Study On A Flexible Control Strategy Of A Combined Solar Energy And Air-source Heat Pump Heating System Based On Time-sharing Heat Demand

Solar heating meets the national strategic requirements of "carbon peaking,carbon neutralization" and sustainable development.Due to the randomness and periodicity of solar radiation,proper heat storage devices and auxiliary heat sources can ensure the relative sustainability of heating.However,at present,the capacity scale of auxiliary heat source systems is often configured according to the most unfavorable conditions,which leads to the fact that some solar heating applications often have a large proportion of the actual input of auxiliary heat sources,or even play a leading role.The improper system control strategy and the unreasonable optimization of the output sequence of heating equipment are some of the major drawbacks that lead to the above-mentioned problems.Generally,simple thermostatic control,temperature difference control,and other control methods are often used to drive and operate solar water heating systems.However,it is reported that such methods are not able to fully harness the capabilities of such solar energy systems.In order to further realize the energy-saving operation of the SHS for indoor heating,it is necessary to allow the indoor temperature to fluctuate within a certain range in combination with the difference in human body heat demand under the conditions of time-sharing and district.This will aid in solving the problem of the working sequence of different heat sources.Therefore,research methods such as investigation summary,theoretical analysis and simulation are adopted in this paper to study the demand for time-sharing heating demand and room temperature control requirements of buildings in northwest China,the flexible control strategy of a combined solar energy and air-source heat pump heating system based on time-sharing heat demand,and the optimization design of control parameters of the combined heating system.The research contents and conclusions are as follows:1.Based on the investigation and analysis of personnel activity status,work and rest system and activity space,the characteristics of time-sharing and district of residential building thermal environment in northwest China are summarized.By linear fitting the indoor thermal sensation voting results of residents,it is obtained that the comfortable temperature range of residents in each region is 12.6 ℃～19.7 ℃ under active state and9.7 ℃～17.2 ℃ under sleeping state.Comprehensively considering the average thermal feeling of residents,the neutral temperature in the active state and sleep state is determined to be 16 °C and 14 °C respectively,and with the goal of achieving neutral warmth in the indoor thermal environment,the comfortable temperature control range of the residents in the active state is determined to be 16～20 ℃,and the comfortable temperature control range of the residents in the sleep state is determined to be 14～17 ℃.2.Based on the summary of the current control methods of solar energy and air source heat pump heating systems,the flexible energy-saving control strategy of a combined solar energy and air-source heat pump heating system based on time-sharing heat demand is proposed with the energy-saving control idea of "solar energy output is preferred and room temperature is allowed to fluctuate".The mathematical models and matching parameters of the system components are determined,and the simulation system of combined heating is built,and the proposed control strategy is applied to the simulation analysis.3.The proposed control strategy is compared with the common thermostatic strategy and the modified thermostatic strategy in three types of cities with different levels of solar energy resources,including Xi’an,Lanzhou,Urumqi,Xining,Yinchuan and Lhasa.Although the room temperature of the proposed control strategy has a wide range of fluctuations,the room temperature can still meet the acceptable temperature range during the day and night.The room temperature is raised to a higher range when only solar energy is used for heating,thus delaying the starting time of the heat pump.When the room temperature is too low at night and the system only relies on the heat pump for heating,the room temperature is kept within the minimum range acceptable to the human body,and the working time of the heat pump is significantly reduced,thereby reducing the total energy consumption by 24%.4.The original ant lion optimization algorithm is improved against the shortcomings of random walk reduction mechanism and ant lion weight coefficient.The improved algorithm is compared with the original ant lion algorithm,particle swarm optimization algorithm,genetic algorithm,slime fungus algorithm and improved grey wolf algorithm to prove the effectiveness of the proposed algorithm,and the improved algorithm is used to synchronously optimize the system control parameters,to enable the system to operate at the optimum design parameters,thereby improving system performance and further reducing energy consumption.Compared with that before optimization,the energy consumption of the system has been reduced after the optimization of control parameters in different cities.The energy consumption reduction rate in Xi’an is 7.3%,Lanzhou is7.4%,Urumqi is 5.0%,Xining is 10.8%,Yinchuan is 9.6%,and Lhasa is 10.2%.