Method for realizing cold and heat balance combined supply by water ring heat pump

Abstract

The application provides a method for realizing cold-heat balance combined supply by a water ring heat pump, and comprises the following steps: S1, system construction; S2, connecting a water ring heat pump unit, a water-cooled centralized cold source, a hot water tank, a refrigeration circulating pump group and a hot water circulating pump group to an upper computer; S3, measuring the water temperature in the hot water tank and the energy of the hot water side of the water ring heat pump unit; measuring the cooling capacity of the water-cooled centralized cold source and the energy of the refrigeration side of the water ring heat pump unit; S4, according to the measured energy and temperature, the upper computer switches the heat supply mode of the hot water side of the water ring heat pump unit to a circulating heating mode or an instant heating mode; and switches the refrigeration side of the water ring heat pump unit to a summer mode or a winter mode. The method realizes air conditioning refrigeration heat recovery, realizes energy cascade utilization, solves the cold-heat combined supply problem, directly produces refrigeration water while producing heat, can be connected to a refrigeration water supply pipeline to eliminate cold load, realizes cold-heat balance and cold-heat coupled operation by adopting cold-heat combined supply, and realizes automatic control and energy-saving operation of the system.

Description

Technical Field

[0001] This invention relates to the field of building energy conservation technology, and in particular to a method for achieving combined cooling and heating balance using a water-loop heat pump. Background Technology

[0002] Building energy systems with both heating and cooling demands are relatively complex, involving diverse and multi-level energy consumption systems. These systems are interconnected and prone to issues such as waste heat, residual heat, and energy waste from single-use applications. To address energy conservation, the industry has proposed solutions for combined cooling and heating (CCHP), such as water-loop heat pump systems. These systems can achieve balanced cooling and heating, recover waste heat from air conditioning systems, and completely replace gas-fired hot water boilers for hot water, achieving cascaded energy utilization. Furthermore, these systems require relatively low investment and have a short payback period. However, traditional water-loop heat pump systems primarily rely on the heat from the cooling tower's cooling water. They reduce the energy consumption of the chiller and produce hot water by absorbing waste heat from the cooling water. From an energy utilization perspective, this doesn't directly achieve CCHP; it indirectly reduces air conditioning energy consumption while providing heating, resulting in relatively indirect and less significant energy savings. Summary of the Invention

[0003] To address the aforementioned problems, the present invention aims to provide a method for achieving combined cooling and heating balance using a water-loop heat pump. The water-loop heat pump unit provides indirect cooling via a water-cooled centralized cold source connected in series on the chiller side, or it can directly provide a cold source for the cooling load. The water-loop heat pump unit heats the hot water source on the hot water side, then supplies hot water to the hot water tank. If the temperature is insufficient, the boiler heat transfer system intervenes to supplement the heat source, ensuring that both the hot water side and the chiller side can meet the cooling and heating requirements of the corresponding load, thus achieving a cooling and heating balance and directly providing combined cooling and heating.

[0004] This invention is implemented using the following method: A method for achieving combined cooling and heating balance using a water-loop heat pump, comprising the following steps: Step S1: Construction of a combined cooling and heating balance system for a water-loop heat pump: On the refrigeration side, the refrigeration side of the water-loop heat pump unit is connected to a refrigeration load or a water-cooled centralized cold source, and a refrigeration circulation pump unit is provided. The water-cooled centralized cold source is connected to the refrigeration load to provide a cold source for the refrigeration load. On the hot water side, the hot water side of the water-loop heat pump unit is connected to a hot water tank, and a hot water circulation pump unit is provided. The hot water tank is also connected to a boiler heat medium system, and the hot water tank is connected to a hot water supply pipeline for hot water supply.

[0005] Step S2: Connect the water-loop heat pump unit, the water-cooled centralized cold source, the hot water tank, the chilled water circulation pump unit, and the hot water circulation pump unit to the host computer;

[0006] Step S3: Measure the water temperature in the hot water tank and the energy on the hot water side of the water-loop heat pump unit; measure the cooling capacity of the water-cooled centralized cold source and the energy on the refrigeration side of the water-loop heat pump unit, as well as the supply water temperature and return water temperature;

[0007] Step S4: The host computer switches the heating mode of the hot water side of the water-loop heat pump unit to either circulating heating mode or instant heating mode based on the measured water temperature in the hot water tank and the energy on the hot water side of the water-loop heat pump unit; the host computer switches the cooling mode of the cooling side of the water-loop heat pump unit to either summer mode or winter mode based on the temperature difference between the supply and return water on the cooling side of the water-loop heat pump unit and by comparing the instantaneous cooling capacity of the water-cooled centralized cold source and the cooling capacity on the cooling side of the water-loop heat pump unit.

[0008] Preferably, step S4 further includes: step S41a, the host computer controls the water-loop heat pump unit and the hot water tank to start, and sets the initial working mode of the hot water side of the water-loop heat pump unit to the circulating heating mode;

[0009] Step S42a: If the energy meter on the hot water side of the water ring heat pump unit exceeds the set value, and the water temperature in the hot water tank is still 3-10°C lower than the set value for 10-60 minutes, the heating mode is switched to instant heating mode.

[0010] Step S43a: If the water temperature in the hot water tank is higher than the set value plus 1-8°C and continues for 10-60 minutes, the heating mode is switched to the circulating heating mode.

[0011] Preferably, step S4 further includes: step S41b, the host computer controls the water-loop heat pump unit and the water-cooled centralized cold source to start, and sets the initial working mode of the water-loop heat pump unit's refrigeration side to summer mode; step S42b, if the instantaneous cooling capacity of the water-cooled centralized cold source is greater than 1.2-3 times the instantaneous energy of the water-loop heat pump unit's refrigeration side, and the chilled water return temperature on the refrigeration side is 2-10°C or higher than the chilled water supply temperature, and this continues for 30-90 minutes, then the summer mode operation is maintained;

[0012] Step S43b: The current mode of the chilled side is summer mode. If the chilled water return temperature of the chilled side is 1-4℃ lower than the set value of the chilled water supply temperature and lasts for 30-90 minutes, the summer mode will be switched to winter mode.

[0013] Step S44b: The current mode of the chilled side is winter mode. If the chilled water supply temperature is 2-8℃ higher than the chilled water supply setting value, or the chilled water return temperature is 7-13℃ higher than the chilled water supply setting value, and this continues for 30-90 minutes, then the system will switch from winter mode to summer mode.

[0014] Preferably, step S1 further includes: connecting the hot water supply port of the water-loop heat pump unit to the hot water tank; connecting the hot water return port of the water-loop heat pump unit to the hot water tank, or a water supply pipe, or a hot water return pipe before the hot water tank; connecting the water-cooled centralized cold source to the refrigeration load through the chilled water supply pipe and the chilled water return pipe; connecting the chilled water supply port of the water-loop heat pump unit to the chilled water supply pipe or the chilled water return pipe through an electric switching valve; and connecting the chilled water return port of the water-loop heat pump unit to the chilled water return pipe.

[0015] Preferably, the summer mode is as follows: the host computer controls the electric switching valve to connect the chilled water supply port of the water-loop heat pump unit to the chilled water return pipeline, and the host computer starts the water-cooled centralized cold source for cooling; the host computer controls the water-loop heat pump unit to operate in either a circulating heating mode or an instant heating mode.

[0016] The winter mode is as follows: the host computer controls the electric switching valve to connect the chilled water supply port of the water-loop heat pump unit to the chilled water supply pipeline, and the host computer shuts off the water-cooled centralized cold source; the host computer controls the water-loop heat pump unit to operate in either circulating heating mode or instant heating mode.

[0017] Preferably, in the circulating heating mode: the host computer controls the boiler heat medium system to shut down, and the host computer controls the start and stop of the water-loop heat pump unit. Initially, no heat pump unit is running. If the hot water tank temperature is 1-3°C lower than the set value and remains so for 5-10 minutes, the hot water circulation pump unit and the chilled water circulation pump unit are started. After detecting that the water flow switch is open, one of the water-loop heat pump units is started for heating. Currently, one of the water-loop heat pump units is running for heating. If the average load rate of the heat pump units is higher than 85%, and the water temperature in the hot water tank remains 1-4°C below the set value for 5-10 minutes, then another heat pump unit is started for heating, until n heat pump units are loaded. If n heat pump units are currently running for heating, and the average load rate of the water-loop heat pump units is lower than 60%, and the water temperature in the hot water tank is 1-3°C above the set value for 5-10 minutes, then one water-loop heat pump unit is shut down, until all water-loop heat pump units are shut down. Preferably, the instant heating mode is as follows: the host computer controls the boiler heat medium system to start and all water-loop heat pump units to run for heating, so that the water temperature in the hot water tank reaches the set value.

[0018] Preferably, in step S3:

[0019] Calculation of cooling capacity of the water-cooled centralized cold source:

[0020] Instantaneous cooling capacity of a water-cooled centralized cooling source = (chilled water return temperature of the water-cooled centralized cooling source - chilled water supply temperature of the water-cooled centralized cooling source) * chilled water flow rate, unit: kW;

[0021] Cumulative cooling capacity of a water-cooled centralized cooling source = Integral of instantaneous cooling capacity of the water-cooled centralized cooling source over time, unit: kJ;

[0022] Energy calculation for the refrigeration side of a water-loop heat pump unit:

[0023] Instantaneous energy output on the chiller side of a water-loop heat pump unit = (chiller side inlet water temperature of the water-loop heat pump unit - chiller side outlet water temperature of the water-loop heat pump unit) * chiller side flow rate of the water-loop heat pump unit, unit: kW;

[0024] The cumulative energy on the chiller side of the water-loop heat pump unit = the integral of the instantaneous energy on the chiller side of the water-loop heat pump unit over time, unit: kJ; the energy calculation on the hot water side of the water-loop heat pump is as follows:

[0025] Instantaneous energy on the hot water side of a water-loop heat pump unit = (outlet water temperature on the hot water side of the water-loop heat pump unit - inlet water temperature on the hot water side of the water-loop heat pump unit) * flow rate on the hot water side of the water-loop heat pump unit, unit: kW;

[0026] The cumulative energy on the hot water side of a water-loop heat pump unit is equal to the integral of the instantaneous energy on the hot water side of the water-loop heat pump unit over time, in kJ.

[0027] Preferably, the hot water circulation pump group is controlled as follows: the hot water side of the water-loop heat pump unit operates in a circulating heating mode: when at least one of the water-loop heat pump units is running, the host computer controls the operating frequency of the hot water circulation pump group and performs PI regulation (positive regulation) on the temperature setpoint of the hot water side return port or the temperature difference setpoint of the hot water side supply and return water of the water-loop heat pump unit to maintain the return water temperature of the hot water side return port or the temperature difference of the hot water side supply and return water of the water-loop heat pump unit at its set value; when no water-loop heat pump unit is running, the host computer shuts down the hot water circulation pump group.

[0028] The hot water side of the water ring heat pump unit operates in instant heating mode: the host computer controls the hot water circulation pump unit to operate at a fixed frequency.

[0029] Preferably, the control of the refrigeration circulation pump group is as follows: when the working mode of the refrigeration side of the water ring heat pump unit is winter mode: the host computer controls the refrigeration circulation pump group to operate at a variable frequency, so that the energy of the refrigeration side of the water ring heat pump unit = the heat of the hot water side of the water ring heat pump * energy conversion efficiency.

[0030] When the working mode of the refrigeration side of the water ring heat pump unit is summer mode: the host computer controls the refrigeration circulation pump unit to operate at a fixed frequency.

[0031] The beneficial effects of this invention are as follows: This invention provides a method for achieving combined cooling and heating balance using a water-loop heat pump. Compared with the prior art, this invention has at least the following technical effects: 1. The water-loop heat pump unit is connected in series and parallel to a water-cooled centralized cold source on the refrigeration side. The water-loop heat pump unit can directly provide a cold source for the cooling load, or it can be connected in series to a water-cooled centralized cold source to indirectly provide a cold source for the cooling load. Through heat exchange between the cold and hot sides of the water-loop heat pump unit, the hot water is heated and then supplied to the hot water tank for hot water supply. The return water on the refrigeration side is cooled to reduce the return water temperature of the water-cooled centralized cold source, thereby directly reducing the energy consumption of the water-cooled centralized cold source. The boiler heat medium system can be used to supplement the heat source in a timely manner to achieve constant hot water supply. When the cooling load is too large, the water-cooled centralized cold source can be used to supplement the cooling capacity in a timely manner, so as to achieve a balance between the cooling capacity on the refrigeration side and the cooling capacity on the hot water side and the corresponding load (i.e., cooling and heating balance). It is suitable for use in various seasons, and keeps the hot water supply temperature within ±2℃. While providing heating, it directly reduces the energy consumption of air conditioning cooling. The application targets are water-to-water source heat pump units and their systems, suitable for buildings with simultaneous heating and cooling needs and employing water-cooled centralized cooling source systems (heating demand refers to domestic hot water usage). Applications include scenarios such as hotels, dormitories, and apartments. The overall cost savings of the entire heating and cooling source system can reach over 70%. Except for heating, the boiler heat transfer system basically does not need to be turned on throughout the year, reducing energy costs. During winter and transitional seasons, the water-cooled centralized cooling source can achieve 100% energy savings, eliminating the need for the chiller to be turned on; during summer, it can achieve 10-20% energy savings, providing some cooling capacity and thus reducing the energy consumption of the cooling system.

[0032] 2. Temperature and energy are measured by thermometers and energy meters on both the hot and cold water sides, which facilitates timely adjustment of the operating frequency of the cold water circulation pump set and the hot water circulation pump set, as well as the opening and closing of the water-cooled centralized cold source and boiler heat medium system, so as to achieve balanced operation of cold and hot water supply.

[0033] 3. By setting an electric on / off valve, the chilled water outlet of the water-loop heat pump unit can be adjusted to either connect to a water-cooled centralized cooling source or directly connect to the chilled water supply pipe to supply cooling to the cooling load. This enables the switching between summer and winter modes of the system. In winter, the chilled water supply pipe is directly connected without starting the water-cooled centralized cooling source, while in summer, it is connected to the water-cooled centralized cooling source, which can reduce the operating power of the water-cooled centralized cooling source and achieve energy-saving effects.

[0034] 4. It can achieve the following functions: automatic operation control of water-to-water loop heat pump units; constant temperature control of domestic hot water; automatic start-stop control of boiler heat medium system (or other backup heat source system); linkage operation control of water-cooled centralized cold source system; automatic frequency conversion control of chilled water circulation pump unit; automatic frequency conversion control of hot water circulation pump unit; electric switching valve control of water loop heat pump system mode; automatic adjustment control of cold and heat balance; energy consumption monitoring, etc. Attached Figure Description

[0035] Figure 1 This is a block diagram illustrating the control principle of a water-ring heat pump for achieving combined cooling and heating balance according to the present invention.

[0036] Figure 2 This is a schematic diagram of the water-ring heat pump combined cooling and heating system of the present invention.

[0037] Figure 3 yes Figure 2 Enlarged schematic diagram of a portion of the frozen side.

[0038] Figure 4 yes Figure 2 Enlarged schematic diagram of a portion of the hot water side.

[0039] Figure 5 This is a schematic diagram of the control points of the water-ring heat pump cooling and heating balance combined supply system of the present invention.

[0040] Figure 6 yes Figure 5 A magnified schematic diagram of the control points on the freezing side.

[0041] Figure 7 yes Figure 5 A partially enlarged schematic diagram of the control points on the hot water side.

[0042] Explanation of reference numerals: 1-Water-loop heat pump unit, 2-Water-cooled centralized cold source, 3-Boiler heat medium system, 4-Refrigeration circulation pump unit, 5-Hot water circulation pump unit, 6-Hot water tank, 7-Electric switching valve, 8-Manual butterfly valve, 9-Y-type filter, 10-Flexible joint, 11-Pressure gauge, 12-Check valve. Detailed Implementation

[0043] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0044] Please see Figures 1 to 7 A method for achieving combined cooling and heating balance using a water-loop heat pump includes the following steps: S1. Construction of the water-loop heat pump combined cooling and heating balance system: On the refrigeration side, the refrigeration side of the water-loop heat pump unit 1 is connected to a refrigeration load or a water-cooled centralized cold source 2, and a refrigeration circulation pump unit 4 is provided. The water-cooled centralized cold source 2 is connected to the refrigeration load (such as an indoor air conditioning unit) to provide a cold source for the refrigeration load. The refrigeration circulation pump unit 4 is used to circulate the refrigerant generated by the water-loop heat pump unit and the water-cooled centralized cold source between the refrigeration load and the water-loop heat pump unit 1 and the water-cooled centralized cold source 2. On the hot water side, the hot water side of the water-loop heat pump unit 1 is connected to a hot water tank 6, and a hot water circulation pump unit 5 is provided. The hot water tank 6 is also connected to a boiler heat medium system 3. The hot water tank 6 is connected to a hot water supply pipeline for hot water supply, which is used to pump the remaining hot water back to the water-loop heat pump unit 1 for heating, thereby realizing the circulation of hot water.

[0045] Step S2: Connect the water-loop heat pump unit 1, the water-cooled centralized cold source 2, the hot water tank 6, the chilled water circulation pump unit 4, and the hot water circulation pump unit 5 to the host computer; the host computer can be a PLC controller, which is existing technology and will not be described in detail or have specific protection requirements.

[0046] Step S3: Measure the water temperature in the hot water tank 6 and the energy on the hot water side of the water-loop heat pump unit 1; measure the cooling capacity of the water-cooled centralized cold source 2 and the energy on the freezing side of the water-loop heat pump unit 1, as well as the supply water temperature and return water temperature;

[0047] Step S4: The host computer switches the heating mode of the hot water side of the water-loop heat pump unit 1 to either circulating heating mode or instant heating mode based on the measured water temperature in the hot water tank 6 and the energy on the hot water side of the water-loop heat pump unit 1. The host computer also switches the cooling mode of the water-loop heat pump unit 1 to either summer mode or winter mode based on the temperature difference between the supply and return water on the chiller side of the water-loop heat pump unit 1 and by comparing the instantaneous cooling capacity of the water-cooled centralized cold source 2 and the chiller side of the water-loop heat pump unit 1. Steps S3 and S4 are then repeated to continuously monitor temperature and energy, and to switch the operating mode. Connecting the chiller side of the water-loop heat pump unit in series and parallel to the water-cooled centralized cold source allows for direct connection to the chilled load or indirect connection through the water-cooled centralized cold source, enabling the recovery of heat from air conditioning cooling and achieving cascaded energy utilization. Using the hot water side of the water-loop heat pump unit to heat the water source solves the problem of combined cooling and heating: while generating heat, it directly produces chilled water, which can be connected to the chilled water supply line to eliminate the cooling load. Employing an intelligent combined cooling and heating control algorithm, the system achieves cooling and heating balance and coupled operation, enabling automatic system control and energy-saving operation. The water-loop heat pump system, utilizing distributed small-scale water-to-water source heat pump units, offers flexible design and layout, good applicability, and simple construction, making it particularly suitable for retrofit projects. It provides constant-temperature domestic hot water supply and adaptively adjusts chilled water for air conditioning. The system boasts high energy efficiency and low energy costs.

[0048] Please see Figures 1 to 7 Preferably, step S4 further includes: step S41a, the host computer controls the water ring heat pump unit 1 and the hot water tank 6 to start, and sets the initial working mode of the hot water side of the water ring heat pump unit 1 to the circulating heating mode.

[0049] Step S42a: If the energy meter on the hot water side of the water-loop heat pump unit exceeds the set value, and the water temperature in the hot water tank 6 remains 3-10℃ lower than the set value (e.g., 4, 7, 9℃, but not limited thereto) for 10-60 minutes (e.g., 25, 30, 40, 55, 59℃, etc., but not limited thereto), then the heating mode is switched to instant heating mode; (when the heat output of the water-loop heat pump unit has reached its upper limit, but still cannot meet the hot water demand, it is necessary to consider starting the gas-fired hot water boiler for parallel heating; the heat output of the water-loop heat pump unit has reached its upper limit, but the water temperature in the hot water tank has not yet reached the set value). If the water temperature in the hot water tank reaches the set value, it indicates that the water-loop heat pump is fully loaded and cannot raise the temperature of the water tank. Therefore, the boiler heat transfer system needs to be activated immediately to supplement the heat. This situation typically occurs when hotel guests simultaneously use hot water during a peak occupancy period, resulting in a very high instantaneous demand for hot water. Step S43a: If the water temperature in the hot water tank 6 is higher than the set value plus 1-8℃ (e.g., 3, 4, 7℃, but not limited to this) and remains so for 10-60 minutes (e.g., 15, 25, 30, 40, 55, 59℃, etc., but not limited to this), the heating mode switches to the circulating heating mode.

[0050] Please see Figures 1 to 7 Preferably, step S4 further includes: step S41b, the host computer controls the water-loop heat pump unit 1 and the water-cooled centralized cold source 2 to start, and sets the initial working mode of the water-loop heat pump unit's refrigeration side to summer mode.

[0051] Step S42b: If the instantaneous cooling capacity of the water-cooled centralized cold source 2 is greater than 1.2-3 times the instantaneous energy of the chiller side of the water-loop heat pump unit 1 (the cooling capacity amplification factor can be 1.5, 1.7, 2, etc., which can be adjusted and is not limited thereto), and the chilled water return temperature on the chiller side is 2-10℃ higher than the chilled water supply temperature (such as 3, 5, 6, 8, 9℃, which is not limited thereto) and above, and this continues for 30-90 minutes (which can be adjusted, such as 45, 60, 75 minutes, which is not limited thereto), then the summer mode operation is maintained.

[0052] Step S43b: The current mode of the chilled side is summer mode. If the chilled water return temperature of the chilled side is 1-4℃ lower than the set value of the chilled water supply temperature (adjustable, such as 1 or 3℃, but not limited to this), and this temperature remains lower for 30-90 minutes (adjustable, such as 45, 60, or 75 minutes, but not limited to this), then the summer mode will switch to winter mode.

[0053] Step S44b: The current mode of the chilled side is winter mode. If the chilled water supply temperature is 2-8℃ higher than the chilled water supply set value (adjustable, such as 3, 4, 6, 7℃, but not limited to this), or the chilled water return temperature is 7-13℃ higher than the chilled water supply set value (adjustable, such as 8, 9, 10, 12℃, but not limited to this), and this continues for 30-90 minutes (adjustable, such as 45, 60, 75 minutes, but not limited to this), then the system will switch from winter mode to summer mode.

[0054] Please see Figures 1 to 7 Preferably, step S1 further includes: connecting the hot water supply port of the water-loop heat pump unit 1 to the hot water tank 6; connecting the hot water return port of the water-loop heat pump unit 1 to the hot water tank 6, or a water supply pipe, or a hot water return pipe before the hot water tank 6; connecting the water-cooled centralized cold source 2 to the chilled load through chilled water supply pipes and chilled water return pipes; connecting the chilled water supply port of the water-loop heat pump unit 1 to the chilled water supply pipe or chilled water return pipe through an electric switching valve 7; connecting the chilled water return port of the water-loop heat pump unit 1 to the chilled water return pipe. Two electric switching valves 7 are provided, one for the non-air conditioning season and the other for the air conditioning season. Winter mode: the non-air conditioning season electric switching valve is open, and the air conditioning season electric switching valve is closed; Summer mode: the non-air conditioning season electric switching valve is closed, and the air conditioning season electric switching valve is open.

[0055] Please see Figures 1 to 7 Preferably, the summer mode is as follows: the host computer controls the electric switching valve 7 to connect the chilled water supply port of the water-loop heat pump unit 1 to the chilled water return pipeline, and the host computer starts the water-cooled centralized cold source 2 to provide cooling; the host computer controls the water-loop heat pump unit 11 to operate in either a circulating heating mode or an instant heating mode.

[0056] The winter mode is as follows: the host computer controls the electric switching valve 7 to connect the chilled water supply port of the water ring heat pump unit 1 to the chilled water supply pipeline, and the host computer shuts off the water-cooled centralized cold source 2; the host computer controls the water ring heat pump unit 11 to operate in either the circulating heating mode or the instant heating mode.

[0057] Please see Figures 1 to 7Preferably, in the circulating heating mode: the host computer controls the boiler heat medium system 3 to shut down, and the host computer controls the water loop heat pump unit 1 to start and stop. Initially, no heat pump unit is started. Currently, no heat pump unit is running. If the water temperature in the hot water tank 6 is lower than the set value by 1-3℃ (adjustable, such as 1, 2, 3℃, but not limited thereto), and this continues for 5-10 minutes (adjustable, such as 5, 7, 9 minutes, but not limited thereto), then the hot water circulation pump unit and the chilled water circulation pump unit are started. After detecting that the water flow switch is open, one of the water loop heat pump units 1 is started for heating. Currently, one of the water loop heat pump units 1 is started for heating, and the average load rate of the heat pump unit is higher than 85% (adjustable, such as 87%, 90%, 92%, etc., but not limited thereto). If the water temperature in hot water tank 6 remains below the set value of 1-4℃ (adjustable, such as 2 or 3℃, not limited thereto) for 5-10 minutes (adjustable, such as 7, 8, or 9 minutes, not limited thereto), then start one heat pump unit for heating, until n heat pump units (n>1) are loaded; if n heat pump units are currently running for heating, and the average load rate of the water-loop heat pump unit 1 is below 60% (adjustable, such as 55%, 57%, or 53%, not limited thereto), and if the water temperature in hot water tank 6 is above the set value of 1-3℃ (adjustable, such as 2℃, not limited thereto) for 5-10 minutes (adjustable, such as 7, 8, or 9 minutes, not limited thereto), then shut down one of the water-loop heat pump units 1, until all water-loop heat pump units 1 are shut down.

[0058] Please see Figures 1 to 7 Preferably, the instant heating mode is as follows: the host computer controls the boiler heat medium system 3 to start and all the water ring heat pump units 1 to operate and heat, so that the water temperature in the hot water tank 6 reaches the set value.

[0059] Please see Figures 1 to 7 Preferably, in step S3:

[0060] Calculation of cooling capacity for water-cooled centralized cold source:

[0061] Instantaneous cooling capacity of a water-cooled centralized cooling source = (chilled water return temperature of the water-cooled centralized cooling source - chilled water supply temperature of the water-cooled centralized cooling source) * chilled water flow rate, unit: kW;

[0062] Cumulative cooling capacity of a water-cooled centralized cooling source = Integral of instantaneous cooling capacity of the water-cooled centralized cooling source over time, unit: kJ;

[0063] Energy calculation for the refrigeration side of a water-loop heat pump unit:

[0064] Instantaneous energy output on the chiller side of a water-loop heat pump unit = (chiller side inlet water temperature of the water-loop heat pump unit - chiller side outlet water temperature of the water-loop heat pump unit) * chiller side flow rate of the water-loop heat pump unit, unit: kW;

[0065] Cumulative energy on the refrigeration side of a water-loop heat pump unit = Integral of instantaneous energy on the refrigeration side of the water-loop heat pump unit over time, unit: kJ;

[0066] Energy calculation for the hot water side of a water-loop heat pump unit:

[0067] Instantaneous energy on the hot water side of a water-loop heat pump unit = (outlet water temperature on the hot water side of the water-loop heat pump unit - inlet water temperature on the hot water side of the water-loop heat pump unit) * flow rate on the hot water side of the water-loop heat pump unit, unit: kW;

[0068] The cumulative energy on the hot water side of a water-loop heat pump unit is equal to the integral of the instantaneous energy on the hot water side of the water-loop heat pump unit over time, in kJ.

[0069] Please see Figures 1 to 7 Preferably, the control of the hot water circulation pump group is as follows: When the hot water side working mode of the water-loop heat pump unit 1 is the circulation heating mode: when at least one of the water-loop heat pump units 1 is running, the host computer controls the working frequency of the hot water circulation pump group 5 and performs PI adjustment (positive adjustment) on the temperature setpoint of the hot water side return port or the hot water side supply and return water temperature difference setpoint of the water-loop heat pump unit 1, so that the return water temperature of the hot water side return port or the hot water side supply and return water temperature difference of the water-loop heat pump unit 1 is maintained at its set value; when no water-loop heat pump unit 1 is running, the host computer shuts down the hot water circulation pump group 5.

[0070] When the hot water side of the water ring heat pump unit 1 operates in instant heating mode: the host computer controls the hot water circulation pump unit to operate at a fixed frequency (preferably 50Hz fixed frequency operation).

[0071] Please see Figures 1 to 7Preferably, the operating frequency control of the chilled water circulation pump group 4 is as follows: When the chilled side of the water-loop heat pump unit 1 is in winter mode: the host computer controls the chilled water circulation pump group 4 to operate at a variable frequency (detecting the chilled water supply and return pressure difference on the chilled side of the water-loop heat pump unit 1, setting a dynamic lower limit value for the chilled water supply and return pressure difference, prioritizing ensuring that the chilled water supply and return pressure difference after the chilled water circulation pump group 4 is frequency-controlled is not lower than the lower limit value (ensuring cooling of the most unfavorable chilled water pipeline); under the premise of satisfying the first adjustment, the pump frequency of the chilled side circulation pump group is then adjusted by PI (positive adjustment) according to the set value of the chilled water supply and return temperature difference. This refers to proportional and integral regulation, which responds proportionally to system deviations. Once a deviation occurs, the proportional regulation immediately takes effect to reduce it. This maintains the chilled water supply and return temperature difference at its set value. (If the absolute value of the chilled water supply and return temperature difference is less than or equal to 1.5℃ (this value is adjustable; at this time, there is no cooling load, and 1.5℃ considers the pipe temperature rise or fluctuation range), and the chilled water pump frequency reaches the lower limit and continues for 1 hour, then the pump is shut down; otherwise, the chilled water pump is started for automatic variable frequency operation.) This ensures that the energy on the chilled side of the water-loop heat pump unit 1 equals the heat on the hot water side of the water-loop heat pump multiplied by the energy conversion efficiency (adjustable, unit: %).

[0072] Chilled water supply and return temperature difference = chilled water return temperature - chilled water supply temperature; chilled water supply and return pressure difference = chilled water supply pressure - chilled water return pressure;

[0073] When the working mode of the water ring heat pump unit 1 on the refrigeration side is summer mode: the host computer controls the refrigeration circulation pump unit to operate at a fixed frequency (preferably 50HZ fixed frequency operation).

[0074] Please see Figures 2 to 7A water-loop heat pump combined cooling and heating system includes a water-loop heat pump unit 1, a water-cooled centralized cold source 2, and a boiler heat medium system 3. The water-cooled centralized cold source 2 is equipped with a chilled water supply port and a chilled water return port. The chilled water supply port is connected to a chilled water supply pipeline, and the chilled water return port is connected to a chilled water return pipeline. The water-loop heat pump unit 1 is equipped with a chilled water outlet, a chilled water inlet, a hot water outlet, and a hot water inlet. The chilled water outlet is connected to the chilled water return port. Alternatively, it can be directly connected to the chilled water supply pipeline; the chilled water inlet is connected to the chilled water return pipeline, and a chilled water circulation pump set 4 is provided between the chilled water inlet and the chilled water return pipeline; the hot water outlet is connected to the hot water supply pipeline via the hot water tank 6; the hot water tank 6 is connected to the boiler heat medium system 3, the hot water inlet is connected to the hot water return pipeline, a hot water circulation pump set 5 is provided on the hot water return pipeline, and the hot water inlet is also connected to a cold water makeup source. A water-loop heat pump unit 1 is connected in series and parallel to a water-cooled centralized cooling source 2 (preferably a water-cooled chiller unit). The water-loop heat pump unit 1 can directly provide a cooling source for the cooling load, or it can be connected in series with the water-cooled centralized cooling source 2 to indirectly provide a cooling source for the cooling load (preferably a refrigeration system using a water-cooled chiller unit as the cooling source). The water-loop heat pump unit 1 can heat the hot water source on the hot water side of the water-loop heat pump unit 1, and then supply hot water to the hot water tank 6. The water-loop heat pump unit 1 (preferably a small water-to-water source heat pump unit) realizes the exchange of heat between the cooling and hot water sides, enabling the cooling load on the cooling side to cool. The chilled return water transfers heat to the hot water source, while the temperature of the chilled return water is reduced (i.e., water-cooled centralized cold source), directly reducing the energy consumption of the water-cooled centralized cold source 2. The timely intervention of the boiler heat medium system 3 replenishes the heat source in time to achieve constant hot water supply (the heat source may be insufficient only when heating is needed, so the boiler heat medium system 3 is started to replenish the heat source in time. The best boiler heat medium system can be a heating system with a gas-fired hot water boiler as the heat source, or other heat sources that can generate heat). The hot water supply temperature is kept constant within ±2℃, and the energy consumption of air conditioning is directly reduced while providing heating.

[0075] Please see Figures 2 to 7 Preferably, the hot water return pipe is connected back to the hot water inlet via the hot water tank 6; the cold water supply source is connected to the hot water return pipe and is located before the hot water return pipe passes through the hot water tank 6. The hot water tank 6 can preheat the hot water return and supply water, so that the hot water supply temperature can reach the set temperature in a timely manner.

[0076] Please see Figures 2 to 7Preferably, the chilled water circulation pump unit 4 includes a first water pump located between the chilled water return pipe and the chilled water inlet, used to pump the return water in the chilled water return pipe into the water-loop heat pump unit 1. The hot water circulation pump unit 5 has the same structure as the chilled water circulation pump unit 4. This ensures that the chilled water return and hot water return can be promptly delivered to the water-loop heat pump unit 1 for timely heat exchange, achieving combined cooling and heating.

[0077] Please see Figures 2 to 7 Preferably, the water-cooled circulating pump unit 4 further includes a Y-type filter 9, a check valve 12, a manual butterfly valve 8, and a pressure gauge 11; the manual butterfly valve 8, the Y-type filter 9, the first water pump, the pressure gauge 11, and the check valve 12 are connected in series along the return water direction. The Y-type filter 9 can filter impurities in the return water in a timely manner, the check valve 12 prevents backflow of water, and the pressure gauge 11 is used to monitor the return water pressure. Based on the monitoring data of the pressure gauge 11, the working power of the water pump can be adjusted in a timely manner, which can protect the water-loop heat pump unit 1 and ensure that the water-loop heat pump unit 1 can operate stably for a long time. Corresponding temperature meters and flow meters are installed on the remaining pipelines, as shown in the schematic diagram of the control points of the water-loop heat pump cooling and heating balance system.

[0078] Please see Figures 2 to 4 Preferably, both the inlet and outlet ends of the first water pump are connected in series with flexible joints 10. More preferably, the flexible joints are cocoa-flexible rubber joints, which serve to reduce vibration and protect the water pump and pipeline.

[0079] Please see Figures 2 to 4 Preferably, one end of the chilled water outlet is connected to a T-shaped pipe, and the other two ends of the T-shaped pipe are respectively connected to the chilled water supply pipe and the chilled water return pipe. An electric switching valve 7 is connected in series at each of the other two ends of the T-shaped pipe. This valve is used to adjust and control whether the chilled water from the chilled side outlet of the water-loop heat pump unit 1 is connected to the water-cooled centralized cooling source 2 or directly connected to the chilled water supply pipe to directly supply cooling to the cooling load. This enables the switching between summer and winter modes of the system. In winter, direct connection to the chilled water supply pipe eliminates the need to start the water-cooled centralized cooling source 2; in summer, connection to the water-cooled centralized cooling source 2 reduces its operating power, achieving energy savings.

[0080] Please see Figures 2 to 7Preferably, the chilled water outlet is connected to the tee pipe via a chilled water outlet pipe, and a chilled water outlet thermometer and a chilled water energy meter are installed on the chilled water outlet pipe. The hot water outlet is connected to the hot water tank 6 via a hot water outlet pipe, and a hot water outlet thermometer and a hot water energy meter are installed on the hot water outlet pipe. Monitoring the temperature of the outlet water and the energy consumed allows the chilled water circulation pump unit 4 and the hot water circulation pump unit 4 to adjust their operating frequencies in a timely manner, ensuring balanced operation of the chilled water and hot water sides of the water-loop heat pump unit 1.

[0081] Please see Figures 2 to 7 Preferably, the hot water tank 6 is equipped with a coil, the inlet end of which is connected to the heat medium supply end of the boiler heat medium system 3, and the outlet end of which is connected to the heat medium recovery end of the boiler heat medium system 3. This facilitates the heating of the hot water in the hot water tank 6, ensuring timely replenishment of the heat source and maintaining a constant hot water temperature.

[0082] Preferably, all energy meters should be pipe-mounted electromagnetic flow meters / energy meters or insertion ultrasonic flow meters, installed on the corresponding pipes, as per [reference needed]. Figures 5 to 7 Hot water tank temperature sensor: The temperature probe is installed at the bottom of the hot water tank (the lower the water temperature, the higher the density; theoretically, the water temperature at the bottom of the tank is the lowest temperature inside. To ensure that the temperature inside the hot water tank does not fall below the minimum temperature setpoint, the temperature at the bottom of the tank needs to be detected). All water temperature sensors: Insertion-type temperature sensors are used, refer to... Figures 5 to 7 Installed on the corresponding pipes or equipment. Water pump frequency conversion: The host computer has a chilled water circulation pump frequency converter on the chilled side to control the chilled water circulation pump group; the host computer also has a hot water circulation pump frequency converter on the hot water side to control the hot water circulation pump group. Non-air conditioning season electric switching valve: Installed on the pipe section between the chilled water outlet pipe of the water source heat pump and the chilled water supply pipe, refer to... Figures 5 to 7 Air conditioning seasonal electric switching valve: Installed on the pipe section between the chilled water inlet pipe and the chilled water return pipe on the chilled water side of the water source heat pump, refer to... Figures 5 to 7 The host computer is equipped with a cold source system controller to control the water-cooled centralized cold source. The host computer is also equipped with a boiler heat medium system controller to control the boiler heat medium system. Finally, the host computer is equipped with a water source heat pump unit controller to control the water-loop heat pump unit.

[0083] The present invention has the following working principle:

[0084] The water-loop heat pump unit connects to a water-cooled centralized cooling source in series and parallel on the chiller side. The water-loop heat pump unit can directly provide cooling for the cooling load, or it can be connected in series with the water-cooled centralized cooling source to indirectly provide cooling for the cooling load. Through heat exchange between the hot and cold sides of the water-loop heat pump unit, the hot water is heated and then supplied to the hot water tank for hot water supply. The return water on the chiller side is cooled to reduce the return water temperature of the water-cooled centralized cooling source, thus directly reducing the energy consumption of the water-cooled centralized cooling source. Furthermore, the timely intervention of the boiler heat transfer system can replenish the heat source in a timely manner to achieve a constant hot water supply temperature, suitable for use in all seasons, keeping the hot water supply temperature within ±2℃. While providing heating, it directly reduces the energy consumption of air conditioning. In colder seasons, the cold source generated by the heat exchange of the water-loop heat pump unit directly supplies cooling for the air conditioner, without requiring the water-cooled centralized cooling source to start. 1. It realizes the recovery of heat discharged from air conditioning, achieving cascaded energy utilization. 2. Solve the combined cooling and heating problem: While generating heat, chilled water is directly produced and can be connected to the chilled water supply pipeline to eliminate cooling load. 3. Employ an intelligent combined cooling and heating control algorithm to achieve cooling and heating balance and coupled operation, realizing automatic system control and energy-saving operation. 4. Utilize a distributed small-scale water-to-water source heat pump unit water loop heat pump system, which allows for flexible design and layout, good applicability, and simple construction, making it particularly suitable for renovation projects. 5. Provides constant temperature supply for domestic hot water and adaptive adjustment of chilled water for air conditioning. 6. The system has a high energy saving rate and low energy costs. I. Hot Water Side – Coupled Heating Control of Water Loop Heat Pump Unit and Boiler Heat Medium System

[0085] 1. Constant temperature heating mode

[0086] a) Heating mode determination and switching conditions

[0087] i. After the system is powered on, the initial heating mode is the circulating heating mode;

[0088] ii. The current heating mode is circulating heating mode. If the energy meter on the hot water side of the water loop heat pump unit exceeds the set value...

[0089] (Adjustable) If the hot water tank temperature is 5℃ lower than the set value (adjustable) and remains below the set value for 30 minutes (adjustable), the heating mode will switch to instant heating mode. (When the heat output of the water-loop heat pump unit has reached its upper limit and is still insufficient to meet the hot water demand, it is necessary to consider starting the gas-fired hot water boiler for parallel heating. If the heat output of the water-loop heat pump unit reaches its upper limit and the hot water tank temperature has not yet reached the set value, it indicates that the water source heat pump is fully loaded and cannot raise the water temperature in the pressurized heat exchange tank. In this case, the gas-fired hot water boiler needs to be started immediately to supplement the heat. This situation generally occurs when hotel guests use hot water simultaneously during a concentrated period of time, the occupancy rate is high, and the instantaneous demand for hot water is very large.)

[0090] iii. The current heating mode is instant heating mode. If the water temperature in the hot water tank is 2℃ higher than the set value (adjustable) and continues for 30 minutes (adjustable), the heating mode will switch to circulating heating mode.

[0091] 2. Circulating heating mode control

[0092] b) Circulating heating mode control

[0093] i. Boiler heat medium system control

[0094] 1. When the boiler heat medium system is shut down, a system shutdown command is sent to the boiler heat medium system controller.

[0095] ii. Start-up, shutdown, and number control of water-ring heat pump units

[0096] 1. After switching to the circulating heating mode, it enters the initial state, in which no water-loop heat pump unit starts;

[0097] 2. Currently, no water-loop heat pump units are operating. If the hot water tank temperature is 1°C lower than the set value (adjustable) and remains below the set value for 5 minutes (adjustable), the hot water side and chilled water side circulating water pumps will be turned on. After the water flow switch is detected to be open, one water-loop heat pump unit will be turned on for heating.

[0098] 3. Currently, one water-loop heat pump unit is in operation for heating, and the average load rate of this water-loop heat pump unit is higher than 90%.

[0099] (Adjustable) If the water temperature in the hot water tank is 1℃ lower than the set value (adjustable) and continues for 5 minutes (adjustable), then after the water flow switch is detected to be open, one water ring heat pump unit will be started to heat, until the load is applied to n water ring heat pump units.

[0100] 4. Currently, i water-loop heat pump units (i = 1 to n, a total of n water-loop heat pump units) are started for heating, and the average load rate of the water-loop heat pump units is less than 60% (adjustable). If the water temperature in the hot water tank is higher than the set value plus 1℃ (adjustable) and continues for 5 minutes (adjustable), then unload (shut down) 1 water-loop heat pump unit, until the unloaded water-loop heat pump units are 0.

[0101] iii. Control of hot water circulation pump unit on the hot water side of water-loop heat pump unit

[0102] 1. When at least one water-loop heat pump unit is started, the hot water circulating pump unit is controlled as follows:

[0103] a) The frequency of the hot water circulation pump unit is adjusted by PI (positive adjustment) according to the hot water side return water temperature setting value (or hot water side supply and return water temperature difference setting value) of the water ring heat pump unit, so that the hot water side return water temperature setting value (or hot water side supply and return water temperature difference setting value) is maintained at its set value.

[0104] b) The frequency of the hot water circulation pump set shall not be lower than the lower frequency limit (adjustable).

[0105] 2. If the waterless circulating heat pump unit is currently running, then the hot water circulating pump unit should be shut down.

[0106] 3. Instant heating mode control

[0107] c) Instant heating mode control

[0108] i. Boiler heat medium system control:

[0109] 1. The boiler heat medium system is started, and a system start command is sent to the boiler heat medium system controller.

[0110] ii. Start-up, shutdown, and number control of water-ring heat pump units

[0111] 1. Turn on the hot water circulation pump on the hot water side and the chilled water circulation pump on the chilled side of the water-loop heat pump unit. After the water flow switch is detected to be open, turn on all water-loop heat pump units for heating.

[0112] iii. Hot water circulating pump unit control

[0113] 1. The hot water circulating pump set operates at 50Hz.

[0114] II. Chilling Side – Water-loop Heat Pump Unit and Water-cooled Central Cooling Source Heat and Cold Balance Control

[0115] 1. Heat balance calculation for the cold and hot sides of a water-ring heat pump unit

[0116] a) Calculation of cooling capacity for water-cooled centralized cold source:

[0117] i. Instantaneous cooling capacity of a water-cooled centralized cooling source = (chilled water return temperature - chilled water supply temperature) * chilled water flow rate, unit: kW

[0118] ii. Cumulative cooling capacity of a water-cooled centralized cooling source = Integral of instantaneous cooling capacity of the water-cooled centralized cooling source over time, unit: kJ

[0119] b) Calculation of chiller-side energy for water-loop heat pump units:

[0120] i. Instantaneous energy output on the chiller side of a water-loop heat pump unit = (chiller side inlet water temperature of the water-loop heat pump unit - chiller side outlet water temperature of the water-loop heat pump unit) * chiller side flow rate of the water source heat pump, unit: kW

[0121] ii. Cumulative energy on the chiller side of a water-loop heat pump unit = Integral of instantaneous energy on the chiller side of the water-loop heat pump unit over time, unit: kJ

[0122] c) Energy calculation for the hot water side of the water-loop heat pump unit:

[0123] i. Instantaneous energy output on the hot water side of the water-loop heat pump unit = (Outlet water temperature on the hot water side of the water-loop heat pump unit - Inlet water temperature on the hot water side of the water-loop heat pump unit) * Flow rate on the hot water side of the water-loop heat pump unit, unit: kW

[0124] ii. Cumulative energy on the hot water side of a water-loop heat pump unit = Integral of instantaneous energy on the hot water side of the water-loop heat pump unit over time, unit: kJ

[0125] 2. Start-up and frequency conversion control of refrigeration circulation pump unit

[0126] a) Temperature difference between chilled water supply and return water in a water-loop heat pump unit = Chilled water return temperature - Chilled water supply temperature

[0127] b) Chilled water supply and return pressure difference of water-loop heat pump unit = Chilled water supply pressure - Chilled water return pressure

[0128] c) Variable frequency control of the chilled circulation pump set:

[0129] i. Detect the chilled water supply and return pressure difference, set a dynamic lower limit for the chilled water supply and return pressure difference, and prioritize ensuring that the chilled water supply and return pressure difference after the chilled water circulation pump unit is frequency-controlled is not lower than the lower limit (to ensure cooling of the most unfavorable chilled water pipeline);

[0130] ii. Provided that the first adjustment is met, the frequency of the chilled water cycle is adjusted according to the set value of the chilled water supply and return water temperature difference.

[0131] PI regulation (positive regulation) maintains the temperature difference between the chilled water supply and return water at its set value.

[0132] d) Start-up and shutdown control of refrigeration circulation pump unit

[0133] i. If the absolute value of the chilled water supply and return temperature difference is less than or equal to 1.5℃ (this value is adjustable; there is no cooling load at this time, 1.5℃)

[0134] If the frequency of the chilled circulation pump unit reaches the lower limit and continues for 1 hour, considering the temperature rise or fluctuation range of the pipeline, the water pump should be shut down.

[0135] ii. Otherwise, start the refrigeration circulation pump set to operate automatically via frequency conversion.

[0136] 3. Switching between initial operating mode and operating mode on the refrigeration side

[0137] a) The initial mode is the summer mode;

[0138] b) If the instantaneous cooling capacity of the water-cooled centralized cold source is greater than the instantaneous energy of the water-loop heat pump unit on the chiller side * 1.5 (cooling capacity amplification factor, adjustable), and the chilled water return temperature is higher than the chilled water supply temperature by +3.0℃ (adjustable) or more, and this continues for 1 hour (adjustable), the heat balance mode will enter the summer mode.

[0139] c) The current mode is summer mode. If the chilled water return temperature is lower than the chilled water supply temperature set value +1℃ (adjustable) and this continues for 1 hour (adjustable), the hot and cold balance mode will switch to winter mode.

[0140] d) The current mode is winter mode. If the chilled water supply temperature is higher than the chilled water supply setting value +4℃ (adjustable) or the chilled water return temperature is higher than the chilled water supply setting value +9℃ (adjustable) and this continues for 1 hour (adjustable), the hot and cold balance mode will switch to summer mode.

[0141] 4. Summer Mode Control

[0142] a) Electric valve switching control

[0143] i. The electric valve for switching between non-air conditioning seasons is closed;

[0144] ii. When the air conditioning seasonal switching electric valve is opened, the chilled water outlet of the water source heat pump is connected to the chilled water return line.

[0145] b) Water-cooled centralized cooling source control

[0146] i. The water-cooled centralized cooling source is turned on, and a system operation command is sent to the water-cooled centralized cooling source controller;

[0147] ii. Water-cooled centralized cooling source, which provides cooling on demand according to the control program of the water-cooled centralized cooling source controller.

[0148] c) Control of water-loop heat pump units and water source heat pump chiller circulation pumps

[0149] i. Water-ring heat pump unit control

[0150] 1. The water-loop heat pump unit is controlled according to the procedure in "Hot Water Side - Water-loop Heat Pump Unit and Boiler Coupled Heating Control";

[0151] ii. Control of the chilled circulation pump set on the chiller side of the water-loop heat pump unit

[0152] 1. Start the refrigeration circulation pump unit;

[0153] 2. The refrigeration circulation pump unit operates at 50Hz.

[0154] 5. Winter Mode Control

[0155] a) Electric valve switching control

[0156] i. When the non-air conditioning season switching electric valve is opened, the chilled water outlet of the water loop heat pump unit is connected to the chilled water supply line;

[0157] ii. The air conditioning seasonal switching electric valve is closed.

[0158] b) Water-cooled centralized cooling source control

[0159] i. When the water-cooled centralized cooling source is shut down, a system shutdown command is sent to the water-cooled centralized cooling source controller (water cooling means the centralized cooling source is shut down);

[0160] ii. In water-cooled centralized cold sources, keep the electric valves at the inlet and outlet of the chilled water unit open.

[0161] c) Control of water-loop heat pump units and chilled circulation pump units on the chiller side of water-loop heat pump units

[0162] i. Water-ring heat pump unit control

[0163] 1. The water-loop heat pump unit is controlled according to the procedure in "Hot water side - water-loop heat pump unit and boiler heat medium system coupled heating control";

[0164] ii. Control of the chilled circulation pump on the chiller side of the water-loop heat pump unit

[0165] 1. The chilled circulation pump unit on the chiller side operates by frequency conversion, so that the chiller side cooling capacity of the water-loop heat pump unit is equal to the hot water side heat capacity multiplied by the energy conversion efficiency (adjustable, unit: %).

[0166] Several points should be noted: First, in the description of this application, it should be noted that, unless otherwise specified and limited, the terms "installation", "connection" and "linkage" should be interpreted broadly, and can be mechanical or electrical connection, or internal connection between two components, or direct connection. "Up", "down", "left", "right", etc. are only used to indicate relative positional relationship. When the absolute position of the described object changes, the relative positional relationship may change.

[0167] Secondly: The accompanying drawings of the embodiments disclosed in this invention only involve the structures involved in the embodiments disclosed in this invention. Other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of this invention can be combined with each other.

[0168] Finally, the above description is only a preferred embodiment of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. All technical solutions that fall within the scope of the present invention are within the scope of protection of the present invention.

[0169] It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of this invention should also be considered within the scope of protection of this invention.

Claims

1. A method for achieving combined cooling and heating balance using a water-loop heat pump, characterized in that: Step S1: Construction of the water-loop heat pump cooling and heating balance system: On the refrigeration side, the refrigeration side of the water-loop heat pump unit is connected to the refrigeration load or a water-cooled centralized cold source, and a refrigeration circulation pump set is provided. The water-cooled centralized cold source is connected to the refrigeration load to provide a cold source for the refrigeration load. On the hot water side, the hot water side of the water-loop heat pump unit is connected to a hot water tank, and a hot water circulation pump set is provided. The hot water tank is also connected to the boiler heat medium system. The hot water tank is connected to the hot water supply pipeline for hot water supply. Step S2: Connect the water-loop heat pump unit, the water-cooled centralized cold source, the hot water tank, the chilled water circulation pump unit, and the hot water circulation pump unit to the host computer; Step S3: Measure the water temperature in the hot water tank and the energy on the hot water side of the water-loop heat pump unit; measure the cooling capacity of the water-cooled centralized cold source and the energy on the refrigeration side of the water-loop heat pump unit, as well as the supply water temperature and return water temperature; Step S4: The host computer switches the heating mode of the hot water side of the water-loop heat pump unit to either circulating heating mode or instant heating mode based on the measured water temperature in the hot water tank and the energy on the hot water side of the water-loop heat pump unit; the host computer switches the cooling mode of the cooling side of the water-loop heat pump unit to either summer mode or winter mode based on the temperature difference between the supply and return water on the cooling side of the water-loop heat pump unit and by comparing the instantaneous cooling capacity of the water-cooled centralized cold source and the cooling capacity on the cooling side of the water-loop heat pump unit. Step S1 further includes: connecting the hot water supply port of the water ring heat pump unit to the hot water tank; Connect the hot water return port of the water-loop heat pump unit to the hot water tank, or to the water supply pipe, or to the hot water return pipe before the hot water tank; connect the water-cooled centralized cold source to the chilled load through the chilled water supply pipe and the chilled water return pipe; connect the chilled water supply port of the water-loop heat pump unit to the chilled water supply pipe or the chilled water return pipe through an electric switching valve; connect the chilled water return port of the water-loop heat pump unit to the chilled water return pipe. The summer mode is as follows: the host computer controls the electric switching valve to connect the chilled water supply port of the water-loop heat pump unit to the chilled water return pipeline, and the host computer starts the water-cooled centralized cold source for cooling; the host computer controls the water-loop heat pump unit to operate in either circulating heating mode or instant heating mode. The winter mode is as follows: the host computer controls the electric switching valve to connect the chilled water supply port of the water-loop heat pump unit to the chilled water supply pipeline, and the host computer shuts off the water-cooled centralized cold source; the host computer controls the water-loop heat pump unit to operate in either circulating heating mode or instant heating mode. The circulating heating mode is as follows: the host computer controls the boiler's heat transfer system to shut down, and the host computer controls the start and stop of the water-loop heat pump unit. Initially, no heat pump unit is running. If the hot water tank temperature is 1-3°C lower than the set value and remains so for 5-10 minutes, the hot water circulation pump unit and the chilled water circulation pump unit are activated. After detecting that the water flow switch is open, one of the water-loop heat pump units is activated for heating. Currently, one water-loop heat pump unit is activated for heating, and... If the average load rate of the heat pump unit is higher than 85%, and the water temperature in the hot water tank remains 1-4°C below the set value for 5-10 minutes, then another heat pump unit will be started to heat the water, until all n heat pump units are loaded. If n heat pump units are currently running and the average load rate of the water-loop heat pump unit is lower than 60%, and the water temperature in the hot water tank is 1-3°C above the set value for 5-10 minutes, then one water-loop heat pump unit will be shut down, until all water-loop heat pump units are shut down. Instant heating mode: The host computer controls the boiler heat medium system to start and all the water loop heat pump units to operate and heat, so that the water temperature in the hot water tank reaches the set value; Control of the hot water circulation pump group: When the hot water side of the water-loop heat pump unit is in circulation heating mode: when at least one of the water-loop heat pump units is running, the host computer controls the operating frequency of the hot water circulation pump group and performs PI adjustment on the temperature setpoint of the hot water side return port or the temperature difference setpoint of the hot water side supply and return water of the water-loop heat pump unit to maintain the return water temperature of the hot water side return port or the temperature difference setpoint of the hot water side supply and return water of the water-loop heat pump unit at its set value; when no water-loop heat pump unit is running, the host computer shuts down the hot water circulation pump group. When the hot water side of the water ring heat pump unit operates in instant heating mode, the host computer controls the hot water circulation pump unit to operate at a fixed frequency.

2. The method of claim 1, wherein the water ring heat pump is used to realize cold and heat balance combined supply. Step S4 further includes: step S41a, the host computer controls the water-loop heat pump unit and the hot water tank to start, and sets the initial working mode of the hot water side of the water-loop heat pump unit to the circulating heating mode; Step S42a: If the energy meter on the hot water side of the water ring heat pump unit exceeds the set value, and the water temperature in the hot water tank is still 3-10°C lower than the set value for 10-60 minutes, the heating mode is switched to instant heating mode. Step S43a: If the water temperature in the hot water tank is higher than the set value plus 1-8℃ and continues for 10-60 minutes, the heating mode is switched to the circulating heating mode.

3. The method of claim 1, wherein the water ring heat pump is used to realize cold and heat balance combined supply. Step S4 further includes: step S41b, the host computer controls the water-loop heat pump unit and the water-cooled centralized cold source to start, and sets the initial working mode of the water-loop heat pump unit on the refrigeration side to summer mode; Step S42b: If the instantaneous cooling capacity of the water-cooled centralized cold source is greater than 1.2-3 times the instantaneous energy of the chilled side of the water-loop heat pump unit, and the chilled water return temperature on the chilled side is 2-10°C or higher than the chilled water supply temperature for 30-90 minutes, then the summer mode operation shall be maintained. Step S43b: The current mode of the chilled side is summer mode. If the chilled water return temperature of the chilled side is 1-4℃ lower than the set value of the chilled water supply temperature and lasts for 30-90 minutes, the summer mode will be switched to winter mode. Step S44b: The current mode of the chilled side is winter mode. If the chilled water supply temperature is 3-6℃ higher than the chilled water supply setting value, or the chilled water return temperature is 7-13℃ higher than the chilled water supply setting value, and this continues for 30-90 minutes, then the system will switch from winter mode to summer mode.

4. The method of claim 1, wherein the water ring heat pump is used to realize cold and heat balance combined supply. In step S3: Calculation of cooling capacity for water-cooled centralized cold source: Instantaneous cooling capacity of a water-cooled centralized cooling source = (chilled water return temperature of the water-cooled centralized cooling source - chilled water supply temperature of the water-cooled centralized cooling source) * chilled water flow rate, unit: kW; The cumulative cooling capacity of a water-cooled centralized cooling source = the integral of the instantaneous cooling capacity of the water-cooled centralized cooling source over time, in kJ; Energy calculation for the refrigeration side of a water-loop heat pump unit: Instantaneous energy on the chiller side of a water-loop heat pump = (chiller side inlet water temperature of the water-loop heat pump unit - chiller side outlet water temperature of the water-loop heat pump unit) * chiller side flow rate of the water-loop heat pump unit, unit: kW; Cumulative energy on the refrigeration side of a water-loop heat pump unit = Integral of instantaneous energy on the refrigeration side of the water-loop heat pump unit over time, unit: kJ; Energy calculation for the hot water side of a water-loop heat pump unit: Instantaneous energy on the water side of a water-loop heat pump unit = (outlet water temperature on the hot water side of the water-loop heat pump unit - inlet water temperature on the hot water side of the water-loop heat pump unit) * hot water flow rate on the hot water side of the water-loop heat pump unit, unit: kW; The cumulative energy on the hot water side of a water-loop heat pump unit is the integral of the instantaneous energy on the hot water side of the water-loop heat pump unit over time, in kJ.

5. The method of claim 3, wherein the water ring heat pump is used to realize cold and heat balance combined supply. Control of the refrigeration circulation pump group: When the working mode of the refrigeration side of the water ring heat pump unit is winter mode: the host computer controls the refrigeration circulation pump group to operate by frequency conversion, so that the energy of the refrigeration side of the water ring heat pump unit = the heat of the hot water side of the water ring heat pump * energy conversion efficiency; When the working mode of the refrigeration side of the water ring heat pump unit is summer mode: the host computer controls the refrigeration circulation pump unit to operate at a fixed frequency.

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