A high efficiency ventilation heating method for suppressing hot air supply buoyancy lift

Abstract

An efficient ventilation and heating method for suppressing the upward buoyancy of hot air supply is disclosed. This method comprises high-temperature internal air supply and sub-high-temperature external air supply. The external air supply above the internal air supply exerts an upward pressure on the internal air supply, while the external air supply below the internal air supply exerts a downward pull on the internal air supply. The internal and external air supply are decoupled at the air outlets, delaying their mixing and fully utilizing the synergistic effect of the external air supply's upward pressure and downward pull on the internal air supply. This effectively suppresses the upward buoyancy of the internal air supply, allowing it to be efficiently used in the working area. Furthermore, the return air vent is located in the upper part of the room, effectively collecting the heat accumulated in the upper part of the room due to buoyancy and using it for external air supply, achieving tiered utilization of air supply energy and further increasing the utilization rate of heat supply in the working area. This method achieves a 40% suppression rate of upward buoyancy of the supply air, a 16% suppression rate of temperature decay in the supply air jet, and a 13% increase in the utilization rate of heat supply in the working area.

Description

Technical Field

[0001] This invention pertains to building ventilation and heating methods, and specifically relates to a highly efficient ventilation and heating method for suppressing the upward buoyancy of hot air supply. Background Technology

[0002] Winter thermal comfort significantly impacts human health and work efficiency, making winter heating a crucial need for ensuring people's well-being. Simultaneously, winter heating consumes substantial amounts of building energy. Compared to radiant heating, ventilation heating, due to its rapid thermal response, represents a reasonable low-carbon heating technology. However, ventilation heating faces the bottleneck of low energy efficiency caused by the buoyancy of hot air supply. Due to buoyancy, hot air flows towards the upper part of the room, accumulating heat there. This results in wasted heat in the upper parts of the room where thermal comfort is not a concern, while heating efficiency is low in work areas where thermal comfort is required. This is a common problem faced by existing ventilation methods for heating. For example, mixed ventilation aims to distribute air evenly throughout the room, but due to the buoyancy of hot air supply, thermal stratification also occurs, with heat accumulating in the upper part of the room, resulting in higher temperatures in the upper part and lower temperatures in the lower part. Displacement ventilation is an advanced ventilation method that is more energy-efficient than mixed ventilation in creating a thermally comfortable environment during cooling; however, due to the buoyancy of the hot air supply, displacement ventilation is not suitable for winter heating. Stratum ventilation is a relatively mature (and relatively newer) and advanced ventilation method, such as interactive cascade ventilation and graded ventilation. Stratum ventilation can improve energy efficiency by over 20% and 40% compared to displacement ventilation and mixed ventilation, respectively, during cooling, but it also faces the problem of wasted heat due to the buoyancy of the hot air supply. Summary of the Invention

[0003] To alleviate the problem of wasted heat from hot air supply caused by the buoyancy of the hot air supply, the present invention aims to propose an efficient ventilation and heating method that suppresses the upward buoyancy of hot air supply. The air supply consists of internal air supply and external air supply. Based on the difference in buoyancy, the internal air supply is suppressed from rising due to buoyancy, so that the internal air supply is used efficiently to heat the working area and improves the utilization efficiency of the heat from the hot air supply in the working area.

[0004] To achieve the above objectives, the technical solution of the present invention is as follows: An efficient ventilation and heating method for suppressing the upward buoyancy of hot air supply comprises two types of air supply: internal and external air supply at different temperatures. The internal air supply is high-temperature air, while the external air supply is at a slightly lower temperature. Due to the high temperature of the internal air supply, its buoyancy is greater than that of the external air supply. Because of this difference in buoyancy, the slightly higher temperature external air supply above the internal air supply exerts an "upward pressure" effect on the internal air supply, while the slightly higher temperature external air supply below the internal air supply exerts a "downward pull" effect. The external air supply wraps around the internal air supply, forming a wrapping double-jet ventilation system. This suppresses the upward buoyancy of the internal air supply, allowing it to be efficiently used to heat the working area and improving the utilization efficiency of the supplied air heat in the working area.

[0005] The internal and external air supply are decoupled at the air outlets, meaning they do not mix before flowing through them. In existing ventilation methods where the air supply consists of multiple types of air (such as fresh air and return air), these air types typically mix before passing through the air outlets. Because the internal and external air supply do not mix before passing through the outlets, they mix as they move towards the work area, effectively delaying the mixing process. This allows the external air supply to fully exert its synergistic "upward pressure" and "downward pull" effect on the internal air supply. This means that before the internal and external air supply are completely mixed, the external air supply exerts a synergistic "upward pressure" and "downward pull" effect on the internal air supply as it travels towards the work area, effectively suppressing the upward buoyancy of the internal air supply and allowing more internal air to be delivered to the work area, thus improving the utilization efficiency of the internal air supply's heat within the work area.

[0006] The internal air supply requires heating and purification treatment, and is mainly responsible for the heat load and fresh air load of the work area, ensuring thermal comfort and air quality in the work area. The external air supply is return air that does not require heating but needs to be purified. Using return air as external air supply meets the secondary high temperature requirements of external air supply and plays a synergistic role in "pressurizing" and "pushing down" the internal air supply.

[0007] Meanwhile, using return air as the peripheral supply air means that the heating method proposed in this invention requires only a single heat source of varying energy levels, thus reducing the complexity of the heat source system. The supply air in the heating method proposed in this invention consists of two supply air units at different temperature levels. However, through the tiered utilization of supply air energy, the supply air, through a single heat source, achieves supply air at two different temperature levels. Specifically, the heat-treated supply air is first used as high-temperature internal supply air, and then the return air is used as secondary high-temperature peripheral supply air. This tiered utilization of supply air energy further improves the efficiency of supply air heat utilization. The return air needs to undergo purification treatment to ensure air quality in the breathing zone.

[0008] The air supply outlet is located in the center of the room and is adjusted according to the height of the work area (e.g., sitting or standing posture) to directly supply air into the work area for heating. The peripheral air supply uses air outlets located at the top of the room, higher than the supply outlet, as the return air. The air outlets have two different heights: one located at the top of the room, higher than the supply outlet; and the other located at the bottom of the room, lower than the supply outlet. Due to the buoyancy of the supplied air, thermal stratification occurs in the indoor air, meaning the air temperature at the top of the room is higher than the air temperature at the bottom. This results in the air temperature at the top outlet being higher than that at the bottom outlet. The air from the top outlet is used as return air, while the air from the bottom outlet flows outdoors, thus achieving the recycling of the higher-temperature air. The higher-temperature air supply at the top of the room is used as return air, which essentially means that the heat accumulated in the supply air at the top of the room is sent back into the working area, improving the efficiency of the energy utilization of the supply air and further enhancing the utilization efficiency of the supply air heat in the working area.

[0009] Compared with the prior art, the advantages of the present invention are: 1. This invention proposes to utilize the "upward pressure" and "downward pull" effect of the secondary high-temperature peripheral air supply on the high-temperature internal air supply. The peripheral air supply wraps around the internal air supply to form a wrap-around double-jet ventilation, which effectively suppresses the upward buoyancy of the internal air supply and improves the heat utilization efficiency of the internal air supply working area.

[0010] 2. The decoupling of the peripheral air supply and the internal air supply at the air outlet of the present invention delays the mixing of the peripheral air supply and the internal air supply, so that the peripheral air supply can give full play to its synergistic effect of "pressing up" and "pulling down" on the internal air supply.

[0011] 3. This invention proposes to use return air as secondary high-temperature peripheral air supply, thereby realizing the cascade utilization of air supply energy, further improving the utilization efficiency of air supply heat working area, and reducing the complexity of heat source system.

[0012] 4. This invention uses the air supply located at the top of the room as return air, effectively collecting the heat of the supply air accumulated at the top of the room and reusing it to heat the working area, improving the perfection of the cascade utilization of supply air energy, which further improves the utilization efficiency of supply air heat in the working area.

[0013] In summary, this invention suppresses the upward movement of internal air supply due to buoyancy based on the difference in buoyancy, thereby enabling the internal air supply to be used efficiently for heating the working area and improving the utilization efficiency of the heat supplied by the working area.

[0014] It is worth noting that the technical modification of adjusting the temperature of the external air supply by simply mixing the internal air supply and return air is consistent with the core technology of this invention and still falls within the protection scope of this invention. Attached Figure Description

[0015] Figure 1This is a schematic diagram of the heating method proposed in this invention.

[0016] Figure 2 This refers to the jet center location in the layered ventilation and heating method proposed in this invention.

[0017] Figure 3 This refers to the temperature decay at the center of the air jet in the layered ventilation and heating method proposed in this invention.

[0018] Figure 4 The enthalpy values ​​of the air at the upper and lower air outlets of the heating method proposed in this invention are shown in the embodiments of this invention.

[0019] Figure 5 This refers to the utilization coefficient of the working area for the supply air heat in the layered ventilation and heating method proposed in this invention. Detailed Implementation

[0020] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0021] This invention proposes a highly efficient ventilation and heating method to suppress the upward buoyancy of hot air supply. It utilizes the synergistic effect of the "upward pressure" and "downward pull" of the secondary high-temperature peripheral air supply on the high-temperature internal air supply, effectively suppressing the upward buoyancy of the internal air supply and improving the utilization efficiency of the internal air supply heat working area. The decoupling of the peripheral and internal air supply at the air outlets delays their mixing, allowing the peripheral air supply to fully exert its synergistic "upward pressure" and "downward pull" effect on the internal air supply. Furthermore, this invention proposes using return air as secondary high-temperature peripheral air supply, achieving tiered utilization of air supply energy. This further improves the utilization efficiency of the air supply heat working area and reduces the complexity of the heat source system. The air outlet located at the top of the room is used as return air, effectively collecting the accumulated air supply heat at the top of the room and reusing it for heating the working area, improving the completeness of the tiered utilization of air supply energy, which further enhances the utilization efficiency of the air supply heat working area.

[0022] Example This invention proposes a highly efficient ventilation and heating method to suppress the upward buoyancy of hot air supply. Figure 1 As shown in the figure. This embodiment applies the heating method proposed in this invention to an office with dimensions of 4.30 m × 4.55 m × 2.85 m (length × width × height). The air supply vent is 1.30 m above the ground (serving seated personnel), the upper return air vent is 2.70 m above the ground, and the lower return air vent is 0.30 m above the ground. The ratio of the external supply air area to the internal supply air area is 1.3, with the internal supply air being fresh air and the external supply air being return air; the supply air velocity is 3.3 m / s, and the supply air temperature is 28℃. For comparison, the air supply volume of the tiered ventilation system is the same as that of the heating method proposed in this invention (i.e., the sum of the internal and external supply air), and the supply air temperature is also the same.

[0023] This invention proposes an efficient ventilation and heating method to suppress the upward buoyancy of hot air supply. The air supply consists of internal and external air supply. The internal air supply is high-temperature air, while the external air supply is slightly warmer than the internal air supply. Due to the high temperature of the internal air supply, its buoyancy is greater than that of the external air supply. Because of this difference in buoyancy, the slightly warmer external air supply above the internal air supply exerts an upward pressure on it, while the slightly warmer external air supply below the internal air supply exerts a downward pull on it. This suppresses the upward movement of the internal air supply due to buoyancy, allowing it to be efficiently used for heating the working area and improving the utilization efficiency of the supplied heat.

[0024] This invention proposes a highly efficient ventilation and heating method to suppress the upward buoyancy of hot air supply. In this method, the internal and external air supply are decoupled at the air outlet, meaning they do not mix before flowing through the outlet. In existing ventilation methods, where the air supply consists of multiple types of air (such as fresh air and return air), these air types typically mix before flowing through the outlet. Because the internal and external air supply do not mix before passing through the outlet, they mix as they move towards the work area, effectively delaying the mixing process. This allows the external air supply to fully exert its synergistic "upward pressure" and "downward pull" effect on the internal air supply. This means that before the internal and external air supply are completely mixed, the external air supply exerts a synergistic "upward pressure" and "downward pull" effect on the internal air supply as it travels towards the work area, effectively suppressing the upward buoyancy of the internal air supply. This allows more internal air supply to be delivered to the work area, improving the utilization efficiency of the internal air supply's heat within the work area.

[0025] This invention proposes a highly efficient ventilation and heating method to suppress the upward buoyancy of hot supply air. The internal supply air requires heating and purification treatment, primarily responsible for the heat load and fresh air load of the work area, ensuring thermal comfort and air quality. The external supply air is unheated return air. Using return air as external supply air meets the requirements of the secondary high temperature of the external supply air, leveraging its synergistic effect of "upward pressure" and "downward pull" on the internal supply air. Simultaneously, using return air as external supply air means that the heating method proposed in this invention requires only a single heat source of energy grade, thereby reducing the complexity of the heat source system. The heating method proposed in this invention consists of supply air at two different temperature levels, but through the cascaded utilization of supply air energy, a single heat source can achieve supply air at two different temperature levels. Specifically, the heat-treated supply air is first used as high-temperature internal supply air, and then the return air is used as secondary high-temperature external supply air. The cascaded utilization of supply air energy further improves the utilization efficiency of supply air heat. The return air requires purification treatment to ensure air quality in the breathing area.

[0026] This invention proposes a highly efficient ventilation and heating method to suppress the upward buoyancy of hot air supply. The air supply outlet is located in the center of the room and adjusted according to the height of the work area (e.g., seated or standing posture), allowing the air supply to directly reach and heat the work area. It has two air outlets at different heights: one located in the upper part of the room, higher than the supply outlet; and one located in the lower part of the room, lower than the supply outlet. Due to the buoyancy of the supply air, thermal stratification occurs in the indoor air, meaning the air temperature in the upper part of the room is higher than that in the lower part. This results in the air outlet at the upper part of the room having a higher outlet temperature than the one at the lower part. The air from the upper outlet is used as return air, while the air from the lower outlet flows outdoors, thus recovering and utilizing the higher-temperature air. Using the higher-temperature air from the upper part of the room as return air essentially re-introduces the accumulated heat from the supply air in the upper part of the room into the work area, improving the efficiency of the energy cascade utilization of the supply air and further enhancing the utilization efficiency of the supply air heat in the work area.

[0027] An experimentally validated CFD model was used to simulate the indoor flow field, thereby obtaining results such as... Figures 2-5 The results are shown below, and the relevant results are explained below.

[0028] like Figure 2 As shown, in tiered ventilation, the heated air rises due to buoyancy, causing the centerline of the air jet to continuously rise during its journey. As the air jet moves away from the air outlet, the upward buoyancy of the tiered ventilation intensifies, causing the air to rise from 1.30 m to 1.40 m (an increase of 0.1 m) when it reaches the personnel microenvironment (i.e., 3.3 m from the air outlet). The heating method proposed in this invention can effectively suppress the upward buoyancy of the supplied air, causing the air to rise from 1.30 m to 1.36 m (an increase of 0.06 m) when it reaches the personnel microenvironment. This means that the heating method proposed in this invention achieves a 40% suppression rate of the upward buoyancy of the supplied air.

[0029] like Figure 3As shown, the temperature at the center of the air jet in a tiered ventilation system continuously decreases as the air travels. At the air outlet, the temperature at the center of the air jet reaches 0°C, indicating that the air components (fresh and return air) are completely mixed there. When the air reaches the microenvironment of the personnel, the temperature at the center of the air jet decreases by 3.2°C. The heating method proposed in this invention results in a temperature decrease of less than 0°C at the air outlet, only reaching 0°C at a distance of 0.8 m. This means the mixing of the external and internal air supply is delayed from the air outlet to 0.8 m, allowing the external air supply to fully exert its synergistic effect of "upward pressure" and "downward pull" on the internal air supply, thereby effectively suppressing the temperature decrease at the center of the air jet. When the air reaches the microenvironment of the personnel, the heating method proposed in this invention suppresses the temperature decrease at the center of the air jet to 2.7°C, representing a suppression rate of 16%.

[0030] like Figure 4 As shown, the enthalpy of the air outlet at the upper vent of the heating method proposed in this invention is 42.8 kJ / kg, and the enthalpy of the air outlet at the lower vent is 39.5 kJ / kg. This invention proposes using the air from the upper vent as external air supply, thereby accumulating the heat from the upper air supply for heating the working area, increasing the heat accumulation and reuse rate of the upper air supply by 8%, thus improving the completeness of the cascade utilization of air supply energy.

[0031] like Figure 5 As shown, due to buoyancy, the heated air rises to the upper part of the room, and the utilization coefficient of the layered ventilation system in the working area is only 0.47 (i.e., the ratio of air energy in the working area to the total air energy in the room is 0.47). Because the heating method proposed in this invention utilizes the synergistic effect of the "upward pressure" and "downward pull" of the secondary high-temperature peripheral air supply on the high-temperature internal air supply, it effectively suppresses the upward buoyancy of the internal air supply, improving the utilization efficiency of the internal air supply heat in the working area. Furthermore, this invention proposes using return air as secondary high-temperature peripheral air supply, achieving tiered utilization of air supply energy; the outlet air located at the upper part of the room is used as return air, effectively collecting the accumulated heat from the air supply in the upper part of the room and reusing it to heat the working area, improving the completeness of the tiered utilization of air supply energy, which further enhances the utilization efficiency of the air supply heat in the working area. Figure 5 This invention increases the utilization coefficient of the air supply heat working area to 0.53, which means that the utilization rate of the air supply heat working area is increased by 13%.

Claims

1. A highly efficient ventilation and heating method for suppressing the upward buoyancy of hot air supply, characterized in that, Its air supply consists of two types of air supply at different temperatures: internal air supply and external air supply. The internal air supply is high-temperature air supply, while the external air supply is a slightly higher-temperature air supply with a lower temperature. The buoyancy of the internal air supply is greater than that of the external air supply. Due to the difference in buoyancy, the slightly higher-temperature external air supply above the internal air supply exerts an "upward pressure" effect on the internal air supply, while the slightly higher-temperature external air supply below the internal air supply exerts a "downward pull" effect on the internal air supply. The external air supply wraps around the internal air supply, forming a wrap-around double-jet ventilation, thereby suppressing the internal air supply from rising due to buoyancy. This allows the internal air supply to be used efficiently for heating the working area, improving the utilization efficiency of the heat from the supplied air in the working area.

2. The efficient ventilation and heating method for suppressing the upward buoyancy of hot air supply according to claim 1, characterized in that, The internal and external air supply are decoupled at the air outlet, meaning they do not mix before flowing through the outlet. As they move towards the work area, they mix, effectively delaying the mixing process. During the movement of the internal air supply towards the work area, the external air supply exerts a combined "upward pressure" and "downward pull" effect, effectively suppressing the upward buoyancy of the internal air supply and allowing more internal air to be delivered to the work area, thus improving the utilization efficiency of the internal air heat in the work area.

3. The efficient ventilation and heating method for suppressing the upward buoyancy of hot air supply according to claim 1, characterized in that, The internal air supply requires heating and purification treatment, while the external air supply is return air that does not require heating but needs to be purified. Using return air as external air supply meets the requirement of secondary high temperature for external air supply and gives full play to its synergistic effect of "upward pressure" and "downward pull" on internal air supply.

4. The efficient ventilation and heating method for suppressing the upward buoyancy of hot air supply according to claim 1, characterized in that, The air supply uses a single heat source to achieve air supply at two different temperatures: first, the heat-treated air is used for high-temperature internal air supply, and then the return air is used for secondary high-temperature external air supply.

5. The efficient ventilation and heating method for suppressing the upward buoyancy of hot air supply according to claim 1, characterized in that, The air supply outlet is located in the middle of the room and is adjusted according to the height of the work area so that the air is directly delivered to the work area for heating. The peripheral air supply uses an air outlet located at the top of the room, which is higher than the air supply outlet, as the external air supply. The air outlet has two different heights: one is located at the top of the room, higher than the air supply outlet; the other is located at the bottom of the room, lower than the air supply outlet. The air outlet at the bottom of the room flows to the outside.

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