Development of fan-coil units of large water temperature difference

Presents the research background and technical paths of the unit, and probes into the test data in different conditions. The results show that the cooling capacity of the unit is reliable, reaching or superior to that of conventional on conditions of entering water temperature 7, 6, 5 ℃ and corresponding water temperature difference 7, 8, 9 ℃; that the cooling capacity increases to a certain degree while the entering water temperature decreases 1 ℃ and water temperature difference increases 1 ℃; and that in heating conditions, the heating capacity is higher than the value specified in the national standard in the condition of the high and medium grades with entering water temperature 55 ℃ while heating capacity approaches the standard value with entering water temperature 50 ℃ and is lower markedly than the standard value with entering water temperature 45 ℃. The test result shows that the rated water resistant is within the rational range (resistant head 2 to 5 m). An analysis of the test data shows that the unit is more energy efficient by adopting brushless DC motor especially in medium and low speed conditions. Energy consumption of an actual hotel shows that the additional investment of the electric commutated motor can be reclaimed within 3 years.