Application Analysis Of A Multi-Energy System With Solar&Air&Waste Water In Residential Building Renovation

With the development of urbanization,China's construction has completed the three-step energy-saving goal,after which the renovation of low-energy residential buildings will play a role key for future energy-saving.This paper proposes a multi-energy system with solar-air-waste water,discusses its feasibility of low-energy retrofit in existing residential building in terms of its performance and energy consumption,control strategy,applicability to different climate zones and economic analysis.Firstly,each part of the multi-energy system for a typical urban residential building is well designed.The space heating load and domestic hot water load are determined according to the design standards,and then the solar heat collection system,air source heat pump system,waste heat recovery and sewage source heat pump system are designed.The energy consumption simulation platform TRNSYS is used to establish the system model,and the experimental data is used to verify the reliability of the simulation system.Secondly,the system simulation model is used to analyze the impact of some main operating parameters and equipment parameters on the performance of each sub-system and the overall system.The energy proportion of each sub-system is illurstrated,and design advice for each sub-system is given.The results show that the solar collector should preferably optimize the lower limit of the flow range.Under the premise of ensuring that the outlet temperature of the solar collector meets the requirements,further reducing the solar system flow can effectively improve its heat collection and efficiency,and also extend its operating time.For the air source system,on the premise of meeting the set temperature and hot water guarantee rate in the stratified hot water tank,the heat capacity of the air source heat pump can be appropriately reduced,fully utilizing the heat storage performance of the water tank.For the sewage source heat pump,it is necessary to comprehensively consider the temperature and heat storage of the stratified water tank before determining its heat capacity.Thirdly,the applicability analysis of the control strategy of the multi-energy system is carried out.Taking the system heat collection,heating guarantee rate and domestic hot water guarantee rate as evaluation indexes,the applicability under different energy consumption rules is analyzed.The energy-saving effect of multi-energy systems under different heating strategies is simulated,and a "temperature-flow" heating strategy is proposed whose application possibility in this system is pointed out.The paper optimizes the start-stop strategy of each sub-system,and putx forward the domestic hot water priority strategy.The results show that the heat collection of the solar system is mainly affected by the upper limit temperature,and its operating time is affected by both upper and lower limit temperatures,while the related value to heat collection efficiency is mainly affected by the lower limit temperature.The upper and lower temperature limits of the survey results [5,2] are roughly consistent with the simulation optimization results.Finally,the applicability and economic analysis of climate zoning of six systems including solar-air-waste water multi-energy system are carried out,and suggestions for selecting energy systems under three typical cities are given,providing reference and optimization solutions for future multi-energy system design.