A gas heat pump driven combined air conditioning system coupled with a dehumidification runner

Abstract

The present application relates to a kind of gas heat pump driven and dehumidification runner coupling composite air conditioning system, the system includes power and heat recovery subsystem, refrigeration subsystem and dehumidification runner subsystem, power and heat recovery subsystem includes gas engine, cylinder liner cooling plate heat exchanger and exhaust heat exchanger, refrigeration subsystem includes the refrigerant circulation loop formed by compressor, condenser, evaporator and throttle valve, dehumidification runner subsystem includes dehumidification runner and heat recovery runner, using outdoor fresh air as processing side air, after dehumidification runner and heat recovery runner, realize indoor dehumidification.Compared with prior art, the system effectively utilizes the waste heat of gas heat pump, saves fossil energy, improves economy, recycles condensing waste heat, avoids heat pollution of flow field around unit;Accurately control indoor humidity, improve indoor thermal comfort, and the process of heat and moisture decoupling does not produce condensate water, and does not breed bacteria, create healthy indoor environment.

Description

Technical Field

[0001] This invention relates to gas-fired heat pump systems, and more particularly to a combined air conditioning system that couples a gas-fired heat pump drive with a dehumidifying impeller. Background Technology

[0002] Energy structure adjustment, gradually reducing coal consumption, and accelerating the development of clean energy have led to the vigorous promotion of natural gas due to its cleanliness and efficiency. With the booming development of the gas industry, the seasonal imbalance in gas consumption in many cities has become increasingly prominent. At the same time, the widespread use of electric air conditioners has resulted in peak electricity loads in summer. The significant peak-valley difference between gas and electricity supply is complementary; therefore, developing gas-fired air conditioning is one of the effective measures to increase summer gas consumption, reduce summer load on the power system, and balance the uneven seasonal distribution of energy.

[0003] at present:

[0004] (1) The initial investment for gas heat pump equipment is much higher than that for electric air conditioners;

[0005] (2) The COP of the gas heat pump unit is low during actual operation, which fails to give full play to the advantages of the gas heat pump unit's good performance under partial load, ultimately resulting in high energy consumption of the gas heat pump unit.

[0006] In addition, during the summer, the exhaust heat from gas engines and the waste heat from cylinder liner cooling water are directly discharged outdoors, causing both environmental heat pollution and energy waste.

[0007] To ensure that gas-fired heat pump air conditioning systems operate continuously within their optimal performance range, researchers have proposed numerous optimization schemes. These include strategies and optimizations for controlling the gas engine speed to improve its stability and anti-interference capabilities, ensuring the engine speed remains as stable as possible and allowing the gas-fired heat pump system to operate within its optimal operating range; combining energy storage technology with the gas-fired heat pump system to match energy supply with building load and maintain system stability; and proposing a gas compression absorption hybrid system that uses the waste heat from the gas engine as a heat source for the absorption heat pump, fully utilizing waste heat.

[0008] Therefore, in order to operate gas heat pumps within their optimal performance range, reduce their operating costs, and improve their market competitiveness, it is essential to optimize and upgrade them. Summary of the Invention

[0009] The purpose of this invention is to overcome the defects of the prior art and provide a composite air conditioning system that couples a gas heat pump drive with a dehumidifying rotor.

[0010] The objective of this invention can be achieved through the following technical solutions:

[0011] A composite air conditioning system driven by a gas heat pump and coupled with a dehumidifying impeller is disclosed. The system includes a power and heat recovery subsystem, a refrigeration subsystem, and a dehumidifying impeller subsystem. The power and heat recovery subsystem includes a gas engine, a cylinder liner cooling plate heat exchanger, and a flue gas heat exchanger. The refrigeration subsystem includes a refrigerant circulation loop consisting of a compressor, a condenser, an evaporator, and a throttling valve. The dehumidifying impeller system includes a dehumidifying impeller and a heat recovery impeller. By using outdoor fresh air as the treatment-side air, the air becomes low-temperature and low-humidity air after passing through the dehumidifying impeller and the heat recovery impeller, thus achieving indoor dehumidification.

[0012] The gas engine transmits mechanical energy to the compressor via a shaft, and the flue gas produced by its combustion passes through the casing and heat pipes in sequence before being discharged outdoors.

[0013] When the refrigeration subsystem is in refrigeration mode, the refrigerant undergoes adiabatic compression in the compressor, passes through the condenser, exchanges heat with the outdoor air, and then passes through the expansion valve to be cooled and depressurized before entering the indoor evaporator. After absorbing heat from the indoor air to achieve indoor cooling, the low-temperature, low-pressure gaseous refrigerant returns to the compressor, and the cycle repeats.

[0014] The waste heat from the combustion of the gas engine and the waste heat from the cylinder liner cooling water are recovered through the cylinder liner cooling plate heat exchanger and the exhaust heat exchanger. The heated water is then fed into the surface heat exchanger to heat the condensed exhaust air after heat exchange in the condenser. After reaching the working temperature of the dehumidification wheel, the heated water is fed into the dehumidification wheel to achieve dehumidification.

[0015] The evaporator serves as a cold source, and the low-temperature refrigerant inside it is introduced into the front surface cooler to exchange heat with the outdoor fresh air. The outdoor fresh air, which is in a high-temperature and high-humidity state, is cooled down to a low-temperature and high-humidity state and then sent into the dehumidification wheel to achieve dehumidification and change it to a high-temperature and low-humidity state.

[0016] The fresh air in the high temperature and low humidity state is introduced into the heat recovery rotor for sensible heat exchange and cooling.

[0017] The evaporator serves as a cold source. The low-temperature refrigerant inside is introduced into the surface cooler and exchanges heat with the outdoor fresh air that has been cooled by sensible heat exchange, further cooling the air. Finally, it is mixed with the indoor air and sent into the room to achieve the effect of dehumidification.

[0018] The exhaust air generated in the indoor environment is discharged into the outdoor environment after entering the heat recovery rotor.

[0019] The gas engine uses a mixer to mix atmospheric pressure oxygen-containing air and low-pressure gas before the mixture enters the gas engine for combustion and heat release.

[0020] The exhaust gas produced by the combustion of the gas engine passes through a heat pipe and then through a muffler before being discharged outdoors to reduce exhaust noise.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] I. This system utilizes economical heat sources such as the condensation waste heat of the air-cooled condenser and the flue gas waste heat of the gas engine, reducing the heat on the regeneration side of the dehumidification rotor, saving fossil energy, and reducing carbon emissions.

[0023] Second, this invention recovers and reuses the condensation waste heat, avoiding the problem of thermal pollution in the flow field around the unit, improving the unit's energy efficiency ratio to a certain extent, and reducing the system's operating costs.

[0024] Third, rotary dehumidification technology is an active dehumidification method that can precisely control indoor humidity, improve indoor thermal comfort, and thus enhance employee work efficiency.

[0025] Fourth, the heat and humidity decoupling process does not use condensation dehumidification, so it will not produce condensate or breed bacteria. In addition, the desiccant inside the rotor can adsorb indoor pollutants such as VOCs and ETS, creating a healthy indoor environment. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the gas-driven and dehumidifying rotor coupled composite air conditioning system of the present invention.

[0027] Figure 2 This is a schematic diagram of the dehumidifying impeller of the present invention.

[0028] Figure 3 This is an HD diagram of the adsorption process in the dehumidification rotor of the present invention.

[0029] Explanation of markings in the diagram:

[0030] 1. Exhaust gas, 2. Muffler, 3. Heat pipe, 4. Sheath, 5. Mixer, 6. Gas engine, 7. Shaft, 8. Compressor, 9. Condenser, 10. Throttling valve, 11. Evaporator, 12. Rear surface cooler, 13. Heat recovery impeller, 14. Surface heat exchanger, 15. Dehumidification impeller, 16. Front surface cooler, 17. Indoor air supply. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be described below with reference to the accompanying drawings. It should be noted that the description of these embodiments is only for the purpose of helping to understand the present invention, but does not constitute a limitation of the present invention.

[0032] Example

[0033] This invention addresses the shortcomings of existing gas heat pump systems in terms of insufficient waste heat utilization by providing a gas heat pump driven and desiccant-wheel assisted hybrid air conditioning (GDHA) system. This system can effectively improve the operating performance of the gas heat pump unit, reduce its condenser exhaust temperature, realize the cascade utilization of energy, and enhance energy saving and emission reduction effects.

[0034] This invention modifies existing gas-fired heat pump systems by coupling a dehumidifying rotor subsystem with the gas-fired heat pump system, forming a composite air conditioning system that couples a gas-fired heat pump drive with a dehumidifying rotor, such as... Figure 1 As shown, this system consists of three subsystems: a power and heat recovery subsystem, a refrigeration subsystem, and a dehumidification impeller subsystem. Key components include a compressor 8, a condenser 9, an evaporator 11, a throttle valve 10, a gas engine 6, a surface cooler, a heater, a heat recovery impeller 13, and a dehumidification impeller 15. The refrigeration subsystem achieves room cooling / heating through a thermodynamic cycle. The power and heat recovery subsystem collects waste heat from the flue gas and the cooling water of the gas engine 6 cylinder liner through the casing 4 and coolant, and uses this heat to heat the regeneration side air of the dehumidification impeller 15, improving its dehumidification efficiency. The dehumidification impeller subsystem uses fresh outdoor air as the treatment side air; after passing through two impeller stages, the air becomes low-temperature, low-humidity air, achieving indoor dehumidification.

[0035] like Figure 1 As shown, Figure 1 In addition to the main components of the system, lines are used to represent high-temperature hot water, chilled water, refrigerant, outdoor fresh air, indoor exhaust air, and outdoor condensate exhaust air.

[0036] In the power and heat recovery subsystem, atmospheric pressure oxygen-containing air and low-pressure gas are mixed in mixer 5 and then enter gas engine 6 for combustion and heat release. After converting thermal energy into mechanical energy, the mechanical energy is transferred to compressor 8 through shaft 7. The flue gas generated by combustion passes through sleeve 4, heat pipe 3, and silencer 2 before being discharged outdoors. In order to make full use of the combustion waste heat and flue gas waste heat of gas engine 6, hot water is used to recover this heat through surface heat exchanger 14 to heat the condenser exhaust air and make it reach the working temperature of dehumidification rotor 15.

[0037] In the refrigeration subsystem, the unit operates under refrigeration conditions. The refrigerant is adiabatically compressed in the compressor 8, and then passes through the air-cooled condenser 9, where it exchanges heat with the outdoor air. After passing through the expansion valve 10, it is cooled and depressurized. When the refrigerant passes through the indoor evaporator 11, it absorbs heat from the indoor air, achieving the purpose of cooling the room. Finally, the low-temperature, low-pressure gaseous refrigerant returns to the compressor 8, and the cycle repeats.

[0038] The main component of the dehumidification rotary system is the dehumidification rotor 15. To achieve better dehumidification, the outdoor fresh air needs to be cooled. The cold source comes from the evaporator 11. The refrigerant and the outdoor fresh air exchange heat in the front surface cooler 16. At this time, the outdoor fresh air changes from a high-temperature and high-humidity state to a low-temperature and high-humidity state. After being sent into the dehumidification rotor 15, it becomes a high-temperature and low-humidity state. To save energy consumption of the refrigeration unit, the dehumidified fresh air needs to be cooled before being sent into the room. Therefore, the indoor return air and the high-temperature air exchange sensible heat in the heat recovery rotor 13, and then the air is further cooled by the rear surface cooler 12. Finally, it is mixed with the indoor supply air 17 and sent into the room to achieve the dehumidification effect.

[0039] like Figure 2 As shown, a dehumidification rotor model is constructed. The principle of the dehumidification rotor is that the liquid / solid desiccant can absorb the moisture in the air on the treatment side under certain temperature and humidity conditions. Then, after being heated by the high-temperature air on the regeneration side, the moisture is released and the system is regenerated, and the cycle repeats.

[0040] like Figure 3 As shown, the state change process of the fresh air side is illustrated. Point 1 represents the air state before treatment, and point 2 represents the air state after treatment. The heat and moisture balance equation involved in process 1-2 is:

[0041] Gh2 = Gh1 - W k c w t2-g a W k +420W k

[0042] Gd2=Gd1-W k

[0043] The above equation is the heat balance equation for air changes, and the below equation is the moisture balance equation for air changes.

[0044] In the formula, G is the amount of air to be treated entering the rotor, kg / h; h1 is the enthalpy of the untreated air, i.e., the specific enthalpy of state point 1, kJ / kg. 干空气 h2 represents the enthalpy of the treated air, i.e., the specific enthalpy at state point 2; kJ / kg 干空气 W k The amount of water vapor condensed by the desiccant in one hour, expressed in kg; cw Specific heat capacity of air, J / kg K; g a t1 is the heat used to heat the adsorbent and the adsorber structure, in J; 420 is the specific heat of wetting, in kJ / kg of adsorbed moisture; t2 is the temperature of the air at state point 2, in K; d1 is the moisture content of the air at state point 1, in g / kg; d2 is the moisture content of the air at state point 2, in g / kg.

[0045] The process of air change on the regeneration side is described in 3-4, and its heat and moisture balance equation is as follows:

[0046] Gh3 = Gh4 - W k c w t4-g a W k +420W k

[0047] Gd3 = Gd4 - W k

[0048] This invention uses Klingenburg's SECO software to collect dehumidification data under different operating conditions. The data is then imported into Dymola software, and the state point of the outlet air is calculated using interpolation. The SECO software can select different impeller models and sizes, and input the airflow, temperature, and humidity conditions of the inlet air on the treatment and regeneration sides to obtain the state of the treated air and regenerated air at the outlet, such as temperature, humidity, moisture content, and enthalpy.

[0049] To verify the accuracy of the rotary model, the air state points calculated by the software and those simulated by the Dymola model will be compared and analyzed. It is assumed that the airflow rate on both the treatment and regeneration sides is 7500 m³ / h, and the temperature and humidity of the inlet air on both sides are generated into 10 pairs of arrays using random sequences.

[0050] A comparison of the temperature and humidity simulations of the treatment-side outlet air obtained using SECO and Dymola software, and a comparison of the simulations of the regeneration-side outlet air temperature and humidity, shows that the simulation error for the treatment-side outlet air temperature is 0.78%, and the simulation error for the humidity content of the treatment-side outlet air is 2.23%. The simulation error for the regeneration-side outlet air temperature is 0.87%, and the simulation error for the humidity content of the regeneration-side outlet air is 5.18%. In conclusion, the dehumidifier rotor model established using Dymola software has higher accuracy.

[0051] According to the GDHA system proposed in this invention, a system model was established using Dymola software. Its main component is the dehumidifying impeller. The fresh air operation, indoor exhaust air operation, and condensate exhaust air operation were simulated using on-site measured data from the gas-fired heat pump unit during actual operation. The data points were directly read for simulation. This invention simulated the optimized GDHA composite air conditioning system using Dymola software and a BP neural network model, yielding the following conclusions:

[0052] (1) The average supply air temperature of the optimized GDHA system is 19℃, which is basically the same as the average supply air temperature of the EHP fresh air unit before optimization. However, the supply air temperature of the optimized system fluctuates less, which can improve the situation of large fluctuations in supply air temperature before optimization.

[0053] (2) The partial load rate of the optimized GDHA system was improved, and more than 90% of the data points were in the optimal performance range of 45%-65% partial load rate; for more than 79% of the operating time, the COP of the optimized unit was higher than the COP value before optimization.

[0054] (3) The exhaust temperature of the regeneration side outlet of the rotor after optimization is 32℃-41℃, which is significantly lower than the condenser exhaust temperature of the system before optimization (30℃-52℃), which can effectively alleviate the thermal pollution caused by excessive exhaust temperature.

[0055] (4) The optimized GDHA system no longer uses the EHP fresh air unit, which effectively reduces the power consumption of the EHP fresh air unit. The daily operating cost is 233 yuan, which is lower than the daily operating cost of 348 yuan before optimization and lower than the daily operating cost of 266 yuan of the EHP unit, thus improving the economic efficiency.

[0056] (5) Before optimization, the CO2 emissions of the GEHP unit + EHP fresh air unit were 6127 kg, and the CO2 emissions of the EHP cooling and fresh air supply unit were 5519 kg. After optimization, the CO2 emissions of the GDHA system were 3246 kg, which reduced CO2 emissions by 47% and 41% respectively, effectively reducing carbon emissions and making it more environmentally friendly.

[0057] In summary, the present invention provides a composite air conditioning system coupled with a gas-fired heat pump and a dehumidifying rotor. The dehumidifying rotor replaces the electric heat pump air conditioning unit in handling the indoor humidity load. It utilizes the waste heat from the gas-fired heat pump engine and flue gas to heat the condensing exhaust air, and then uses the heated exhaust air to regenerate the dehumidifying rotor, thus utilizing the unit's waste heat and solving the problem that the condensing exhaust air temperature cannot reach the rotor's regeneration temperature. Furthermore, it uses the evaporator of the gas-fired heat pump unit as the cold source for the surface cooler, providing cooling capacity to both the indoor unit and the dehumidifying rotor's surface cooler, increasing the gas-fired heat pump unit's partial load rate and effectively improving the unit's COP value.

[0058] The advantages of this system are as follows: It utilizes the waste heat of the gas heat pump in summer, saving fossil energy and improving the system's economy; it recovers and reuses the condensation waste heat, avoiding thermal pollution problems in the flow field around the unit; the rotary dehumidification technology is an active dehumidification method, which can accurately control indoor humidity, improve indoor thermal comfort, and thus improve employee work efficiency; the heat and humidity decoupling process does not use the condensation dehumidification method, so it will not produce condensate water or breed bacteria. In addition, the desiccant inside the rotor can adsorb indoor pollutants such as VOCs and ETS, creating a healthy indoor environment.

Claims

1. A composite air conditioning system coupled with a gas-fired heat pump drive and a dehumidifying impeller, characterized in that, The system includes a power and heat recovery subsystem, a refrigeration subsystem, and a dehumidification impeller subsystem. The power and heat recovery subsystem includes a gas engine (6), a cylinder liner cooling plate heat exchanger, and a flue gas heat exchanger. The refrigeration subsystem includes a refrigerant circulation loop consisting of a compressor (8), a condenser (9), an evaporator (11), and a throttle valve (10). The dehumidification impeller subsystem includes a dehumidification impeller (15) and a heat recovery impeller (13). By using outdoor fresh air as the treatment side air, the air becomes low-temperature and low-humidity air after passing through the dehumidification impeller (15) and the heat recovery impeller (13), thus achieving indoor dehumidification. The gas engine (6) transmits mechanical energy to the compressor (8) through the shaft (7), and the flue gas generated by its combustion passes through the sleeve (4) and the heat pipe (3) in sequence before being discharged outdoors; When the refrigeration subsystem is in refrigeration mode, the refrigerant is adiabatically compressed in the compressor (8) and then passes through the condenser (9). After exchanging heat with the outdoor air, it is cooled and depressurized by the throttle valve (10) and enters the indoor evaporator (11). After absorbing the heat of the indoor air to achieve indoor cooling, the low-temperature and low-pressure gaseous refrigerant returns to the compressor (8) and cycles repeatedly. The waste heat of the flue gas generated by the combustion of the gas engine (6) and the waste heat of the cylinder liner cooling water of the gas engine (6) are recovered through the cylinder liner cooling plate heat exchanger and the exhaust heat exchanger. The heated water is then fed into the surface heat exchanger (14) to heat the condensed exhaust air after heat exchange in the condenser (9). After reaching the working temperature of the dehumidification wheel (15), the water is fed into the dehumidification wheel (15) to achieve dehumidification. The evaporator (11) serves as a cold source. The low-temperature refrigerant inside is input into the front surface cooler (16) to exchange heat with the outdoor fresh air. The outdoor fresh air, which is in a high-temperature and high-humidity state, is cooled to a low-temperature and high-humidity state and then sent into the dehumidification wheel (15) to achieve dehumidification and become a high-temperature and low-humidity state. The fresh air under high temperature and low humidity conditions is cooled by sensible heat exchange in the heat recovery rotor (13); The evaporator (11) serves as a cold source. The low-temperature refrigerant inside is input into the surface cooler (12) and exchanged with the outdoor fresh air after sensible heat exchange for further cooling. Finally, it is mixed with the indoor air supply (17) and sent into the room to achieve the effect of dehumidification.

2. The composite air conditioning system coupled with a gas heat pump drive and a dehumidifying impeller according to claim 1, characterized in that, The exhaust air generated in the indoor environment is discharged to the outdoor environment after entering the heat recovery rotor (13).

3. The composite air conditioning system coupled with a gas heat pump drive and a dehumidifying impeller according to claim 1, characterized in that, The gas engine (6) mixes atmospheric pressure oxygen-containing air and low-pressure gas through a mixer and then enters the gas engine (6) for combustion and heat release.

4. The composite air conditioning system coupled with a gas heat pump drive and a dehumidifying impeller according to claim 1, characterized in that, The flue gas generated by the combustion of the gas engine (6) passes through the heat pipe (3) and then through the muffler (2) before being discharged outdoors to reduce exhaust noise.

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