Advanced hybrid thermochemical-compression seasonal solar energy storage and heat pump system (Solar S&HP)

Lead Research Organisation: Durham University
Department Name: Engineering

Abstract

Solar energy can provide both electricity and heat without greenhouse gas emissions. The amount of solar radiation incident on the roof of a typical UK home still exceeds its heating demand over the year. However, there is only 1% of renewable heat from solar currently exploited in the UK. The paramount reason for that is the seasonal mismatch between heating demand and solar thermal energy availability and the lack of extensive deployment of thermal energy storage in the UK. Secondly, because of relatively weak solar radiation being far away from equator leads to relatively low temperature heat using the existing solar thermal collectors, particularly during periods outside summer. In this case, it is imperative to develop a seasonal solar energy storage that can effectively store abundant but relatively low temperature solar heat in summer and utilise this at the desired temperature for space and hot water heating in winter, so that 100% solar fraction can be used for space and hot water 'zero-carbon' heating.
Thermochemical sorption energy storage technology offers higher energy density with minimum loss due to the temperature-independent means of storage, storing energy as chemical potential. However, its desorption temperature (i.e. temperature of the energy charging process) is relatively high, which makes it problematic to recover solar energy in high-latitude regions like the UK when using the most mature and economic solar thermal collector technology (flat-plate or evacuated tube type). Therefore, an advanced hybrid thermochemical sorption and vapour compression processes is proposed in this project, the integration of the electric-driven compressor, using a small amount of electricity input, enables a large amount of low or ultra-low temperature solar heat (<50 degC) to be efficiently used for thermochemical desorption, leading to enhance the efficiency, capability and flexibility of solar energy storage and heat pumping (Solar S&HP). Since such a hybrid system utilises thermal energy and electric energy simultaneously, it is a win-win solution when it couples with a solar hybrid thermal-photovoltaic (T-PV) collector. The solar T/PV collector supplies the hybrid storage system with solar heat and electricity, whilst the timely extraction of solar heat from the hybrid solar T-PV collector also allows the PV cell to operate at a lower temperature to increase its electrical conversion efficiency, leading to substantially improved overall solar energy conversion efficiency. Some other detailed advantages of the proposed system are, (1) the quality (thermal only) and quantity of different energy inputs (both thermal and electrical) can be adjusted to complement each other whilst storing energy so as to cope with highly variable weather conditions whilst maximising solar energy conversion. Even if solar electricity is not available, electricity from the grid in summer can be used, which has a ~15% lower carbon intensity than in winter. (2) The hybrid thermochemical cycle has a lower desorption temperature which reduces sensible heat loss from the solid sorbent and metallic reactor during the energy storage process which further increases the overall energy efficiency of storage system. (3) During thermal discharging in winter: (a) primary energy consumption for heating can be eliminated, and (b) the collective effect of thermal-driven and electric-driven heat pump processes can be used in extremely cold weather conditions. The whole SSTES system can provide heating at near zero carbon intensity, its carbon emission is approximately 92% and 85% lower comparing to gas boiler and electric heat pump technology, as revealed by the preliminary calculation results.

Planned Impact

The success of this project will eventually establish a reliable technology to achieve sustainable and 'zero carbon' heating technology. The transformative nature of the proposed technology will benefit across multiply sectors and potentially transform the landscape of the UK heat market through its interdisciplinary research and significant stakeholder engagement with project partners, e.g. the world's largest electric heating manufacturer Glen Dimplex, the internationally leading buildings and environment consultancy Arup and the Local Authority Eastbourne Borough Council who is pioneering local energy systems' ownership and management. Industrial forums and Impact Event will be organised to disseminate research outcomes and promote commercialisation of the technology. This will be under the support of Durham Energy Institute(DEI) and will be used by Project Management Committee to engage with relevant industry partners and other stakeholders to provide overarching guidance, valuable technical information and exploitation.
1) Government and policy makers: These beneficiaries need economically and technically viable solutions for mitigating carbon emissions whilst safeguarding energy security, industrial productivity and competitiveness, and jobs in the UK. Evidence produced in this project will support the development of policies which could result in greater use of renewable energy for energy demand reduction.
2) Society and environment: Technology proposed in this project will support the UK achieving its legally binding carbon emission reduction target. Ultimately, consumers will benefit from a marketplace which includes low cost, low carbon and low fuel consumption heating technologies.
3) UK industries: Research results will have a direct, immediate relevance to a range of UK industries who are working on energy storage, domestic heating and solar thermal technologies. In terms of market value, the upstream fuel production sector is by far the largest component of the UK's heat sector. As the leading solution to realise substituting for fossil fuel in the heat sector with renewable energy, that implicates huge market potential and investment opportunities for renewable energy. The new business opportunities arisen from this project will result in a positive industrial impact financially, commercially and environmentally.
4) The national and international research community will benefit from this project through the planed journal publications, and these benefits will be enhanced via close engagement with relevant EPSRC networks and planned attendance at leading academic conferences and workshops.
5) PRDAs and PhD students: Activities associated with exploitation, application, communication, engagement and collaboration will benefit the project's PRDAs and relevant PhD students by developing their capacity and skills and supporting their development towards becoming independent researchers. In close collaboration with all project partners, the researchers will be also given the opportunity to understand the current and future challenges of low carbon heating, and to develop specialist knowledge and skills in the multidisciplinary research fields, which expands across mechanical, chemical, control technologies and economic-environmental appraise.
 
Description The project has discovered that the integration of compressor into a conventional ammonia thermochemical system enables the maximum solar fractoin for space heating. The study shows that the Solar S&HP system can entirely cover the space heating demand of a typical UK dwelling without relying on any backup heater when using the low-temperature heating facility. Additionally, the study shows that the efficacy of the Solar S&HP system in fulfilling the space heating demand of a dwelling depends on the feed temperature level of the heating facilities. Lower operating temperatures result in the less frequent use of the backup heater and a higher share of solar energy to supply space heating demands. Overall, the findings reveal that the Solar S&HP system has great potential to reduce the reliance on non-renewable energy sources for space heating in residential buildings even for high-latitude regions, such as the UK, where relatively limited solar energy is available.
The best design of ammonia thermochemical system has been established, including optimal material manufacturing process, material loading process, heat exchanger design, compressor type and thermodynamic cycle. A near commerical prototype has been designed and constructed.
Exploitation Route Part of outcomes have been published in international journal, 2 more maunscripts are under peer review.
Majority of outcomes have been disseminated through workshops, EPSRC heating and cooling network events and social media to wide publics.
Sectors Energy

 
Description A case study and consultant activity are ongoing about using the technology developed in this project to do waste heat recovery from a producer of forged and cast steel rolls (Union Electric Steel UK Ltd) in Gateshead.
First Year Of Impact 2024
Sector Energy
Impact Types Policy & public services

 
Description Whitepaper for European Energy Research Alliance
Geographic Reach Europe 
Policy Influence Type Contribution to new or improved professional practice
Impact More than 100 people attended the launching event. A significant portion of audients shifted their perceptions on industrial TES to 'very important' and began to think about 'deployment of TES instead of battery storage'.
 
Description Geothermal Energy from Mines and Solar-Geothermal heat (GEMS)
Amount £1,421,760 (GBP)
Funding ID EP/V042564/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 08/2021 
End 08/2024
 
Description Tx Cooling Heat Exchanger Cooling of Tx's in Urban Locations
Amount £10,000 (GBP)
Organisation Northern Powergrid 
Sector Private
Country United Kingdom
Start 06/2022 
End 06/2024
 
Title Combined IDEAS+ and Solar S&HP (Discharging only) Model 
Description This model in MATLAB and Simulink combines the IDEAS+ building model with the Solar S&HP discharging model to simulate the energy demand in the winter months being met by the Solar S&HP model. The building being simulated is a standard SAP insulated house. 
Type Of Material Computer model/algorithm 
Year Produced 2023 
Provided To Others? No  
Impact The combination of the two models now allows for the assessment of how well the Solar S&HP model performs to meet the heat energy demand of a given building. 
 
Title IDEAS+ Model 
Description The IDEAS+ model is a continuation of the Inverse Dynamics based Energy Assessment and Simulation (IDEAS) model. The IDEAS model was originally developed as a building physics model to simulate the heating energy demand of a space and the updated model, IDEAS+, now has a new thermal comfort algorithm to better assess the heating requirement of the space. 
Type Of Material Computer model/algorithm 
Year Produced 2023 
Provided To Others? No  
Impact The new IDEAS+ model was presented at the 9th Smart Energy Systems International Conference in Copenhagen, Denmark and has subsequently been requested to be developed into a journal paper. 
 
Title Simulation tool for ammonia adsorption 
Description A simulation tool was developed for ammonia adsorption in a finned-tube reactor. 
Type Of Material Computer model/algorithm 
Year Produced 2023 
Provided To Others? No  
Impact This simulation allows the investigation on a scale-up ammonia adsorption system for the purpose of energy storage and heating pump. 
 
Title Simulation tool of a Pneumatic Radial Piston expander 
Description A dynamic model of Pneumatic Radial Piston expander was developed and validated by experiments. 
Type Of Material Computer model/algorithm 
Year Produced 2023 
Provided To Others? Yes  
Impact This simulation tool is a validated tool for Pneumatic Radial Piston expandert, the simulation method has been published in an open acess journal. 
URL https://doi.org/10.3390/en16041954
 
Title Simulation tool of an Oscillating Diaphragm Compressor 
Description A dynamic model was developed for an Oscillating Diaphragm Compressor which has been validated by experiment. 
Type Of Material Computer model/algorithm 
Year Produced 2023 
Provided To Others? Yes  
Impact The simulation method has been published in an open access journal. 
URL https://doi.org/10.3390/en16010489
 
Description Company visit and presentation 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact Three people from Wah Kwong Shipping (Hongkong) came to Durham University, Dr Zhiwei Ma gave a presentation about sorption research at Durham University. Potential collaboration on using sorption techology to recover waste heat from energy system in ships are under discussion.
Year(s) Of Engagement Activity 2024
 
Description Decarbonising Heat Knowledge Share and Networking 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact More than 50 academics attended this workshop to discuss 'decarbonisation of heating and cooling'
Year(s) Of Engagement Activity 2021
 
Description Durham Energy Institute Westminster Heating and Cooling Event 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Policymakers/politicians
Results and Impact The technology developed in this project was presented in a event organised by Durham Energy Institute in Portcullis House, Westminster. MPs were invited and came to attend this event.
Year(s) Of Engagement Activity 2023
 
Description Heating and Cooling network 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Research dissemination through EPSRC Heating and Cooling Network
Year(s) Of Engagement Activity 2023
 
Description Presentation at the 9th Smart Energy Systems- International Conference in Copenhagen (Denmark) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact A presentation was given to introduce the updated Inverse Dynamics based Energy Assessment and Simulation (IDEAS+) methodology which is a building physics model for modelling the heating requirement of a space. The updated model includes a new thermal comfort algorithm to better assess the heating requirement of a space. The conference overall had around 300 attendees but my talk was received by around 40-50 attendees from business and academia. The presentation has subsequently been asked to be developed into a journal paper which is currently in development.
Year(s) Of Engagement Activity 2023
 
Description Renewable Energy Conference 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Participant an international conference about renewable energy in China.
Year(s) Of Engagement Activity 2023
 
Description Talks to MPs at Portcullis House 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Policymakers/politicians
Results and Impact Project team dissiminate the soprtion technology to MPs and industries at Portcullis House in an event organised by Durham Energy Institute.
Year(s) Of Engagement Activity 2023
 
Description UK-China energy storage workshop 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Research dissemination between UK and China academics on the topic of 'Thermochemcial energy storage'
Year(s) Of Engagement Activity 2022
 
Description Univesity visit and knowledge exchange 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact PI was invited by a colleague in Tianjin University to visit their thermal energy lab and give a talk to them about sorption researchs at Durham University.
Year(s) Of Engagement Activity 2023
 
Description Whitepaper launching 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact Research team led a whitepaper writing on industrial thermal energy storage for European Energy Research Alliance with other four EU research institutes. The whitepaper was launched in Dec 2022 with live TV webinaer with more than 100 audiences.
Year(s) Of Engagement Activity 2022