Underground pipe heat exchanger drilling hole refilling material

A technology of buried pipe heat exchanger and cementitious material, which is applied in the field of building materials, can solve the problems of increasing the total length of the borehole, small thermal conductivity, and increasing the thermal resistance of the borehole, so as to reduce the length of the buried pipe and improve the thermal conductivity. coefficient, the effect of improving workability

Inactive Publication Date: 2006-11-29
JIANGSU LIANZHONG CASING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the commonly used grouting backfilling materials are mostly mixed slurry of bentonite and fine sand (or cement). The thermal conductivity of this kind of backfilling is only 0.65-0.9W / m.K, and this kind of bentonite backfilling material is easy to dry, shrink and crack. Therefore, in dry areas, the thermal conductivity of this backfill material will drop very little, and the increase in contact thermal resistance due to dehydration will have a serious negative impact on heat transfer.
The use of backfill materials with poor thermal conductivity will significantly increase the thermal resistance in the borehole, resulting in an increase in the total length of the borehole required under the same conditions, which also means an increase in the initial investment and operating costs of the system

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Embodiment 1, buried pipe heat exchanger drilling backfill material weight ratio according to cementitious material 100 (wherein ordinary Portland cement (P O32.5R) 60, fly ash 40), quartz sand 213, defoamer (Organosilicon NFX) 0.1, bentonite (sodium base) 2, water reducing agent (naphthalene NF-B) 1.5. During on-site construction, add water according to 60% of the weight of the cementitious material and stir to form a slurry and inject it into the borehole of the buried pipe. Its thermal conductivity is 2.21W / (m.K), and its thermal diffusivity is 0.86mm 2 / s, specific heat 2.56MJ / (m 3 .K), consistency 10.7cm, expansion rate 0.02%, flexural strength 2.2-5.0MPa, compressive strength 4.8-20.7MPa.

Embodiment 2

[0028] Example 2, the weight ratio of buried pipe heat exchanger drilling backfill material is 100 of ordinary Portland cement (P O32.5R), 200 of quartz sand, 0.05 of defoamer (organosilicon NFX), and bentonite (sodium base) 1.1, made of water reducer (Naphthalene NF-B) 1.5. During on-site construction, add water to 50% of the weight of the cementitious material and stir to form a slurry and inject it into the borehole of the buried pipe. Its thermal conductivity is 2.19W / (m.K), and its thermal diffusivity is 0.97mm 2 / s, specific heat 2.27MJ / (m 3 .K), consistency 10.8cm, expansion rate 0.03%, flexural strength (28d) 8.2MPa, compressive strength (28d) 22.4Mpa.

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Abstract

A refiller material for the drilled hole used for the buried pipe of geothermic exchanger in geothermic air conditioner system is proportionally prepared from cementing material, quartz sand, defoaming agent, bentone, and water reducing agent. It is applied through mixing it with water in situ, and filling the mixture in said hole.

Description

technical field [0001] The invention belongs to the technical field of building materials, and in particular relates to a buried pipe backfill material used in a ground source heat pump air conditioning system. Background technique [0002] Buried pipe ground source heat pump heating and air conditioning technology is receiving more and more attention because of its energy saving and environmental protection characteristics. Backfilling is an important link in the construction process of the buried tube heat exchanger, that is, after the drilling is completed and the U-shaped tube is lowered, the backfilling material is injected into the borehole. It is between the buried pipe of the buried pipe heat exchanger and the wall of the borehole, and is used to enhance the heat exchange between the buried pipe and the surrounding rock and soil, prevent the surface water from penetrating into the ground through the borehole, and protect the groundwater from surface pollutants pollu...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B28/00C04B14/06C04B18/08
CPCC04B2111/70C04B2111/00724C04B28/02Y02W30/91C04B14/06C04B14/104C04B18/08C04B2103/302C04B2103/50
Inventor 贾立群陈卫翠方肇洪刘巧玲
Owner JIANGSU LIANZHONG CASING
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