Chris Goggin of Rinnai explores how the drive for net zero is changing the provision of hot water heating in commercial sites.
Hot water heating provision in commercial sites can be satisfied by a wide variety of systems, especially now with the move to achieve net zero targets, which is still the main market driver. There is a pressing need to use hot water heating systems based on the principle of ‘practical, economic and technical’ feasibility.
Product developments for commercial sites – those found in healthcare, hospitality, leisure, retail and offices – have come fast in the last 10 years or so since the net zero ethos took hold. Before then it was usually one of the following – domestic and/or commercial boilers ganged together to meet the demand and load, direct-fired cylinders and indirect cylinders support by boilers or electric heating.
But change was coming because the big selling point of continuous flow was that they were much more economical, lighter, space saving and with virtually non-stop flows of hot water that is temperature accurate. These were gas-fired units dedicated to only heating and delivering hot water, and the capital and operational cost was dramatically less than the stored equivalent.
Today, there are a number of reputable manufacturers offering a range of commercial continuous flow hot water heating units that meet and exceed UK regulations and current legislation. While some still believe in storing hot water in cylinders ready for when demand kicks in, the capital and operational expenditure on gas-fired hot water heaters has been proven to be less than the stored mode.
The biggest change to hot water heating – and the whole market – is the advent of net zero targets. These are accepted as being necessary and the consensus on energy efficiency appears to be that we must do what we are doing but do it faster. The UK is seeing an inexorable move towards ‘renewables’ gaining market share with all points of the supply chain, from end user through to component manufacturer.
Of course, things don’t change overnight and gas will be employed for many years yet. In 2021, the UK Oil & Gas Industry Association said the following about the future use of fossil fuels in its publication ‘Energy Demand Scenarios: A Window into the future’:
“Globally, oil and gas are expected to provide at least half of total cumulative energy demand over the next thirty years through to 2050 against a range of scenarios, albeit these may not all comply with the aims of the Paris Agreement.
“In all UK Climate Change Committee (CCC) scenarios (all of which are net-zero compatible) oil and gas accounts for between 47% and 54% of total cumulative energy demand between 2020- 2050.
“In 2020 domestic offshore oil and gas production accounted for more than 70% of UK oil and gas demand and has the potential to continue to meet at least half of demand through to 2050.”
This means gas-fired water heaters are here for a good while yet, but there are changes you can offer customers if they want to reduce their carbon footprint and contribute to meeting our net zero targets. One of the biggest advances is the hybrid system – a system configuration of either solar and or heat pumps plus auxiliary hot water heaters.
One final point to keep in mind in the rush to renewables – on a site in London recently, a new and expensive hotel, the owner insisted on heat pumps to provide the hot water system. They had to be sited on the very top level in a plant room, which required steel girder reinforcement of the floor as the units weighed almost 500kg. The equivalent continuous flow unit was a single 55kW hot water heater weighing 29kg and providing the same flow rates and outputs. Clearly, critical to the future of heating and domestic hot water is understanding the true practical, economical, and technical feasibility of all our nuanced UK building stock.
