Low Carbon Hot Water - A Costly Lesson In Sustainability

Responsible for as much as 50% of UK greenhouse gas emissions, achieving climate-neutral building stock by 2050 is high on the agenda for educational organisations. One facet of education buildings that exhibits consistent year-round demands and dependency is domestic hot water or DHW, as a result it can deliver instant sustainability wins. Addressing in-use energy consumption should save carbon and reduce bills, however there are pitfalls and hidden costs that can make the process both complex and expensive if not approached with care.
Schools, colleges, and universities will typically exhibit significant, but varied, hot water usage pattern. The design of applications for commercial hot water systems has remained remarkably consistent and if a building is more than ten years old it is going to be built around either a condensing gas water heater or an indirect water heater and boiler. Gas-based hot water systems were specified because this was, and remains one of the most cost-effective and ways of producing high-temperature hot water. The carbon emissions of modern appliances are much reduced, but this has been matched and is being exceeded by grid electricity, driving calls to adopt alternatives, even though most will be more currently expensive to operate.  

To meet the Government’s aggressive net zero Strategy, there are currently two core technology options for decarbonising DHW, air source heat pumps (ASHP) or solar thermal. Although both can provide low or zero-carbon heat, neither can fully replace an existing water heating system. Since commercial DHW systems must operate in excess of 60°C to prevent the threat of legionella, ASHP efficiency, designed to work with lower temperatures, rapidly falls away limiting supply. Solar thermal on the other hand is limited by the sun’s availability across the year, and it is worth remembering will not provide space heating either. However, both can be used to as a source of preheat to reduce energy use. Both will work equally well with after heat provided by gas or direct electric.

For new build properties, the expectation is for specification to default to a mixture of heat pumps  providing excellent decarbonisation and direct electric afterheat which can be expensive to operate. The addition of a compact, low maintenance solar thermal installation can quickly offset these additional operational costs. For new education builds, consultants are specifying for greater electrical load to account for the additional power demands. This though is a costly addition for large legacy properties wanting to introduce electrification for hot water and heating.

For buildings already on gas and that rely on large amounts of DHW then solar preheat is the preferable option, offsetting the use of gas, but not sacrificing the connection should green gas alternatives, such as hydrogen become commonly available. Existing buildings therefore gain some future proofing as they continue to roll out evolving net zero technology in the coming decades.  

Proudly independent, Adveco brings a unique mix of application design, technology supply that embraces modern gas-fired appliances through to an ever-broadening range of renewables, offsite prefabrication and manufacturer grade servicing. That brings a consistency to bespoke designed hot water systems, ensuring they are optimised to control initial investment and reduce operational costs for the lifetime of the system.
Far too often, school, college and university hot water systems suffer from poor application design leaving them oversized and demanding more appliances, ancillaries, space and complex installation than necessary. Inefficient and less environmentally friendly, such systems will prove more costly to build and operate for their entire lifespan.

Oversizing inherently comes from a lack of understanding of different types of hot water system. Understanding the application demands - from large storage & intense peak demands to continuous demand - is critical when sizing a dynamic hot water system. At Adveco, our dedicated application design team can provide onsite monitoring services for the most accurate assessment of your building’s actual hot water usage, enabling bespoke sizing for refurbishment and new build projects.

Once correctly sized, we can recommend, supply, commission, and service the optimal appliances whether they be gas, electric or a mixed hybrid approach that incorporates low carbon and renewable technologies such as solar thermal and heat pumps. This is the best way of ensuring hot water demands are met in the most cost-effective and sustainable manner.

The drive to adopt sustainable and renewable technology is encouraging, but there currently remains no single technology that supplies all the answers for hot water projects of a scale required by education buildings. Whether a new build or refurbishment project, the physical limitations of a site will always propel or preclude certain options. A practical, open minded approach to driving decarbonised hot water through a mix of replacement gas and renewables is what will really propel buildings towards 2050 net zero targets while also delivering considerable comfort and benefits to those using these buildings.
Contact Adveco to discuss your school, college or university’s hot water needs