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The concept of a building thermal battery refers to storing the supplied heat and releasing it the another time through radiation and convection. The introduction of building thermal battery performance has created a more convenient solution to the problems of building load estimation, control and optimization, building-grid integration, etc. Some literatures have expanded the original definition of building thermal batteries, including PV RE (photovoltaic renewable energy), HVAC and other units. Starting from the building body, this investigation studies a building energy system. With reference to the performance parameters of traditional rechargeable batteries, the corresponding performance parameters of building thermal batteries are developed. The RC model is further used to model the performance parameters of the building thermal battery respectively. Among them, the corresponding parameter values of the RC model are obtained by parameter identification. Finally, the heat storage and heat release characteristics of the building integrated energy system are obtained. It makes the application of buildings as batteries more flexible in the urban energy network.

The energy in the district heating system is transforming into a clean, low-carbon and integrated production and consumption mode to reduce greenhouse gas emissions and dependence on fossil energy. The district heating system has developed to the fifth generation currently, and the water temperature is continuously reduced, and thus the heating efficiency is improved. The proportion of renewable energy sources such as solar, wind, and geothermal energy in substations will continue to increase. In this paper, substation configurations of the fifth-generation district heating system are firstly reviewed, and the exergy analysis is applied to the thermodynamic simulation of the district substations. Thermal simulation models of several types of substations mainly based on solar water heating, water source- and air source- heat pumps or combined forms are developed, the conventional heat exchanger substation is also modeled to compare their performance. The optimization algorithm in Matlab/Simulink is used to solve the thermodynamic numerical model, and performance indicators such as exergy and efficiency are selected to evaluate the performance of these systems.

PbZrO 3 thin films with (100) and (111) orientation were prepared by a simple sol–gel method. X-ray diffraction results revealed that post-annealing temperatures played an important role on the orientation of PbZrO 3 films. The frequency dependence of dielectric properties and the ferroelectric characteristics were measured. Giant energy-storage density and energy-storage efficiency calculated from hysteresis loops achieved about 25.25 J/cm 3 and 62% for PbZrO 3 film with thickness of 292 nm, respectively, results indicated that PbZrO 3 thin films had a potential application in energy-storage device. Optical properties of PbZrO 3 thin films were analyzed by a spectroscopic ellipsometer, results revealed that (111)-orientated PbZrO 3 thin films exhibited higher refractive index than that of the (100)-orientated PbZrO 3 thin films. [ABSTRACT FROM AUTHOR]