperature range. The performance of the new compressor was predicted by an ARI standard 540 map-based compressor model and verified by a semi-open drying heat pump system constructed for this purpose. A comparison of the experimental data with the predicted data proved that the new scroll compressor used in the drying heat pump works well, can supply a wide range of condensing temperatures (30–80°C) (without auxiliary heating), and has a minimum coefficient of performance (COP) above 2.0, even in the worst condition.