Publication date: October 2015
Source:Building and Environment, Volume 92
Author(s): Zhe Wang , Borong Lin , Yingxin Zhu
The intermittent heating is considered to be able to achieve a high energy saving rate compared with the continuous heating. This paper builds a two-stage lumped parameter model to study the thermal dynamic process of the intermittent heating. Meanwhile, the on-site measurement was carried out on a residence in Cambridgeshire to verify the correctness of the model. On-site measurement validates the model we build and shows that the intermittent heating system we measured is able to provide comfort indoor thermal environment. However, the associated energy saving rate is only about 5% compared with the continuous heating system, which is not significant. Both the model and the on-site measurement show that the temperature change of the indoor air after the heating was recovered follows the exponent law and accordingly the thermal dynamic process of intermittent heating can be characterized by the thermal time constant. The thermal time constant is found to be a key index of intermittent heating. Low thermal capacity and high heat transfer coefficient lead to a small thermal time constant. The intermittent heating system with small thermal constant time is able to elevate indoor temperature quickly and has large energy saving potential. The thermal time constant of the intermittent heating system we surveyed has been calculated. Lastly, suggestions for improving the energy saving rate of intermittent heating systems have been provided in this paper.
Source:Building and Environment, Volume 92
Author(s): Zhe Wang , Borong Lin , Yingxin Zhu