Research On The Assembled Large Capacity Gas Instantaneous Water Heater

In recent years, with the development of the national economy and the improvement of people's life, more and more locations need hot water supply, especially such as in scriptoriums, hotels, public bathrooms and hairdressing shops the demand of hot water become bigger than ever. However, most of these commercial building are using positive displacement hot water supply equipments, and most of these equipments use electricity as their heat sourse. Using electricity to heat up water is a process to transfer high-grade energy (electrical energy) into low-grade energy (thermal energy), it is really uneconomic. In addition, the inhomogeneity of the hot water applied load of commercial building leads to that the thermal loss become bigger in the periods that there is no user uses hot water. Therefore the overall thermal efficiency of positive displacement water heaters reduced. This thesis tries to design an assembled large capacity gas instantaneous water heater which use natual gas as its main energy to replace positive displacement water heater which use electricity as its energy.This research has designed hardware and control program for the assembled large capacity gas instantaneous water heater. In the aspect of hardware, a scheme that paralleling several gas water heaters to supply hot water was adopted; in the aspect of control program, the variation of hydraulic pressuer was imposed as the control parameter of flux of yielding water, and the distribution according to needs of hot water was achieved. Besides the assembled large capacity gas instantaneous water heater could also offer large capacity hot water to multiple points. Otherwise, via controlling the temperature of the yielding water and installing a circulating pump, the problem of cooling down of hot water in pipes when the water heater stopped for a long time was solved. And there would be no cold water stream out.The comparison and analysis of energy consumption between assembled large capacity gas instantaneous water heater and positive displacement electric water heater were taken in this paper. The conclusion was: in the same hot water supply scale, the consumption of seconsary energy source of the latter was less than that of the former; but the consumption of primary energy source of the former was less than that of the latter about 60%.The study indicated that in the same hot water supply scale assembled large capacity gas instantaneous water heater could provide homothermal and isobaric hot...