Project Summary

Project

This project will support the decarbonisation of heat by increasing the efficiency of hybrid heat pumps ("HHP") when coupled with thermal stores through an innovative heat exchanger design, phase change material ("PCM") based thermal store and intelligent control system.

Aims

This will meet the aims of Innovation Challenge 4 by removing barriers to entry preventing consumers from accessing affordable decarbonised heating.

This is achieved by:

• Increasing the efficiency of heating incorporating thermal storage
• Increasing the energy density of thermal storage
• Reducing the proportion of gas used within hybrid systems

We will demonstrate that increasing energy efficiency and flexibility together can reduce costs decarbonised heating and improve consumer experience.

Innovation

The innovation will incorporate direct coupling of the HHP working fluid (e.g. propane) to a PCM based thermal store and intelligent control systems to optimise the performance.

By direct coupling, the energy efficiency is improved compared to a HHP and a traditional water based thermal store as the heat pump can generate heat at a lower temperature closer to end user requirements. The innovation also allows the HHP and store to be discharged in parallel, providing a boost in capacity during peak heating periods.

PCM store achieves a higher energy density compared to traditional thermal stores. This allows for either increased storage duration or smaller store footprint.

The advanced control system will optimise the operation of the HHP with storage to improve equipment performance and lifespan.

Users

The end users of the innovation will be heat consumers e.g homeowners, heat network operators etc. They require heating and hot water on demand even during extreme grid and weather events. Consumers are also becoming more discerning and want lower carbon heat, for no more cost than fossil fuelled equivalents.

By improving efficiency and optimising the sizing of the heating and storage equipment our project provides decarbonised heat at an affordable cost whilst prioritising consumer heat security.

Partners

SGN are the lead partner, bringing expertise in gas and hydrogen as well as numerous sites in urban areas.

Vital Energi are the heat network provider. They are UK market leader in district heating schemes with 83,000 homes connected.

Imperial College London will be the academic partner, having developed an integrated whole energy systems (IWES) model.

University of Birmingham (UoB) will be an academic partner specialising in phase change material.

Glasgow City Council and West Dunbartonshire Council will be Local Government partners.

Innovation Justification

Barriers to entry preventing consumers from accessing decarbonised heating are:

• On-going costs are currently higher than gas heating
• Initial investment cost is high
• Incorporating traditional thermal storage reduces efficiency
• Traditional storage has a large space requirement
• Requires complex decision making for the consumer

Innovative integration of a HHP and PCM store with intelligent controls will improve efficiency and reduce the energy requirements which will reduce the cost and timescales of installing and operating decarbonised heating.

The Innovation

The project incorporates three novel elements:

• storage of energy within a phase change material
• heat exchanger design directly transferring energy from the heat pump working fluid to the PCM
• control system to optimise and co-ordinate the operation of the 3 core elements

The project partners are not aware of a similar product which is available. There is the risk that the resulting design will be too expensive or not perform to a sufficient degree to be viable.

Knowledge Gap

The integration of the separate elements has yet to be tested. The preliminary designs and control philosophies have identified the potential benefits however the work to date has only explored limited scenarios using standard modelling. We will use advanced modelling techniques to identify the optimum equipment specification.

There are several options for both PCMs and heat pump working fluid and we have yet to identify the optimum configuration. We will carry out a detailed analysis of the options which will also take into account; upfront and lifecycle costs, sustainability, and suitability for integration with third party equipment.

The control system is yet to be developed, the project modelling will identify the operational parameters of the product. This can subsequently be used to develop the functional design specification of the product's control system.

Appropriate Counterfactual

Heating provided by modular HHP with separate sensible thermal storage:

Economic Benefits:

• Reduced equipment cost for same functionality
• Increased efficiency reduces operating costs
• Provides more heat from same energy source therefore reduces investment required in generation, transmission, and distribution reinforcement

Sustainability Benefits:

• Increases the proportion of heating from electricity, thus reducing CO2
• Allows for increased penetration of renewables by improving flexibility and efficiency

Price Control

SIF funding is the only option within price control. It wouldn't attract any other type of funding as it is research led and is risky as it requires new models and control systems to be developed and proven.

Project Benefits

Financial - future reductions in the cost of operating the network

The key metric will be installed gas capacity (MWth) of the hybrid system which is required to meet the heating demand (MWth). We expect to achieve a significant reduction in installed capacity of gas versus the counterfactual of gas only heating. This would be achieved at the point of installation with benefits to the network depending on the level of deployment.

Financial - cost savings per annum on energy bills for consumers

A key metric will be the profile of the power (MWe) and gas demands (MWth) which are required to meet the heating demand (MWth). This will form part of the study. The average heating cost of a hybrid system will be lower than gas heating once the price of electric heating becomes cheaper than gas heating. This will occur either through changes to the relative power and natural gas prices which are expected, or as a result of the switch to green hydrogen which is more expensive due to the comparative inefficiency of conversion to heat.

Environmental - carbon reduction -- direct CO2 savings per annum against a business-as-usual counterfactual

The metrics will be the ratio of heat produced from electricity versus gas. The National Grid is forecast to be Net Zero by 2035. As such there will be zero CO2 emissions attached to the heat supplied from electricity. In 2017 the average household generated 2,745 kg of CO2 emissions from heating. The full savings would be apparent after 2035 at the point of installation, subject to the status of the gas grid. Prior to this date a portion of these CO2 savings would be applicable to the power consumption.

In an all-hydrogen scenario, we estimate significant levels of hydrogen would be blue hydrogen (there is 1kg of CO2 emissions for every 1kg of blue hydrogen). The associated savings from our zero-carbon solution would be apparent after 2035 at the point of installation subject to the status of the gas grid.

New to market -- products, processes, and services

Success will be once the product is available to supply heat to customers' homes. We expect this to be in a 4-5 year time period. Initially we expect the product to be incorporated into heat networks (500+ homes connected) before being made available at scale suitable for individual domestic properties.