Study On The Energy Supply System Performance Of System Combined Heating,Power And Biogas In Gannan Tibetan Area

Tibetan area in China is located at a higher altitude and very cold climate in winter.Most of the residents in Tibetan area are mainly farming and animal husbandry,which makes the local buildings dispersed.The energy consumption mode using coal and dried cow dung as fuel is relatively backward.The energy utilization rate is low,and at the same time,it causes serious pollution to the environment.However,due to the high altitude,Tibetan area is still very rich in solar energy resources in winter,so solar energy is used for energy supply.In order to effectively solve the problem o f building energy supply in Tibet and realize the efficient and clean utilization of solar energy,this paper based on the previous research results of the research group,investigates the living habits,building structure and actual needs of farmers and herdsmen,and utilizes the abundant solar energy and biomass energy resources in the area of a building in Shanglangkanmu Village of Gansu Province.A heat,power and biogas combined system was built on a building area 170 m² single building with passive sunspace.The system uses solar energy and biomass energy as energy input,and can provide users with winter heating,household electricity,domestic hot water and cooking gas to meet different levels of energy demand.Through the test on the spot of the system during the whole heating season,the energy supply performance of the system under the actual working conditions is studied,and the corresponding optimization scheme is put forward through energy analysis of the system.Finally,the economic and environmental and social benefits of the system are evaluated.The main results of this thesis are as follows:?1?For the solar active-passive combined heating subsystem,the heat demand of buildings can be fully met in most test time.Only in the coldest mont h,the heat supply of the system is slightly lower than the heat demand of buildings.In the whole heating season,the heat supply of the system accounts for 94.4%of the total heat demand of buildings.When the average temperature of the environment is h igher than–4.1?,the system can fully meet the heating demand of buildings.When the daily average solar radiation is less than 15.9 MJ/m² in the coldest month,the heating capacity of the system can not meet the building heat demand.?2?For the PV power generation subsystem,the average daily power generation is 3.1 kWh during the test period,and the actual photoelectric conversion efficiency is7.6%.In most of the test time,the power generation is higher than the electricity consumption,and the remaining power generation can be stored in the battery.in.In the case of insufficient power generation,battery packs can be used to meet the demand for electricity.The relationship between daily power generation and solar radiation and ambient temperature is obtained by multiple linear regression.Solar radiation is positively correlated with PV power generation and negatively correlated with ambient temperature.?3?For the solar constant temperature fermentation subsystem,the temperature of the biogas slurry is stable at 28°C during the test period.The system processes a total of 2.7 m³ of sheep manure,and the cumulative production of biogas is 95 m³.The average gas production per day of the biogas tank is 0.76 m³,and the average methane content is 52.4%,although the daily biogas volume fluctuates,relying on the remaining biogas in the gas storage bag can also provide the user with continuous cooking gas to meet the gas demand of the user.?4?Analyze the energy distribution of the whole system in December and January of the coldest month.The total input energy is 10513 kWh and the output energy is4536 kWh.The output energy and heat loss of the system account for 43.1%and43.9%of the total input energy,respectively.After optimizing the l ocation of the collector's hot water storage tank,the output energy of the system will increase by39.3%,and the building energy saving rate after the external thermal insulation transformation is 22.8%.?5?The initial investment of the system is 41055 yuan,and the payback period of dynamic investment is 7.5 years.Compared with the traditional energy-using mode,the system can save 6908 yuan annually,equivalent to reducing the burning of standard coal by 6.5t,reducing the CO₂,dust,SO₂ and NOx by 16.1 t,4.4 t,0.49 t and0.24 t,respectively.The economic and environmental and social benefits of the system are remarkable.In conclusion,the application and popularization of combined heat,electricity and biogas based on solar energy and biomass energy in this area has changed the backward energy consumption mode,improved the energy utilization efficiency,improved the comfort of farmers and herdsmen indoors,reduced the use of fossil fuels and improved the natural environment.This topic can be use d to guide the optimization of renewable energy supply system in different areas.Design and application.The innovation of this paper is as follows:?1?Utilizing the abundant solar and biomass energy resources in the Tibetan area and combining with the local building structure,a combined heat,power and biogas supply system was built for the first time in the cold reservoir area,and the whole heating season was tested.The performance of the combined heat,power and gas supply system in the cold reservoir area during the whole heating season was revealed.Based on the whole life cycle,the economy,energy saving and social benefits of the system were evaluated.Price.?2?The theory reveals the mechanism that the performance of cogeneration system is affected by environmental factors in this area.