Welcome, Net Zero News readers!

In the quest to create a sustainable future, every step towards reducing carbon emissions is crucial. Today, we shine a spotlight on an innovative solution introduced by Rinnai, a leading manufacturer in the heating sector. They have successfully implemented a low carbon Domestic Hot Water (DHW) Heat Pump system for a call centre in Northwest England, demonstrating a commitment to aligning with government guidance on carbon reduction. This upgrade not only enhances efficiency but also sets a precedent for future energy solutions in commercial settings.

The Need for Change

The call centre previously relied on a traditional hot water system comprising two 20kW water heaters, each equipped with a 300-litre storage tank. Unfortunately, this system operated at a mere 77% efficiency, which is far from ideal in an era where energy conservation and carbon reduction are paramount. The need for a more efficient, environmentally friendly solution became evident, prompting the search for alternatives that would meet both operational demands and sustainability goals.

Data-Driven Decisions

In order to assess the best possible options for the site, Rinnai’s Technical Design Team meticulously gathered data on hot water usage. The analysis revealed a peak hot water demand of approximately 542 litres, with a recovery time of under one hour. Armed with this critical information, the team explored two distinct approaches tailored to the site’s needs:

1. Hybrid Electric System

• 3 x 9kW R290 Heat Pumps
• 1 x 300L Heat Pump Storage
• 1 x 215L Electric Cylinder with 2 x 9kW immersion ports

2. Heat Pump System

• 4 x 9kW R290 Heat Pumps
• 1 x 500L Heat Pump Storage

Due to the site being limited to single-phase power, the decision was made to deploy multiple 9kW R290 heat pumps. This approach optimally balances efficiency with the existing infrastructure, ensuring that all hot water needs for the call centre staff—across sinks, showers, and wash basins—are met seamlessly.

Comparative Analysis: H2 Hybrid vs. H3 Heat Pump

To empower the client with informed choices, Rinnai conducted a thorough analysis comparing the operational efficiency, carbon emissions, and costs associated with both systems. The results were illustrated through various graphs that detailed the Seasonal Performance Factors (SPF), operational expenditure, carbon output, capital expenditure, and lifetime costs of the two systems.

The findings are telling. The SPF graph displayed that, when assessing the overall efficiency of the systems, the H2 Hybrid Electric system achieves an average SPF of 2.50, while the H3 Heat Pump system surpasses it with an average SPF of 2.72. The lower efficiency of the H2 system can be attributed to the inclusion of electric cylinders, which do not match the performance of the higher-efficiency heat pumps.

When examining operational expenditure over a decade, the H2 Hybrid system consistently showed higher costs. The projected operational expenditure for the H2 system is approximately £52,705, while the H3 system is forecasted to cost around £42,405, representing a 19.5% reduction in operating costs attributed to the superior efficiency of the heat pumps compared to electric immersion cylinders.

Furthermore, the analysis of carbon emissions revealed a significant difference over a ten-year period. The H2 system is expected to emit 20,584kg of CO2, whereas the H3 system will only produce 16,562kg, showcasing a commendable 24.3% reduction in carbon emissions. This stark contrast underlines the importance of choosing solutions that not only meet current operational demands but also prioritise environmental stewardship.

Understanding Capital Expenditure

In terms of capital expenditure, the H2 Hybrid Electric system’s costs amount to £23,245, while the H3 Heat Pump system requires an investment of £26,754—a 13% increase. This cost differential is primarily due to heat pumps typically being more expensive than electric immersion cylinders. However, this initial investment can be viewed as a long-term benefit, as the operational savings provided by the H3 system will quickly offset the upfront costs.

Long-Term Considerations

When combining both capital and operational expenditure over a ten-year period, the lifecycle costs further reinforce the advantages of the H3 Heat Pump system. It is anticipated that the H3 system will save the client £6,791 over a decade compared to the H2 Hybrid Electric system, with a payback period of just two years to reach cost parity.

Rinnai’s Commitment to Sustainability

Rinnai is acutely aware of the UK’s increasing demand for cost-effective and reliable appliances that consistently deliver clean hot water and heating solutions across both domestic and commercial sectors. Their commitment to providing low-cost, practical solutions extends across all energy options, ensuring that customers can make choices that are not only financially sound but also environmentally responsible.

Engage with Rinnai’s Expertise

If you are interested in exploring Rinnai’s innovative heat pump solutions or would like to take advantage of their design services, we encourage you to reach out. For more information, visit their website at Rinnai’s Commercial Heat Pumps or contact them directly through this link.

Continuing Education Opportunities

For those keen on expanding their knowledge, Rinnai also offers a free CIBSE accreditation SPF CPD training session. This is an excellent opportunity for professionals in the field to enhance their understanding of seasonal performance factors and their implication on system efficiency. Enrol today at CIBSE CPD Training.

In conclusion, the successful implementation of Rinnai’s low carbon DHW Heat Pump solution at the Northwest call centre serves as a powerful example of how innovative technology can pave the way for a sustainable future. By choosing the H3 Heat Pump system, the client not only meets the immediate hot water demands but also contributes to significant carbon reductions, showcasing a model that others in the industry can aspire to follow.

For more information on Rinnai’s products and commitment to sustainability, visit www.rinnai-uk.co.uk or reach out via email at engineer@rinaiuk.com.

This insightful article originally appeared in the April 2025 issue of Energy Manager magazine. Stay informed by subscribing for more updates and innovations in the energy sector.