Capacity Assesment Of Shallow Geothermal Energy Application With GSHPs At City Scale:Based On Micro Spatial Form And Supply-Demand Balance

The development of shallow geothermal energy based on Ground Source Heat Pump(GSHP)would reduce construction energy consumption by 60% to 70% compared with traditional energy in ideal conditions,which would have a significant effect on optimizing construction energy-resource structure,reducing traditional energy consumption and greenhouse gas emissions,relieving urban heat island effect and improving the micro-environment of constructions.There is a considerable instability between GSHP and the construction of the hot and cold supply-demand system.The key issue to promote GSHP in high density area of the city involves how to optimize the heat pump coupling construction energy supply system and accurately predict the suitable development location and market potential.In light of the influences of urban typical micro space form on the shallow geothermal energy supply capacity and the cooling and heating load of constructions,this study regards the supply and demand ratio of ground thermal energy capacity and the cooling and heating load of constructions as the criterion for evaluating the suitability of the urban specific space to install the GSHPs.Studying the influences of spatial form factors on effective development potential and its change rule,this research analyzes the balance of the supply and demand of shallow geothermal energy in several typical urban spaces.Taking Xicheng District of Beijing as an example,a test study on the suitability and potential of quantitative evaluation for the development of shallow geothermal energy in large scale urban space is carried out.This study has an enlightening value to predict and identify the suitable area and project type of shallow geothermal development and make development plans and policies.The main research results include:1.Combing typical types of constructions and the urban space morphology of constructions in heating and cooling load and explaining construction types and volume rate can be the main indicators to evaluate the demand side potential of urban shallow layer geotemermal energy at the macroscopic.2.Analysis of the urban elements of spatial entities,like buildings,green spaces,plazas and open spaces,roads,etc.,built stage and morphological characteristics of effects of immersed tubes,and horizontal and vertical buried pipe mode selection,buried pipe drill hole layout and bundle methods,geological effects of buried pipe.The evaluation parameters are given,and the calculation model and method of heat transfer are selected.3.Based on the supply-demand ratio index and the evaluation unit of urban construction land,the quantitative evaluation model and framework of the effective development potential of shallow geothermal energy in large scale urban space can be constructed4.Based on spatial form and the supply-demand ratio index,this research measures and analyzes demand-supply balance of shallow geothermal energy in several typical space.The results show that: 1)The plane combination form of constructions has little effect on the shallow geothermal energy supply capacity.2)With the increase of construction density,the supply-demand ratio decrease gradually;3)With the increase of volume rate,the supply-demand ratio significantly reduces.The results above indicate that the main factors that affect the development of urban shallow geothermal energy are spatial intensity index and spatial shape scale suitability.5.Based on spatial factors classification and supply-demand ratio coupling index evaluation method,this research takes Xicheng District of Beijing City as an example,conducting scenario prediction of geotemermal energy in large scale space.