Application And Research Of Jet Pump Water Mixing Device In Heating System

Based on the serious phenomenon of current energy waste and common hydraulic imbalance,this paper firstly discusses the necessity of energy-saving reform in heating systems.Considering the general phenomenon of inhomogeneous cold and heat,combined with the structure and operating principle of jet pump equipment,the jet pump mixed water heating system was proposed.Its working process was completed by the change of fluid pressure and velocity inside the jet pump.The supply and return water is mixed in front of the user's building to relieve the serious energy waste caused by the“large flow,small temperature difference”operation mode.Secondly,through the introduction of the working principle and main parameters of the jet pump mixing water heating system,its energy saving effect can be reflected in these two aspects:(1)Due to the mixing of the return water and supply water,the flow rate through the circulation pump is reduced on the premise of ensuring the heating effect.For a 100,000 m~2 heating community test,the total head of the circulating pump before and after the transformation was basically unchanged.So the power consumption of the circulation pump is reduced based on P?GH,resulting in a power-saving effect;(2)By reducing the pressure drop in delivery process,the heat balance between the proximal and end users can be realized,so that the overheat loss in proximal users and low temperature phenomenon in end users can be eliminated,resulting in good heat-saving effect.Next,a residential area in Beijing was chosen to carry out the injection pump system transformation,The heat consumption,power consumption and users'room temperature change during the operation were tested to verify the energy-saving effect of jet pump mixed water heating system.Also,this new system can improve the user's living comfort to a certain extent.Besides,the paper makes calculation of investment cost for retrofitting,including equipment costs,resistance component costs,heat meter costs,manual installation costs,insulation,electrical welding costs and other expenses as well as profits,taxes,and so on.And the saving cost corresponding to energy-saving section can be calculated according to the local eletricity price,heat(gas)price standard.Then these two values are combined to calculate the dynamic investment payback period of transformation process.At the same time,the reduction of heat consumption also means a reduction in the use of fuel energy,so the environmental benefits generated by the jet pump system are also very significant.In addition,the balance of room temperature and the elimination of non-compliance at room temperature also promoted the formation of a harmonious relationship between heat users and heating company.Although there are still some defects in the operation of the jet pump system,such as the low efficiency,and the real-time effect of the adjustment is hard to achieve,it still has good development potential,and can play an important role in heating retrofit of the old district.