Analysisand And Optimization Of On-site Operating Energy Efficiency Ratio Of Heating Ventilation And Air Conditioning System Of Public Building

The energy consumption in buildings has exceeded 1/4 of the total energy consumption in China, and the numbre will increase to 1/3 accompany with the improve of people's living standards. Public buildings waste a lot. Public building includes office buildings (such as office buildings, government offices, etc.), commercial buildings (such as shopping malls, finance buildings, etc.), tourism buildings (such as hotels, entertainment places, etc.), science, educational, cultural and sanitary buildings (including culture, educational, science, sanitary, gymnastic buildings, etc.), communication building (such as post and telecommunications, communications, broadcasting building), as well as transportation building (such as airports, stations, etc.). At present, it is about 2 billion m2 building completed each year in China, in which public buildings are about 400,000,000 m2. In the annual energy consumption of public buildings (in particular, the large-scale shopping malls, luxury hotels, high-grade office buildings, etc.), the HVAC system takes about 50% to 60%, the lighting system takes about 20% to 30% . The HVAC system consumes most part of energy, and it has the largest potential for energy-saving.Based on the existing energy efficiency rating system, this article proposed air-conditioning systems running energy efficiency ratio (OEER), which is defined as the ratio of the actual cooling load of air-conditioning system and the sum of actual equipment power of air-conditioning system. The purpose of proposed this concept is to rating the energy efficiency of the AC system in the actual operate condition. OEER can represent the transient efficiency, the efficiency of a period of time, and it can even reflect the efficiency of a season. The bigger OEER is, the higher the efficiency of air-conditioning system is.Through two project examples, this article analysed the status quo of energy efficiency of air-conditioning system and the impact factors. The result indicate that the host COP and x, which means the ratio of the host power consumption and the power consumption of the total air-conditioning systems, is the decisive factor of energy efficiency. The host COP and x are affected by the host load, the exhaust water temperature of host, the operating scheme of water systems, the operating scheme of cooling towers, etc. Based on this effect, they changed the OEER.Based on the mechanism of analysis, this article established the mathematical model of optimized energy efficiency ratio of air-conditioning system. According to the model, the article obtained optimized parameters under the part-load condition by using the mathematics software MATLAB, and it also analysed the affect of changing the operating scheme and management measures, as well as reset the operating parameters based on the existing system without big changes. As the objective function, the sensitivity analysis on the OEER was completed by direct derivation method, then the trend and degree of the's changes with several independent variables was indicated.Based on resetting the operating parameters, this paper analyzed the impact of energy efficiency ratio of air-conditioning system by application of some existing, feasible energy-saving technology, and given the cost-effectiveness analysis. At last, the paper provided some reference for the alternation of air-conditioning system.