Way To Optimize The Energy Efficiency Of Solar Hot Water Systems Supply Water In Changsha City

It is a trend of world development that renewable energy is gradually to replace conventional energy, and solar collector technology, which meets buildings needs of hot water, heating, power supplying etc. by utilizing solar energy, is an important means of the use of renewable energy.In this paper, by analyzing climate characteristics of Changsha area, appropriate design parameters for the the solar water heating system (SWHS) of Changsha area were proposed with a software TRNSYS and numerical model. Combined the engineering example, The regular water-supplying was proposed by analyzing with numerical model. With the immediate replenishment, the numerical model of the SWHS was established.It was assumed that the collector area was certain, this paper investigated the effects of different tank volumes on the storage temperature, daily fluctuation in the storage temperature, average collector efficiency, average storage efficiency and solar fraction, and fuether analysis the solar fraction as a function of the ratio of the storage tank volume to the solar collector area. The results showed that immediate replenishment had many shortcomings, and then approximate water replenishment was raised. Based on the two replenishment modes, the annual performance of the SWHS was analyzed. It was assumed that the tank volume, collector area and desired load temperature was certain, solar fraction, average collector efficiency and average storage efficiency for two replenishment modes were analyzed and compared. The analytic results showed that it was significant for consumer to use reasonable replenishment mode, which had a important role in improving solar fraction, average collector efficiency and average storage efficiency.Lastly, on the basis of the above theory and technology research, the paper carried on a contrast analysis of SWHS with some other traditional ways from the three aspects which were energy saving benefit, economic benefit and conservation benefit. Of which economic benefit contrast used cost year-end value method, and conservation aspect was detailedly analyzed discharge amount of primary energy pollutants, greenhouse gas reduction. Besides, the solar fraction as an impact factor on the annual energy consumption was discussed in this paper.Above all results indicated that on the condition of the climate features in ChangSha area, compared with other tradlitional heat source ways, the natural gas assisted SWHS with approximate water replenishment is the most economical manner with the lowest energy consumption, and also it call result into pollutants'reduction due to its energy saving, which produces positive effects on the present environmental status of this area.