Research Of Air-conditioning Systems Control The Relative Humility In Different Condition

When an air-conditioned space experiences only part of its design heat load, its humidity tends to rise as a result of the air-conditioning system trying to control the indoor temperature by reducing its cooling capacity. If the relative humidity do not exceed the permitted range, we do not need to control it. This requires that we now research variable flow air-conditioning systems. Find out what changes in the flow of air-conditioning system and what kind of load changes in circumstances, to maintain the relative humidity in the scope of the permit. So that we do not use the relative humidity of a separate control, but also ensure that people in the relative humidity within the scope of the permission to meet the comfort and energy-saving purposes.In this paper, the establishment of four common variable flow air-conditioning system mathematical model, which is constant air volume system, secondary return air system, variable air volume system, by pass variable air volume system. Simulate the capacity of the dehumidifier of four air-conditioning system is in a load when the load in different designs. Namely: observe the indoor relative humidity changes for some indoor load, when the variable flow air-conditioning system control room temperature constant.The results show that:When the latent load keeps constant and sensible load changes: by pass variable air volume system and secondary air return system control relative humidity well when DSHF is big and control relative humidity bad when DSHF is small. Variable air volume system and constant air volume system control relative humidity bad.When the latent load and sensible load both change: by pass variable air volume system controls relative humidity best, to meet the high demand, secondary air return system and variable air volume system control relative humidity bad only when the Qs% is small, although the controlled results of the larger, The wind of a system of control of the poor. Constant air volume system control the relative humidity bad.I learned the VAV Laboratory Johnson Metasys system, compiled the Metasys control procedures and control interface. Its simple control interface and simple operation make the operator easily understand and control the whole building air-conditioning running. I completed experiment of constant air volume system and variable air volume system of the simulation systems in the laboratory. The simulation results and experimental results of error is less than 5 percent, so the simulation results showed that a higher credibility.