BSEE-AUG21-P27 Adveco_Layout 1 22/07/2021 15:37 Page 27

HEATING & HOT WATER Balancing Investment in Sustainable Heating & Hot Water

With the Government’s commitment to attaining Net­Zero by 2050, the pressure is on for public sector and commercial organisations to actively demonstrate what sustainability looks like across their built estates.

of hot water and space heating/cooling. Though quick and easy to install, simply opting for just air source heat pumps (ASHP) which provide a lower grade of heat will not always be the most practical alternative for larger properties. For sites exhibiting a large domestic hot water (DHW) load – especially leisure, education and healthcare – there remains a strong argument for employing a mix of gas fired heating and renewables.


Heat pumps also become considerably less cost effective when operating at higher temperatures. When assessing the efficiency of ASHP technology, we calculate the ratio between the electricity invested to run the ASHP and its output, this is the coefficient of performance or COP. Since 2015 the wholesale price of electricity has climbed 20%, yet gas prices over the same period are down on average 15%. The difference between the wholesale market price of electricity and it’s cost of production using natural gas provides us with the spark spread.

Just as electricity has become greener, the expectation by the close of the decade is for gaseous fuels to be more commonly blended with hydrogen and other synthetic fuels providing an alternative green energy that harnesses the existing gas infrastructure. With less adaptation required this is both a practical and cost-effective alternative, particularly in terms of refurbishment of older buildings where physical limitations, such as lack of roof space, can preclude some options.

Politically, the hybrid approach may not be optimal, but the reality is we remain in a bridging phase as technology races to catch up with the demands of achieving Net Zero. The availability of nationwide hydrogen is not likely until the early to mid-2030s, and heat pumps alone struggle to achieve the consistent high temperatures (+60°C) demanded for safe commercial DHW systems.

Currently the spark spread is calculated to be 5.7. As a result, even the best commercial ASHP system available will realistically exhibit a maximum COP lower than the necessary 5.15 to start delivering greater savings. The Adveco FPi32-6, marks the latest generation of commercial ASHP, and we can demonstrate a COP of a 5.23, but even then, this is when ambient temperatures are at 12°C. Far more representative is the seasonal COP, this reflects efficiency across the entire year with all the variances in seasonal temperatures. For the FPi32- 6 the SCOP is 4.74 with a consistent provision of hot water at 55°C. As a result, for commercial DHW we question the validity of current ASHP technology when used in isolation. This does not discount the value of ASHPs, far from it, but there needs to be an expectation set.

You cannot simply remove an old boiler/water heater set up and replace it with an ASHP, at the most

basic a buffer tank/indirect water heating cylinder is going to be required, with the ASHP providing a proportion (up to 70%) of preheat for the system. Under this scenario, capital costs are going to be higher, but operational costs will significantly reduce along with the reduction in carbon that comes from greater efficiencies. That said, it is still worth remembering that the latest generation of commercial gas boilers will exhibit even greater efficiencies, for example, Adveco’s MD boiler range and latest gas water heaters can achieve a NET combustion efficiency of 106%, making it extremely cost effective to secure high temperatures for heating and hot water. Where the latest generation of ASHP do provide a real advantage, and one that ticks that all important environmentally friendly box, is in the replacement of R410A refrigerant. If a kilo of R410A refrigerant, which is a

hydrofluorocarbon (HFC), were to be released into the atmosphere it would do 2,090 times the damage of a kilo of carbon. This is its Global Warming Potential or GWP. The refrigerant gas is a crucial element of an ASHP enabling the extraction of heat from the air, so reducing the GWP of the technology is an important step forward. The Adveco FPi ASHP range replaces R410A with R-32 refrigerant, creating a more efficient, compact and environmentally friendly product. Not only is the GWP of R-32 a third that of R410A, but because far less is required to achieve similar operational specifications, the FPi32 can demonstrate an 80% reduction in GWP compared to the previous generation of ASHP. And there is zero potential for ozone depletion.

The development process for ASHPs is accelerating as technology improves to deliver more efficient products that can achieve suitably high temperatures with reduced GWP. But for the moment, a hybrid approach to


commercial scale projects, despite the additional complexity remains a necessity. The ensure best return on investment, both economical and sustainable, depends on good application design. Whether a new build or refurbishment project, correctly optimising the provision for heating, and especially hot water, ensures a system is not oversized, avoiding the need for additional capital and long-term operational expenditure. Done right, investment can be properly focussed on the active reduction of carbon from across a site, with clear operational savings and all without

compromising services that are so often seen as business critical.

he expectation is for commercial new builds to adopt a combination of direct electric heating, heat pumps and/or solar thermal for the provision


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