Research On Heating System Of Direct Heating Transfer

Winter heating has a great influence on the stability of the city and the living of the residents.The comfortable living and working environment can reflect the social progress and development.China's annual average for winter heating costs70 billion yuan,accounting for the total energy consumption of 1/4.The existing heating system has the problems of “ low safety,high energy consumption,and high pollution”.It is very important to build a“safe,energy-saving,clean and efficient ” heating system.In this paper,a new type of individual household heating system is designed,using direct contact heat transfer and forced down-flow hot heating.The heating system includes heating exchanger,heating open-close safety valve and heating exchange pool,which integrates the control functions of the safety,water consumption and combustion.The key performance of heating system is simulated and experimentally tested.The highlight problems is improved.Based on the Realizable k-? model,the DPM discrete phase model and the component transport model,the numerical simulation of the direct heating transfer of the gas and water in the internal heating exchanger is carried out by using Fluent,the software of computational fluid dynamics(CFD).The results indicating:The internal pressure distribution of the heating device is stable,andit is far lower than the atmospheric pressure.The best heating transfer of gas and water is in the gas diffusion zone at the right side of the inlet.The heating transfer produces a large amount of water vapor.the internal condition of the heating exchanger is poor,and the relative humidity is larger.According to the GB/T10180-2003 relative standards,the thermal performance of heating device is studied,and the thermal parameters(such as heating capacity,flow rate,exhaust temperature,etc.)are obtained.Through the positive balance method,the heating efficiency of heating exchanger is calculated as 83.8%.Finally,for the exhaust waste heating and water vapor wasting,the installation of energy recovery device of tail gas is put forward,and the detailed scheme of energy recovery of tail gas is given.An energy recovery device is developed by using the dual energy recovery technology of heat pipe and condensation.The main heat carrier is the outer longitudinal finned tube,and the internal heat transfer area is 4.2m2.The test results show that the maximum power of the exhaust gas energy recovery is 90.4kW and the working efficiency of the heating device can be increased by1.5%.Due to the internal temperature difference,the water vapor can be condensed and recovered.In order to understand the actual working conditions of the heating exchanger and the energy recovery device for tail gas,the experimental study is carried out.The experimental results shown that the average water heating temperature of the whole heat exchange system is 4.619?.The heating capacityof heating device is accounting for about 76% of the total heating capacity,and the energy recovery device for tail gas occupying by 24%.This paper is an innovative attempt to study this heating system.The research findings have practical value,which can provide reference for further research work.