Energy Saving Characteristics Of Marine Air Conditioning Based On Temperature And Humidity Independent Control

Due to the need to ensure the safety of the ship during navigation and the comfort of the crew in the cabin,the ship air conditioning system is generally considered in accordance with the most severe conditions.Traditionally,ship air conditioning systems are generally inefficient and energy intensive,resulting in a large amount of energy.waste.Taking this into account,the independent control of temperature and humidity,that is,the energy-saving advantages of high-temperature cold water+solution dehumidification air-conditioning units combined with ships has a considerable market and broad development prospects.In this paper,the sensible heat load and wet load of ship air-conditioning are calculated and analyzed.On this basis,the variation law of sensible heat load and wet load ratio of ship air-conditioning system is obtained.Taking the "Yuyu"wheel of the Maritime University as an example,the analysis results show that the ambient temperature and relative humidity have a great effect on the sensible heat load and wet load ratio of the ship air conditioner.The average increase of the ambient temperature by 1? increases the ratio by 72%..After that,load calculation and energy consumption analysis were performed on three air conditioning systems:conventional chillers,high temperature cold water+low temperature chillers,high temperature cold water+solution dehumidification units.The results show that the high-temperature cold water+solution dehumidification unit has the lowest energy consumption under standard conditions,which can save 20.2%energy consumption.The high-temperature cold water+low-temperature chiller takes the second place,saving 11%energy consumption.The conventional chiller has the highest energy consumption,and with the environment The increase of temperature,relative humidity and fresh air ratio,the energy saving rate of high temperature cold water+low temperature chiller and high temperature cold water+solution dehumidification unit are gradually increasing,therefore,we initially judge[MMIM]DMP solution as a desiccant.The physical properties of different desiccants in the dehumidifier during solution dehumidification were analyzed by experimental study.1-butyl-3-methylimidazolium tetrafluoroborate([BMIM]BF4),1-ethyl 3-methylimidazole was measured.Saturated vapor pressure,thermal conductivity,viscosity and surface tension of four ionic liquids and lithium bromide solutions of tetrafluoroborate([EMIM]BF4)and 1,3 dimethylimidazolium phosphate dimethyl ester([MMIM]DMP)Physical quantity.Experiments show that the surface vapor pressure of[BMIM]BF4solution is very high,close to the saturated vapor pressure of pure water,and the dehumidification effect for solution is not ideal.When the concentration of[EMIM]BF4solution is as high as 90%,the vapor pressure is very close to that of lithium bromide.Instead of the traditional desiccant to provide theoretical possibilities,30%of[MMIM]DMP solution has a similar saturated vapor pressure as lithium bromide.Then,the thermal conductivity,viscosity and surface tension characteristics of each liquid were measured in the respective concentration ranges.It was found that the viscosity of the three ionic liquids and the lithium bromide solution increased gradually as the concentration of the solution increased,and the three ionic liquids and lithium bromide.The thermal conductivity of the solution is decreasing,and their surface tension is rising as a whole,except that the surface tension of the lithium bromide solution is much higher than that of the three ionic liquids.The temperature and humidity independent control air conditioning system is combined with the actual ship to establish an overall design plan.The calculation and analysis of the residual heat of the ship and the heat balance analysis,the residual heat fully meets the heat required by the solution dehumidification regenerator part,determines the air supply state point of the ship air conditioning system,and uses the variable frequency water pump to further save energy for the dehumidification unit.In the solution dehumidification unit,the design parameters of each part are clearly defined.Due to the use of the ship's residual heat,the unit only consumes energy from the fan and the solution pump,so the energy saving effect is very good.