The Research On Enegy Saving Control Of Water System And Fan Coil Units In Central Air-conditioning System

The energy problem affects the national economy and the people's livelihood and restricts the economic growth rate. With the rapid economic development, the building energy consumption has exceeded 1/4 of the total energy consumption, within which the central air-conditioning energy consumption has reached 65%. The energy saving of the air-conditioning system has significant meaning to relief the supply and demand contradiction.The energy saving of the air-conditioning system is mainly reached from the buildings and the operation process of the air-conditioning systems. To the energy saving of the buildings, the nation has drawn up relevant regulations to restrict the shape of the buildings and the thermal characteristic of the envelope structures. Many new energy saving techniques about air-conditioning system have been researched and applied to actual engineering and produced significant energy saving results. But the actual energy saving effect largely relies on the control method.This paper aims at the energy saving of the air conditioning system, mainly researches the influence of the control method on the energy consumption of the air-conditioning system. To the most widely employed air-conditioning systems, the Fan Coil Units systems, based on a concrete example, using the Fortran language to program, dynamically simulates the movements of the fans and valves of the FCUs, the air-conditioning effect and the actual cool consumption under different control methods. Analyzes the characteristics of various control methods and their respective adaptive capacity under partial load, which can give certain instructions when chooses proper control method under different air-conditioning accuracy. To variable cold water energy saving technique, analyzes the main factors that influence the energy saving of the pumps. Constructs a simplified cold water system as model, contrastively calculates the energy saving effect of the variable cold water system under different control methods when the flow rate of the terminals changes in different types. Points out the applicability of different control methods and proposes the most effective energy saving control method applicable in actual engineering. To large temperature difference technique, analyzes different views about energy saving effect of large temperature difference and their respective applicability. Researches the energy saving effect of the cold water large temperature difference technique and its influence on the performance of the chillers and terminals, with the conclusion that the most economic and effective energy saving supply and return water temperature should be calculated according to the actual equipment applied when employs cold water large temperature difference technique. Analyzes the influence of the cooling water large temperature difference technique on the performance of the chiller and the cooling tower, with the conclusion that when employs cooling water large temperature difference technique, the supply water temperature should be as low as possible...