Research On The Hydraulic Balance And The Water-mixer’s Performance Of Distributed And Mixed Water Heating System

Because of energy saving effect of the distributed and mixed heating system, which is relative to traditional heating system, it is important for the distributed and mixed heating system to study characteristics of water-mixer and hydraulic balance of the distributed and mixed heating system. Based on summary of research status of characteristics of water-mixer and hydraulic balance of the distributed and mixed heating system in the world, we take a distributed and mixed heating system in Beijing as an example. We also make a model of water-mixer, then we use CFD software to simulate the temperature field and the flow field of interior water-mixer. We use formulae to build the mathematical model of water-mixer, and we can get the mathematical relationship and curve between the mixing water ratio and the opening of adjustable panel or the hole radius of regulating plate. Compared to regulation curve of control valve, we can know that it is feasible to use water-mixer. It can provide a reference method for improving heat transfer efficiency and accurate regulation of mixing ratio.Firstly, we analyze differences between the distributed and mixed heating system and the traditional heating system, and we take a distributed and mixed heating system as an example to calculate its energy saving effects. Then, we can know that the more heating users and lager flow, the more energy saving effects.Secondly, we analyze structures and operation principles of plate type adjustable water-mixer and worm type adjustable water-mixer, then we take a distributed and mixed heating system in Beijing as an example, by calculating we can get relevant regulation formulae and curves. The conclusions are as follows: 1) Plate type adjustable water-mixer is suitable to quantity adjustment heating system. When heating loads vary, it is unnecessary for heating system to change its heat source parameters, by adjusting the opening of adjustable plate, it can match water mixing ratio requirements as well as energy saving target.2) Worm type adjustable water-mixer is suitable to quantity adjustment heating system. When heating loads vary, it is unnecessary for heating system to change its heat source parameters, by adjusting the radius of adjustable holes, it can match water mixing ratio requirements as well as energy saving target.Thirdly, we build a model of weather compensators used in the distributed and mixed heating system, by analyzing we can know that weather compensators can adjust heating according to fact heating loads as well as reach the control of hydraulic balance and energy saving target.Finally, we analyze selection method of the primary and the secondary networks as well as circulating water pumps.