Construction method of heat energy recovery cold water preheating system based on heat pump

Abstract

The invention relates to a construction method of a heat energy recovery cold water preheating system based on a heat pump. The construction method comprises the following steps: investigating and analyzing construction industry energy consumption data; building cooling and heating load standards are formulated; a cooling and heating load demand model and operation target parameters are constructed; determining heating and ventilation cooling and heating loads; simulation data under different working conditions are obtained; calculating an optimal operation management and control strategy of the heat pump based on the analog data; and a system is constructed. According to the method, the heating and ventilation heat load is determined by combining the operation target parameters of the heat pump with the actual building heat load of the heat supply object, and working condition simulation is performed according to the mapping relation between the operation target parameters and the building cooling and heating load, so that the operation parameters and the operation efficiency of the heat pump are matched with the building business state; and meanwhile, a controller and a waste heat recovery assembly in the building industry are matched to form a preheating system for whole heat energy recovery, waste heat recovery is conducted on waste water discharged from the interior of the building, fresh water is preheated, and the building adopting the system meets the relevant requirements of the green building evaluation standard.

Description

Technical Field

[0001] The present invention belongs to the technical field of heat energy recovery of heat pumps, and in particular to a method for constructing a heat energy recovery cold water preheating system based on a heat pump. Background Art

[0002] Heat pump water heater is a highly efficient heat energy lifting and transfer device based on reverse Carnot cycle. It uses a small amount of electric energy as power and refrigerant as carrier to continuously absorb low-grade heat energy in the air and convert it into usable high-grade heat energy. It then releases the high-grade heat energy into the water that needs to be heated to produce domestic hot water, which is then delivered to users through hot water pipelines.

[0003] The existing air source heat pump operation control does not take into account the specific actual operating environment and the building heat load of the heating object, resulting in a deviation between the heating temperature and the operating target; at the same time, since some parameters of the manufacturer's machine are theoretical calculation values ​​rather than actual measurements, this leads to various different conditions in the actual use of the heat pump unit, and the actual operating conditions of the equipment are inconsistent with the target conditions, resulting in high operating energy consumption of the entire air source heat pump system, which in turn leads to reduced operating efficiency of the air source heat pump system. At the same time, corporate buildings currently use a method of natural cooling followed by biochemical treatment, which wastes a lot of heat. The heat pump device only unilaterally reduces the heating energy consumption and cannot achieve waste heat recovery. The waste heat of the wastewater needs to be recycled to better utilize resources. For this reason, it is crucial to propose a heat energy recovery cold water preheating system based on a heat pump. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and propose a method for constructing a cold water preheating system based on a heat pump for heat energy recovery, which solves the problem that in the prior art, the heat pump operation control does not take into account the specific actual operating environment and indicators such as the building heat load of the heating object, resulting in a deviation between the heating temperature and the operating target, and the heat pump device only unilaterally reduces the heating energy consumption and cannot achieve waste heat recovery. The waste heat of the wastewater needs to be recycled in order to better utilize resources.

[0005] The present invention solves the technical problem by adopting the following technical solutions:

[0006] A method for constructing a heat pump-based heat energy recovery cold water preheating system comprises the following steps:

[0007] Step S1, investigating and analyzing building energy consumption data;

[0008] Step S2: According to the research and analysis of the building energy consumption data in step S1, formulate the building cooling and heating load standard:

[0009] Step S3, formulating the building cooling and heating load standard according to step S2, constructing the cooling and heating load demand model and the operation target parameters;

[0010] Step S4, determining the HVAC cooling and heating loads according to the mapping relationship between the operation target parameters and the building cooling and heating loads;

[0011] Step S5, simulating the working conditions of the heat pump at different temperatures according to the cooling and heating loads to obtain simulation data under different working conditions;

[0012] Step S6, calculating the optimal operation control strategy of the heat pump according to the simulation data;

[0013] Step S7: construct a heat recovery system according to the optimal operation control strategy of the heat pump.

[0014] Moreover, the specific implementation method of step S1 is:

[0015] Step S1.1, data collection: It is necessary to collect the energy consumption data of the building, including the usage of electricity, water and gas energy, which can be completed by checking the energy bills, meter reading data and records of energy monitoring equipment of the building;

[0016] Step S1.2, energy sub-item analysis: Analyze the energy consumption data by different energy types to understand the usage of each energy and find out the existing problems;

[0017] Step S1.3, comparing the current energy usage with the building's historical data or industry standards to identify areas with high or low energy usage;

[0018] Step S1.4: By analyzing the building system, find out the root causes of energy waste and determine the key points for improving energy saving.

[0019] Moreover, the calculation standard of the heat load in step S3 is:

[0020] Q=U*A*AT

[0021] Among them, Q is the heat load, U is the heat transfer coefficient, A is the heat transfer area, and AT is the indoor and outdoor temperature difference.

[0022] Moreover, the specific implementation method of step S5 is: under the premise of meeting the HVAC heat load, determine the initial operation strategy of the air source heat pump system, determine the HVAC design plan according to the HVAC heat load, and determine the equipment unit, water pump and terminal equipment model of the air source heat pump system; select a temperature within a certain range of fluctuation above and below the target heating temperature as different temperatures for simulated operation, and based on the air source heat pump system operation design plan, simulate the operation of the air source HVAC design plan at different temperatures, so as to determine the operation parameters of the initial operation strategy of the air source heat pump under different operating conditions according to the HVAC heat load.

[0023] Moreover, the specific implementation method of step S7 is: based on the data support of steps S1 to S6, a suitable heat pump component is selected and installed at a suitable location of the building, and the heat pump component is connected to each unit independent controller and a waste heat recovery component, and the waste heat recovery component is installed on the air conditioner and refrigerator of the building, so that the heat pump component, the controller and the waste heat recovery component constitute a whole heat energy recovery system.

[0024] The advantages and positive effects of the present invention are:

[0025] The present invention determines the HVAC heat load through the operation target parameters of the heat pump combined with the actual building heat load of the heating object, and performs operating condition simulation according to the mapping relationship between the operation target parameters and the building's cooling and heating loads to ensure that the operation parameters and operation efficiency of the heat pump match the building format. At the same time, the controller and waste heat recovery components in the building format are cooperated to form a preheating system for the entire heat energy recovery, which recovers the waste heat of the wastewater discharged from the building and preheats the new water, so that the building using the system meets the relevant requirements of the green building evaluation standard. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a flow chart of the present invention;

[0027] Figure 2 This is a schematic diagram of the operating framework of the present invention. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below with reference to the accompanying drawings.

[0029] Example:

[0030] like Figure 1-2 As shown, an embodiment of the present invention provides a heat energy recovery cold water preheating system based on a heat pump, characterized in that it includes the following steps:

[0031] S1. Research and analyze building energy consumption data:

[0032] a. Data collection: First, you need to collect the building's energy consumption data, including the use of electricity, water, gas and other energy sources. This can be done by looking at the building's energy bills, meter reading data and records from energy monitoring equipment;

[0033] b. Energy item analysis: Analyze energy consumption data by item according to different energy types to understand the usage of each energy source and identify possible problems;

[0034] c. Compare current energy usage with the building’s historical data or industry standards to identify areas where energy is being used too much or too little;

[0035] d. Through the analysis of building systems, find out the root causes of energy waste and determine the key points for improving energy saving;

[0036] S2. Formulate building cooling and heating load standards:

[0037] Determine HVAC heat load based on building heat load, geographic information and local climate environment;

[0038] S3. Construct cooling and heating load demand model and operation target parameters:

[0039] The calculation standard of heat load in S3 is:

[0040] Q=UXAXAT

[0041] Among them, Q is the heat load, U is the heat transfer coefficient, A is the heat transfer area, and AT is the indoor and outdoor temperature difference. In addition, factors such as the heat transfer resistance of the building exterior wall, the heat transfer resistance of the window, and the heat transfer resistance of the ceiling must also be considered in the heat load calculation.

[0042] S4. Determine the HVAC cooling and heating loads based on the mapping relationship between the operating target parameters and the building cooling and heating loads:

[0043] The heating load of a building mainly depends on the heat transferred to the outside through the vertical enclosure structure (walls, doors, windows, etc.). It is related to the plane size and floor height of the building, so it does not directly depend on the floor area of ​​the building. The heating volume heat index is used to characterize the size of the building's heating load. The physical concept is clear. For general civil residential projects with a floor height of less than 3m, the area heat index method can be used for rough estimation. Since the indoor design temperature of each area is different, and the maintenance structure and cold air infiltration of each area are different, if a more accurate calculation is required, it should be calculated separately according to the position of each area in the building (such as: whether it is close to the exterior wall, doors and windows on the exterior wall) and the conditions of doors and windows (whether there is cold air infiltration). For the bathroom, if it is not close to the exterior wall, it can be estimated by multiplying the heat load of the bedroom and other areas by 1.2;

[0044] S5. Simulate the working conditions of the heat pump at different temperatures based on the cold and hot loads to obtain simulation data under different working conditions;

[0045] In S5, the initial operation strategy of the air source heat pump system is determined on the premise of meeting the HVAC heat load, and the HVAC design scheme is determined according to the HVAC heat load, that is, the equipment connection scheme of the air source heat pump system. The equipment units, water pumps and terminal equipment models of the air source heat pump system are determined according to the HVAC design scheme;

[0046] Based on the operation design scheme of the air source heat pump system, the air source HVAC design schemes at different temperatures were simulated and operated respectively, so as to determine the operating parameters of the initial operation strategy of the air source heat pump under different operating conditions according to the HVAC heat load.

[0047] S6. Calculate the optimal operation control strategy of the heat pump based on the simulation data:

[0048] a. Performance testing

[0049] Heat pump system performance testing is an important means of evaluating its heat pump capacity and energy utilization. General test indicators include heating capacity, cooling capacity, energy consumption, COP, etc. The test method usually adopts two methods: operating condition test and constant temperature test. By using test instruments to record and analyze data, the performance parameters of the heat pump system are obtained, and performance evaluation is carried out based on the test results;

[0050] b. Operation status monitoring

[0051] In addition to performance testing, the heat pump system also needs to monitor its operating status, that is, to determine whether the equipment is operating normally by real-time monitoring of temperature, humidity, pressure and other data. Commonly used monitoring instruments include thermometers, hygrometers, pressure gauges, etc. By analyzing the monitoring data, problems in the operation of the heat pump system can be discovered in time and handled;

[0052] c. Fault diagnosis

[0053] During the operation of the heat pump system, various faults may occur, such as decreased cooling capacity, increased noise, reduced heating capacity, etc. At this time, fault diagnosis is required to determine the cause of the fault and repair it. Fault diagnosis usually includes measuring the parameter values ​​of various parts of the system, analyzing the moment and time of the fault, etc., and finally drawing conclusions and making repairs.

[0054] S7. Based on the above data, a suitable heat pump assembly is selected and installed at a suitable location in the building, and the heat pump assembly is connected to the independent controller of each unit and the waste heat recovery assembly, and the waste heat recovery assembly is installed on the air conditioner, refrigerator and other equipment in the building, so that the heat pump assembly, the controller and the waste heat recovery assembly constitute a whole heat recovery system. A temperature sensor is installed in the whole heat recovery system and electrically connected to the controller, so as to monitor the heat temperature of the whole system and accurately start the heat pump for operation;

[0055] The whole waste heat recovery system adopts modular design, and multiple units are connected in parallel in one system to meet the design requirements of different places. The water with constant high temperature directly enters the insulated water tank, which can improve the utilization rate of the water tank. There will be no phenomenon that the water tank temperature drops and cannot meet the use requirements due to the cold water added to the water tank when a large amount of water is used. The whole system adopts full-automatic intelligent control and runs around the clock. The powerful system full-automatic intelligent control program ensures that the unit does not need special supervision and realizes unmanned operation. It can work as usual during the day, night, indoors or outdoors, whether it is sunny, cloudy, windy or rainy, and provides constant temperature hot water 24 hours a day. It can be used for domestic hot water in hotels, guesthouses, schools, hospitals, factories and mines, saunas, beauty salons, swimming pools, greenhouses, farms, food factories, laundries, residential areas, villas, etc. It can be used individually or in a centralized manner. Different heating requirements can choose different product series and installation designs, and the main machine uses famous compressors and plate heat exchangers: it adopts multiple anti-rust technologies and is durable.

[0056] When installing a heat pump in S7, you need to pay attention to the following issues:

[0057] (1) Selection of heat pump installation location: Heat pumps should be installed away from areas susceptible to pollution, such as low-lying and humid areas or industrial areas, to prevent airflow from being disturbed, thereby affecting the operation of the heat pump;

[0058] (2) Ensure the adequacy of power supply: Heat pumps require a large amount of power supply, so before installation, it is necessary to confirm whether the power line is stable enough and ensure that the quality of the wires meets the standards;

[0059] (3) Protection of the internal pipes of the heat pump: The internal pipes of the heat pump need to be kept clean and free of dust and debris, as these substances may enter the compressor and cause machine failure;

[0060] (4) System inspection after installation: After installation, a system inspection must be carried out to ensure that the heat pump is operating normally.

[0061] The principle of heat pump heat recovery to preheat cold water in S7 is:

[0062] (1) The domestic and industrial wastewater of the building enters the water source heat pump system. This wastewater is usually generated during the production or processing process and has a high temperature. The wastewater is pumped to the heat exchanger of the water source heat pump through a water pump;

[0063] (2) The water source heat pump uses the heat exchange tubes in the heat exchanger to transfer the heat energy in the wastewater to the new water that needs to be heated. During the heat transfer process, the heat in the wastewater is absorbed and the refrigerant in the water source heat pump is heated;

[0064] (3) The heated refrigerant increases its temperature and pressure through the compressor, and then the refrigerant dissipates heat through the condenser and transfers it to the new water that needs to be heated;

[0065] (4) The condensed refrigerant is depressurized through the expansion valve and returns to the heat exchanger for a new round of heat exchange. This process is carried out continuously, realizing the recovery and utilization of waste heat from wastewater and the preheating of cold water.

[0066] It should be emphasized that the embodiments described in the present invention are illustrative rather than restrictive. Therefore, the present invention includes but is not limited to the embodiments described in the specific implementation manner. Any other implementation manners derived by those skilled in the art based on the technical solution of the present invention also fall within the scope of protection of the present invention.

Claims

1. A method for constructing a heat pump-based heat energy recovery cold water preheating system, characterized in that: The following steps are involved: Step S1, investigating and analyzing building energy consumption data; Step S2: According to the research and analysis of the building energy consumption data in step S1, formulate the building cooling and heating load standard: Step S3, formulating the building cooling and heating load standard according to step S2, constructing the cooling and heating load demand model and the operation target parameters; Step S4, determining the HVAC cooling and heating loads according to the mapping relationship between the operation target parameters and the building cooling and heating loads; Step S5, simulating the working conditions of the heat pump at different temperatures according to the cooling and heating loads to obtain simulation data under different working conditions; Step S6, calculating the optimal operation control strategy of the heat pump according to the simulation data; Step S7: construct a heat recovery system according to the optimal operation control strategy of the heat pump.

2. The method for constructing a heat pump-based heat energy recovery cold water preheating system according to claim 1, characterized in that: The specific implementation method of step S1 is: Step S1.1, data collection: It is necessary to collect the energy consumption data of the building, including the usage of electricity, water and gas energy, which can be completed by checking the energy bills, meter reading data and records of energy monitoring equipment of the building; Step S1.2, energy sub-item analysis: Analyze the energy consumption data by different energy types to understand the usage of each energy and find out the existing problems; Step S1.3, comparing the current energy usage with the building's historical data or industry standards to identify areas with high or low energy usage; Step S1.4: By analyzing the building system, find out the root causes of energy waste and determine the key points for improving energy saving.

3. The method for constructing a heat pump-based heat energy recovery cold water preheating system according to claim 1, characterized in that: The calculation standard of the heat load in step S3 is: Q=U*A*AT Among them, Q is the heat load, U is the heat transfer coefficient, A is the heat transfer area, and AT is the indoor and outdoor temperature difference.

4. The method for constructing a heat pump-based heat energy recovery cold water preheating system according to claim 1, characterized in that: The specific implementation method of step S5 is: under the premise of meeting the HVAC heat load, determine the initial operation strategy of the air source heat pump system, determine the HVAC design plan according to the HVAC heat load, and determine the equipment unit, water pump and terminal equipment model of the air source heat pump system; select a temperature within a certain range of fluctuation above and below the target heating temperature as different temperatures for simulation operation, and based on the air source heat pump system operation design plan, simulate the operation of the air source HVAC design plan at different temperatures respectively, so as to determine the operation parameters of the initial operation strategy of the air source heat pump under different operating conditions according to the HVAC heat load.

5. The method for constructing a heat pump-based heat energy recovery cold water preheating system according to claim 1, characterized in that: The specific implementation method of step S7 is: based on the data support of steps S1 to S6, a suitable heat pump component is selected and installed at a suitable location of the building, and the heat pump component is connected to each unit independent controller and a waste heat recovery component, and the waste heat recovery component is installed on the air conditioner and refrigerator of the building, so that the heat pump component, the controller and the waste heat recovery component constitute a whole heat energy recovery system.

Images