Study On Thermal Efficiency Of Concentrated Heat Supply System With Concentrated Heat Pipe Type Vacuum Tube

Solar energy has been utilized in Yunnan provance, however defects occur such as small size in scale, deficiency in hate collocted. As such brings about large area occupied, costing too much in land, and impact up landscape, therefore the defects may become the technical bottlenect of promoting centralized heat supply, relying on mainly solar energy. In this paper, a condensing heat pipe vacuum tube type solar energy heat collecting parameters in central heating system,are studied, providing design parameters for the further expansion of the system.The study group had carried on pre-studies, researching the energy consumption in industrial park of Yunnan province, carried out experimental study experiments. The research results indicated that it was very positive to develop multi-energy resources complementarily distributed systems, relying mainly on solar energy. This study summarized previous research results and existing problems, further optimizing them. The main content of this research is to study the heat collecting parameters of solar central heating system, including the collection of heat, heat per unit area and its influence factor; thermal parameters, such as the unit area of heat loss and the heat storage water tank temperature; and the operation condition (conditions of seasonal change, mainly in response to set the heat change, the unit area of heat change etc, and the insulation effect of the change, the energy consumption of the system change and so on); the matters needing attention in operation; economic benefit analysis etc1Study on the heat collecting efficiency systemThrough the research, the system average collector efficiency was0.6916. Influence of heat collecting system experimental results suggest that, light intensity, relative velocity, cloud cover, the fluid entrance temperature and average temperature effects have on the system thermal efficiency. The collector efficiency increases with the increase of average light intensity and environment temperature, and decreases with the increase of the relative speed of wind and cloud cover, with the increase of temperature of fluid entrance presented first increasing and then decreasing variation.2The heat preservation effect of heat storage tankThe early research in the study of heat storage tank used polyester foam material with huge heat lose. It was not ideal heat preservation materials. In this study, heat storage tank was HDG modular water tanks with thermal insulation layer of80mm thick polyurethane. In this experiment, water temperature of the tank dropping per hour was less than1.11℃. The average heat loss was only1.56%and the per unit time heat loss was50.34kJ/min. The tank had a good heat preservation effect.3. The temperature of hot water supply.The annual hot water supply temperature was50-80℃, the water tank water temperature of about56%stable at50～60℃,60℃above reaches as high as44%, of which about30%at60～70℃,70℃is about13%. The annual water consumption is767.4m3, the average daily water consumption is2.10m3, the overall stability and good water status.4.The heating speed test system.Research shows that, with the increase of temperature,10℃every increase of heating time required decreases, the heating speed gradually. Rate of heating system for an average of0.51℃/min, every increase of10℃,21.82min of average time.5Economic benefit analysisThis article analyzing initial investment, operating cost, service life, and energy conservation and emissions reduction of the solar central heating system indicated that this system can provide a year of effective heat of157233MJ and have a shorter payback period and higher economic feasibility, comparing with other heat sources system.6Environmental benefit analysisThis article analyzing the environmental benefit of a daily producing2tons of80℃hot water in solar energy system indicated that annual saving amount of standard coal was3.729t. The emission reductions of carbon dioxide, nitrogen dioxide, sulfur dioxide and fuel dust respectively were186.87t,0.73t,1.34t and2.24t t in15years.7. Safety and durability evaluation systemThe relevant provisions of the safety and durability of the system in accordance with GBT50604-2010"solar water heating system of civil building evaluation criteria".This project basing on the previous studies and the actual situation, meanwhile, collecting local meteorological data, designed a solar central heating system. The project also installed moduled the system. The thesis researched the actual engineering application indexes and the results were with important practical reference value and significance for the application of solar energy resources in Yunnan province.