タグアーカイブ 空気対空気熱交換器

The utilization of air-to-air heat exchangers in ventilation and energy-saving engineering

The core function of an air-to-air heat exchanger is to transfer the residual heat carried in the exhaust air (indoor exhaust air) to the fresh air (outdoor intake air) through heat exchange, without directly mixing the two airflows. The entire process is based on the principles of heat conduction and energy conservation, as follows:

Exhaust waste heat capture:
The air expelled indoors (exhaust) usually contains a high amount of heat (warm air in winter and cold air in summer), which would otherwise dissipate directly to the outside.
The exhaust air flows through one side of the heat exchanger, transferring heat to the heat conducting material of the heat exchanger.
Heat transfer:
Air to air heat exchangers are usually composed of metal plates, tube bundles, or heat pipes, which have good thermal conductivity.
Fresh air (air introduced from outside) flows through the other side of the heat exchanger, indirectly contacting the heat on the exhaust side, and absorbing heat through the wall of the heat exchanger.
In winter, fresh air is preheated; In summer, the fresh air is pre cooled (if the exhaust air is air conditioning cold air).
Energy recovery and conservation:
By preheating or pre cooling fresh air, the energy consumption of subsequent heating or cooling equipment is reduced. For example, in winter, the outdoor temperature may be 0 ° C, with an exhaust temperature of 20 ° C. After passing through a heat exchanger, the fresh air temperature may rise to 15 ° C. This way, the heating system only needs to heat the fresh air from 15 ° C to the target temperature, rather than starting from 0 ° C.
Airflow isolation:
Exhaust and fresh air flow through different channels in the heat exchanger to avoid cross contamination and ensure indoor air quality.
technological process
Exhaust collection: indoor exhaust gas is guided to the air-to-air heat exchanger through a ventilation system (such as an exhaust fan).
Fresh air introduction: Outdoor fresh air enters the other side of the heat exchanger through the fresh air duct.
Heat exchange: Inside the heat exchanger, exhaust and fresh air exchange heat in isolated channels.
Fresh air treatment: Preheated (or pre cooled) fresh air enters the air conditioning system or is directly sent into the room, and the temperature or humidity is further adjusted as needed.
Exhaust emission: After completing heat exchange, the exhaust temperature decreases and is finally discharged outdoors.
Types of air-to-air heat exchangers
Plate heat exchanger: composed of multiple layers of thin plates, with exhaust and fresh air flowing in opposite or intersecting directions in adjacent channels, resulting in high efficiency.
Wheel heat exchanger: using rotating heat wheels to absorb exhaust heat and transfer it to fresh air, suitable for high air volume systems.
Heat pipe heat exchanger: It utilizes the evaporation and condensation of the working fluid inside the heat pipe to transfer heat, and is suitable for scenarios with large temperature differences.
アドバンテージ
Energy saving: Recovering 70% -90% of exhaust waste heat, significantly reducing heating or cooling energy consumption.
Environmental Protection: Reduce energy consumption and lower carbon emissions.
Enhance comfort: Avoid direct introduction of cold or hot fresh air and improve indoor environment.

Mine exhaust heat extraction box with built-in air-to-air heat exchanger

The built-in air-to-air heat exchanger in the mine exhaust heat extraction box is a device specifically designed to recover waste heat from mine exhaust air. Mine exhaust refers to the low-temperature, high humidity waste gas discharged from a mine, which usually contains a certain amount of heat but is traditionally discharged directly without being utilized. This device uses a built-in air-to-air heat exchanger (i.e. air-to-air heat exchanger) to transfer heat from the exhaust air to another stream of cold air, thereby achieving the goal of waste heat recovery.

動作原理
Lack of air input: The mine's lack of air is introduced into the heat extraction box through the ventilation system. The temperature of the exhaust air is generally around 20 ℃ (the specific temperature varies depending on the depth of the mine and the environment), and the humidity is relatively high.
Function of Air to Air Heat Exchanger: The built-in air to air heat exchanger usually adopts a plate or tube structure, and the exhaust air and cold air exchange heat through a partition type in the heat exchanger. The heat from the lack of wind is transferred to the cold air, while the two airflows do not mix directly.
Heat output: After being heated by heat exchange, the cold air can be used for anti freezing of mine air inlet, heating of mining area buildings, or domestic hot water, while the exhaust air is discharged at a lower temperature after releasing heat.
Characteristics and advantages
Efficient and energy-saving: Air to air heat exchangers do not require additional working fluids and directly utilize the heat transfer from air to air. They have a simple structure and low operating costs.
Environmental friendliness: By recycling exhaust heat and reducing energy waste, it meets the requirements of green and low-carbon development.
Strong adaptability: The equipment can be customized and designed according to the flow rate and temperature of the mine exhaust, suitable for mines of different scales.
Easy maintenance: Compared to heat pipe or heat pump systems, air-to-air heat exchangers have a relatively simple structure and require less maintenance.
アプリケーションシナリオ
Anti freezing at the wellhead: Use the recovered heat to heat the mine air intake and avoid freezing in winter.
Building heating: providing heating for office buildings, dormitories, etc. in the mining area.
Hot water supply: Combined with the subsequent system, provide a heat source for domestic hot water in the mining area.
precautions
Moisture treatment: Due to the high humidity of the exhaust air, the heat exchanger may face the problem of condensation water accumulation, and a drainage system or anti-corrosion materials need to be designed.
Heat transfer efficiency: The efficiency of an air-to-air heat exchanger is limited by the specific heat capacity and temperature difference of the air, and the recovered heat may not be as high as that of a heat pump system, but its advantage lies in its simple structure.

Plate type air-to-air heat exchanger made of polymer PP material

The plate type air-to-air heat exchanger made of polymer PP (polypropylene) material is a heat exchange device based on polypropylene material, mainly used for heat exchange between gases. Here are its main features and application areas:

Main features:
Corrosion resistance: PP material has strong chemical corrosion resistance and is suitable for acidic or alkaline gas environments, especially performing well in industrial environments with strong corrosiveness.

Lightweight: Compared to metal heat exchangers, PP material heat exchangers are lighter in weight, making them easier to install and maintain.

Good thermal stability: Polypropylene has good thermal stability and can typically operate within a temperature range of -10 ° C to+95 ° C.

High cost-effectiveness: Due to the low cost of PP material and relatively easy processing, the overall cost is relatively economical.

Environmental friendliness: Polypropylene is a recyclable polymer material with minimal impact on the environment after disposal.

Main application areas:
Chemical and pharmaceutical industries: used for heat recovery or temperature regulation of corrosive gases.
Exhaust gas treatment system: During the air purification process, heat is recovered from harmful gases through a heat exchanger.
Food processing: In some food production processes, it is used for gas exchange to maintain the stability of environmental temperature.
HVAC system: Used in the ventilation and air conditioning systems of buildings for air preheating or pre cooling, improving energy efficiency.
The plate type air-to-air heat exchanger made of polypropylene material has become an ideal choice for many specific industrial fields due to its unique corrosion resistance and good cost-effectiveness.

プレート式空気対空気熱交換器の動作原理

プレート空対空熱交換器は一般的に使用される熱交換装置であり、その動作原理は次のとおりです。

プレート式空気対空気熱交換器は一連の平行な金属プレートで構成され、プレート間に一連のチャネルが形成されます。これらの流路には熱媒体が流れます。プレート式気体熱交換器に熱媒体が流れると、熱媒体はプレートに熱を伝え、プレートは熱媒体の反対側に熱を伝え、熱伝達と熱交換が行われます。

プレート式空気対空気熱交換器の動作原理は、直接熱伝達と間接熱伝達の 2 つの方法に分けることができます。

直接熱伝達:直接熱伝達とは、熱媒体がプレート内を直接流れ、熱媒体の反対側に熱を伝達することです。この方法は、熱媒体の両側の温度差が小さい場合に適しています。

間接熱伝達: 間接熱伝達とは、熱媒体がプレートを介して熱媒体の反対側に熱を伝達することを指します。熱媒体の両側の温度差が大きい場合に適した方式です。

プレート式空気熱交換器では、熱媒体の流れに一方向の流れと双方向の流れがあります。一方向流とは熱媒体が一方向にしか流れないことをいい、双方向流とは熱媒体が二方向に流れることができることをいいます。二方向の流れを備えたプレート式空気対空気熱交換器は熱交換効率が高くなりますが、より複雑で高価でもあります。

要約すると、プレート空気対空気熱交換器は、プレート間のチャネルを介して熱媒体間の熱伝達と熱交換を実現します。その動作原理は直接熱伝達と間接熱伝達に分けられ、熱媒体の流れには一方向の流れと双方向の流れがあります。

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