热回收型离心式冷水机组的控制优化设计

Optimization design of control for heat recovery centrifugal chiller

某光伏硅材料生产企业新建厂房面积大、负荷变化大,且当地属于温带大陆性气候,春秋季昼夜温差大,气温波动明显。针对厂房的不同负荷需求和使用特点,空调系统冷源采用离心式冷水机组和热回收型离心式冷水机组进行集中供冷。热回收型离心式冷水机组采用新型带热回收功能的冷凝器,体积比常规冷凝器大,且制冷剂充注量大于常规热回收机组。长时间处于停机状态的热回收型离心式冷水机组蒸发器和冷凝器温差过大,会发生制冷剂迁移,再次启动时容易出现吸气带液现象,在启动时增加排制冷剂控制程序可以有效解决吸气带液问题。昼夜温差大时,冷负荷与热回收负荷不平衡,热回收型离心式冷水机组在启动后只调节冷负荷,无法平衡热回收负荷,严重时会引起冷凝压力过高,在冷却水路和热回收水路增加可调节电动阀及其控制程序可以解决冷凝高压报警问题。

The newly-built plant of one photovoltaic silicon material production company has a large area and complex load changes,and the local climate is temperate continental.The temperature difference between day and night in the spring or autumn is large,and the temperature fluctuation is obvious.According to virious load demands and usage characteristics of the plant,the centrifugal chillers and heat recovery centrifugal chillers are adopted as the cold source of air-conditioning system for centralized cooling.The new condenser with heat recovery function used in the heat recovery centrifugal chiller has a larger volume than the conventional condenser,and the refrigerant charge volume is also larger than that of the conventional heat recovery chiller.For the heat recovery centrifugal chiller during the time of shutdown,if the temperature difference between the evaporator and the condenser is too large,it will have refrigerant migration phenomenon.If the heat recovery centrifugal chiller starts at this time,the suction liquid compression can easily happen.By adding the refrigerant discharge control program at start-up,the issue of suction liquid compression can be solved effectively.When the temperature difference between day and night is large,the cooling capacity and heat recovery capacity are unbalanced.The heat recovery centrifugal chiller only adjusts the cooling capacity after start-up and cannot balance the heat recovery capacity,which will cause higher condensation pressure.By adding adjustable electric valves at cooling waterway and heat recovery waterway and corresponding control program,the issue of high pressure alarm can be solved.