Performance Research Of Solution Dehumidification Fresh Air System Driven By Multifunctional CO₂ Water Source Heat Pump

Based on the problems of high energy consumption and poor air quality of traditional cooling and dehumidifying air conditioners,this paper proposes a multi-purpose CO₂water source heat pump driven solution dehumidification fresh air system for winter and summer.This system ingeniously combines the CO₂ cycle and the solution dehumidification cycle,uses CO₂ high-temperature exhaust gas to realize solution regeneration,and introduces groundwater to reduce the CO₂ cycle throttling loss.This article introduces the working principle of the system,and uses the modular modeling method to establish a steady-state model of the system.Based on this,the following research is carried out:Firstly,the heat recovery efficiencyη_rof the system solution was investigated.The results show that the changes of the solution concentration and air temperature at the inlet of the regenerator have less effect on the solution regeneration heat efficiencyη_r.The higher the system exhaust pressure,the lower the air moisture content,and the larger the solution flow rate,the greater the solution regeneration heat efficiencyη_r..When the regeneration air flow rate increases,η_r.increases first and then decreases.There is an optimal gas-liquid ratioR_bestto maximizeη_r.TheR_bestvalue is affected by the outside air temperature,moisture content,and exhaust pressure.For this system,under standard air conditions,when R is set to 0.12～0.17,the solution regeneration heat efficiencyR_bestis high.Secondly,using the unit performance evaluation coefficient as the optimization goal,the influence of eight controllable or uncontrollable key factors on the system’s summer operation performance was explored.The results show that the higher the temperature of the solution at the inlet of the dehumidifier,the higher the temperature at the groundwater inlet,and the higher the temperature at the fresh air inlet,the smaller the system COP_sys;The regeneration air flow has no significant effect on the system performance;when the outdoor air moisture content and the concentration of the dehumidifier inlet solution increase,COP_sys increases first and then decreases,when the moisture content is between15g/kg～23g/kg,When the solution concentration is 42%,COP_sys is high.Under the summer air-conditioning outdoor calculation parameters,when the controllable parameters in the unit are:the total flow of the dehumidification solution is 0.5kg/s,the dehumidification or regeneration internal circulation ratio is 0.65,and the dehumidifier inlet airflow ratio is 0.34,the stable operation of the COP_sys is 4.38;under winter outdoor air-conditioning design parameters,the system COP_sys is 5.41.Finally,the system area and environment adaptability were explored.For the same building in different regions,when the unit’s controllable parameters are the same,the system’s dehumidification matching degree x₀ applied to the humid area III is higher.For the same building,when the system is applied to cities in humid area III,dehumidification requirements can be achieved when the total flow m_s of the solution is 0.5kg/s.COP_sys is about 3.59;for cities in humid area II,m_s Only 0.9kg/s can meet the requirements of dehumidification.COP_sys is about 3.06,so the system has better performance when it is applied to the humidⅢzone.The environmental adaptability of the system was explored by simulating the operating characteristics of the unit under different environmental conditions in typical daily and air-conditioning seasons.In a typical day,the unit COP_sys fluctuates between 2.11～4.41,with an average value of 3.06;in the air-conditioning season,the COP_sys fluctuates between 2.69～5.19,with an average value of3.79,so the system is adaptable to outdoor environment changes Stronger.