Heat Pump Fully Integrated with Thermochemical Store (HP-FITS)

利用可再生电力对建筑（包括住宅和商业建筑）脱碳热量的贡献是众所周知的，也很容易理解。然而，如果认为有足够的风力涡轮机、光伏板等来生产可再生电力，有足够的电热泵来为家庭和其他建筑供暖，问题就会得到解决，那就太简单化了。即使使用非常高效的热泵，冬季早晨的峰值电力负荷可能是目前电网和配电系统容量的2到3倍，这还不包括同时为未来预期的大量电动汽车充电的影响。由于脱碳气体（无论是氢气还是沼气）在新的或重新利用的燃气网中的可能性，电网的部分增强等，问题变得更加复杂。缓解这些问题的可能方法包括电力和热储存，以管理峰值负荷，无论是在消费者层面还是更集中的层面。这一建议集中在热存储上，每兆焦耳的成本比电力存储低很多倍。这个概念是将热量储存在消费者的（家庭或商业）热泵中，以便热泵可以在对系统最有利的时候运行，即当有剩余的可再生电力（主要是风能和光伏）时。当对可再生电力的需求较高或可用性较低时，从存储中提取热量。这里我们考虑的存储时间是小时到一天，而不是周或跨季节。这本身并不是一个新想法，但提出良好解决方案的尝试遇到了一些仍有待解决的挑战。阿尔斯特大学的休伊特教授使用了一个传统的热泵，该热泵与一个热水库相连，为一个（被占用的）测试房提供热水。该系统使用来自北爱尔兰电网的信号（该电网拥有很高比例的风力发电能力），通过算法运行，当用户的电力成本反映了可变的生产成本时，该算法将在未来被使用。这为系统运行和控制提供了宝贵的经验，但总体性能受到存储热损失和商用热泵在温度输出和调节方面的限制的阻碍。我们将在一个集成的封装中使用新颖的存储、热泵和控制系统，这将展示如何为用户和国家能源供应基础设施实现能源和经济效益：热存储将基于一种新的热化学吸收系统，该系统可以在接近环境温度的情况下将所需的热量存储在更小、低损耗的封装中。热泵将结合最佳实践，在复杂的经济蒸汽喷射（EVI）循环中使用变速压缩机，以在60℃下输送热量时实现5的性能系数（COP =热量输出/电力输入）。控制策略将包括电网状态和热泵、存储和房屋负荷模型的预测时变电价，以确保成本效益与低排放相结合。完整的集成系统将在阿尔斯特大学的“露台屋”中展示；这是一座新建筑，但建于20世纪初的露台，以促进旧建筑中新技术的改造，同时由“真实”的人居住。

The contribution to decarbonising heat in buildings (both domestic and commercial) when utilising renewable electricity are well known and easy to appreciate. However, it is simplistic to think that with enough wind turbines, PV panels, etc. to produce renewable electricity and enough electric heat pumps to heat homes and other buildings that the problem will be solved.Even with very efficient heat pumps the peak electricity load on a Winter's morning might be 2 or 3 times the present grid and distribution system capacity and this does not include the effect of simultaneously charging the large number of electric vehicles expected in the future. The problem is complicated by the possibility of decarbonised gas (whether hydrogen or biogas) in a new or repurposed gas grid, partial enhancement of the electricity grid, etc.Possible ways to mitigate these problems will include both electricity and thermal storage to manage peak loads, either at consumer level or more centralised. This proposal concentrates on heat storage, which is many times less costly per MJ that electricity storage. The concept is to store heat at the consumer's (domestic or commercial) heat pump so that the heat pump can operate when most advantageous to the system, i.e. when there is surplus renewable electricity (predominantly wind and PV). Heat is drawn from the store when there is a higher demand for or lower availability of renewable electricity. Here we consider storage times of hours to a day, but not weeks or inter-seasonally.This is not a new idea in itself but attempts to come up with good solutions have met a number of challenges still to be solved. Prof Hewitt at Ulster has used a conventional heat pump linked to a hot water store supplying an (occupied) test house. Using signals from the Northern Ireland grid (which has a high proportion of wind capacity) the system has been operated using algorithms that would be utilised in future when the cost of electricity to the user reflected the variable production costs. This provided valuable experience in system operation and control but the overall performance was hampered by store heat losses and the limitations of the commercially available heat pump in terms of temperature output and modulation. We will use novel storage, heat pump and control systems in an integrated package that will demonstrate how both energy and economic benefits to the user and the national energy supply infrastructure can be achieved: Heat storage will be based on a new thermochemical absorption system that can store the required heat in a much smaller and low-loss package at close to ambient temperature. The heat pump will combine best practice with using a variable speed compressor in a sophisticated Economised Vapour Injection (EVI) cycle to achieve a Coefficient Of Performance (COP = Heat out / Electricity in) of 5 when delivering heat at 60 C. The control strategy will encompass the state of the grid and predicted time-variable tariffs with heat pump, store and house load models to ensure cost effectiveness combined with low emissions.The complete integrated system will be demonstrated in Ulster University's 'Terrace House'; a new building but built as an early 1900s terrace to facilitate retrofitting of new technology in old buildings whilst occupied by 'real' people.