Due to building regulations, renewable, all-electric hot water systems are being specified for new builds, with particular focus on heat pumps, plus solar thermal where appropriate. As with retrofit, we are still seeing projects encountering problems with cost, infrastructure and design when it comes to successfully integrating new technologies, meaning many projects revert to gas-fired alternatives.
One answer is to separate the heat source from the water storage. Using indirect heating means domestic hot water (DHW) design is not limited to a single heating source when looking to switch to more sustainable heating sources or wanting additional backup options. Indirect systems employ large, insulated cylinders that incorporate a single or twin coil heat exchanger. This coil connects to the heat source, such as a boiler, heat pump, or solar thermal system. This makes them a positive choice when specifying low-carbon water systems that address net zero requirements of new and refurbished buildings. As hot water circulates through the coil, it transfers heat to the surrounding water in the tank, creating a readily available reservoir of hot water. The separation of the heat source from the water storage, which is well insulated, minimises heat loss, so hot water stays hot for longer, reducing the need for frequent reheating and making indirect cylinder systems (calorifiers) potentially more efficient compared to direct heating systems. This versatility enables designs to leverage more cost-effective and sustainable options for a building’s needs, particularly those with moderate to high hot water demand such as hotels, care homes, restaurants, hospitals, sports facilities, and light manufacturing.
For larger commercial systems or applications with greater demands, high-capacity cylinders or multiple cylinders in parallel can be used to increase hot water storage further. Gauging the correct capacity in DHW design is especially important for curbing costs, with systems traditionally oversized through incorrect demand calculation or concerns over business continuity. Most recently capacity issues have also resulted in under sizing. This is due to a failure to recognise a need for larger storage capacity in heat pump-based systems. To optimise delivery for consistent service, especially during peak demand periods, requires a balance between the availability of heating energy and storage. Lower temperature systems require more time to replenish the levels of hot water, so require greater storage which also adds further costs to the system. For applications requiring consistently high hot water flow, the indirect cylinder should incorporate twin coils for a mix of heating inputs. Consistent low-level pre-heat, such as gained from a heat pump or solar thermal system and primary top-up/peak demand heating - preferably an electric boiler, though potentially gas if a building has an existing connection.
a hot water specialist, Adveco is a leading expert in the provision of hybrid systems, combining the indirect water heater with low-carbon technologies such as electric boilers, heat pumps and solar thermal to provide enhanced versatility, business resiliency and carbon reduction in line with corporate sustainability goals. It also stocks the widest range of commercial hot water cylinders in the UK, offering a wealth of capacities and additional features for optimised hot water management, and integration with renewables. For many commercial DHW applications, indirect cylinders will have been bespoke, and typically demand stainless steel construction, especially if water conditions are soft, to avoid aggressive corrosion over time. This again adds further capital costs to a system specification.
To help address this, Adveco offers a range of off-the-shelf, low-cost cylinders with carbon steel shells and a high-quality inorganic enamel lining designed for commercial hot water systems with a maximum working pressure of up to 10 bar and temperatures up to 85°C. The GLC offers a single fixed indirect heating coil at a low level designed to serve as an indirect water heater or preheat vessel, which will also accept 180mm 3-36kW electric immersion. The GLT model incorporates two fixed indirect heating coils, one each at low and high levels, designed for use with two separate heat sources. GLC and GLT models are available in 200 to 3000-litre capacities.
With their lower cost, the GL range of indirect cylinders presents a compelling option for commercial hot water needs, offering efficiency, fuel flexibility, and scalability in new build and retrofit projects.
https://adveco.co/commercial-hot-water-cylinders/