Method for dehumidification and heat recovery for indoor swimming pools in winter

Abstract

The application discloses a method for dehumidification and heat recovery of an indoor swimming pool in winter, and a heat exchange device for implementing the method, wherein the heat exchange device comprises a sensible heat exchanger, a compressor, a gas-liquid separator, a first heat exchanger, a first evaporator and a second evaporator; the method comprises the following steps: mixing outdoor fresh air with first indoor return air after the outdoor fresh air is warmed by the sensible heat exchanger, then sending the mixed air to the indoor as supply air after the mixed air is warmed by the first heat exchanger; sending second indoor return air to outdoor exhaust air after the second indoor return air is sequentially cooled and dehumidified by the sensible heat exchanger, the second evaporator and the first evaporator; and sending third indoor return air to the indoor as supply air after the third indoor return air is cooled and dehumidified by the second evaporator. The method can control the air humidity of the indoor swimming pool and improve the heat recovery efficiency.

Description

Technical Field

[0001] This application relates to the field of heat recovery technology, and in particular to a method for dehumidifying and recovering heat in indoor swimming pools during winter. Background Technology

[0002] Most of the heat loss in indoor swimming pools is due to the evaporation of water from the pool surface into water vapor. The heat of the pool water is carried into the pool air by the water vapor, which greatly increases the enthalpy and humidity of the air. Since the pool water contains toxic gases such as chlorine, the pool needs to be ventilated. However, if the air in the pool is directly exhausted, it will result in a large amount of enthalpy loss (i.e., energy loss).

[0003] The relative humidity in a swimming pool should generally be maintained between 65% and 85%. Too low a relative humidity will lead to faster evaporation from the pool surface and the human body, making people feel colder. Too high a relative humidity will also increase the discomfort of people and make it easy for condensation to form on the outer enclosure structure, thereby reducing the service life and thermal insulation performance of the enclosure structure. Therefore, it is necessary to control the humidity of the swimming pool. If the heat from dehumidification is not recovered, it will also cause a large energy loss.

[0004] Based on the above characteristics of swimming pools, there are many existing technical methods for heat recovery from the exhaust air of swimming pools in summer. For example, the heat pump condensation heat recovery method involves cooling and dehumidifying the indoor return air through the evaporator and then recovering the heat to the condenser. The heat is then used by the condenser for dehumidification, reheating, and heating of the pool water.

[0005] In existing technologies, many swimming pools do not ventilate during winter to reduce heat loss, which is not conducive to dehumidification and the removal of toxic gases such as chlorine from the room. Alternatively, they use the same circulating exhaust heat recovery method to achieve heat recovery in both winter and summer, which is not very effective. Summary of the Invention

[0006] Based on this, a method for dehumidification and heat recovery in indoor swimming pools during winter is provided, which controls the air humidity of the indoor swimming pool on the one hand, and improves the efficiency of heat recovery on the other.

[0007] A method for dehumidification and heat recovery in indoor swimming pools during winter, wherein the heat exchange equipment for implementing the method includes:

[0008] Sensible heat exchanger;

[0009] The compressor has a first inlet, a second inlet, a third inlet, and an outlet for refrigerant flow;

[0010] A gas-liquid separator for refrigerant gas-liquid separation, having an inlet, a gas outlet, and a liquid outlet, wherein the gas outlet is connected to a third inlet of the compressor;

[0011] The first heat exchanger has a refrigerant inlet connected to the compressor outlet and a refrigerant outlet connected to the gas-liquid separator inlet.

[0012] The first evaporator has a refrigerant inlet connected to the liquid outlet of the gas-liquid separator, and the refrigerant outlet of the first evaporator is connected to the first inlet of the compressor.

[0013] The second evaporator has its refrigerant inlet connected to the liquid outlet of the gas-liquid separator, and its refrigerant outlet connected to the second inlet of the compressor.

[0014] The method includes:

[0015] Outdoor fresh air is heated by a sensible heat exchanger and then mixed with the first indoor return air. After being heated by the first heat exchanger, it is then supplied to the room.

[0016] The return air in the second room is cooled and dehumidified in sequence through the sensible heat exchanger, the second evaporator and the first evaporator before being exhausted to the outside.

[0017] The return air from the third room is cooled and dehumidified by the second evaporator before being supplied to the room.

[0018] Several alternative methods are provided below, but they are not intended as additional limitations on the overall solution above. They are merely further additions or optimizations. Provided there are no technical or logical contradictions, each alternative method can be combined individually with respect to the overall solution above, or multiple alternative methods can be combined with each other.

[0019] Optionally, the heat exchange equipment further includes a pool hot water heat exchanger, wherein the refrigerant inlet of the pool hot water heat exchanger is connected to the outlet of the compressor, and the refrigerant outlet of the pool hot water heat exchanger is connected to the inlet of the gas-liquid separator.

[0020] Optionally, to reduce the relative humidity of an indoor swimming pool, one of the following methods can be used as needed:

[0021] (1) Increase the outdoor fresh air volume and reduce the return air volume in the third room;

[0022] (2) Reduce the outdoor fresh air volume and increase the third indoor return air volume.

[0023] Optionally, the outdoor fresh air is heated to 20-30°C by a sensible heat exchanger and then mixed with the first indoor return air.

[0024] Optionally, the outdoor fresh air is heated by a sensible heat exchanger and mixed with the first indoor return air. After being heated to 35-45°C by the first heat exchanger, the air is then supplied to the room.

[0025] Optionally, the return air in the second room is cooled to 20–28°C after passing through a sensible heat exchanger.

[0026] Optionally, the return air in the second room is cooled to 10-15°C after passing through the second evaporator.

[0027] Optionally, the enthalpy of the outdoor exhaust air is the same as that of the outdoor fresh air.

[0028] Optionally, the return air from the third room is cooled to 10-15°C by the second evaporator before being supplied to the room.

[0029] This application improves the condensation heat recovery method for indoor swimming pools in winter conditions. On the one hand, it increases the evaporation temperature in winter, thereby improving the overall system efficiency. On the other hand, it can introduce fresh air to improve indoor air quality and regulate indoor air humidity load. Attached Figure Description

[0030] Figure 1 A schematic diagram of the structure of a heat exchange device for implementing a winter dehumidification and heat recovery method for indoor swimming pools;

[0031] Figure 2 A schematic diagram illustrating a method for dehumidifying and recovering heat from an indoor swimming pool in winter;

[0032] Figure 3 This is a schematic diagram of the refrigerant circulation.

[0033] Figure 4a An enlarged view of the enthalpy-humidity diagram of the air supplied in the airflow for dehumidification and heat recovery in indoor swimming pools during winter;

[0034] Figure 4b An enlarged view of the enthalpy-humidity diagram of the exhaust air in the dehumidification and heat recovery process of an indoor swimming pool during winter;

[0035] Figure 4c An enlarged view of the enthalpy-humidity diagram of the return air in the dehumidification and heat recovery process of an indoor swimming pool during winter;

[0036] Figure 5 TS diagram of a heat exchange device for winter dehumidification and heat recovery in indoor swimming pools;

[0037] Figure 6 This is a TS diagram for condensation heat recovery in a typical swimming pool heat pump. Detailed Implementation

[0038] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0039] To better describe and illustrate the embodiments of this application, reference may be made to one or more accompanying drawings, but the additional details or examples used to describe the drawings should not be considered as limiting the scope of any of the inventive creations of this application, the embodiments or preferred methods described herein.

[0040] It should be noted that when a component is said to be "connected" to another component, it can be directly connected to the other component or it can be connected to a component in between. When a component is said to be "set on" another component, it can be directly set on the other component or it may be set to a component in between.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0042] See Figure 1 , Figure 2 As shown, a method for dehumidification and heat recovery in indoor swimming pools during winter, wherein the heat exchange equipment for implementing the method includes:

[0043] Sensible heat exchanger;

[0044] The compressor has a first inlet (port a in the figure), a second inlet (port b in the figure), a third inlet (port c in the figure), and an outlet (port d in the figure) for the flow of refrigerant.

[0045] A gas-liquid separator is used for refrigerant gas-liquid separation and has an inlet (port g in the figure), a gas outlet (port e in the figure), and a liquid outlet (port f in the figure). The gas outlet is connected to the third inlet of the compressor.

[0046] The first heat exchanger has its refrigerant inlet connected to the compressor outlet, and its refrigerant outlet connected to the gas-liquid separator inlet.

[0047] The first evaporator has a refrigerant inlet connected to the liquid outlet of the gas-liquid separator, and the refrigerant outlet of the first evaporator is connected to the first inlet of the compressor.

[0048] The second evaporator has its refrigerant inlet connected to the liquid outlet of the gas-liquid separator, and its refrigerant outlet connected to the second inlet of the compressor.

[0049] The method includes:

[0050] Outdoor fresh air is heated by a sensible heat exchanger and then mixed with the first indoor return air. After being heated by the first heat exchanger, it is then supplied to the room.

[0051] The return air in the second room is cooled and dehumidified in sequence through the sensible heat exchanger, the second evaporator and the first evaporator before being exhausted to the outside.

[0052] The return air from the third room is cooled and dehumidified by the second evaporator before being supplied to the room.

[0053] The first indoor return air, the second indoor return air, and the third indoor return air, together with the indoor supply air, form a circulating flow of air in the pool. The first indoor return air, the second indoor return air, and the third indoor return air are only used to distinguish the direction of different return air, that is, to distinguish the next processing procedure of the return air. There is no substantial difference between the return air itself.

[0054] See Figure 1 As shown, the heat exchange equipment also includes a pool hot water heat exchanger, the refrigerant inlet of which is connected to the compressor outlet, and the refrigerant outlet of which is connected to the gas-liquid separator inlet.

[0055] See the refrigerant circulation process in heat exchange equipment. Figure 3 As shown, Figure 3 In the diagram: Point 1 is the state point when the refrigerant from the first evaporator enters the compressor; Point 1' is the state point when the refrigerant from the second evaporator enters the compressor; Point 1" is the state point of the gaseous refrigerant separated by the gas-liquid separator; Points 1, 1', and 1" enter the compressor and are compressed, reaching state points 2, 2', and 2" respectively. The three are mixed and reach state point 3 at the compressor outlet. State point 3 passes through the pool hot water heat exchanger and the first heat exchanger to reach state point 4. Then, it passes through the first electronic expansion valve to become state point 5 and then enters the gas-liquid separator. Liquid refrigerant is separated in the gas-liquid separator and becomes state point 6. It then passes through the second and third electronic expansion valves to reach state points 7' and 7 respectively. Finally, it passes through the first and second evaporators to reach state points 1 and 1' respectively.

[0056] In winter, outdoor fresh air has a lower humidity level, which not only helps reduce the relative humidity of the swimming pool, but also reduces the content of toxic gases such as chlorine in the indoor swimming pool air.

[0057] When exhausting air to the outside, the gas enthalpy is reduced by a cascaded heat recovery process involving a sensible heat regenerator, a second evaporator, and a first evaporator. Heat is recovered using the sensible heat exchanger, the second evaporator, and the first evaporator. The recovered heat is transferred to the pool water and indoor air through the pool hot water heat exchanger and the first heat exchanger, respectively. Outdoor fresh air enters the sensible heat exchanger and then mixes with the first indoor return air. Compared to fresh air directly mixing with indoor return air, this reduces the entropy increase caused by mixing gases of different temperatures.

[0058] The second evaporator and the first evaporator provide different evaporation temperatures for dehumidification. Compared with a single heat cycle recovery system, the evaporation temperature is increased, thus improving system efficiency.

[0059] See the enthalpy-humidity diagram for the fresh air flow process. Figure 4a As shown, outdoor fresh air (enthalpy and humidity) Figure 4a The fresh air (point 1) is heated to a constant humidity after passing through the sensible heat exchanger. Figure 4a The fresh air at point 2, after mixing with the first indoor return air (point 1), changes its air state point to... Figure 4a The mixed air, after being heated by the first heat exchanger, is used as winter supply air (enthalpy-humidity). Figure 4a The air supply point is used to deliver air into the swimming pool.

[0060] See the exhaust flow enthalpy-humidity diagram. Figure 4b As shown, exhaust air 1 (i.e., the second indoor return air) is processed by the sensible heat exchanger to exhaust air point 2, and then sequentially processed by the second evaporator to exhaust air point 3, and by the first evaporator to exhaust air point 4. Exhaust air at point 4 is processed to the same enthalpy as the outdoor air before being discharged outdoors, thus avoiding the waste of exhaust air enthalpy.

[0061] See the enthalpy-humidity diagram of the return air flow. Figure 4c As shown, the return air in the third room is processed by the second evaporator before reaching the return air outlet.

[0062] This application can use the following two methods for humidity control:

[0063] (1) See Figure 4c As shown, the humidity decreases during the process from the return air point to the return air outlet. By controlling the return air volume, dehumidification can be achieved.

[0064] (2) Introduce fresh air from outdoors with lower relative humidity. The larger the volume of fresh air, the better. Figure 4a The further to the left the mixing point, the lower the relative humidity of the supply air.

[0065] The two methods described above can be flexibly adjusted. When more fresh air is needed to ventilate the pool, the return air volume of the third room can be reduced. When the pool requires less ventilation, the return air volume of the third room can be increased to reduce relative humidity.

[0066] To reduce the relative humidity of an indoor swimming pool, one of the following methods can be used as needed:

[0067] (1) Increase the outdoor fresh air volume and reduce the return air volume of the third indoor return air;

[0068] (2) Reduce the outdoor fresh air volume and increase the return air volume of the third indoor return air.

[0069] The reasons for the improved efficiency of the indoor swimming pool winter dehumidification and heat recovery method provided in this application are as follows:

[0070] See Figure 5 As shown, Figure 5 There is a winter return air dehumidification cycle and two winter exhaust heat recovery cycles (the exhaust heat recovery cycles formed by passing through the second evaporator and the first evaporator, respectively). The heating energy efficiency ratio of the winter return air dehumidification cycle and the exhaust heat recovery cycle (passing through the second evaporator) is T1 / (T1-T2); under ideal conditions, the heating energy efficiency ratio of the exhaust heat recovery cycle (passing through the first evaporator) is T1 / (T1-T3).

[0071] See Figure 6 As shown, under ideal conditions, the heating efficiency ratio of a conventional swimming pool heat pump condensing heat recovery is T1 / (T1-T3). Since T2>T3, T1 / (T1-T2)>T1 / (T1-T3). Therefore, under ideal conditions, the average heating efficiency ratio of the three cycles in this application is greater than that of a conventional swimming pool heat pump condensing heat recovery.

[0072] Outdoor fresh air volume is calculated using the following two standards, and the larger value is selected as the fresh air volume:

[0073] (a) Indoor air exchange rate is 50%–100% per hour;

[0074] (b) Replace 30-50m of water per person (number of swimmers) per hour. 3 .

[0075] Example illustration:

[0076] In this embodiment, the outdoor calculated temperature for winter air conditioning is 3°C, relative humidity is 80%, enthalpy is 12.516 kJ / kg dry air, and moisture content is 3.785 g / kg dry air. The indoor dry-bulb temperature of the swimming pool is 28°C, relative humidity is 85%, moisture content is 20.6 g / kg dry air, and enthalpy is 80.921 kJ / kg dry air.

[0077] For ease of explanation, the change in dry air density is negligible in this calculation, and is consistently 1.17 kg / m³. 3 (Density changes have minimal impact on energy consumption calculations). Temperature changes affect a pool area of ​​600m². 2 The pool has a water area of ​​500m² 2 The room is 3.5m high, with an indoor heat load of 50kw in winter, and an additional heating load of 125kw required to maintain a constant temperature in the swimming pool. The indoor humidity load is 97kg / h.

[0078] To facilitate the illustration of the system's superior performance (the ultimate value achievable under ideal conditions), all calculations and comparisons in this study are based on ideal conditions. The following calculations compare the single-cycle pool heat pump condensing heat recovery operation with the maximum and minimum fresh air volume conditions described in the invention.

[0079] This example demonstrates the condensation heat recovery process for a single-cycle swimming pool heat pump. Considering the heat recovery from the pool exhaust air, the exhaust air temperature is treated by an evaporator to reach the outdoor air isenthalpic point of 2°C, with 95% relative humidity and a moisture content of 4.189 g / kg dry air. Ideally, the evaporator evaporation temperature T3 is 275 K (2°C), and the condenser condensation temperature T1 is 313 K (40°C). The difference in moisture content between the fresh and exhaust air is 20.6 - 3.785 = 16.815 g / (kg dry air). Based on the moisture load calculation: Exhaust air volume = Indoor moisture load / (Exhaust air moisture content - Fresh air moisture content) / density = 97 * 1000 / 16.815 / 1.17 = 4930. The exhaust air heat recovery enthalpy is 4930 * 1.17 (80.921 - 12.516) / 3600 = 109.6 kW. At this time, the fresh air volume equals the exhaust air volume, which is 4930m³. 3 / h, fresh air is treated from the outdoor air state point to an indoor dry-bulb temperature of 28 degrees Celsius. At this point, the fresh air state point is a dry-bulb temperature of 28°C, with an enthalpy of 37.941 kJ / (kg dry air). The fresh air heat load is 4930*1.17*(37.941-12.516) / 3600=40.74 kW. If we perform ideal calculations based on an evaporation temperature of 275 K and a Carnot cycle efficiency of 313 K, the condenser heat dissipation is (T1 / T3*heat recovery)=313 / 275*109.6=124.76 kW, which can meet the indoor heat load plus the fresh air heat load requirement (50+40.74=90.74). The excess heat (124.76-90.74=34.02 kW) can be used to heat the pool water. The ideal compressor power is (T1-T3) / T1*heat recovery capacity = (313-275) / 275*109.6 = 15.15 kW. Assuming a total pressure of 300 Pa for both the fresh air fan and exhaust fan, and a fan efficiency of 0.75, the total pressure is 4930 m³ / h. 3 The total power of the selected exhaust fan is 1.1kw (0.55*2), so the total power consumption is 16.25kw (15.15+1.1), and it provides 34.02kw of heat for heating the pool water. Under the premise of ensuring indoor temperature and humidity, the evaluation standard is the heat supply efficiency for heating the pool water. At this time, the heat supply efficiency is 34.02 / 16.25=2.09.

[0080] The minimum fresh air intake condition for this invention is as follows: When the number of people in the swimming pool is less than 33, the minimum fresh air volume is calculated at 0.5 air changes per hour (50% of the indoor air is replaced per hour), at which point the fresh air volume is 1050 m³ / h. 3 / h(600*3.5*0.5), the outdoor fresh air is heated to 28℃ by the sensible heat exchanger and then mixed with the first indoor return air. After being heated to 40℃ by the first heat exchanger, the fresh air is supplied to the room. The fresh air heat load is fresh air mass * (fresh air enthalpy 2 - fresh air enthalpy 1) = 1050 * 1.17 * (37.941 - 12.516) / 3600 = 8.676 kW. This fresh air heat load is provided by the sensible heat exchanger recovering the heat from the exhaust air.

[0081] Since exhaust volume equals fresh air volume, according to the energy conservation within the sensible heat exchanger, the increase in enthalpy of fresh air equals the decrease in enthalpy of exhaust air. Therefore, it can be calculated that exhaust air 1 is cooled by the sensible heat exchanger to exhaust air 2 (19.8℃, enthalpy 55.496kJ / kg dry air, moisture content 13.97g / kg dry air), and then cooled by the second evaporator to exhaust air 3 (10℃, enthalpy 28.551kJ / kg dry air, moisture content 7.324g / kg dry air). The heat recovered by the second evaporator is the exhaust air mass * (enthalpy of exhaust air 2 - enthalpy of exhaust air 3) = 1050 * 1.17 * (55.496 - 28.551) / 3600 = 9.195kW. The humidity difference between the fresh and exhaust air is calculated as: Exhaust air mass * Exhaust air moisture content - Fresh air mass * Fresh air moisture content = 1050 * 1.17 * (20.623 - 3.785) / 1000 = 20.69 kg / h. The remaining moisture load is 97 - 20.69 = 76.31 kg / h. This remaining moisture load must be entirely borne by the return air dehumidification cycle. Therefore, the return air volume passing through the second evaporator is the remaining... Moisture load / (Return air moisture content - Return air outlet moisture content) / Dry air density = 76.31 * 1000 / (20.623 - 7.324) / 1.17 = 4904.3 m3 / h, Return air heat recovery = Return air mass * (Return air enthalpy - Return air outlet enthalpy) = 4904.3 * 1.17 * (80.921 - 28.551) / 3600 = 83.47 kW. The total heat recovered by the second evaporator = exhaust air heat recovery + return air heat recovery = 9.195 + 83.47 = 92.665 kW. Ideally, the heat recovered by the second evaporator can be pumped to obtain heat = 92.665 * T1 / T2 = 92.665 * 313 / 283 = 102.488 kW. However, this part of the heat needs to be reduced by the heat load of the return air being heated to an indoor temperature of 28℃ (enthalpy 46.975 kJ / kg dry air) to obtain the usable heat load. The return air heat load = 4904.3 * 1.17 * (46.975 - 28.551) / 3600 = 29.37 kW. Therefore, the usable heat after the heat recovered by the second evaporator is pumped is 102.488 - 29.37 = 73.122 kW. Finally, the exhaust air is cooled by the first evaporator to exhaust air point 4 (2℃, enthalpy 12.51kJ / kg dry air, moisture content 4.188g / kg dry air) before being exhausted outdoors. The heat recovered by the first evaporator is the exhaust air mass * (exhaust air enthalpy 3 - exhaust air enthalpy 4) = 1050 * 1.17 * (28.551 - 12.51) / 3600 = 5.47kw. Under ideal conditions, the heat recovered by the first evaporator can be pumped to obtain heat = 5.47 * T1 / T3 = 5.47 * 313 / 275 = 6.226kw.Therefore, the usable heat after the first and second evaporators recover usable heat and is pumped is 73.122 + 6.226 = 79.348 kW. After deducting the indoor heat load of 50 kW, it provides 29.348 kW (79.348 - 50) of heat for heating the pool water. The compressor power is (T1-T2) / T2*heat recovered by the second evaporator + (T1-T3) / T3*heat recovered by the first evaporator = (313-283) / 283*102.488 + (313-275) / 275*6.226 = 10.86 + 0.86 = 11.72 kW. The total power of the ventilation system (fresh air fan + exhaust fan + return air fan) is 0.11 * 2 + 0.45 = 0.67 kW (fresh air and exhaust fans have a total pressure of 300 Pa, return air fans have a total pressure of 250 Pa, and both have an efficiency of 0.75). Therefore, the total energy consumption is 11.72 + 0.67 = 12.39 kW. Under the premise of maintaining indoor temperature and humidity, using the efficiency of heating the pool water as the evaluation standard, the energy efficiency of heating the pool water is 29.348 / 12.39 = 2.37. Compared with a single-loop pool heat pump condensing heat recovery system, the energy efficiency is improved by 13.3%.

[0082] The maximum fresh air intake condition of this invention is as follows: when the number of people in the swimming pool is less than 42, the minimum fresh air volume is calculated based on 1 air change per hour, at which point the fresh air volume is 2100 m³ / h. 3 / h(600*3.5*1), the outdoor fresh air is heated to 28℃ by the sensible heat exchanger and then mixed with the first indoor return air. After being heated to 40℃ by the first heat exchanger, the fresh air is supplied to the room. The fresh air heat load is fresh air mass * (fresh air enthalpy 2 - fresh air enthalpy 1) = 2100 * 1.17 * (37.941 - 12.516) / 3600 = 17.352kw. This fresh air heat load is provided by the sensible heat exchanger recovering the heat from the exhaust air.

[0083] Since exhaust volume equals fresh air volume, according to the energy conservation within the sensible heat exchanger, the increase in enthalpy of fresh air equals the decrease in enthalpy of exhaust air. Therefore, it can be calculated that exhaust air 1 is cooled by the sensible heat exchanger to exhaust air 2 (19.8℃, enthalpy 55.496kJ / kg dry air, moisture content 13.97g / kg dry air), and then cooled by the second evaporator to exhaust air 3 (10℃, enthalpy 28.551kJ / kg dry air, moisture content 7.324g / kg dry air). The heat recovered by the second evaporator is the exhaust air mass * (enthalpy of exhaust air 2 - enthalpy of exhaust air 3) = 2100 * 1.17 * (55.496 - 28.551) / 3600 = 18.39kW. The humidity difference between the fresh and exhaust air is calculated as: Exhaust air mass * Exhaust air moisture content - Fresh air mass * Fresh air moisture content = 2100 * 1.17 * (20.623 - 3.785) / 1000 = 41.38 kg / h. The remaining moisture load is 97 - 41.38 = 55.62 kg / h. This remaining moisture load must be entirely borne by the return air dehumidification cycle. Therefore, the return air volume passing through the second evaporator is the remaining... Moisture load / (Return air moisture content - Return air outlet moisture content) / Dry air density = 55.62 * 1000 / (20.623 - 7.324) / 1.17 = 3574.6 m3 / h, Return air heat recovery = Return air mass * (Return air enthalpy - Return air outlet enthalpy) = 3574.6 * 1.17 * (80.921 - 28.551) / 3600 = 60.84 kW. The total heat recovered by the second evaporator = exhaust air heat recovery + return air heat recovery = 18.39 + 60.84 = 79.23 kW. Ideally, the heat recovered by the second evaporator can be pumped to obtain heat = 79.23 * T1 / T2 = 79.23 * 313 / 283 = 87.63 kW. However, this part of the heat needs to be reduced by the heat load of the return air being heated to an indoor temperature of 28℃ (enthalpy 46.975 kJ / kg dry air) to obtain the usable heat load. The return air heat load = 3574.6 * 1.17 * (46.975 - 28.551) / 3600 = 21.4 kW. Therefore, the usable heat after the heat recovered by the second evaporator is pumped is 87.63 - 21.4 = 66.23 kW. Finally, the exhaust air is cooled by the first evaporator to exhaust air point 4 (2℃, enthalpy 12.51kJ / kg dry air, moisture content 4.188g / kg dry air) before being exhausted outdoors. The heat recovered by the first evaporator is the exhaust air mass * (exhaust air enthalpy 3 - exhaust air enthalpy 4) = 2100 * 1.17 * (28.551 - 12.51) / 3600 = 10.94kw. Under ideal conditions, the heat recovered by the first evaporator can be pumped to obtain heat = 10.94 * T1 / T3 = 10.94 * 313 / 275 = 12.45kw.Therefore, the usable heat after the first and second evaporators recover usable heat and is pumped is 66.23 + 12.45 = 78.68 kW. After deducting the indoor heat load of 50 kW, it provides 28.68 kW (78.68 - 50) of heat for heating the pool water. The compressor power is (T1-T2) / T2 * heat recovered by the second evaporator + (T1-T3) / T3 * heat recovered by the first evaporator = (313-283) / 283 * 87.63 + (313-275) / 275 * 12.45 = 9.29 + 1.72 = 11.01 kW. The fan power is the power of the fresh air fan + exhaust fan + return air fan = 0.22 * 2 + 0.33 = 0.77 kW (the fresh air exhaust fan has a total pressure of 300 Pa, the return air fan has a total pressure of 250 Pa, and both fans have an efficiency of 0.75). Therefore, the total energy consumption = 11.01 + 0.77 = 11.78 kW. Under the premise of ensuring indoor temperature and humidity, using the efficiency of heating the pool water as the evaluation standard, the energy efficiency of heating the pool water is 28.68 / 11.78 = 2.43. Compared with a single-cycle pool heat pump condensing heat recovery system, the energy efficiency is improved by 16.5%.

[0084] The following are explanations of terms involved in the calculation: Exhaust air 1 is the second indoor return air. Exhaust air 1 becomes exhaust air 2 after being processed by the sensible heat exchanger. Exhaust air 2 becomes exhaust air 3 after being processed by the second evaporator. Exhaust air 3 becomes exhaust air 4 after being processed by the first evaporator.

[0085] Based on the above case analysis, it can be seen that when meeting the requirements of pool heat and humidity load and exhaust air treatment to the outside enthalpy point before discharge, the minimum fresh air condition of this application can theoretically improve the efficiency of a single-loop pool heat pump condensing heat recovery system by 13.3%, and the maximum fresh air condition can theoretically improve the efficiency of a single-loop pool heat pump condensing heat recovery system by 16.5%.

[0086] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0087] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for dehumidification and heat recovery in indoor swimming pools during winter, characterized in that, The heat exchange equipment for implementing the method includes: Sensible heat exchanger; A compressor having a first inlet, a second inlet, a third inlet, and an outlet for refrigerant flow; A gas-liquid separator for refrigerant gas-liquid separation, having an inlet, a gas outlet, and a liquid outlet, wherein the gas outlet is connected to a third inlet of the compressor; The first heat exchanger has a refrigerant inlet connected to the compressor outlet and a refrigerant outlet connected to the gas-liquid separator inlet. The first evaporator has a refrigerant inlet connected to the liquid outlet of the gas-liquid separator, and the refrigerant outlet of the first evaporator is connected to the first inlet of the compressor. The second evaporator has a refrigerant inlet connected to the liquid outlet of the gas-liquid separator, and a refrigerant outlet connected to the second inlet of the compressor. The method includes: Outdoor fresh air is heated by a sensible heat exchanger and then mixed with the first indoor return air. After being heated by the first heat exchanger, it is then supplied to the room. The return air in the second room is cooled and dehumidified in sequence through the sensible heat exchanger, the second evaporator and the first evaporator before being exhausted to the outside. The return air from the third room is cooled and dehumidified by the second evaporator before being supplied to the room.

2. The method for dehumidification and heat recovery in indoor swimming pools during winter as described in claim 1, characterized in that, The heat exchange equipment also includes a pool hot water heat exchanger, the refrigerant inlet of which is connected to the compressor outlet, and the refrigerant outlet of which is connected to the gas-liquid separator inlet.

3. The method for dehumidification and heat recovery in indoor swimming pools during winter as described in claim 1, characterized in that, To reduce the relative humidity of an indoor swimming pool, one of the following methods can be used as needed: (1) Increase the outdoor fresh air volume and reduce the return air volume in the third room; (2) Reduce the outdoor fresh air volume and increase the third indoor return air volume.

4. The method for dehumidification and heat recovery in indoor swimming pools during winter as described in claim 1, characterized in that, Outdoor fresh air is heated to 20-30°C by a sensible heat exchanger and then mixed with the first indoor return air.

5. The method for dehumidification and heat recovery in indoor swimming pools during winter as described in claim 1, characterized in that, Outdoor fresh air is heated by a sensible heat exchanger and then mixed with the first indoor return air. After being heated to 35-45°C by the first heat exchanger, the air is then supplied to the room.

6. The method for dehumidification and heat recovery in indoor swimming pools during winter as described in claim 1, characterized in that, The return air in the second room is cooled to 20-28°C after passing through the sensible heat exchanger.

7. The method for dehumidification and heat recovery in indoor swimming pools during winter as described in claim 1, characterized in that, The return air in the second room is cooled to 10-15℃ after passing through the second evaporator.

8. The method for dehumidification and heat recovery in indoor swimming pools during winter as described in claim 1, characterized in that, The enthalpy of the outdoor exhaust air is the same as that of the outdoor fresh air.

9. The method for dehumidification and heat recovery in indoor swimming pools during winter as described in claim 1, characterized in that, The third indoor return air is cooled to 10-15℃ by the second evaporator before being supplied to the room.

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