Energy Efficiency Test Set And Performance Analysis For Gas-fired Water Heater

The test conditions and experimental methods for the gas-fired water heater are studied, mainly to automatic adjustment the heat load and on this basis, the energy efficiency test system is established, thus realized determining the thermal performance index automatically, rapidly and accurately. By means of the system the energy efficiency performance of water heater are studied experimentally. The major works of this paper are as follows.The energy efficiency test system for the gas-fired water heater is established by combining computer and the data acquisition and control module. The testing procedure is designed based on virtual instrument (KINGVIEW) and the system realized the automatic data acquisition, automatic processing and the automatic regulation. In addition to the supervisory control function, the system has the function of real-time monitoring, real-time test curve and real-time test reports.The techniques to the heat load regulation were investigated, which mostly tied in the control of the water. The control scheme of the dominant role of electric control valve and the subsidiary role of frequency pump-control-motor was determined. The control system was designed based on the cascade control principle, thus ensuring the load regulation. The influence of the heat load deviation to the energy efficiency is decreased.The automatic weighing technology was studied and the weighing pipelines of the test system was designed. The different strategy control scheme was established. After experimental analysis and comparison of artificial measurement, the static measurement and dynamic measurement, the last method was more precise. The accuracy of the system is enhanced by the improvement of the measurement accuracy for the temperature, the flow and the gas pressure. The energy efficiency evaluation experiment of the typical prototype were completed by the test system. Wide investigation were made to study effect of the injection temperature, the hot-water temperature rise, the heating temperature difference and the environmental temperature and humidity. The thermal efficiency is decreased with increasing temperature and the maximum is at the temperature 313k approximately. When the heating temperature difference is about 293k, the heating efficiency is the maximum. The thermal efficiency is suffering from the environmental temperature and humidity. The thermal efficiency of part load was experimental studied and the major change could affect the judgement result. So the efficiency standards is suggestted that the part load is confirmed 30% rated load. The actual operation efficiency of the gas-fired water heater is lower than the rated load. In order to improve the energy utilization rate, the efficiency standards could add the test part load and rule the minimum allowable values of energy efficiency.