Mitigation potential of horizontal Ground Coupled Heat Pumps for current and future climatic conditions: UK environmental modelling studies

这是决策者的主要优先事项，以减少化石碳的燃烧，从而减缓地球大气中二氧化碳浓度的增加。英国在研究可再生能源方面做出了相当大的努力，如风能、海洋能和太阳能，以及生物能。然而，相对较少的工作已经进行的主题，地面耦合热泵系统（GCHP），一个相对未充分利用的技术在英国，相比之下，其他国家，如美国，瑞士和瑞典。简单地说，GCHP利用（土壤和空气之间的）温差来提供空间供暖。增加对替代性低或非二氧化碳排放能源的吸收是冬季和夏季降温之一。这是通过在地下放置塑料管（充满含有防冻剂的流体）来实现的，这样它们就可以与土壤交换热量，所谓的热交换器。这种热量通过热泵“升级”为家庭或其他建筑物供暖，从而提供可持续，可再生和可靠的能源。这些GCHP的性能取决于热交换器的设计和配置（例如管道长度、安装深度、管道间距）。然而，与更昂贵的垂直钻孔系统相比，水平安装系统的性能也以相当复杂的方式受到环境的影响。我们的意思是土壤，植被和大气条件，这将显着不同，在英国和随着时间的推移（昼夜，季节和年际变化）。本提案中描述的研究旨在调查这些系统的长期（约50年，GCHP系统的平均寿命）性能在整个英国的变化。我们的研究结果将成为向地方政府（和用户）提出建议的基础，这些建议涉及这些系统的位置依赖性经济可行性及其减少碳排放的潜力，同时明确考虑到我们的气候正在以显著的速度变化。此外，根据从地面带走和返回地面的热量之间的平衡，热交换器附近的土壤温度可能下降或上升;与此相关的是土壤水分远离或朝向热交换器的运动。这些过程也将影响系统在其寿命期内的性能。土壤和GCHP之间的这些复杂的相互作用可以通过计算机模型模拟来模拟，并且GCHP设计人员和安装人员可以使用各种软件包。然而，这些类型的软件已经被开发为在逐站点的基础上工作，并且它们简化了环境的影响。此外，它们只涉及短时间跨度（约1-3年）。在本提案中，我们将使用详细的地表模型，例如英国气象局用于预测天气的模型。首先，我们将对其进行改进，以确保考虑地下热交换器和土壤（热量和水分流动，包括地下水）之间的所有重要相互作用。然后，我们将对其进行测试，并随后使用长期数据驱动模型，这些数据用于代表整个英国的气候，土壤类型和植被（及相关属性）。只有这样，我们才能获得有关英国范围内GCHP系统长期性能及其在减少二氧化碳排放方面的有效性的可靠估计。这使我们能够建议在英国特定地区增加吸收，并表明如何对GCHP系统的设计和配置（例如管道类型和安装深度）进行具体更改，以提高性能，从而增加其减少CO2排放的潜力。

the key priorities for policymakers in order to decrease combustion of fossil carbon, thereby slowing the increase of CO2 concentration in the Earth's atmosphere. A considerable amount of UK effort has gone into investigating renewable energy sources such as wind, marine and solar power, as well as into bio-energy. However, relatively little work has been undertaken on the topic of ground coupled heat pump systems (GCHP), a relatively underused technology in the UK, in contrast to other countries such as USA, Switzerland and Sweden. To put it simply, GCHPs use temperature differences (between soil and air) to provide space heating An increased uptake of alternative low- or non-CO2 emitting energy sources is one of in the winter and cooling in the summer. This is achieved by placing plastic pipes (filled with fluid containing anti-freeze) in the ground so that they can exchange heat with the soil, so called heat exchangers. This heat is 'upgraded' by a heat pump to heat homes or other buildings, thereby providing a sustainable, renewable and reliable source of energy. The performance of these GCHPs depends on the design and configuration of the heat exchangers (e.g. length of pipes, depth of installation, spacing between pipes). However, the performance of horizontally installed systems, as opposed to the more expensive vertical borehole ones, is also affected, in a rather complex way, by the environment. With this we mean soil, vegetation and atmospheric conditions, which will significantly differ over the UK and over time (diurnal, seasonal and inter-annual variation). The research described in this proposal aims to investigate how the long-term (~50 years, the average lifespan of GCHP systems) performance of these systems varies throughout the UK. Our findings would form the basis of recommendations to local governments (and users) on the location-dependent economic viability of these systems and their potential to reduce carbon emissions, while explicitly taking into account that our climate is changing at a significant rate. Also, depending on the balance between how much heat is taken away from and returned to the ground, the soil temperature in the neighbourhood of the heat exchangers may fall or rise; related to this is the movement of soil moisture away from or towards the heat exchanger. These processes will also affect the performance of the system during its life span. These intricate interactions between soil and GCHP can be mimicked by computer model simulations and various packages are available for use by GCHP designers and installers. However, these types of software have been developed to work on a site-by-site basis and moreover they simplify the effect of the environment. Also, they address short time spans only (~1-3 years). In this proposal we will use a detailed land surface model, such as the one used by the UK Meteorological Office to predict the weather. First we will improve it to ensure that all important interactions between the below-ground heat exchangers and the soil (heat and moisture flow, including groundwater) are taken into account. We will then test it and subsequently drive the model with long-term data, generated to represent the climate, soil type, and vegetation (and related properties) throughout the UK. Only then can we obtain reliable estimates about the UK-wide long-term performance of GCHP systems and their effectiveness in reducing CO2 emissions. This allows us to recommend increased uptake in specific UK areas as well as indicate how specific changes to the design and configuration of GCHP systems (e.g. type of tube and installation depth) can improve performance and hence increase its potential for reduction in CO2 emission.