Isabel attended the Hot Water Forum 2022

April 19, 2022 Admin Dwr

Isabel Schestak

Water heating is the most energy and carbon intensive process along the domestic water chain, responsible for more carbon emissions than water supply or wastewater treatment.

The Hot Water Forum 2022, organised by the American Council for an Energy-Efficient Economy (ACEEE), brought together manufacturers, researchers and policy makers to exchange knowledge and collaborate towards a low-carbon future for water heating.

Our team member Isabel attended the virtual conference in March which informed about new technologies, best practices and case studies for domestic and commercial water heating, focusing mainly on heat pumps and solar water heating. It offered a range of live presentations and panel discussions, as well as pre-recorded sessions. Heat pumps were said to be the fastest growing renewable water heating technology.

A study by Claire Miziolek from Energy Solutions on water heating in Massachusetts forecasted heat pumps and electric water heaters to be the almost exclusive sources for hot water in 2050. Heat pump systems in many different configurations and running on different energy sources were presented, such as heat pumps suitable to run on 120V instead of 240V electricity, or heat pumps using gas or hydrogen as energy source. A case study from California showed great energy and carbon emission benefits where a heat pump was used by several apartments together instead of using an individual heat pump per apartment.

Thank you to our funders from the European Regional Development Fund for the opportunity to attend the conference!

Cross-sector Sustainability Benchmarking: Another Path to Improvement

April 4, 2022 Admin Dwr

Nathan Walker

The benefits of benchmarking are so widely understood that it is common practice in many industries to achieve ambitious goals (Castro and Frazzon, 2017), however, the challenge remains of how to compare the performance of different organisations from different sectors (Bititci et al., 2013). Companies can gain value from this by being able to identify leaders in other sectors to then begin the process of learning from them, ultimately instigating improvements in their company, dependent on what they were measuring and analysing (Cankar and Petkovsek, 2013). Similar benefits can be gained from within-sector benchmarking (Walker et al., 2021a) but by transcending sector boundaries and possibly common practice dogma, companies have the possibility to learn something that could not have been garnered from peers.

We conducted research to investigate the performance of UK utilities across the water and sewage, energy, and communications sectors, and develop a methodology to compare whole companies effectively across sectors. A methodology was constructed based on service, environmental and economic metrics, and cross-sector benchmarking was undertaken which generated performance scores based on company metrics relative to sector peers. For example, if a company in the water sector performed the best for their customer service, they got a score of 5, then this score could then be compared to companies in the energy and communications sectors and their customer service scores. This approach avoided issues of indicators often being mismatched across sectors and the lack of relevance and context when sectors do use similar indicators.

Results showed that the sample of 18 utilities had two distinct clusters, one of eight sector leaders and the other of ten lower performers (Figure 1). The two distinct groups of sector leaders and lower performers can be employed to specifically identify other companies that may offer opportunities for learning. Top performers can assess top performers in other sectors to identify how they might continue improving, rather than be potentially limited within their own sectors. Conversely, lower companies can look within and across sectors to begin identifying best practices to improve their performance.

**Figure 1**. 3-D plot of company group scores with highlighted K-means clusters.

This research is under review with the journal ‘Utilities Policy’ for publication, thus a full peer-reviewed version of this research will be available in the upcoming months.

References

Bititci, U. S., Firat, S. U. O. and Garengo, P. (2013) ‘How to compare performances of firms operating in different sectors?’, Production Planning & Control: The Management of Operations, 24(12), pp. 1032-1049. doi: 10.1080/09537287.2011.643829

Cankar, S. S. and Petkovsek, V. (2013) ‘Private And Public Sector Innovation And The Importance Of Cross-Sector Collaboration’, J. Appl. Bus. Res., 29(6), pp. 1597–1606. doi: doi.org/10.19030/jabr.v29i6.8197

Castro, V.F.d. and Frazzon, E. M. (2017) ‘Benchmarking of best practices: an overview of the academic literature’, Benchmarking: An International Journal, 24(3), pp. 750-744. doi: doi.org/10.1108/BIJ-03-2016-0031

Walker, N. L., Styles, D., Gallagher, J. Williams, A. P. (2021a) ‘Aligning efficiency benchmarking with sustainable outcomes in the United Kingdom water sector’, J. Environ. Manag., 287, pp. 112317. doi: 10.1016/j.jenvman.2021.112317

Collaboration with The Rediscovery Centre: how drain water heat recovery can be part of the circular economy

March 28, 2022 Admin Dwr

Ajeet Singh

As part of our work aimed at developing a grease trap fitted with a heat exchanger to recover heat from wastewater in commercial kitchens, we monitored the grease trap at the café of the Rediscovery Centre (RDC) in Ballymun, Dublin (Ireland).

The centre is the National Centre for the Circular Economy in Ireland: a circular economy model aims at minimising waste, so why not also minimising the heat that is wasted from their commercial kitchen by reusing it?

The interest to explore opportunities to highlight the circularity of the heat embedded in wastewater arose after staff of RDC took part in one of our Sustainability Webinars on drain water heat recovery in March last year. The onsite café, equipped with a grease trap, serves food and drinks to the visitors and customers of the facility.

To assess how much heat could be recovered from the wastewater passing through the grease trap, it is necessary to know the temperature of the water over time and how much water flows through the grease trap. To monitor the water temperature, a small heat sensor (Figure 2) was placed inside the grease trap for three weeks in December 2021. The hotter the water, the greater the potential. The sensor was recovered and data was analysed to see the range of temperatures occurring within the grease trap. The maximum temperature recorded was 35.1 and the average was about 32 ; moreover, a consistent thermal gradient (difference in temperature between the wastewater entering the grease trap and the cold freshwater of the supply lines) of more than 15 was maintained during the kitchen operational hours. The number of customers served during the monitoring period has been used to estimate the amount of water that flowed through the grease trap.

The data will be used to predict the feasibility of exploiting the thermal gradient to preheat the freshwater by installing a heat exchanger, also called thermal recovery unit, in the grease trap. Next steps will include assessing the necessary pipeline arrangements to carry the pre-heated freshwater to the hot water storage tank as well as a cost-benefit analysis. If installed, the system would reduce the primary energy consumption for hot water production, saving costs and emissions (where replacing fossil fuels).

Smart Network Control Work Package - Here is what it is about

March 21, 2022 Admin Dwr

Djordje Mitrovic

Water distribution networks (WDNs) are one of the most essential infrastructure for normal functioning of the modern society. Supplying water from the sources to our taps is very energy intensive process. Leakages present in the networks further decrease the efficiency of the water supply. Leakages in WDNs do not represent only the water losses but also significant energy losses embedded in treatment and distribution (pumping) of the lost water. For perspective, on the level of EU the values of water losses span from single digit values in Germany, Denmark and Netherlands up to around 45% in Ireland, with an average of 23% (EurEau, 2017). One strategy that has been extensively used by water practitioners to control and thus reduce leakage is division of the networks in smaller sectors, so called district metered areas (DMAs) (Vicente et al., 2016). DMAs are the sectors of WDNs with defined boundaries where the flow that comes in and leaves is constantly metered for leakage monitoring. If there is excess pressure at the entrances of these sectors that is not necessary for normal operation of downstream consumers the practitioners also install pressure reduction valves (PRVs) to further reduce leakages rate as it is well known that it is a function of the pressure (van Zyl, 2014).

However, the excess pressure (i.e., excess energy) that is dissipated at the PRVs is irreversibly lost. Here in Dwr Uisce project our team investigates the potential of improving the energy efficiency of the WDNs by coupling the classical pressure management with hydropower generation. In other words, we investigate the potential of replacing (or coupling) the PRVs with hydropower turbines which would use the existing excess pressure for generation of clean renewable electricity. In terms of hydropower turbines, pumps as turbines (PATs) found to be the most suitable for this application primarily because of their significantly lower cost in comparison to the traditional turbines, which is the result of their mass production (García et al., 2019). The focus of the smart network control work package is to define algorithms for the optimal selection and control of these devices in WDNs. In addition, we investigate strategies to find the optimal number and locations within the networks for installation of these devices to maximize the energy recovery but also minimize the installation costs.

An example of PAT application in a pilot site at SMPGA's drinking water facility in St Pair sur Mer in Normandy (REDAWN Project).https://www.redawn.eu/case-study/drinking-water-networks-france

Reducing the energy consumption for water supply through the implementation of hydropower energy recovery can be one of the solutions for mitigating the impacts of the current energy crisis.

References

EurEau, 2017. Europe’s water in figures.

García, I.F., Novara, D., Mc Nabola, A., 2019. A Model for Selecting the Most Cost-Effective Pressure Control Device for More Sustainable Water Supply Networks. Water 11, 1297. https://doi.org/10.3390/w11061297

van Zyl, J.E., 2014. Theoretical Modeling of Pressure and Leakage in Water Distribution Systems. Procedia Eng. 89, 273–277. https://doi.org/10.1016/j.proeng.2014.11.187

Vicente, D.J., Garrote, L., Sánchez, R., Santillán, D., 2016. Pressure Management in Water Distribution Systems: Current Status, Proposals, and Future Trends. J. Water Resour. Plan. Manag. 142, 04015061. https://doi.org/10.1061/(ASCE)WR.1943-5452.0000589

Don’t flush money down the kitchen drain!

February 23, 2022 Admin Dwr

Isabel Schestak

Commercial kitchens in the UK hospitality and food service sector consume more energy for the preparation of meals than cooking in domestic kitchens. However, they can also play a vital role in climate change mitigation. The heat in the drain water of commercial kitchens is a valuable source of energy, which - when recovered - saves energy for hot water heating and hence carbon emissions but also costs.

The technology is simple: a heat exchanger – a double walled copper pipe – replaces a part of the kitchen’s drain, through which heat is transferred from the warm drain water to the cold incoming water. The boiler receives the pre-warmed water and requires less energy to heat the water to the desired temperature. If all food outlets in the UK were to install a heat recovery system, an estimated 500 000 tonnes of CO2 equivalent could be saved every year and make a significant contribution to a net zero hospitality sector.

For instance, a restaurant with a water consumption of 2,000 m3/year could recover approx. 16,000 kWh/year and save 4,000 kg CO2 equivalent – considering that natural gas is replaced. With a gas price of 3 p/kWh this translates to savings of about £5,000 for 10 years of operation. If the kitchen uses electricity for water heating at a rate of 14 p/kWh, heat recovery would save £22,000 in 10 years. An analysis of the commercial kitchens in the UK showed that the majority would be able to achieve a financial payback within less than 10 years after considering the installation costs of the heat recovery system.

Free sustainability webinar - RELOADED

Following the positive feedback we received last year, we are offering our free webinar on heat recovery for commercial kitchens for a second time. It addresses owners, operators, managers, and all interested stakeholders involved with commercial kitchens in hotels, restaurants, pubs, cafes, canteens etc. In this free 1hr-webinar, participants can learn how recovering heat from drain water works, which equipment is needed and will be able get an individual estimate for the savings achievable on a case- by-case basis, using our Heat Recovery Tool specifically developed for commercial kitchens. During the webinar, the installation of the technology at the demonstration site at the café of Penrhyn Castle, Wales, run by the National Trust, will also be illustrated.

Register now: “Don’t flush money down the kitchen drain!”. March 15 2022, 10-11am GMT.

Ty Mawr Wybrnant hydro site receives repairs and an upgrade

February 9, 2022 Admin Dwr

Daniele Novara

The 3.68 kW demonstration hydro site developed by the Dŵr Uisce project and National Trust Wales was put online in September 2019 after several months of design and construction.

Its main novelty with respect to a regular hydropower scheme lays in the use of a Pump As Turbine (PAT) device instead of a conventional custom-made hydro turbine, which allowed a significant cost reduction. As covered by several news outlets (https://www.bbc.com/news/uk-wales-50474384), the electricity generated by the hydro is self-consumed within the premises of the property and helps to maintain the correct temperature and humidity necessary to the collection of rare bibles preserved in the historical farmhouse.

Unfortunately, though, the turbine and the powerhouse received repeated damaged by two different storms in 2020 and 2021 and therefore needed a general overhaul. Taking advantage of the lifting of travel restrictions in early 2022, the damaged intake level sensor has been repaired and the PAT has been upgraded to a more robust stainless steel unit which will offer a greater resistance to erosion and corrosion over the original cast iron unit.

Upon completing the performance and acceptance tests, Ty Mawr Wybrnant hydro is now ready to be brought back online for the years to come.

Communication for sustainability

January 24, 2022 Admin Dwr

Roberta Bellini

Science communication to promote actions and results in research projects has become more and more embedded into policy, funding and practice over the past few years with emphasis on reaching multiple audiences using multiple means of communication. Research projects therefore need well designed plans and strategies that, from the beginning to the end of the project lifespan, share clear and meaningful messages to meet funding agencies requirements.

Furthermore, the climate crisis has brought to the fore the necessity for scientific knowledge to be accessible and understandable at all levels in society, to respond to their need to understand better, to deepen their literacy and awareness and to support informed actions. It is the researchers’ responsibility to respond to those needs and to reconfirm the relevance of research to solve those challenges. This scientific knowledge must be conveyed using means that speak and are familiar to different strands of society, in a way that is relevant to them, offers opportunity to reflect and create value.

As a team of researchers involved in an interdisciplinary cross-border initiative on the water-energy nexus, the Dŵr Uisce team members are actively engaged in sharing the knowledge generated, raising awareness of the climate action potential of water-energy efficiency and disseminating our research outputs. Water-energy science communication, outreach and engagement are at the core of one of the project areas, as well as an overarching theme across all areas.

Our communication efforts are structured in a plan that includes a variety of means to broaden the number of people (our reach), the depth and complexity of the message (our richness), the number of communication items (our volume) and level of engagement (our interaction with the message across a spectrum from one -way information channels to a two-way dialogue).

Any member of the community can browse our website, stay up to date with our Twitter feeds, watch some interesting videos on our Youtube channel, connect in LinkedIn. As a member of the Dŵr Uisce Cluster, you receive our newsletter. If what you are looking for is more technical and detailed information, our peer-reviewed journal articles and conference proceedings can help you delve deeper. Did you miss our Sustainability Webinar Series? No worries, you can get in touch and view the recordings in our Members Area.

Science communication is a team effort. All Dŵr Uisce team members have a critical role in providing new knowledge and in contributing to the different activities in various capacities and from different perspectives- engineering, environmental sciences, geography and management. Inputs from additional disciplines such as social sciences, pedagogy and marketing feed into the plan.

Assessing the impacts of our efforts is included in our plan, to demonstrate the value of our project and to support a greater societal recognition of the relevance to climate action potential of water-energy efficiency. What we have achieved so far, and plan to continue, is conveying understandable scientific concepts in formats that allow for reflection on their relevance to different groups in society, and that can influence behaviour towards a more sustainable use of resources within the water-energy nexus.

Behind the Scenes of our Heat Recovery Work

January 6, 2022 Admin Dwr

Madhu Murali

In the past few months, our work related to heat recovery, particularly for industries, has been focused on experiments using our lab-scale Dissolved Air Flotation (DAF) tank at Trinity College Dublin. The background to this work is detailed in our previous blog post. Recently, our researchers have been trying to characterize the flow of water and dissolved air within the DAF tank. This characterization will be used to calibrate and validate the performance of a computer model of the DAF tank as well as look at the impacts of placing a heat exchanger in different parts of the lab-scale DAF tank. To assist with the flow characterization, a plexiglass viewing window was installed on our lab-scale DAF tank (Figure 1) by the technical staff at the School of Engineering in Trinity College Dublin.

Our researchers have been using the viewing window to get a look into the internal flow dynamics of the DAF tank and use a camera to record the development of this flow.

A somewhat unorthodox recording setup (Figure 2) was required to make these videos to reduce glare and capture enough detail.

Some initial video outputs showing the development of the plume of microbubbles in the tank (Figure 3) and the tank after the introduction of fluorescein dye (Figure 4) are seen below.