| Today,when transportation is changing rapidly,high-speed rail travel has become very popular in China.In the highly comfortable cabin environment of the high-speed rail,the air conditioning and ventilation needs a lot of energy.If applying heat pipe recovery system to high-speed rail ventilation system,the fresh air and the exhaust air are exchanged for energy,reducing the heating or cooling capacity of the fresh air,which is energy saving Effective measures.This article summarizes the research background and the current status of heat pipe research at home and abroad,and then specifically introduces the design theory of heat pipes,and designs a heat pipe heat exchanger suitable for high-speed rail air-conditioning systems based on the specific application environment of high-speed rail car air-conditioning systems.Then use numerical simulation to calculate the total of 2 rows of heat pipe heat exchangers,4 rows of heat pipe heat exchangers,6 rows of heat pipe heat exchangers,8 rows of heat pipe heat exchangers,10 rows of heat pipe heat exchangers,and 12 rows of heat pipe heat exchangers.The heat transfer capacity,unit pressure drop heat transfer volume and unit volume heat transfer volume are analyzed with simulation experiment,and the comprehensive performance of the6-row heat pipe heat exchanger is better.For the outdoor temperature that affects the heat transfer performance,the oncoming wind speed and the exhaust ratio are three.This paper studies the factors;finally,the energy saving performance and the economical efficiency of the heat pipe heat exchanger is calculated.Draw the following main conclusions:(1)When the wind speed of the heat pipe heat exchanger is constant,the total heat exchange capacity of the heat exchanger increases with the increase of the number of tube rows.Among them,the increase of 2 to 6 rows is larger,and the increase of 6 to 12 rows is gradually reduced;the unit pressure drop heat exchange capacity of the heat exchanger decreases with the increase of the number of tube rows,and the 6 rows of tube change The heat exchange rate per unit pressure drop of the heat exchanger is reduced to about half of the 2-pipe heat exchanger;the heat volume per unit volume of the heat exchanger decreases as the number of pipe rows increases,and the unit volume of the 6-pipe heat exchanger The heat exchange volume has dropped to about 60% of the two-row tube heat exchanger.(2)Under summer conditions,the temperature inside the compartment is 26 ℃,and the waste heat recovery efficiency of the heat exchanger increases as the ambient temperature outside the compartment increases,and when the ambient temperature is between 27 ℃ and 35 ℃,The recovery efficiency increases quickly.When the outside temperature of the compartment is between 35 ℃ and 40 ℃,the heat recovery efficiency increases slowly.At the same time,it can be concluded that the waste heat recovery efficiency decreases with the increase of the oncoming wind speed;Under winter conditions,the temperature inside the compartment is 20 ℃.The waste heat recovery efficiency of the heat exchanger decreases with the increase of the ambient temperature outside the compartment.The cold recovery efficiency decreases slowly.When the outside temperature of the compartment is between6 ℃ ～ 18 ℃,the waste cooling recovery efficiency decreases quickly.(3 Under summer conditions,the fresh air exhaust ratio of the heat exchanger will also seriously affect the waste heat recovery efficiency.The temperature inside the compartment is 26 ℃,the outside temperature is 27 ℃ ～ 40 ℃,and the oncoming wind speed is 3m / s.The increase of the fresh air ratio reduces the waste heat recovery efficiency of the heat exchanger.Considering the need to maintain a certain positive pressure in the cabin,the exhaust air ratio of the heat exchanger is generally appropriate between 80% and 90%;Under winter conditions,the fresh air exhaust ratio of the heat exchanger will also seriously affect the recovery efficiency of the waste cooling.The increase of the ratio of fresh air to the exhaust air reduces the recovery efficiency of the waste heat of the heat exchanger.(4)It can be seen that under the same temperature difference between the inside and outside of the carriage,the waste heat recovery efficiency under summer conditions is greater than the waste cooling efficiency under winter conditions.(5)The heat recovery efficiency of the heat pipe heat exchanger is good.After a specific calculation of the energy saving of the heat pipe heat exchanger in this paper,it is concluded that a series of Wuhan-Guangzhou high-speed rail can recover821659839.07 k J / a energy one year.(6)The economic benefits of heat pipe heat exchanger is good,.The annual economic recovery benefit of the full life cycle is 47,000 yuan / a,and the dynamic recovery cycle is 3.19 years. |
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