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.

The purpose of the proposed research programme is to address the challenge of providing domestic hot water (DHW) using low carbon heat pump technology given the overwhelming trend away from conventional hot water tanks in homes and the inability of present heat pumps to provide instant hot water. We intend to develop a suite of heat pump / storage / control technologies, using either electricity or gas that function without conventional storage cylinders and can deliver energy efficient affordable hot water to a wide range of dwellings well into the future. Ulster will use a novel compressor being developed by industrial partner Emerson that has an exceptional range of running speeds, enabling the same device to either deliver e.g. 25 kW for instantaneous hot water or 10 kW or less for space heating. This would be used in conjunction with a small buffer store to overcome the delay in start-up before hot water is available. Present gas fired heat pumps (both commercial and under development at Warwick) are easier to modulate but are physically large if delivering 20 or 30 kW and also have a long start up time (5 minutes). The Warwick goal is to use new composite adsorbent heat exchangers to reduce start up time to one minute, even when meeting a 25 kW load and to reduce key component sizes to achieve a compact system. Thermal storage is a vital part of DHW provision by heat pumps. A small buffer store may be needed to overcome starting transients, or a large capacity store might be needed to provide a bath-full of water quickly. An intermediate capacity store might work together with a heat pump to meet peak loads. Our research will encompass buffers, compact PCM stores that could be sited in unused spaces such as corners in kitchens and 'flat' stores using vacuum or aerogel insulation that could fit under kitchen cabinets or other available unused spaces. To bring this all together into a range of integrated systems suited to different housing types etc there needs to be both an understanding of the consumer's needs and preferences plus a smart adaptive control system. In addition to data in the literature we have access to data from detailed monitoring studies previously carried out by Loughborough. Consumer preferences will be investigated by the use of surveys carried out by the User Centred Design Research Group at Loughborough Design School. Ulster will assume overall responsibility for sensor choice, control hardware and software. They will devise a system controller that adapts to and meets consumer needs in an optimal way. In the long term this will be part of a house-wide wirelessly linked system including 'wet' appliances such as dishwashers and washing machines and 'smart taps' that communicate with the DHW system so that it responds optimally to the size and type of load demanded.

Lot-NET considers how waste heat streams from industrial or other sources feeding into low temperature heat networks can combine with optimal heat pump and thermal storage technologies to meet the heating and cooling needs of UK buildings and industrial processes. Heating and cooling produces more than one third of the UK's CO2 emissions and represent about 50% of overall energy demand. BEIS have concluded that heat networks could supply up to 20% of building heat demand by 2050. Heat networks have previously used high temperature hot water to serve buildings and processes but now 4th generation networks seek to use much lower temperatures to make more sources available and reduce losses. Lot-NET will go further by integrating low temperature (LT) networks with heat pump technologies and thermal storage to maximise waste and ambient heat utilisation. There are several advantages of using LT heat networks combined with heat pumps: - They can reuse heat currently wasted from a wide variety of sources in urban environments, e.g. data centres, sewage, substation transformers, low grade industrial reject heat. - Small heat pumps at point of use can upgrade temperature for radiators with minimal electricity use and deleterious effect on the electricity grid. - Industrial high temperature waste can be 'multiplied' by thermal heat pumps increasing the energy into the LT network. - By operating the heat network at lower temperatures, system losses are reduced. Heat source availability is often time dependant. Lot-NET will overcome the challenges of time variation and how to apply smart control and implementation strategies. Thermal storage will be incorporated to reduce the peak loads on electricity networks. The wider use of LT heat networks will require appropriate regulation to support both businesses and customers and Lot-NET will both need to inform and be aware of such regulatory changes. The barrier of initial financial investment is supported by BEIS HNIP but the commercial aspects are still crucial to implementation. Thus, the aim of LoT-NET is to prove a cost-effective near-zero emissions solution for heating and cooling that realises the huge potential of waste heat and renewable energies by utilising a combination of a low-cost low-loss flexible heat distribution network together with novel input, output and storage technologies. The objectives are: 1. To develop a spatial and temporal simulation tool that can cope with dynamics, scale effects, efficiency, cost, etc. of the whole system of differing temperature heat sources, distribution network, storage and delivery technologies and will address Urban, Suburban and Exurban areas. 2. To determine the preferred combination of heat capture, storage and distribution technologies that meets system energy, environmental and cost constraints. Step change technologies such a chemical heat transport and combined heat-to-power and power-to-heat technologies will be developed. 3. To design, cost and proof of concept prototype (as appropriate) seven energy transformation technologies in the first two-three years. They consist of both electrically driven Vapour Compression and heat driven Sorption technologies. Priority for further development will be then given to those which have likely future benefits. 4. To determine key end use and business/industry requirements for timely adoption. While the Clean Growth Strategy and the Industrial Strategy Challenge Fund initially support future implementation, innovative business models will reduce costs rapidly for products or services that customers want to buy and use. Thus, engagement with stakeholders and end users to provide evidence of possible business propositions will occur. 5. To demonstrate/validate the integrated technologies applicable to chosen case studies. The range of heating, cooling, transformation and storage technologies studied will be individually laboratory tested interacting with a simulated netw