Tube Indirect+direct Multi-stage Evaporative Air Conditioning Units Of The Optimization And Applied Research

With the development of our national economy, energy consumption and pollutant discharge has greatly increased, the past’s " Eleventh five-year plan" and now "Twelfth five-year plan", energy conservation and emission reduction in our country has become the main trend. But the building energy consumption of the air conditioning system is the main part, so the air conditioning system of energy saving is particularly important. Evaporative cooling this kind of energy saving, environmental protection, high efficient air conditioning way more and more be taken seriously, in the northwest of our country has been widely used. But evaporative air conditioning system is not perfect, in actual application of there is also some technology and process problems, needs to be improved and perfected. Among them, the evaporative air conditioning engineering existing in the application of the most important problems:1、the way to the water pipe indirect evaporative cooler part of heat exchange tube surface appear have no oval drench water (dry point);2、the secondary air into the wind way to gush to drench water and secondary air, the heat aexchange between wet not fully, the heat exchange efficiency is not high, the temperature drop limited. So how to optimize the practical engineering application in improving the problems found in and improve existing evaporative cooling air conditioning units for the thermal efficiency, make "dry air " use of maximizing the efficiency, we should be aimed at the practical problems proposed solutions. This article from that starting point, through to the dry areas and medium humidity area pipe indirect section+direct two level or three level evaporation air conditioning units examples of engineering application of test and debug result analysis, respectively from the pipe indirect evaporative cooler part of the cloth water means and secondary air into the wind patterns and direct segment of the spray pump selection aspects of optimization design, and the experiment test. Optimum design for in-depth analysis of the performance of the unit, the authors built a tube indirect+cooler+direct three evaporative air conditioning prototype test-bed, and compare the different seasons of the blocks running on different test results, experimental results show that:(1) Through the tube indirect evaporative cooler test results show that:strengthen the high-pressure piston pump nozzle atomization, symmetrical arrangement of spray nozzles to regulate the use of water and surrounded by the secondary air inlet means of optimization of indirect evaporative cooling tube significantly improve the efficiency of devices, and the efficiency value with the best secondary/primary air ratio value increases gradually become larger, when the ratio reaches a value of1, the best design, the efficiency can reach80%and there is an upward trend.(2) In the medium humidity area transition season, pipe indirect+direct two levels of evaporative air conditioning units of the temperature drop with outdoor air dry wet ball and the increase of temperature difference is reduced, and the temperature drop unit up to15℃above, the characteristics of the dry areas with the change rule, so can predict in medium humidity area even higher humidity area transition season, pipe indirect+direct multi-stage evaporative air conditioning can replace mechanical refrigerationair conditioning system, achieve the effect of energy saving.(3) Operating conditions in the summer when the tube indirect evaporative cooler efficiency value with the best secondary/primary air ratio value increases first and then decreased when the ratio reached0.8, the efficiency reaches the maximum value of83%; when to calculate the optimum design value of1, its efficiency decreased to80%and there is a downward trend. Region at moderate humidity secondary/primary air ratio is the best amount of0.8, this rule is in line with graduate student Fan Lijuan in the middle region of the evaporative air conditioning and humidity to run tests in that variation.(4) Through the contrast analysis in summer running condition, mechanical refrigeration air conditioning and evaporative air conditioning uses a central type system is running the new deal with total cold quantity QX=qm (hCx-hLx) and QX1=qm (hCx1-hLx) comparison, evaporative air conditioning system always cold quantity QX1less than QX, it can verify the description of evaporative air conditioning load to bear a part of the cold air return system, with the new winds of different energy-saving effect compared to a mechanical refrigeration air conditioning return air system is more significant; while the two air-conditioning system EER contrast, the evaporative air conditioning units EER is almost three times the mechanical refrigeration air conditioning unit, fully proved that evaporative air conditioning system operating costs far less than the mechanical refrigeration air conditioning systems.