The UK has set a target to reach net zero emissions by 2050. Heat accounts for nearly half of the UK's energy consumption. Among several possible solutions, heat pumps are considered as one of the most promising technologies for decarbonising the domestic heating sector. Among all heat pumps, air source heat pumps (ASHP) are the most cost-effective option for householders. the Committee on Climate Change (CCC) recommends mass deployment of heat pumps to comply with the net zero target, and their net zero 'Further Ambition' scenario includes the deployment of 19 million heat pumps in homes by 2050. However, the uptake of heat pumps in the UK is very low at present. In 2018, heat pump sales in the UK were around 27,000 units (most are ASHPs), significantly lower than other EU countries. This represents a grand challenge for the government, industry, business, and research communities. There are a number of technological and non-technological barriers hindering the wide uptake of heat pumps, particularly air source heat pumps in the UK. There is a mismatch between the current ASHP products and the existing infrastructure and property configuration. Over 80% of houses in the UK use gas boilers for space heating, so their heat emitters (i.e., radiators) are designed for high temperature heat supply using gas boilers. However, most ASHPs available in the market have a relatively low heat production temperature. Secondly, ASHPs are vulnerable to ambient conditions. Their heating capacity and coefficient of performance drop dramatically as the ambient air temperature falls. Furthermore, frost starts to build up at the surface of the outdoor unit when the air temperature drops to around 6 C, so the outdoor units have to be regularly defrosted. Non-technical barriers have also played an important role behind the low uptake of heat pumps. The current UK heat pump market suffers from high capital cost and a low awareness of the product. This project, based on the PI's pending patent (Application number: 2015531.3), aims to develop a novel flexible, multi-mode air source heat pump (ASHP). This offers energy-free defrosting and is capable of continuous heating during frosting, thus eliminating the backup heater that is required by current ASHPs. We will address the key technical and non-technical challenges through interdisciplinary innovations. Our project is also supported by leading industrial companies with substantial contributions (e.g. the compressor). The developed technology offers energy-free defrosting and can be operated at different modes to benefit from off-peak electricity and/or warm air during the daytime. It will be much more energy-efficient than the current products, and thus could facilitate rapid uptake of air source heat pumps, making an important contribution to the decarbonisation of the domestic heating sector in the UK.

The cooling sector currently consumes around 14% of the UK's electricity and emits around 10% of the UK's greenhouse gases. Global electricity demand for space cooling alone is forecast to triple by 2050. Moreover, as air temperature increases, the cooling demand increases, but a refrigerator's Coefficient of Performance decreases. This results in a time mismatch between a refrigerator's efficient operation and peak cooling demand over a day. Clearly, this problem will deteriorate over the coming decades. Indeed, research by UKERC recently reported that cooling sector will cause a 7 GW peak power demand to the grid by 2050 in the UK. A solution is to employ cold thermal energy storage, which allows much more flexible refrigeration operation, thereby resulting in improved refrigeration efficiency and reduced peak power demand. Large-scale deployment of cold thermal energy storage could dramatically reduce this peak demand, mitigating its impact to the grid. Moreover, the UK curtails large amounts of wind power due to network constraints. For example, over 3.6TWh of wind energy in total was curtailed on 75% of days in 2020. Therefore, through flattening energy demand, cold thermal energy storage technology provides a means to use off-peak wind power to charge cold thermal energy storage for peak daytime cooling demand. This project, based on the proposed novel adsorption-compression thermodynamic cycle, aims to develop an innovative hybrid technology for both refrigeration and cold thermal energy storage at sub-zero temperatures. The resultant cold thermal energy storage system is fully integrated within the refrigerator and potentially has significantly higher power density and energy density than current technologies, providing a disruptive new solution for large scale cold thermal energy storage. The developed technology can utilise off-peak or curtailed electricity to shave the peak power demand of large refrigeration plants and district cooling networks, and thus mitigates the impacts of the cooling sector on the grid and also reduces operational costs.

The UK has set a target to cut its greenhouse gas emissions by at least 80% by 2050, relative to 1990 levels. To achieve this target, a reduction in energy consumption of around 40% will be required, and therefore significant improvements in energy efficiency are necessary. Energy recovery from industrial waste heat sources is considered to offer a significant contribution to improving overall energy efficiency in the energy-intensive industrial sectors. In the UK, a report recently published by the Department of Energy & Climate Change (DECC) identified 48 TWh/yr of industrial waste heat sources, equivalent to around one sixth of UK industrial energy consumption. Although waste heat recovery is broadly welcomed by industry, there is a lack of implementation of waste heat recovery systems in UK industrial sectors due to a number of barriers, the most important being poor efficiency. The forecast for global waste heat recovery systems market value is growth to 53 billion US Dollar by 2018, with a compound annual growth rate of 6.5% from 2013 to 2018. Needless to say, there is a huge national and global market for innovative waste heat recovery technologies. Although there are several alternative technologies (at different stages of development) for waste heat recovery, such as heat exchanger, heat pump, Stirling engine and Kalina Cycle power plant, the Organic Rankine Cycle system remains the most promising in practice. Large Organic Rankine Cycle systems are commercially viable for high-temperature applications, however, their application to low-temperature waste heat (<250 Degree C) is in its infancy. Yet more than 60% of UK industrial waste heat sources are in the low temperature band (<250 Degree C). There is clearly a mismatch between Organic Rankine Cycle technology supply and demand, so innovative research and development are highly in demand. This First Grant Scheme project, in response to the challenge of industrial waste heat recovery identified by DECC, aims to develop an innovative Dynamic Organic Rankine Cycle (ORC) system that uses a binary zeotropic mixture as the working fluid and has mechanisms in place to adjust the mixture composition dynamically during operation to match the changing heat sink temperatures, and therefore the resultant system can achieve significant higher annual average efficiencies. The preliminary research shows that a Dynamic Organic Rankine Cycle system can potentially generate over 10% more electricity from low temperature waste heat sources than a traditional one annually. The research will firstly develop a novel Dynamic Organic Rankine Cycle concept by integrating a composition adjusting mechanism into an Organic Rankine Cycle system, so that the mixture composition can be adjusted during the operation of the power plant. A steady-state numerical model will be developed to simulate and demonstrate the working principle and benefits of such a Dynamic Organic Rankine Cycle system. A dynamic numerical model will then be developed to simulate and optimise the control strategy of mixture composition adjustment. Finally, a prototype of such Dynamic Organic Cycle system will be designed and constructed. The Dynamic Organic Rankine Cycle concept and the two numerical models will be validated through a comprehensive experimental research. The Dynamic Organic Rankine Cycle power plants developed through this project can be widely applied to energy intensive industrial sectors such as the iron and steel industry, ceramic manufacturers, cement factories, food industrial, etc. As such power plants can achieve a much higher efficiency; the payback period can be significantly reduced, which would make energy recovery from industrial waste heat sources more profitable. The wide installation of such waste recovery power plants will ultimately reduce the energy demand of these industrial sectors, and therefore improve our energy security.

The provision of cold is a vital foundation of modern society to underpins many aspects of modern life, consumes up to 14% of the UK's electricity, and is also responsible for around 10% of UK's greenhouse gas emissions, including both CO2 associated with their power consumption and leakage of refrigerants with high Global Warming Potential (GWP). In order to achieve net-zero emission target in 2050 in the UK, we must significantly decarbonise the cooling sector. The decarbonisation of the cooling section requires to tackle two key challenges. Firstly, the leakage of traditional, refrigerants with high GWP is a key issue of the greenhouse gas emission of the cooling sector. It is, therefore, necessary to substitute them with low GWP natural refrigerant such as CO2. Secondly, the high-power consumption of the cooling sector also results in greenhouse gas emission if non-renewable power is consumed. Hence, cost-effective cold storage capacity will need to be deployed to maximise the use of intermittent renewable energy and cheap off-peak electricity. The recent study concluded that the addition of cold storage can potentially provide a 43% decrease in peak period consumption. In response to the challenges identified above, this project aims to develop a novel integrated system for cold energy generation and storage using CO2 hydrate as both refrigerant and storage material, contributing to the decarbonisation of the cooling sector in the UK and more widely the global. The multidisciplinary consortium, consisting of six leading researchers from the Universities of Birmingham, Glasgow and Heriot-Watt, processes a wide range of well-balanced expertise including chemical engineering, thermodynamics, heat transfer, CFD, and economics to address several key scientific and technical challenges, and is further supported by several leading industrial partners to maximise knowledge exchange and impact delivery.

The UK has set a target to reach net zero emissions by 2050. Heat accounts for nearly half of the UK's energy consumption. Among several possible solutions, heat pumps are considered as one of the most promising technologies for decarbonising the domestic heating sector. Among all heat pumps, air source heat pumps (ASHP) are the most cost-effective option for householders. the Committee on Climate Change (CCC) recommends mass deployment of heat pumps to comply with the net zero target, and their net zero 'Further Ambition' scenario includes the deployment of 19 million heat pumps in homes by 2050. However, the uptake of heat pumps in the UK is very low at present. In 2018, heat pump sales in the UK were around 27,000 units (most are ASHPs), significantly lower than other EU countries. This represents a grand challenge for the government, industry, business, and research communities. There are a number of technological and non-technological barriers hindering the wide uptake of heat pumps, particularly air source heat pumps in the UK. There is a mismatch between the current ASHP products and the existing infrastructure and property configuration. Over 80% of houses in the UK use gas boilers for space heating, so their heat emitters (i.e., radiators) are designed for high temperature heat supply using gas boilers. However, most ASHPs available in the market have a relatively low heat production temperature. Secondly, ASHPs are vulnerable to ambient conditions. Their heating capacity and coefficient of performance drop dramatically as the ambient air temperature falls. Furthermore, frost starts to build up at the surface of the outdoor unit when the air temperature drops to around 6 C, so the outdoor units have to be regularly defrosted. Non-technical barriers have also played an important role behind the low uptake of heat pumps. The current UK heat pump market suffers from high capital cost and a low awareness of the product. This project, based on the PI's pending patent (Application number: 2015531.3), aims to develop a novel flexible, multi-mode air source heat pump (ASHP). This offers energy-free defrosting and is capable of continuous heating during frosting, thus eliminating the backup heater that is required by current ASHPs. We will address the key technical and non-technical challenges through interdisciplinary innovations. Our project is also supported by leading industrial companies with substantial contributions (e.g. the compressor). The developed technology offers energy-free defrosting and can be operated at different modes to benefit from off-peak electricity and/or warm air during the daytime. It will be much more energy-efficient than the current products, and thus could facilitate rapid uptake of air source heat pumps, making an important contribution to the decarbonisation of the domestic heating sector in the UK.