Air conditioner energy-saving control method and device based on cooling water temperature adjustment

Abstract

According to the air conditioner energy-saving control method based on cooling water temperature adjustment, when the cooling water temperature is lower than the cooling water temperature range needed by optimal refrigeration operation of a water-cooled central air conditioner main unit, the water-cooled central air conditioner main unit works within the cooling water temperature range needed by optimal refrigeration operation of the air conditioner main unit by adjusting the temperature of cooling water; the cooling water temperature adjustment comprises the steps of adjusting the cooling water flow and the cooling efficiency of a cooling tower cooling fan and changing the cooling water circulation path to bypass the cooling tower. The water-cooled central air conditioning unit can stably operate in autumn and winter, and faults are reduced; the starting operation effect of the air conditioner is obviously improved, and the technical problem of starting failure caused by low cooling water temperature, poor oil return effect, incapability of establishing oil pressure and the like is solved; the operation efficiency and balance of the air conditioner are improved, and meanwhile the operation energy consumption of the air conditioner is remarkably reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of air conditioning, and in particular to an air conditioning energy-saving control method and device based on cooling water temperature regulation. Background Art

[0002] When the water-cooled central air-conditioning unit runs 24 hours a day in autumn and winter, the cooling water temperature is lower than 23℃ because the ambient temperature is far below 23℃. When the cooling water temperature is too low, the water-cooled central air-conditioning unit may not be able to start and operate normally. When the ambient temperature is between 23℃ and 30℃, the water-cooled central air-conditioning unit is not in the best working efficiency range, resulting in a lot of energy waste.

[0003] If the water-cooled central air-conditioning unit is operated at a temperature corresponding to the optimal working efficiency range, i.e. 28°C to 30°C, by heating the cooling water, although the working efficiency of the water-cooled central air-conditioning unit is improved, heating the cooling water will also cause a large amount of energy waste. Summary of the invention

[0004] The present invention discloses an air conditioning energy-saving control method based on cooling water temperature regulation. When the cooling water temperature is lower than the cooling water temperature range required for the optimal refrigeration operation of a water-cooled central air conditioning host, the method regulates the temperature of the cooling water so that the air conditioning host operates within the cooling water temperature range required for the optimal refrigeration operation of the air conditioning host. The specific method for regulating the cooling water temperature is as follows:

[0005] When the cooling water temperature is within the preset temperature range, the cooling water flow rate is reduced to increase the temperature of the cooling water when passing through the condenser, and / or the cooling efficiency of the cooling tower cooling fan is reduced to increase the temperature of the cooling water until the cooling water temperature of the water-cooled central air-conditioning host reaches the cooling water temperature range required for the optimal cooling operation of the water-cooled central air-conditioning host;

[0006] The preset temperature range is lower than the cooling water temperature range required for optimal cooling operation of a water-cooled central air-conditioning host.

[0007] Furthermore, when the cooling water temperature is lower than a preset temperature range, the cooling water flow path bypasses the cooling tower to circulate and absorb heat to complete the temperature rise until the cooling water temperature of the water-cooled central air-conditioning host reaches a preset temperature range.

[0008] Furthermore, the cooling water temperature range required for optimal cooling operation of the water-cooled central air-conditioning host is 28°C to 30°C, and the preset temperature range is 24°C to 27°C.

[0009] Further, reduce the cooling water flow rate, the specific method is as follows:

[0010] The cooling water temperature is used as a feedback signal to adjust the working quantity of the cooling water pump.

[0011] Further, reduce the cooling water flow rate, the specific method is as follows:

[0012] The cooling water temperature is used as a feedback signal to adjust the frequency of the cooling water pump equipped with a vector inverter.

[0013] Further, the heat dissipation efficiency of the cooling tower heat dissipation fan can be reduced by:

[0014] The cooling water temperature is used as a feedback signal to adjust the working quantity of the cooling tower heat dissipation fan.

[0015] Further, the heat dissipation efficiency of the cooling tower heat dissipation fan can be reduced by:

[0016] The cooling water temperature is used as a feedback signal to adjust the frequency of the cooling tower heat dissipation fan equipped with a vector inverter.

[0017] Furthermore, the cooling water flow path bypasses the cooling tower to circulate and absorb heat to complete the temperature rise. The specific method is as follows:

[0018] Install a temperature-controlled linkage electric valve on the cooling water circuit;

[0019] When the cooling water temperature is higher than the lower limit of the preset temperature range, the temperature control linkage electric valve remains closed;

[0020] When the cooling water temperature is lower than the lower limit of the preset temperature range, the temperature control linkage electric valve remains open.

[0021] Due to the adoption of the above technical solution, the present invention has the following beneficial effects:

[0022] 1. The present invention enables the water-cooled central air-conditioning unit to operate in a balanced manner in winter, thereby reducing the occurrence of malfunctions.

[0023] 2. It can significantly improve the start-up and operation effect of the air conditioner, and solve the technical problem of start-up failure due to the inability of the cooling water temperature to establish oil pressure.

[0024] 3. While improving the efficiency and balance of air-conditioning operation, it significantly reduces the energy consumption of air-conditioning operation.

[0025] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings of the present invention are as follows.

[0027] Figure 1 This is the schematic diagram of the inverter connection circuit.

[0028] Figure 2 This is a schematic diagram of the overall process of Example 5. DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0030] The cooling water temperature range required for optimal cooling operation of the water-cooled central air-conditioning host is set to 28℃ to 30℃, and the preset temperature range is 24℃ to 27℃.

[0031] Embodiment 1:

[0032] An air conditioning energy-saving control method based on cooling water temperature regulation, when the cooling water temperature is between 24°C and 27°C, the cooling water flow rate is reduced so that the cooling water is heated when passing through a condenser.

[0033] In this embodiment, the cooling water pumps are three 15kW cooling water pumps, all of which are Guangyi GDD150-20A, with a flow rate of 224m3 / h and a head of 15m. If the cooling water temperature is 24°C, the cooling water is delivered by only one cooling water pump, and the cooling water flow rate is low. When passing through the condenser, the heat dissipated is absorbed, and the cooling water temperature rises rapidly, so that the cooling water temperature of the water-cooled central air-conditioning host increases, approaching the optimal cooling temperature of 28°C. If the cooling water temperature is 28°C, turn on the three cooling water pumps to deliver cooling water, and the cooling water temperature maintains the working cooling water temperature of the water-cooled central air-conditioning host.

[0034] After cooling, the cooling water finally flows into the cooling tower to dissipate heat and start the next cycle.

[0035] Embodiment 2:

[0036] An air conditioning energy-saving control method based on cooling water temperature regulation, when the cooling water temperature is between 24°C and 27°C, the cooling water temperature is increased by adjusting the frequency of a cooling water pump equipped with a vector inverter.

[0037] In this embodiment, the closer the cooling water temperature is to 24° C., the lower the operating power of the cooling water pump controlled by the vector inverter, and the closer the cooling water temperature is to 27° C., the higher the operating power of the cooling water pump controlled by the vector inverter.

[0038] After cooling, the cooling water finally flows into the cooling tower to dissipate heat and start the next cycle.

[0039] Embodiment 3:

[0040] An air conditioning energy-saving control method based on cooling water temperature regulation, when the cooling water temperature is between 24°C and 27°C, the cooling water temperature is increased by reducing the heat dissipation efficiency of the cooling tower heat dissipation fan.

[0041] In this embodiment, the heat dissipation efficiency of the cooling tower is determined by the number of working heat dissipation fans. If the cooling water temperature is 24°C, the number of working heat dissipation fans of the cooling tower is 1, and the cooling water temperature rises rapidly, so that the cooling water temperature of the water-cooled central air conditioner host increases and approaches the optimal cooling temperature of 28°C. If the cooling water temperature is 28°C, the number of working heat dissipation fans of the cooling tower is 3, and the cooling water temperature maintains the working cooling water temperature of the water-cooled central air conditioner host.

[0042] Embodiment 4:

[0043] An air conditioning energy-saving control method based on cooling water temperature regulation, when the cooling water temperature is between 24°C and 27°C, the cooling water temperature is increased by reducing the heat dissipation efficiency of the cooling tower heat dissipation fan.

[0044] In this embodiment, the heat dissipation efficiency of the cooling tower heat dissipation fan is determined by the fan speed of the cooling tower equipped with a vector inverter. If the cooling water temperature is 24°C, the cooling tower heat dissipation fan works at low power, and the cooling water temperature increases rapidly, so that the cooling water temperature of the water-cooled central air conditioner host increases and approaches the optimal cooling temperature of 28°C. If the cooling water temperature is 28°C, the cooling tower heat dissipation fan works at high power, and the cooling water temperature maintains the working cooling water temperature of the water-cooled central air conditioner host.

[0045] Embodiment 5:

[0046] An air conditioning energy-saving control method based on cooling water temperature regulation, the specific method is as follows:

[0047] When the cooling water temperature is between 24°C and 27°C, the cooling water temperature is regulated by simultaneously adjusting the heat dissipation efficiency of the cooling tower and the cooling water flow rate, so that the water-cooled central air-conditioning host operates within the cooling water temperature range required for the optimal cooling operation of the water-cooled central air-conditioning host.

[0048] When the cooling water temperature is lower than 24℃, the cooling water will bypass the cooling tower to absorb heat and complete the temperature rise until the cooling water temperature of the water-cooled central air conditioner reaches between 24℃ and 27℃. If the cooling water temperature is higher than 24℃, the temperature control linkage electric valve will remain closed, and the cooling water will circulate normally into the cooling tower; if the cooling water temperature is lower than 24℃, the temperature control linkage electric valve will open, and the cooling water will no longer circulate into the cooling tower, thereby achieving the purpose of rapid temperature rise.

[0049] Experimental verification:

[0050] The cooling fan and cooling water pump are both equipped with CM800 series open-loop vector control inverters from Nichia Electric Co., Ltd. The inverter connection is as follows: Figure 1As shown. According to the actual situation of the cooling water temperature of the cooling tower, in order to facilitate operation and management, the inverter adopts an operation mode: the wiring terminal adopts CN2, the inverter is set to internal adjustment, and the external start. A temperature sensor probe is installed at the water pipe of the cooling tower tray outlet, and the sensor is connected to the transmitter control board. The voltage transmitted by the transmitter changes between 0-5V. The voltage signal transmitted by the transmitter is input to the inverter control terminal. Since the design temperature of the cooling water temperature at the start of the host is 28. C---30. C, the corresponding transmitter output voltage changes between 0.72V----5V. When the voltage changes from 0.72V to 5V, the frequency transmitted by the inverter changes between 30HZ-50HZ. Based on multiple trial runs under the condition of running the water tower fan at a low frequency, it is determined that when the motor operating frequency of the fan is lower than 30HZ, the temperature of the cooling fan rises faster, and the temperature of 30HZ and above is normal and basically stable, and can quickly respond to control the rise and fall of the cooling water temperature to meet the working environment requirements of the unit start-up operation. That is, when the inverter inputs the last operating parameters, the lower limit frequency is set to 30HZ. When the cooling water temperature is less than 23°C, the corresponding inverter output frequency is 30HZ. When the cooling water temperature is greater than 28°C or equal to 30°C, the frequency conversion frequency changes between 30HZ and 50HZ. When the cooling water temperature is greater than 30°C, the frequency conversion frequency runs stably at 50HZ. As the frequency increases, the heat dissipation of the fan increases, and the cooling water temperature stabilizes or decreases. Similarly, when the cooling water temperature decreases, the inverter frequency decreases, the heat dissipation of the fan decreases, and the cooling water temperature stabilizes or increases. In this way, the inverter output frequency is adjusted by the change of the cooling water temperature to realize the automatic adjustment of the cooling air volume of the cooling fan. To ensure that the working environment required for the unit to start and run is matched, there is no energy waste, no startup fault alarm, and better meet the unit's operating working environment, and the air conditioner is normally cooled, and the ultimate goal of green energy saving.

[0051] The cooling water temperature of the vector inverter is 0℃ to +40℃, and the humidity is 40%---90%; the control cabinet is installed vertically, keeping more than 0.5 meters away from other equipment, and ensuring good ventilation and heat dissipation; since it is installed in the control room, the distance is within 20 meters, and shielding and anti-interference measures are adopted.

[0052] The air conditioning energy-saving control using the present invention is compared with the traditional air conditioning operation.

[0053] The operating results of traditional air conditioners are shown in the following table:

[0054]

[0055] The results of the air conditioning energy saving control performed by the present invention are shown in the following table:

[0056]

[0057] The actual measured operating data of the fan after installing the inverter: (digital table DT---266) Under the premise of ensuring the quality of the workshop air-conditioning temperature, the arithmetic mean value of one winter quarter was calculated to show that the power saving was reduced from 122800kwh before the transformation to 64800kwh=58000kwh after the transformation.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. An air conditioning energy-saving control method based on cooling water temperature regulation, characterized in that: When the cooling water temperature is lower than the cooling water temperature range required for optimal cooling operation of the water-cooled central air-conditioning host, the method adjusts the cooling water temperature so that the air-conditioning host operates within the cooling water temperature range required for optimal cooling operation of the air-conditioning host. The specific method for adjusting the cooling water temperature is as follows: When the cooling water temperature is within the preset temperature range, the cooling water flow rate is reduced to increase the temperature of the cooling water when passing through the condenser, and / or the cooling efficiency of the cooling tower cooling fan is reduced to increase the temperature of the cooling water until the cooling water temperature of the water-cooled central air-conditioning host reaches the cooling water temperature range required for the optimal cooling operation of the water-cooled central air-conditioning host; The preset temperature range is lower than the cooling water temperature range required for optimal cooling operation of a water-cooled central air-conditioning host.

2. An air conditioning energy-saving control method based on cooling water temperature regulation, characterized in that: When the cooling water temperature is lower than the preset temperature range, the cooling water flow path bypasses the cooling tower to circulate and absorb heat to complete the temperature rise until the cooling water temperature of the water-cooled central air-conditioning host reaches the preset temperature range.

3. The air conditioning energy-saving control method based on cooling water temperature regulation according to claim 1 or 2, characterized in that: The cooling water temperature range required for the optimal cooling operation of the water-cooled central air-conditioning host is 28°C to 30°C, and the preset temperature range is 24°C to 27°C.

4. The air conditioning energy-saving control method based on cooling water temperature regulation according to claim 1 or 2, characterized in that: Reduce the cooling water flow rate. The specific methods are as follows: The cooling water temperature is used as a feedback signal to adjust the working quantity of the cooling water pump.

5. The air conditioning energy-saving control method based on cooling water temperature regulation according to claim 1 or 2, characterized in that: Reduce the cooling water flow rate. The specific methods are as follows: The cooling water temperature is used as a feedback signal to adjust the frequency of the cooling water pump equipped with a vector inverter.

6. The air conditioning energy-saving control method based on cooling water temperature regulation according to claim 1 or 2, characterized in that: Reduce the heat dissipation efficiency of the cooling tower heat dissipation fan. The specific methods are as follows: The cooling water temperature is used as a feedback signal to adjust the working quantity of the cooling tower heat dissipation fan.

7. The air conditioning energy-saving control method based on cooling water temperature regulation according to claim 1 or 2, characterized in that: Reduce the heat dissipation efficiency of the cooling tower heat dissipation fan. The specific methods are as follows: The cooling water temperature is used as a feedback signal to adjust the frequency of the cooling tower heat dissipation fan equipped with a vector inverter.

8. The air conditioning energy saving control method based on cooling water temperature regulation according to claim 2, characterized in that: The cooling water flow path bypasses the cooling tower to absorb heat and complete the temperature rise. The specific method is as follows: Install a temperature-controlled linkage electric valve on the cooling water circuit; When the cooling water temperature is higher than the lower limit of the preset temperature range, the temperature control linkage electric valve remains closed; when the cooling water temperature is lower than the lower limit of the preset temperature range, the temperature control linkage electric valve remains open.

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