[en] The vacuum-powders insulation is the commonest cryogenic insulation. Adding metal powders improves the performance of the insulation, but it is concerned that metal powders sink resulting from vibration, shock and thermal cycling in the using process decreasing the performance of the insulation. In this paper it was obtained that the above effect was eliminated if the diameter of metal powder reached a critical value by theoretical analyses, calculations and experimental result. A method was proposed that extended this insulation application and improved the performance of insulation

[en] In this study, the heating performance of a gas engine driven air to water heat pump was analyzed using a steady state model. The thermodynamic model of a natural gas engine is identified by the experimental data and the compressor model is created by several empirical equations. The heat exchanger models are developed by the theory of heat balance. The system model is validated by comparing the experimental and simulation data, which shows good agreement. To understand the heating characteristic in detail, the performance of the system is analyzed in a wide range of operating conditions, and especially the effect of engine waste heat on the heating performance is discussed. The results show that engine waste heat can provide about 1/3 of the total heating capacity in this gas engine driven air to water heat pump. The performance of the engine, heat pump and integral system are analyzed under variations of engine speed and ambient temperature. It shows that engine speed has remarkable effects on both the engine and heat pump, but ambient temperature has little influence on the engine's performance. The system and component performances in variable speed operating conditions is also discussed at the end of the paper