Simulation And Analysis On Energy Consumption Of Air-conditioned Intermittent Operation In An Office Building In Changsha

Several researches indicate that the energy consumption of air conditioning has taken up about 30% of the building energy consumption in our country. In daily routine, it’s greatly influenced on air-conditioned energy consumption due to different air-conditioned operation caused by users’behavior. People generally considered that the mode of air-conditioned operation that turn off the air conditioning when people had left the room and turn it on when people came back, could reduce the energy consumption and achieve energy saving. This mode is feasible to the building using unitary air-conditioning system. In case of those buildings using central air-conditioning system, if people only go out for a short time, intermittent running of the air conditioning of that room might not reach the purpose of energy saving, and on contrary may increase the energy consumption and running cost due to the heat removed as the air conditioning was restarted and the heat transfer from neighboring rooms in intermittent period. Meanwhile, sunshade measure and the number of furniture indoor may also influence on energy consumption of air-conditioned intermittent operation. Hence it is significant to study on intermittent air-conditioned operation.The calculation and analysis of intermittent air-conditioned process are sophisticated. In the past, a number of researchers used the testing method to study. But this method was limited because it could not control and analyze numerous factors accurately. And it was difficult to reflect the interaction among the air-conditioned areas in the building. Therefore, computer simulation is used in this study. The dynamic numerical simulation method of full operation condition and multiple parameters is employed in this paper and the air-conditioned operation of a normal office building in Changsha is adopted as an example, simulate calculation and economic analysis have been done on the variation characteristics of cooling load, energy consumption, indoor temperature and other parameters of this office, in order to provide economic guidance of energy-saving for users’behavior. The results of the simulation show that, in summer office time, it can achieve energy-saving in condition of the air conditioning was turned off when the people left room for more than 1 hour. On contrary, the air conditioning didn’t need to be turned off if the people merely went out for less than 1 hour. But in winter, the energy consumption of intermittent air conditioning in 2 hours is larger than the energy of continuous air conditioning. So it didn’t need to turn off air conditioning while people left room. In case of existing more than regular regenerators like furniture inside the room, it is not energy-saving that running the air conditioning intermittently. Taking common curtain as sunshade measure in summer could effectively reduce cooling load and heat storage indoor and thus save more energy. Whether curtain is taken in winter has little influence on energy saving.The theory and the analysis process in this study are universal and could be applied to different buildings in different cities. Then the guidance on daily energy-saving behavior could be provided for people to achieve the purpose of building energy conservation.