Non Steady Analytical Models for Energy Pile Testing and Design

能源桩测试和设计的非稳态分析模型

• 批准号: EP/P001351/1
• 负责人: Fleur Loveridge
• 金额: $ 12.71万
• 依托单位: University of Leeds
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FP001351%2F1
• 关键词: Non; Steady; Analytical; Models; Energy

Europe's building stock is increasing in floor area by approximately 1% per annum. This represents an additional operational energy demand of over 4.5 million tonnes of oil equivalent, year on year. Of that energy requirement up to three quarters is related to space heating (or cooling), representing about half of total energy usage in Europe and North America. Ground source heat pumps, which can reduce the net consumption of energy for space heating by approximately 75%, can therefore play a significant and timely role in tackling the energy and carbon emissions challenge. Despite the urgent need to curb the increasing energy requirements of new buildings, the market for ground source heat pump systems faces a number of barriers to expansion. While some of the barriers are related to regulation, investment cost intensity remains an important factor. Consequently, research and development must focus on increasing energy efficiency and reducing capital costs. One route to reducing investment capital costs is through the combined use of building foundations for the heat exchanger component of the system, thereby avoiding the need for construction of special purpose heat exchangers such as boreholes. This has the potential to both reduce capital expenditure and deliver increased energy per drilled metre of the heat exchanger. Piles are the most common type of deep foundation. These are typically constructed by augering a hole which is infilled with concrete and steel reinforcement. Energy pile is the term used for a foundation pile which is equipped with heat transfer pipes to act as the heat exchanger part of a ground source heat pump system. Energy piles were first trialled in Austria in 1984, but thermal analysis and design methods have lagged substantially behind the practical application. Recent breakthroughs have shown the importance of the concrete part of the pile in storing thermal energy on a short term basis. This is significant because fluctuating operational energy demand means that a thermal steady state in the piles is rarely achieved. Despite this, most routine design approaches still characterise energy pile in terms of a steady state thermal resistance parameter. This means that any storage of energy in the concrete is neglected and the energy capacity of the system is routinely underestimated. Indeed, the steady state assumption has been shown to underestimate the potential energy saving available from energy piles by around 20%. This proposal outlines planned work which will develop new non-steady models for use with the thermal analysis of energy piles. The work will also include application of these models to in situ thermal response tests which are used to determine the thermal characteristics of the soil surrounding the pile. Hence the new models will contribute to both improved soil parameter selection and less conservative design approaches. This work is novel because there are currently no analytical models that appropriately simulate the transient behaviour of energy piles. By the introduction of appropriate non steady models this work will lead to improved and less conservative assessment of energy available from energy piles and hence increase their uptake in practice. This work is pressing because the alternative of using inappropriate steady state models will result in the under-prediction of ground source heat pump system performance and thereby inhibit uptake of this key renewable heat technology.

欧洲的建筑面积以每年约1%的速度增长。这意味着每年额外的运营能源需求超过450万吨油当量。其中高达四分之三的能源需求与空间供暖(或制冷)有关，约占欧洲和北美总能源使用量的一半。因此，地源热泵可以将空间供暖的能源净消耗减少约75%，因此可以在应对能源和碳排放挑战方面发挥重要和及时的作用。尽管迫切需要抑制新建筑日益增长的能源需求，但地源热泵系统的市场面临着许多扩展障碍。尽管一些障碍与监管有关，但投资成本强度仍是一个重要因素。因此，研发必须把重点放在提高能源效率和降低资本成本上。降低投资资本成本的一个途径是综合使用系统的热交换器组件的建筑基础，从而避免建造特殊用途的热交换器，如钻孔。这既有可能减少资本支出，又有可能增加热交换器每钻米的能量。桩是最常见的深基础类型。这些通常是通过增加一个填满混凝土和钢筋的洞来建造的。能量桩是指在地源热泵系统中安装换热管作为换热器部分的基桩。能量堆于1984年在奥地利首次试验，但热分析和设计方法远远落后于实际应用。最近的突破表明了桩的混凝土部分在短期储存热能方面的重要性。这一点很重要，因为波动的运行能量需求意味着堆中的热稳定状态很少实现。尽管如此，大多数常规的设计方法仍然以稳态热阻参数来描述能量堆。这意味着混凝土中的任何能量储存都被忽视了，系统的能量容量经常被低估。事实上，稳态假设已被证明低估了能源堆潜在的节能20%左右。该提案概述了计划中的工作，这些工作将开发新的非稳态模型，用于能量堆的热分析。这项工作还将包括将这些模型应用于现场热响应测试，以确定桩周围土壤的热特性。因此，新的模型将有助于改进土壤参数的选择和不那么保守的设计方法。这项工作是新颖的，因为目前还没有合适的分析模型来模拟能量堆的暂态行为。通过引入适当的非稳态模型，这项工作将导致对能量堆可用能量的改进和不那么保守的评估，从而增加它们在实践中的吸收。这项工作迫在眉睫，因为替代使用不适当的稳态模型将导致对地源热泵系统性能的低估，从而抑制这一关键的可再生热技术的吸收。

项目成果

Energy Geotechnics - SEG-2018

能源岩土工程 - SEG-2018

• DOI: 10.1007/978-3-319-99670-7_1
• 发表时间: 2019
• 作者: Woodman N

A fast approximate method for simulating thermal pile heat exchangers

热电堆换热器模拟的快速近似方法

• DOI: 10.1016/j.gete.2022.100368
• 发表时间: 2022
• 期刊: Geomechanics for Energy and the Environment
• 影响因子: 5.1
• 作者: Loveridge F