Commercial new build stipulates the use of electric heating for the provision of domestic hot water (DHW), and specifications will typically seek to deploy heat pumps to supply the building’s space and water heating. However, commercial systems should be approached separately as hot water requires consistent, year-round storage at or above 60°C for daily supply, plus they must be able to meet unexpected or extended peak demands, as well as regular high temperature flushing to prevent any Legionella bacterial growth. This has consequently driven developments in high-temperature heat pumps, said to be capable of achieving temperatures of up to 70°C under optimal conditions. These appliances, using CO² or R290 (propane) as a refrigerant, are typically large, heavy and therefore expensive to purchase and install. There also remain unresolved concerns over the use of larger quantities of flammable refrigerant, especially when installed in proximity to other electrical devices, which have the potential to become a source of ignition should there ever be a leak.

After much consideration, Adveco believes a hybrid approach, which still leverages heat pumps, but to supply DHW system preheat only, is the optimal method for the delivery of water heating. This maximises the effective capability of heat pump technology designed to work at lower temperatures (sub 55°C), meaning smaller, lower-cost units operating with safer R32 refrigerant can be used to offset primary electrical heating costs as well as providing highly effective carbon reduction. Adveco has developed the ADV-W range of heat pumps, offering single and three-phase units with heating capacities from 9 to 110 kW, making them suitable for the majority of commercial DHW applications.

To then gain the necessary higher system temperatures, Adveco recommends the use of a commercial electric boiler deployed in indirect configuration with a cylinder for storage. Adveco ARDENT is a range of compact wall-hung or floor-standing electric boilers with heat outputs from 9 to 100 kW. Easy-to-integrate, high-capacity, reliable, they provide a compact response to the needs for primary top-up of electric hot water and central heating demands in commercial buildings.

With multiple electric heating elements immersed in ARDENT’s integrated water storage tank, the boiler provides a rapid and reliable source of thermal energy with stepped power control and integrated overheat protection, reducing start-up current and economically adjusting the heating load when approaching the set point temperature.

Using pre-heated stored water, the ARDENT boiler operating at a relatively low temperature (80°C) quickly brings the system water up desired working temperatures. But without the heating intensity on surfaces typically seen in direct immersion-based systems, destructive limescale build-up in hard water areas can be very effectively reduced. With ARDENT used in a sealed ‘primary loop’ configuration, little to no scale build is seen as the boiler recirculates the same finite amount of water through the heat exchanger, maintaining efficient operation and improved response time over an extended lifespan due to the increased reliability.

Adveco’s award-winning FUSION electric water heating system brings all this functionality and advantage together in a single, pre-sized system which mounts ARDENT to the cylinder and is packaged with controls and pre-built pipework for up to 750 litre capacities and up to 52 kW nominal heating output with the addition of an optional air source heat pump. An immersion can also be added, providing extra redundancy to what is already built into the ARDENT boiler, ensuring no single point of failure for business-critical applications.

The hybrid approach to electric water heating, encapsulated by the new FUSION TW system with ASHP, more than meets the sustainability demands of new buildings, delivering up to a 48% reduction in carbon emissions compared to equivalent direct electric systems. But it can also be applied to existing properties seeking to upgrade and transition away from gas water heating. In this scenario, carbon emissions of up to 68% are possible. Electric water heating does still come at a price, both in terms of new appliances and higher operational costs, despite the use of heat pumps.

Offsetting as much of the energy demand for primary heating is therefore incredibly valuable, and properly sized and installed hybrid systems such as FUSION can gain as much as 70% of system heat for the heat pump. And if you size correctly, the need for large, costly high-temperature heat pumps can be avoided. For commercial operations with basin and sink-led demands, typified by schools, cafes & restaurants, retailers and offices, the cost of implementing a DHW system can be cut by as much as 90% by adopting the hybrid approach, which makes sustainability strategies not only attractive, but feasible.

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