Research On Energy Saving For Dedicated Ventilation Systems Based On Heat Recovery Technology

This research proposes a dedicated ventilation system based on heat recovery technology.Heat pipe heat exchanger(HPHX)which replaced the total heat exchanger is used to realize the heat recovery technology for recover the most energy in this system.From this system,the precool and reheat process is operating in the dry condition can not consume the extra energy.Therefore,this study disscusses the feasible use of the proposed system and its energy saving potential in the hot and humid climates.This study is designed to establish the optimal model which combined the heat pipe heat exchanger and direct expansion air conditioning unit.The solutions for the dehumidification from cooling are also proposed in this research.A mathematical model which evaluate the characteristics of heat pipe heat exchanger combined with direct expansion air conditioning system is established at the same time.The simulation results which from the mathematical model could be used to establish the experimental model.This research calculates the energy saving potential of heat pipe heat exchanger combined with direct expansion air conditioning system for the different green buildings in the simulation and experiment part.This research also compares and analyzes their energy saving potential for the different green buildings.Eventually come to exist the relationship between the outdoor conditions and the energy saving potential of the proposed system.The simulation results indicate that the dedicated ventilation system with the heat pipe heat exchanger(HPHX)can be applied to save energy for 64% to 80% of the air-conditioned hours;of which only 1.32% to 2.44% of the time the decoupling objective cannot be achieved for the office building.This can be corresponded to 2.3% to 3.5% saving in energy use for air-conditioning.The dedicated ventilation system with the heat pipe heat exchanger(HPHX)can be applied to save energy for 50% to 60% of the air-conditioned hours;of which only 1.53% to 2.62% of the time the decoupling objective cannot be achieved for the cinema.This can be corresponded to 1.3% to 2.3% saving in energy use for air-conditioning.The dedicated ventilation system with the heat pipe heat exchanger(HPHX)can be applied to save energy for 73% to 78% of the air-conditioned hours;of which only 0.31% to 1.62% of the time the decoupling objective cannot be achieved for the laboratory.This can be corresponded to 6.8% to 9.2% saving in the fresh air system and 3.2% to 4.6% saving in energy use for air-conditioning.The experimental results show that this experiment research regresses a linear relationship between the outdoor condition(T0;RH0 and VFA)and heat pipe effectiveness which coefficient of determination(R2)is higher than 0.96.A linear relationship between the outdoor condition(T0;RH0 and VFA)and energy saving potential of three different kinds of building(office building,cinema and laboratory)is also regressed in this experiment research,the coefficient of determination(R2)is higher than 0.94.The relationship between the outdoor conditions and the energy saving potential of the proposed system also be obtained in the experiment research.The comparison between the experimental results and simulation results demonstrate that the research error is within the allowable range.This results reveal that the experimental results and simulation results are consistent.The proposed system most suitable for the laboratory model which have the best energy saving potential of the three different kinds of building(office building,cinema and laboratory).This research demonstrates that the proposed system is suitable for buildings to achieve the energy saving objectives for hot and humid climates where air-conditioning demand is highly variable.