At present, in the field of large-scale central air-conditioning commonly used screw water-cooled chillers, with the gradual improvement of energy-saving requirements, the unit more and more use of flooded evaporator heat exchanger with high heat transfer coefficient. Since the flooded evaporator is boiling heat transfer outside the tube, its heat transfer performance is superior, which can effectively increase the evaporation temperature, reduce the heat transfer temperature difference, thereby improving the energy efficiency ratio of the unit. However, there are also some technical problems in the full-liquid unit, which makes the failure rate higher and the cost higher than the dry unit. The oil return of the full-liquid system is more difficult than that of the dry system, and the unit control is also more complicated, which makes some manufacturers with weak technical capabilities unable to effectively master this technology. However, in recent years, with the promotion and mature application of ester synthetic refrigeration oil, high-efficiency oil separator, high-efficiency full-liquid special evaporation tube, electronic expansion valve and special controller, the full-liquid unit is easier to design and manufacture. As a full liquid evaporator itself, how to improve its heat transfer performance, but also need to be more considered in the design.
Lengde company has been committed to the research and development of efficient heat exchanger, itsflooded evaporatorThe single-machine cooling capacity range of the product is 300kW ~ 2000 kW, and the product is widely used in air conditioning, water/ground heat pump, low temperature and other working conditions. The product adopts patented tooth-shaped high-efficiency enhanced liquid-filled special evaporation tube, which is easy to generate vaporization core. The pipe layout is reasonable, and air flow channels are arranged between the pipes to effectively reduce the bubble rising resistance. The bottom liquid inlet is provided with a liquid equalizing device, which makes the liquid distribution more uniform. The upper part is provided with a liquid blocking device to effectively prevent the gas from carrying liquid. The oil return port is arranged at multiple points and is safe and reliable. The comprehensive heat transfer efficiency, the heat transfer temperature difference is effectively reduced (the maximum evaporation temperature can reach 6.5 ℃ under the condition of 7 ℃ cold water of air conditioner), and the energy saving effect is obvious. At the same time, Lengde also specially equipped with a condenser with a built-in oil separator for the full-liquid system. The oil separation efficiency is extremely high, so that very little refrigerant oil enters the heat exchanger, which greatly improves the heat exchange efficiency of the heat exchanger.