Analysis of the Day-ahead Deviation Plan and Research on the Real-time Scheduling of Photovoltaic Greenhouses Based on Exergy Theory

Yuzhu Wang,Yifeng Ding,Huanna Niu,Xiayun Duan

doi:10.3390/en12203849

Abstract

For the correction problem of day-ahead plan deviation caused by energy prediction deviation in day-ahead scheduling stage of photovoltaic greenhouses, an exergy analysis method is used to propose the deviation model of heat required for photovoltaic greenhouses. Based on the deviation model, a real-time optimization scheduling model is established. The deviation model not only considers the non-negligible exergy loss during heating process of pipes, but also considers the difference between heat and thermal exergy affected by the actual indoor temperature. The goal of the real-time scheduling model is to minimize the absolute value of the difference between the energy supply and demand prediction deviation to be corrected and the adjustment of multi-form energy storage and electric loads, so that develop the real-time adjustment plan of energy storage and electric loads. The analysis results of the actual photovoltaic greenhouse show that of the heat required by a greenhouse based on the exergy theory calculation, the exergy loss of the heating process accounts for about 10%–20% of the total thermal exergy required and it cannot be ignored, so the calculation results can reflect the actual heat required more accurately and the greenhouse temperature is more suitable for plant growth. Moreover, the proposed real-time scheduling model can correct the deviation of the day-ahead plan and improve local consumption. The promotion ratio can reach 7%. Finally, the farmers’ electricity purchases cost is reduced. Thereby the effectiveness of the proposed heat deviation model and real-time scheduling model is verified.

Highlights

IntroductionIntegrated energy systems are an important development direction for future energy systems
Integrated energy systems are an important development direction for future energy systems.They couple multiple energy sources such as electric energy and thermal energy to achieve synergy between the multiple sources [1]
The goal of the real-time scheduling model is to minimize the absolute value of the difference between the energy supply and demand prediction deviation to be corrected and the adjustment of multi-form energy storage and electric loads

Summary

Introduction

Integrated energy systems are an important development direction for future energy systems. They couple multiple energy sources such as electric energy and thermal energy to achieve synergy between the multiple sources [1]. The photovoltaic greenhouse micro-integrated energy system includes electric energy, thermal energy, potential energy and so on. Due to the lack of long-distance transmission channels for electric energy and the saturation of the main network for new energy consumption, local consumption of photovoltaic power is important [3,4]. How to analyze the energy of micro-integrated energy systems to respond to the change rules of the output power of Energies 2019, 12, 3849; doi:10.3390/en12203849 www.mdpi.com/journal/energies

Methods

Results

Conclusion