Active Control Method for Frost Heave Deformation of Underground Heat Exchange Tubes

Abstract

The invention discloses a method for actively controlling frost heaving deformation of an underground heat exchange pipe during operation at low temperature of below 0 DEG C. A control system comprises a heat-absorbing coiled pipe, a heat release coiled pipe, a temperature sensor, an energy storage water tank, a water separator, a water collector, a water supply valve, a water return valve, a water supply pipe, a water return pipe, a circulating pump, a communicating valve, a heat exchange well area and a controller. The temperature of anti-freezing liquid in the energy storage water tank and operation of an underground heat exchange system are controlled actively, so that the temperature of the anti-freezing liquid is changed at the temperature of below 0 DEG C in a fluctuating mode, and the underground heat exchange system operates at the temperature rising stage and stops at the temperature reducing state; intermittent operation of the heat exchange area is realized by virtue of an underground temperature patrol inspection mode, so that frost heaving of underground rock soil is slowed down, frost heaving deformation of the underground heat exchange pipe is reduced or avoided, and guarantee is provided for high-efficiency and stable operation of the system.

Description

technical field [0001] The invention belongs to the technical field of underground energy storage and utilization of ground source heat pumps, and in particular relates to the problem of frost heave deformation control of underground heat exchange pipes operating at a low temperature below 0°C. Background technique [0002] In the low-temperature cold storage of underground energy storage and the heating process of ground source heat pumps in winter, the operating conditions of underground heat exchangers below 0 °C involve the frost heave deformation of heat exchange tubes in rock and soil. For some areas with large cooling loads in summer, the temperature recovery ability of the underground heat exchange area will decrease after long-term operation, and it is necessary to reduce the ground temperature by means of cold storage. Heat exchange with a large temperature difference can greatly improve the efficiency of cold storage. During cold storage, the circulating fluid in ...

AI Technical Summary

Problems solved by technology

First of all, choosing non-frost-heave-sensitive backfill, such as sand-based and cement-based backfill, is beneficial to reduce frost heave, but this method will not only increase the construction investment, but also cause adverse effects due to the different properties of the backfill and the underground geotechnical material. compatibility out of question

Secondly, increasing the internal pressure of the heat exchange tube can also reduce frost heave extrusion deformation to a certain extent, but increasing the internal pressure not only increases the risk of its operation, but also reduces the service life of the buried tube

It can be seen that while taking passive measures to reduce the frost heave deformation of heat exchange tubes, it will inevitably bring certain potential hazards and restrict its long-term application.

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