Experimental Study, Modelling and Design of High-Temperature Ground Thermal Energy Storage for Achieving Energy Efficient Building Energy Systems

蓄热系统是提高能源效率和节约能源的一项关键技术。它通常有助于减少系统中热能需求和供应之间的不匹配，从而提高其效率。因此，在建筑物、后院或前院下随时可用的地面热能储存（GTES）可以在未来应对气候变化、减少化石燃料消耗和提高可再生能源利用方面发挥重要作用。这项技术还可以通过区域供热系统扩展到社区，就像阿尔伯塔省奥科托克市独一无二的德雷克着陆太阳能社区一样。在这里，自2007年以来，通过回收夏季从高温（高达80摄氏度）地面热能储存中储存的太阳能，满足了52户住宅90%的居住空间供暖需求。这相当于每户每年减少约39吉焦的供暖能源（或1,050立方米天然气）和2吨温室气体排放。为了在加拿大和世界范围内广泛使用这种技术，需要一种可靠的工具来模拟和设计一种最节能、最经济的优化系统。所提出的研究将开发出这样一个可靠而强大的计算机软件工具。该软件程序将能够模拟地下热和水耦合运动的复杂性质，以及地面热交换器周围相变材料（pcm）的相变过程，从而实现适当的地面热能储存系统的规模-即能够匹配需求（例如建筑物供暖）和供应(例如：太阳能（来自太阳能集热器）的热能典型使用寿命为20年或更长。为了实现这一目标，将需要实验和建模工作来验证或模拟土壤中热湿耦合运动和土壤热特性的理论。一旦开发和验证，所有模型将被实施到一个计算机程序中，用于研究不同的GTES系统，包括地源热泵（GSHP）、混合GSHP和高温GTES系统。

A key technology in energy efficiency and conservation is a thermal energy storage system. It often helps to reduce the mismatch between demand and supply of thermal energy in a system, thereby improving its efficiency. Thus, a ground thermal energy storage (GTES), readily available under a building, backyard or front yard, can play an important role in the future to combat climate change, reduce fossil fuel consumption, and increase renewable energy utilization. The technology can also be extended to communities through district heating systems, as is the case at the one-of-a-kind Drake Landing Solar Community in Okotoks, Alberta. Here, 90% of residential space heating needs for 52 houses have been met since 2007 by retrieving solar energy stored during the summer season from a high-temperature (up to 80C) ground thermal energy store. The equivalent reduction is approximately 39 GJ of heating energy (or 1,050 m3 of natural gas) and 2 tonnes of greenhouse gas emissions per home, per year. In order to widely use such technology in Canada and the world, a reliable tool is required to simulate and design an optimized system in the most energy- and cost-efficient way. The proposed research will develop such a reliable and powerful computer software tool. The software program will have the capability to simulate the complex nature of coupled heat and water movement in the ground, as well as phase change process of phase change materials (PCMs) around ground heat exchangers, such that an appropriate sizing of a ground thermal energy storage system can be achieved - that is, it will be able to match the demand (e.g., heating for buildings) and supply (e.g., solar energy from solar collectors) of thermal energy over a typical service life of 20 years or longer. To meet this objective, experiment and modeling work will be required to validate or model the theory of coupled heat and moisture movement in soils and soil thermal properties. Once developed and validated, all the models will be implemented into a computer program for studying different GTES systems, including ground source heat pump (GSHP), hybrid GSHP, and high-temperature GTES systems.