冷却水是一种专门用于转移并减少各类设备或系统运行过程中产生的热量，从而确保其维持在适宜工作温度范围内的水介质。在实际生活应用中，冷却水系统能够有效地将空调系统中的废热，包括空调负荷的热量和冷水机组运行产生的热量有效地排放到室外环境中。 Cooling water is a water medium specially used to transfer and reduce the heat generated during the operation of various equipment or systems, so as to ensure that they are maintained within a suitable operating temperature range. In actual life applications, the cooling water system can effectively discharge the waste heat in the air-conditioning system, including the heat of the air-conditioning load and the heat generated by the operation of the chiller, to the outdoor environment.
冷却过程的核心循环机制包括两个关键步骤：The core cycle mechanism of the cooling process includes two key steps:
1、在冷凝器中吸收热量； 1. Absorb heat in the condenser;
2、在冷却塔中释放热量； 2. Release heat in the cooling tower;
因此，冷却水的运行温度受到这两个环节的严格制约。（冷却水的运行温度包括进、出冷凝器和进、出冷却塔四个特征温度，若不考虑管道温度变化，进冷凝器温度=出冷却塔温度；出冷凝器温度=进冷却塔温度） Therefore, the operating temperature of cooling water is strictly restricted by these two links. (The operating temperature of cooling water includes four characteristic temperatures: inlet and outlet condenser and inlet and outlet cooling tower. If the change of pipeline temperature is not considered, the inlet condenser temperature = outlet cooling tower temperature; outlet condenser temperature = inlet cooling tower temperature)
在冷凝器中，制冷剂蒸气和冷却水分别流经冷凝器换热管两侧，进行热交换。为确保冷凝器中冷凝热的顺利传递，冷却水的温度必须低于制冷剂蒸气的冷凝温度（进冷凝器温度上限）。否则，冷凝热将无法有效地传递给冷却水。基于这一原理，我国规定冷凝器的冷却水一般进水温度设定为32℃（额定工况）。 In the condenser, the refrigerant vapor and cooling water flow through the two sides of the condenser heat exchange tubes for heat exchange. To ensure the smooth transfer of condensation heat in the condenser, the temperature of the cooling water must be lower than the condensation temperature of the refrigerant vapor (the upper limit of the inlet temperature of the condenser). Otherwise, the condensation heat will not be effectively transferred to the cooling water. Based on this principle, my country stipulates that the general inlet water temperature of the cooling water of the condenser is set at 32°C (rated operating conditions).
在冷却塔系统中，经冷凝器加热的冷却水与大气直接接触，通过接触和蒸发两种散热方式排放空调废热。通常情况下，冷却塔的进水温度与冷凝器出水温度一致。为了确保冷却水在冷却塔内有效散热，其从冷凝器排出时的温度应设置得稍高于室外空气温度（进冷却塔温度温度下限）。我国规范推荐将冷凝器冷却水出水温度设为37℃（额定工况），这一设定目的是确保在多数环境下冷却塔进水温度高于环境气温，从而提高整个散热效率。 In the cooling tower system, the cooling water heated by the condenser is in direct contact with the atmosphere, and the waste heat of the air conditioner is discharged through two heat dissipation methods: contact and evaporation. Normally, the inlet water temperature of the cooling tower is consistent with the outlet water temperature of the condenser. In order to ensure that the cooling water effectively dissipates heat in the cooling tower, the temperature when it is discharged from the condenser should be set slightly higher than the outdoor air temperature (the lower limit of the inlet temperature of the cooling tower). my country's regulations recommend setting the outlet water temperature of the condenser cooling water to 37°C (rated operating conditions). The purpose of this setting is to ensure that the inlet water temperature of the cooling tower is higher than the ambient air temperature in most environments, thereby improving the overall heat dissipation efficiency.
即：Right now:
冷却水温度的最小值 = 进冷凝器温度 ≤ 制冷剂蒸气的冷凝温度 Minimum cooling water temperature = condenser inlet temperature ≤ refrigerant vapor condensation temperature
冷却水温度的最大值 = 出冷凝器温度 ≥ 室外空气温度 Maximum cooling water temperature = outlet condenser temperature ≥ outdoor air temperature
鉴于进冷凝器温度=出冷却塔温度，出冷凝器温度=进冷却塔温度，因此，只需要判断冷凝器温度区间大小，即可确定冷却水温度范围。 Considering that the inlet condenser temperature = the outlet cooling tower temperature, and the outlet condenser temperature = the inlet cooling tower temperature, it is only necessary to determine the size of the condenser temperature range to determine the cooling water temperature range.
一、冷凝器出水温度为什么不能过低？ 1. Why can’t the condenser outlet water temperature be too low?
1、在制冷循环中，冷凝器出水温度过低会导致冷凝压力下降，进而缩小与蒸发器间的压差。若压差减小，在蒸发器工况不变时，可能引发制冷剂流量不足，触发机组低压报警，影响系统正常运行。 1. In the refrigeration cycle, if the outlet water temperature of the condenser is too low, the condensing pressure will drop, thereby reducing the pressure difference between the condenser and the evaporator. If the pressure difference decreases, when the evaporator working condition remains unchanged, it may cause insufficient refrigerant flow, trigger the low pressure alarm of the unit, and affect the normal operation of the system.
2、许多冷水机组采用封闭式电机设计，并利用冷凝器的一部分制冷剂对电机进行内部冷却。当制冷剂流经电机定子绕组吸收热量后回流至蒸发器时，其流动依赖于冷凝器和蒸发器之间的压差。如果冷凝器出水温度偏低导致冷凝压力大幅降低，则制冷剂的冷却效能将减弱，增加电机过热风险，并可能导致电机保护机制启动。 2. Many chillers use a closed motor design and use part of the refrigerant in the condenser to cool the motor internally. When the refrigerant flows through the motor stator windings to absorb heat and then flows back to the evaporator, its flow depends on the pressure difference between the condenser and the evaporator. If the condenser outlet water temperature is low and the condensing pressure is greatly reduced, the cooling efficiency of the refrigerant will be weakened, increasing the risk of motor overheating and possibly causing the motor protection mechanism to be activated.
3、现今大多数冷水机组压缩机使用滑动轴承，需要连续润滑油润滑。长期处于冷凝器出水温度偏低的状态下，可能会阻碍润滑油的有效循环和分布，从而触发机组缺油报警，严重威胁设备的安全稳定运行。 3. Most chiller compressors today use sliding bearings that require continuous lubrication. If the condenser outlet water temperature is low for a long time, it may hinder the effective circulation and distribution of the lubricating oil, thereby triggering the unit's oil shortage alarm, which seriously threatens the safe and stable operation of the equipment.
在实际工作中，冷凝器的冷却水一般进水温度为32℃（额定工况），但存在最低温度限制，该温度因厂家而异，如特灵在16℃以上，约克在12.8℃，开利在15℃。 In actual work, the cooling water inlet temperature of the condenser is generally 32°C (rated operating conditions), but there is a minimum temperature limit, which varies from manufacturer to manufacturer. For example, Trane is above 16°C, York is 12.8°C, and Carrier is 15°C.
二、冷凝器出水温度为什么不能过高？ 2. Why can’t the condenser outlet water temperature be too high?
1、冷凝器出水温度对于整机效能具有直接关联性。当冷凝器的出水温度下降时，系统整体运行效率得以提升；相反，若出水温度过高，则会显著降低设备的整体能效表现。 1. The outlet water temperature of the condenser is directly related to the overall performance of the machine. When the outlet water temperature of the condenser decreases, the overall operating efficiency of the system is improved; on the contrary, if the outlet water temperature is too high, the overall energy efficiency of the equipment will be significantly reduced.
2、在高温状态下，冷凝器出水温度上升不仅意味着冷凝饱和压力增加，进而对离心式压缩机产生影响，增大其运行压比，有可能触发喘振保护机制。同时，随着冷凝压力不断升高，在用户负载较大的情况下，可能会加剧机组的工作负荷，导致功率消耗和电流过大，从而引发安全问题。 2. Under high temperature conditions, the rise in condenser outlet water temperature not only means an increase in condensation saturation pressure, but also affects the centrifugal compressor, increasing its operating pressure ratio and possibly triggering the surge protection mechanism. At the same time, as the condensation pressure continues to rise, under the condition of heavy user load, it may increase the workload of the unit, resulting in excessive power consumption and current, thus causing safety problems.
3、高温工作环境下的冷凝器容易出现结垢现象，尤其是铜管材质的换热器，随着出水温度的提高，结垢速度加快，这将不利于热交换性能的有效发挥，进一步降低系统的冷却效率。 3. Condensers working in high-temperature environments are prone to scaling, especially heat exchangers made of copper tubes. As the outlet water temperature increases, the scaling rate accelerates, which will be detrimental to the effective performance of heat exchange and further reduce the cooling efficiency of the system.
4、鉴于冷凝器内部压力与出水温度成正比关系，出水温度过高即意味着冷凝器内压力逼近或超出设计上限。为了确保机组安全运作，冷水机组配备了高压保护装置，当出水温度过高引起冷凝器压力超过预设的安全阈值时，系统将会自动触发报警并停机，以防止潜在的风险和损害。 4. Given that the internal pressure of the condenser is proportional to the outlet water temperature, excessive outlet water temperature means that the pressure in the condenser is approaching or exceeding the design upper limit. In order to ensure the safe operation of the unit, the chiller is equipped with a high-pressure protection device. When the outlet water temperature is too high and the condenser pressure exceeds the preset safety threshold, the system will automatically trigger an alarm and shut down to prevent potential risks and damage.
具体案例解释： Specific case explanation:
如某制冷站，运行中发现原有的5台冷水机组只能在冷凝器进水温度25℃以上运行。冷却水温低于25℃时，冷水机组运行异常，主要表现在运行参数超出控制范围，如蒸发器趋近温度快速上升（正常在1℃左右，急剧上升到3℃以上，甚至过5℃）。 For example, in a refrigeration station, it was found that the original five chillers could only operate when the condenser inlet water temperature was above 25°C. When the cooling water temperature was lower than 25°C, the chillers operated abnormally, mainly manifested in operating parameters exceeding the control range, such as the evaporator approach temperature rising rapidly (normally around 1°C, rising sharply to more than 3°C, or even over 5°C).
造成此状况的机理是：冷水机组的设计工况按冷却水32/37℃进行选型配置。在冬季及低冷却水温度情况，由于机组偏离设计工况，蒸发器和冷凝器之间的温差降低，压差也降低，节流装置不匹配，造成蒸发器内表征出缺冷媒的征兆，既蒸发器趋近温度变大。 The mechanism that causes this situation is: the design operating conditions of the chiller are selected and configured according to the cooling water temperature of 32/37℃. In winter and low cooling water temperature conditions, the unit deviates from the design operating conditions, the temperature difference between the evaporator and the condenser decreases, the pressure difference also decreases, and the throttling device does not match, resulting in the evaporator showing signs of lack of refrigerant, that is, the evaporator temperature increases.
常见应急解决方案：对冷水机组的节流装置进行更换改造，使之在低冷却水温度下（下限到18℃）也能正常运行。不利之处在于，节流装置改造后的冷水机组在高冷却水温度工况下机组效率会降低约1%，在效率和宽温之间做一个平衡的选择。 Common emergency solutions: Replace and modify the chiller's throttling device so that it can operate normally at low cooling water temperatures (lower limit to 18°C). The disadvantage is that the chiller's efficiency will decrease by about 1% under high cooling water temperature conditions after the throttling device modification, making a balanced choice between efficiency and wide temperature range.
