Influences Of Heating Time-duration On Energy Consumption In Intermittent Heating Rooms

With the improvement of people’s comfort requirements of the built environment, room heating in winter is becoming more popular in hot summer and cold winter zone. However, as this region is non central heating zone, the rooms are widely used in intermittent heating mode, which the room starts heating when people in and stop heating when people leave. The characteristics of heating behavior is different from the rooms in north China. Therefore, the heat transfer process and energy consumption of the heating room are different from the north area of the country, too. In this heating mode, the indoor temperature varies significantly when the room is heated. Not only the heat loss of external envelope changes guidely with time, the temperature of thermal storage such as internal walls and furniture will f luctuate frenquently. The triditionl methods and research results for buildings in the north regions are difficult to be used directly for buildings in hot summer and cold winter zone, and for this region, the research on influences of heating time-duration on energy consumption in building is still very lack.Under intermittent heating mode, the heat provide to the room not only need for heating indoor air, but also for heating the thermal storage such as inner retaining structure and furniture. In order to get the characteristics of heating energy consumption of residential buildings in hot summer and cold winter zone, the numerical simulation method is used to compare five kinds of heating time characteristics under two different thermal insulation methods. The temperature variation of indoor air, internal heat accumulator and exterior wall of the room is calculated, and the influences of heating time-duration and the insulation layer position on energy consumption are also analyzed, which provides theoretical basis for reducing the energy consumption of the heating room. The influences of the frequency of heating equipment on-and off on indoor air temperature and energy consumption are discussed by the three heating time characteristics with the same heating time span ratio.The simulation results show that the factors such as insulation layer position, heating time-duration and the frequency of heating equipment have great influences on the heating energy consumption. In the process of heating time-duration, the heat loss caused by material storage is less with exterior wall with internal insulation, which makes the heating index of the wall with internal insulation lower than the external insulation, and has a certain energy saving effect. The heating time ratio is smaller, the effect of energy-saving with internal insulation is more obvious. In view of residential building in most families in the hot summer and cold winter area use intermittent heating and continuous heating time is short. Therefore, it is helpful for this area to reduce the heating energy consumption by using the wall with inner insulation in insulation renovation project of building. In hot summer and cold winter area, heating load and heat index can’ copy the steady state calculation method in the north central heating, and the effect of heat absorbing and cooling process of indoor heat storage on the energy consumption of intermittent heating must be taken into account. For the same heating time ratio, the start and stop frequency of the hot air heating equipment is bigger, the fluctuation of indoor air is frequent and the energy consumption is bigger. Otherwise the frequency is smaller, the energy consumption is smaller. The average heat index of the bigger frequency of the heating equipment is greater than that of the low on-off frequency. So it is beneficial to reduce the energy consumption of the heating system by using a small on-off frequency of the heating equipment.