Cabinet type air conditioner efficient heat supply method capable of alternately switching high-temperature hot air supply and low-temperature hot air supply

Abstract

According to the high-efficiency heat supply method for the cabinet type air conditioner capable of alternately switching the high-temperature hot air supply and the low-temperature hot air supply, an air guide pipe is connected to an air inlet of the cabinet type air conditioner, so that the cabinet type air conditioner can utilize the air guide pipe to feed air from the upper space of a room; therefore, high-temperature hot supply air generated by heating of the air conditioner is alternately utilized to provide heat for the room, and low-temperature hot supply air is utilized to transfer heat accumulated in the upper space of the room due to thermal buoyancy to the lower space of the room where the personnel activity area is located, so that the heat of the upper space of the room is recycled to create a thermal environment of the lower space of the room. The embodiment shows that the energy consumption of the air conditioner is reduced by 53.6%, and the head and foot temperature differences of the sitting posture and the standing posture are reduced by 59.0% and 50.3% respectively.

Description

Technical Field

[0001] The present invention belongs to the technical field of air conditioning and heating, and in particular relates to a high-efficiency heating method for a cabinet-type air conditioner with alternating switching between high-temperature and low-temperature hot air supply. Background Art

[0002] Winter heating is essential for creating a thermally comfortable environment. However, it consumes significant amounts of energy and is a key target for energy conservation and emission reduction in the building sector. On-demand heating is a key technical approach to achieving high-efficiency heating.

[0003] Heating methods primarily include radiation and convection. Radiant heating creates a uniform thermal environment and provides high comfort, but its slow thermal response makes it unsuitable for on-demand heating. Convection heating, on the other hand, offers a fast thermal response and is suitable for on-demand heating. Air conditioning is the most common form of convection heating and is widely used in residential and office buildings.

[0004] However, the heat waste and thermal discomfort caused by the thermal buoyancy of convection heating by air conditioning urgently need to be addressed. Because the hot supply air from convection heating is subject to thermal buoyancy, it drifts toward the upper part of the room, where heat accumulates. This accumulated heat cannot be used to create a warm environment in the work area, resulting in wasted energy and low thermal efficiency. Furthermore, this heat accumulation in the upper part of the room causes thermal stratification, leading to thermal discomfort caused by a significant temperature difference between the head and feet.

[0005] Cabinet air conditioners are a common form of air conditioning. Standing on the ground, they typically provide greater heating capacity than wall-mounted units. This means heat accumulates in the upper room, leading to a temperature difference between the head and feet, causing discomfort and high energy consumption, which is a particularly serious problem that needs to be addressed urgently. Summary of the Invention

[0006] In order to overcome the above-mentioned problems of the prior art, the purpose of the present invention is to provide an efficient heating method for a cabinet air conditioner with alternating switching between high-temperature and low-temperature hot air supply, alternately using the high-temperature hot air supply generated by the air conditioner to provide heat to the room, and using the low-temperature hot air supply to transfer the heat accumulated in the upper space of the room due to thermal buoyancy to the lower space of the room where the personnel activity area is located, thereby realizing the reuse of the heat in the upper space of the room to create a thermal environment in the lower space of the room, reducing the energy consumption of the air conditioner; at the same time, reducing the temperature difference between the head and the feet, and improving thermal comfort.

[0007] In order to achieve the above object, the technical solution of the present invention is:

[0008] The invention discloses an efficient heating method for a cabinet air conditioner with alternating switching between high-temperature and low-temperature hot air supply modes. The cabinet air conditioner alternately switches between the high-temperature hot air supply mode and the low-temperature hot air supply mode. The high-temperature hot air supply mode is generated by the heating of the air conditioner to heat the room. The low-temperature hot air supply mode does not require heating by the air conditioner. The low-temperature hot air supply mode re-uses the hot air accumulated in the upper space of the room by the thermal buoyancy in the high-temperature hot air supply mode to create the lower space of the room where the personnel activity area is located, thereby reducing the thermal discomfort caused by the temperature difference between the head and the feet and improving the heating energy efficiency of the air conditioner.

[0009] Connect an air duct to the air inlet of the cabinet air conditioner so that the cabinet air conditioner takes in air from the upper space of the room.

[0010] In high-temperature hot air supply mode, the indoor air entering the air conditioner is heated by the air conditioner and then blown from the air conditioner outlet to the lower part of the room where the personnel activity area is located. The air supply angle and speed of the high-temperature hot air supply are determined according to the thermal comfort standard or the thermal preference of the personnel. The indoor air entering the air conditioner is the air from the upper space of the room through the air duct or the air at the air inlet of a conventional cabinet air conditioner.

[0011] In the low-temperature hot air supply mode, the air inlet of the air conditioner uses an air duct to draw air from the upper space of the room into the interior of the air conditioner; the air entering the interior of the air conditioner is the hot air that is gathered in the upper space of the room due to thermal buoyancy and heated by the air conditioner in the high-temperature hot air supply mode. In the low-temperature hot air supply mode, it does not need to be heated by the air conditioner and is blown from the air conditioner outlet to the lower space of the room where the personnel activity area is located; the air supply angle and speed of the low-temperature hot air supply are determined according to the thermal comfort standard or the thermal preference of the personnel.

[0012] The greater the air supply speed of the low-temperature hot air supply mode, the more hot air from the upper space of the room is supplied to the lower space of the room where the personnel activity area is located, but this causes the air speed in the personnel activity area to increase; the maximum air supply speed of the low-temperature hot air supply mode is determined based on the limit value of the air speed in the personnel activity area caused by the low-temperature hot air supply mode, and the limit value of the air speed in the personnel activity area is determined based on the thermal comfort standard or the thermal preference of the personnel.

[0013] The longer the low-temperature hot air supply mode works relative to the high-temperature hot air supply mode, the higher the air conditioning energy efficiency is. However, since the heat transferred from the upper space of the room is not enough to offset the cold entering the personnel activity area from the outside, the temperature of the personnel activity area decreases. The working time of the low-temperature hot air supply mode relative to the high-temperature hot air supply mode is determined by the limit value of the air temperature in the personnel activity area, and the limit value of the air temperature in the personnel activity area is determined based on the thermal comfort standard or the thermal preference of the personnel.

[0014] Compared with the prior art, the advantages of the present invention are:

[0015] (1) The present invention innovatively proposes a low-temperature hot air supply mode for a cabinet air conditioner, using the cabinet air conditioner as a heat transfer device to transfer the hot air that is heated by the air conditioner in the high-temperature hot air supply mode and is gathered in the upper space of the room due to thermal buoyancy to the bottom space of the room where the personnel activity area is located, thereby alleviating the thermal discomfort caused by the large temperature difference between the head and the feet, and improving the utilization efficiency of the hot air generated in the air conditioner heating mode.

[0016] (2) The present invention utilizes the alternating switching between the high-temperature hot air supply mode and the low-temperature hot air supply mode, so that the cabinet air conditioner conveniently integrates two major functions: (1) air conditioning heating; and (2) heat transfer from the upper space of the room to the lower space of the room where the personnel activity area is located.

[0017] (3) The heat transfer function of the low-temperature hot air supply mode not only increases the heat utilization efficiency of the cabinet air conditioner, but also the cabinet air conditioner does not need to heat in the low-temperature hot air supply mode, which greatly reduces the heating time of the cabinet air conditioner and further reduces the heating energy consumption of the cabinet air conditioner.

[0018] In summary, the present invention reuses the heat in the upper space of the room to create a thermal environment in the lower space of the room, thereby reducing the energy consumption of the air conditioner. At the same time, this method can also reduce the temperature difference between the head and the feet, thereby improving thermal comfort. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a physical picture of the cabinet according to an embodiment of the present invention.

[0020] Figure 2 This is a plan view of an embodiment of the present invention.

[0021] Figure 3 The graph of the measured inlet / outlet air temperature and air velocity of the air conditioner according to the embodiment of the present invention is shown in FIG. Figure 3 (a) is the existing method. Figure 3 (b) is the method of the present invention.

[0022] Figure 4 : The air temperature and air velocity diagram of the L1 measurement line according to an embodiment of the present invention, wherein Figure 4 (a) is the temperature diagram of the existing method. Figure 4 (b) is the velocity diagram of the existing method. Figure 4 (c) is a temperature diagram of the method of the present invention, Figure 4 (d) in FIG. 1 is a velocity diagram of the method of the present invention.

[0023] Figure 5 is a graph of air temperature and air velocity along the L2 measurement line according to an embodiment of the present invention, wherein Figure 5 (a) is the temperature diagram of the existing method. Figure 5 (b) is the velocity diagram of the existing method. Figure 5 (c) is a temperature diagram of the method of the present invention, Figure 5 (d) in FIG. 1 is a velocity diagram of the method of the present invention.

[0024] Figure 6 : The air temperature and air velocity diagram of the L3 measurement line in the embodiment of the present invention, wherein Figure 6 (a) is the temperature diagram of the existing method. Figure 6 (b) is the velocity diagram of the existing method. Figure 6 (c) is a temperature diagram of the method of the present invention, Figure 6 (d) in FIG. 1 is a velocity diagram of the method of the present invention.

[0025] Figure 7 : The air temperature and air velocity diagram of the L4 measurement line in the embodiment of the present invention, wherein Figure 7 (a) is the temperature diagram of the existing method. Figure 7 (b) is the velocity diagram of the existing method. Figure 7 (c) is a temperature diagram of the method of the present invention, Figure 7 (d) in FIG. 1 is a velocity diagram of the method of the present invention.

[0026] Figure 8 This is a diagram of the air temperature difference on the L1-L4 measurement line according to an embodiment of the present invention.

[0027] Figure 9 FIG. 4 is a diagram showing the power consumption of the embodiment of the invention and the conventional method. DETAILED DESCRIPTION

[0028] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] The present invention provides an efficient heating method for a cabinet air conditioner with alternating switching between high-temperature and low-temperature hot air supply. The method alternately uses the high-temperature hot air supply generated by the air conditioner to provide heat to the room, and uses the low-temperature hot air supply to transfer the heat accumulated in the upper space of the room due to thermal buoyancy to the lower space of the room where the personnel activity area is located, thereby realizing the reuse of the heat in the upper space of the room to create a thermal environment in the lower space of the room, reducing the energy consumption of the air conditioner; and the method can reduce the temperature difference between the head and the feet, thereby improving thermal comfort.

[0030] Example

[0031] The specific implementation scenario of the present invention is as follows Figure 1 and 2 Shown is a living room scene arranged in a laboratory environment chamber.

[0032] The invention discloses an efficient heating method for a cabinet air conditioner with alternating switching between high-temperature and low-temperature hot air supply modes. The cabinet air conditioner alternately switches between the high-temperature hot air supply mode and the low-temperature hot air supply mode. The high-temperature hot air supply mode is generated by the heating of the air conditioner to heat the room. The low-temperature hot air supply mode does not require heating by the air conditioner. The low-temperature hot air supply mode re-uses the hot air accumulated in the upper space of the room due to the thermal buoyancy of the hot air to create the lower space of the room where the personnel activity area is located, thereby reducing the thermal discomfort caused by the temperature difference between the head and the feet and improving the heating energy efficiency of the air conditioner.

[0033] An air duct is connected to the air inlet of the cabinet air conditioner so that the cabinet air conditioner can take in air from the upper space of the room. The air duct covers the air inlet of the cabinet air conditioner and extends to the upper space of the room in a cylindrical shape (with a diameter of 190 mm); the air inlet of the air duct is 380 mm away from the ceiling. It is worth noting that the air duct in the embodiment is a simplified version in the laboratory, not a commercial product. The following measured data shows that this simplified version can fully verify the effectiveness of the method of the present invention.

[0034] In the high-temperature hot air supply mode, the indoor air entering the air conditioner is heated by the air conditioner, and then blown from the air conditioner outlet to the lower part of the room where the personnel activity area is located. The air supply degree and speed of the high-temperature hot air supply are determined according to the thermal comfort standard or the thermal preference of the personnel. The indoor air entering the air conditioner can be the air from the upper space of the room through the air duct; it can also be the air at the air inlet of a conventional cabinet air conditioner (usually the air at the air inlet at the bottom of the air conditioner). In this embodiment, based on the thermal preference of the experimenters, the air supply angle of the high-temperature hot air supply is set to horizontal air supply, and the air supply speed is set to automatic mode. The temperature of the high-temperature hot air supply mode is set to 28°C. The indoor air entering the air conditioner can be the air from the upper space of the room through the air duct.

[0035] In low-temperature hot air supply mode, the air inlet draws air from the upper room into the air conditioner through an air duct. The air entering the air conditioner is the hot air that has been heated by the air conditioner in high-temperature hot air supply mode and has accumulated in the upper room due to thermal buoyancy. In low-temperature hot air supply mode, it is not heated by the air conditioner and is blown from the air conditioner outlet to the lower room where the personnel are located. The air supply angle and speed of the low-temperature hot air supply are determined based on thermal comfort standards or the thermal preferences of the personnel. In this embodiment, the air supply angle of the low-temperature hot air supply is set to horizontal and the air supply speed is set to medium speed based on the thermal preferences of the experimenters.

[0036] The higher the air supply speed in the low-temperature hot air supply mode, the more hot air from the upper room is delivered to the lower room where the personnel activity area is located, but this causes the air speed in the personnel activity area to increase. The maximum air supply speed in the low-temperature hot air supply mode is determined based on the limit value of the air speed in the personnel activity area caused by the low-temperature hot air supply mode. The limit value of the air speed in the personnel activity area is determined based on thermal comfort standards or personnel thermal preferences. In this embodiment, the experimenters set the air speed limit in the personnel activity area of the present invention to not exceed the maximum air speed limit in the personnel activity area of the existing method.

[0037] The longer the low-temperature hot air supply mode works relative to the high-temperature hot air supply mode, the higher the air conditioning energy efficiency is. However, since the heat transferred from the upper space of the room is not enough to offset the cold entering the personnel activity area from the outside, the temperature of the personnel activity area decreases; the working time of the low-temperature hot air supply mode relative to the high-temperature hot air supply mode is determined by the limit value of the air temperature in the personnel activity area, and the limit value of the air temperature in the personnel activity area is determined based on the thermal comfort standard or the thermal preference of the personnel. In this embodiment, the experimenter set the duration ratio of low-temperature hot air supply and high-temperature hot air supply to 1:1, both for 15 minutes. The test of the method of the present invention lasted for 90 minutes, that is, the low-temperature hot air supply and high-temperature hot air supply worked alternately for 3 cycles.

[0038] To demonstrate the advantages of the present invention, the examples also tested a conventional method. This conventional method uses the hot air supply from a cabinet air conditioner to heat the room, meaning the cabinet air conditioner is only in heating mode. The parameters set for the heating mode of the conventional cabinet air conditioner are consistent with those of the high-temperature hot air supply mode of the present invention. The conventional method test lasted 60 minutes, with the first 30 minutes representing the air conditioner startup phase and the last 30 minutes entering the conventional method's stable operation phase.

[0039] This embodiment actually measures the inlet and outlet air temperatures and outlet air velocity of the air conditioner. At the same time, the L1-L4 measurement lines ( Figure 2 Each measurement line measures air temperature and velocity at four heights: 0.1m, 1.1m, 1.7m, and 2.7m. Lines L1 and L3 are located near and far from the air conditioning supply jet, respectively. Lines L2 and L4 are located near and far from the air conditioning supply jet, respectively.

[0040] When the existing method is used, when the air conditioner is running stably, the thermal stratification temperature difference of the measurement lines L1-L4 (i.e., the temperature difference at 2.7m and 0.1m) is between 11.0℃–13.2℃ (with an average of 11.8℃) ( Figure 4 – Figure 8 This indicates that the existing method causes a large amount of heat to accumulate in the upper space of the room, resulting in heat waste. The power consumption of the existing method is 2.2kW ( Figure 9 ).

[0041] Under the existing method, the head-to-foot temperature difference in sitting position (i.e., the temperature difference between 1.1m and 0.1m) and the head-to-foot temperature difference in standing position (i.e., the temperature difference between 1.7m and 0.1m) along the measurement lines L1-L4 ranged from 6.1℃ to 13.7℃ (average 8.6℃) and 9.0℃ to 18.8℃ (average 11.6oC), respectively. Figure 4 – Figure 8 ), exceeding the upper limit of the temperature difference between the head and feet stipulated by the thermal comfort standard (i.e. 3°C), leading to thermal discomfort.

[0042] Under the method of the present invention, the temperature difference of thermal stratification (i.e. the temperature difference between 2.7m and 0.1m) is reduced to 5.7℃–7.0℃ (average 6.5℃) ( Figure 4 – Figure 8 ), which shows that the present invention effectively transfers heat from the upper space of the room to the lower space of the room where the personnel are located, creating a thermally comfortable environment in the personnel activity area and reusing the heat that would have been wasted. Because the present invention can efficiently use heat to create a thermally comfortable environment, the present invention reduces power consumption to 1.0kW, which is 53.6% energy saving compared to the existing method ( Figure 9 ).

[0043] Under the method of the present invention, the temperature difference between the head and feet in the sitting position (i.e., the temperature difference between 1.1m and 0.1m) and the temperature difference between the head and feet in the standing position (i.e., the temperature difference between 1.7m and 0.1m) along the measuring lines L1-L4 ranged from 2.1℃ to 5.5℃ (average 3.5℃) and from 3.9℃ to 9.0℃ (average 5.8℃), respectively. Figure 4 – Figure 8 Compared with existing methods, this method reduces the head-to-foot temperature difference by an average of 59.0% and 50.3% in sitting and standing positions, respectively, significantly alleviating the thermal discomfort caused by a large head-to-foot temperature difference.

[0044] In summary, existing cabinet air conditioner heating methods are limited by thermal buoyancy, causing heat to accumulate in the upper space of the room. This leads to low energy efficiency in creating a thermal environment and thermal discomfort caused by a large temperature difference between the head and feet. The present invention utilizes the cabinet air conditioner's high-temperature hot air supply mode to provide heat to the room, and utilizes the cabinet air conditioner's low-temperature hot air supply mode to transfer the heat generated by the cabinet air conditioner's high-temperature hot air supply mode, which accumulates in the upper space of the room due to thermal buoyancy, to the lower space of the room where people move around. This allows the heat in the upper space of the room to be reused to create a thermal environment in the lower space of the room, achieving an energy saving rate of 53.6%. The present invention also reduces the temperature difference between the head and feet by 59.0% and 50.3% in sitting and standing positions, respectively, alleviating the thermal discomfort caused by the large temperature difference between the head and feet.

Claims

1. A high-efficiency heating method for cabinet air conditioners with alternating high-temperature and low-temperature hot air supply, characterized in that: The cabinet air conditioner switches alternately between high-temperature hot air supply mode and low-temperature hot air supply mode. The high-temperature hot air supply mode is generated by the air conditioner to heat the room; the low-temperature hot air supply mode does not require air conditioning heating. The low-temperature hot air supply mode accumulates the hot air in the upper space of the room due to the thermal buoyancy in the high-temperature hot air supply mode and reuses it to create the lower space of the room where the personnel activity area is located, thereby reducing the thermal discomfort caused by the temperature difference between the head and the feet and improving the energy efficiency of air conditioning heating.

2. The high-efficiency heating method for cabinet air conditioners with alternating high-temperature and low-temperature hot air supply according to claim 1, characterized in that: Connect an air duct to the air inlet of the cabinet air conditioner so that the cabinet air conditioner takes in air from the upper space of the room.

3. The high-efficiency heating method for cabinet air conditioners with alternating high-temperature and low-temperature hot air supply according to claim 2, characterized in that: In high-temperature hot air supply mode, the indoor air entering the air conditioner is heated by the air conditioner and then blown from the air conditioner outlet to the lower part of the room where the personnel activity area is located. The air supply angle and speed of the high-temperature hot air supply are determined according to the thermal comfort standard or the thermal preference of the personnel. The indoor air entering the air conditioner is the air from the upper space of the room through the air duct or the air at the air inlet of a conventional cabinet air conditioner.

4. The high-efficiency heating method for cabinet air conditioners with alternating high-temperature and low-temperature hot air supply according to claim 1, characterized in that: In the low-temperature hot air supply mode, the air inlet of the air conditioner draws air from the upper space of the room into the interior of the air conditioner; the air entering the interior of the air conditioner is the hot air that is gathered in the upper space of the room due to thermal buoyancy and heated by the air conditioner in the high-temperature hot air supply mode. In the low-temperature air supply mode, it does not need to be heated by the air conditioner and is blown from the air conditioner outlet to the lower space of the room where the personnel activity area is located; the air supply angle and speed of the low-temperature hot air supply are determined according to the thermal comfort standard or the thermal preference of the personnel.

5. The high-efficiency heating method for cabinet air conditioners with alternating high-temperature and low-temperature hot air supply according to claim 1, characterized in that: The greater the air supply speed of the low-temperature hot air supply mode, the more hot air from the upper space of the room is supplied to the lower space of the room where the personnel activity area is located, but this causes the air speed in the personnel activity area to increase; the maximum air supply speed of the low-temperature hot air supply mode is determined based on the limit value of the air speed in the personnel activity area caused by the low-temperature hot air supply mode, and the limit value of the air speed in the personnel activity area is determined based on the thermal comfort standard or the thermal preference of the personnel.

6. The high-efficiency heating method for cabinet air conditioners with alternating high-temperature and low-temperature hot air supply according to claim 1, characterized in that: The longer the low-temperature hot air supply mode works relative to the high-temperature hot air supply mode, the higher the air conditioning energy efficiency is. However, since the heat transferred from the upper space of the room is not enough to offset the cold entering the personnel activity area from the outside, the temperature of the personnel activity area decreases. The working time of the low-temperature hot air supply mode relative to the high-temperature hot air supply mode is determined by the limit value of the air temperature in the personnel activity area, and the limit value of the air temperature in the personnel activity area is determined based on the thermal comfort standard or the thermal preference of the personnel.

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