Dynamic modeling of building heat network system using Simulink

• The full optimization of the thermal system is necessary for higher energy utilization efficiency.
• Numerical model was developed for complex thermal energy network using Simulink in Matlab.
• A special thermal routine of the pipe was devised for intermittent operation of the system.
• The code was validated by comparing experimental data and showed reasonable agreement.
• Detailed analysis on temperature variations and energy flow characteristic are provided.

Due to the sudden increase of energy consumption from modernization and civilization, energy efficiency has become an important issue in engineering devices. Much research effort has been made to enhance the performance of individual thermal devices. However, enhanced thermal devices are usually components in a larger thermal system such as an energy network connected by pipe networks to circulate an energy-carrying medium. Even when each component operates at maximum efficiency, the general system may not work in harmony to a full extent. Thus optimizing the full thermal system would increase the energy utilization efficiency even further and ultimately decrease the amount of CO2 emission. In this paper, we developed a numerical model for estimating heat flow and temperature variation in a complex energy network system using Simulink in Matlab. Emphasis has been made on heat pump's intermittent operation, where the system can be shut down for specific periods of time. A special thermal routine for the pipe was devised where the conduction becomes major heat transfer mode during the night. The code we developed was validated by comparing experimental data, and detailed analysis on system components' temperature variations and energy flow characteristic are provided.