Study On Variable Load Ratio Characteristics Of Multi-split Air-conditioning System And Its Indoor Air Distribution In Summer

At present, energy-saving and emission reduction policies are implemented with great efforts in China, conservation and efficient use of energy is of great urgency. The variable refrigeration flow air conditioner(VRV) is widely used recently due to its merits such as energy saving, thermal comfort and easily maintainance, etc. However the studies on partial load characteristics of this system are far from satisfaction, which being very important for VRV system's optimization, energy-saving design and reasonable operation mode setting. The study on air distribution of the room by installed VRV air-conditioner would be valuable.The temperature change curves along the refrigerant liquid pipe in summer were tested for an MDV system, which is installed in School of Environmental & Municipal Engineering of Xi'an University of Architecture & Technology. Furthermore, the variable load ratio characteristic of the system and energy cost perfomance were analized. The EER under different load for cooling mode was calculated, and the result shows that EER under the range of load ratio from 50% to 80% is higher than that under other load ratios. According to the national standard of the Multi-split air-conditioning (heat pump) unit (GB/T18837-2002), the IPLV of this system is also calculated.The temperature distributions were measured under the different inletting parameters of an office in Xi'an with VRV air conditioning by data acquisition system of IMP of Solartron firm in Britain. The numerical simulations were also carried out for the above situation. The experimental results match well with the simulation results, which show that the indoor temperature field distribution is more uniform at low wind velocity, the wind velocity of indoor working area is less than 0.3m/s, which satisfy the standard requirement. When inletting temperature (namely indoor set temperature) is lower, the temperatures of indoor working area are lower, so people will feel cold obviously; When inletting temperature (namely indoor set temperature) is higher, the temperature distribution of indoor working area is more uniform, which meet the requirement of thermal comfort for people.