碳中和下低温地热水资源利用技术研究

Research on utilization technology of low temperature geothermal water resources under carbon neutrality

在我国明确提出“碳中和”目标与清洁取暖背景之下,利用低碳能源进行建筑供暖是必然趋势。为探索改造既有建筑燃煤锅炉供暖为低温水热型地热资源供暖的可行性,以陕西某县城老城区为例,结合低温水热型地热能的特点进行了细化设计。通过分析既有建筑群冬季采暖热需求,初步确定采暖设计供/回水温度,对比了单级离心式热泵机组并联系统和两级螺杆式热泵机组串联系统设计。随后,对“小温差,大流量”的并联系统和“大温差,小流量”的串联系统进行了技术经济对比,串联系统比并联系统运行能效高8.1%,增量投资收益率为22.6%。进一步分析了冷凝燃气锅炉作为热源调峰的必要性。研究可为其他地区的既有建筑供暖改造提供技术参考。

Under the background of my country′s clear goal of"carbon neutrality"and clean heating,the use of low-carbon energy for building heating is an inevitable trend.In order to explore the feasibility of transforming the heating of existing coal-fired boilers into low-temperature hydrothermal geothermal resources,taking the old urban area of a county in Shaanxi as an example,a detailed design was carried out in combination with the characteristics of low-temperature hydrothermal geothermal energy.By analyzing the heating demand of the existing buildings in winter,the heating design supply/return water temperature was preliminarily determined,and the design of the single-stage centrifugal heat pump unit parallel system and the two-stage screw heat pump unit series system design were compared.Then,a technical and economic comparison was made between the parallel system of"small temperature difference,large flow"and the series system of"large temperature difference,small flow".The operating energy efficiency of the series system was 8.1%higher than that of the parallel system,and the incremental investment rate of return was 22.6%.The necessity of condensing gas boiler as a heat source for peak regulation was further analyzed.The research could provide technical reference for the heating renovation of existing buildings in other regions.