Abstract

The cooling of rock formations when extracting heat by a borehole heat exchanger and the restoration of the thermal field in the rock during the idle time of the well have been investigated. The heat in the rock during the summer downtime of the well is partially restored due to the influx of heat from the outside formation. The radius of the rock cooling front around the borehole in the heating period can reach 6–8 m. The temperature on the borehole wall is restored by approximately 50% in one month and by 80–85% in summer. Hybrid technology is proposed for the extraction and accumulation of thermal energy from the upper layers of the earth’s crust comprised of a shallow borehole heat exchanger, a heat pump, and solar collectors. The technology provides for both the extraction of heat from the rock during the heating period and transmission of this heat to the heating system with a heat pump and the restoration of the temperature field around the well during the interheating period by accumulating in the rock formation the heat fed to the borehole heat exchanger with hot water from the storage tank. This system was implemented in Makhachkala at the test site of the Joint Institute for High Temperatures, Russian Academy of Sciences, for supplying heat and hot water to cottage-type houses. The main components of the system are solar collectors with a total area of 20 m², a heat-insulated hot water storage tank with a built-in heat exchanger, a 15-kW heat pump, and a 100-m deep borehole heat exchanger. The test results have demonstrated high efficiency of the system for supplying heat to low-power consumers not covered by central heating.

中文翻译：

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一种混合太阳能-地热供热和热水供应系统

摘要

已经研究了通过钻孔换热器提取热量时岩层的冷却以及井闲置期间岩石中热场的恢复。由于外部地层的热量流入，夏季油井停工期间岩石中的热量部分恢复。加热期钻孔周围岩石冷却锋半径可达6～8 m。钻孔壁上的温度在一个月内恢复约 50%，夏季恢复 80-85%。混合技术被提议用于从地壳上层提取和积累热能，包括浅埋管换热器、热泵和太阳能收集器。该技术既可以在加热期间从岩石中提取热量，又可以将这些热量通过热泵传输到加热系统，并在中间加热期间通过在岩层中积累热量来恢复井周围的温度场。热量与来自储罐的热水一起输送到埋管换热器。该系统在马哈奇卡拉的俄罗斯科学院联合高温研究所试验场实施，用于向小屋型房屋供应热能和热水。该系统的主要组成部分是太阳能集热器，总面积为 20 m^{如图2所示}，内置换热器、15kW热泵和100米深埋管换热器的保温储热水罐。测试结果表明，该系统向集中供热未涵盖的低功率消费者供热的效率很高。