Efficiency Evaluation Of Domestic Gas Instantaneous Water Heater

The appliance of Chinese urban gas , whether the scale or the efficiency , has a long distance with advanced countries in the world . The thermal efficiency of Chinese domestic gas instantaneous water heater could increase by ten percent to fifteen percent as compared with advanced countries , so it has very large space to increase. Moreover , with the development of the Big Exploitation of the West and the Western Gas to the East , more and more gas facilities are used . In consequence , the research into the increase of the thermal efficiency in the field is an important task to realize the development of Chinese continuous energy sources.The author in the experiment chooses six kinds of domestic natural gas instantaneous water heaters as samples , adopts normal crisscross tables to arrange the experiment , analyzes experimental data through regression analysis and curve tally , and finally concludes the common rules of thermal efficiency and any factors In the article , he makes a suggestion to enhance heat transfer through analyzing the heat-transfer effect of heat exchanger.During analyzing experimental data , the author finds out that difference in cool-hot water temperature is the most important factor, so he emphases on analyzing the relation of difference in cold-hot water temperature and thermal efficiency . Considering the flown temperature of water heater is 2 to 3"C higher than animal heat of person, so we choose 40 癈 as parameter. Moreover, referring to ChongQing's temperature change in recent several years , we analyze the relation between thermal efficiency and month in ChongQing , and get the value of average efficiency in whole year.Through the above content, the author finds out that the most value of thermal efficiency is in the near of raising 25 "C , which is the rated design of common domestic natural gas instantaneous water heater . At the same time , the least value of thermal efficiency appears in the condition of ultimate limits . The thermal efficiency of all other condition is lower than of the rated condition , so it is very necessary to regulate and restrict the difference to the efficiency of the rated condition . Referring to the first -run efficiency data of correlative Technology and Quality Supervision Bureau(7I. samples) ,the above conclusion and the regulation of country standards . theauthor adopts four percent as the most difference to the rated condition to regulate and restrict the efficiency value in ChongQing. Above all, we adopt the value of first-run efficiency and four percent as standards to evaluate the efficiency of domestic gas instantaneous water heater in ChongQing.