Discussion on chilled hydronic balance based on heat transfer characteristics of cooling coils and solution of chilled water systems

 In order to strengthen the research basis of the control of the cooling coil at the end of the central air conditioning chilled water system in large public buildings, a comparative test of two different variable volume regulation modes, on-off control and proportional control, is carried out on the end cooling coil equipment control valve in a public building. Through the variable volume analysis and discussion on the heat transfer characteristics of the cooling coil, the control theory of “using a control valve with reverse nonlinear characteristics to compensate the non-linearity characteristics of terminal equipment” is questioned, and the defects and shortcomings of the control strategy of the temperature difference between supply and return water of the end cooling coil are pointed out. Under the premise of satisfying the design water supply temperature and design flow rate of the end cooling coil in service of the chilled water system, a distributed control technology based on the chilled hydronic balance of the end cooling coil is proposed, and the automatic adjustment and control of the chilled hydronic balance of the central air conditioning chilled water system is realized.