SUSTAINABILITY SOLUTIONS


TAKING THE PAIN OUT OF HOT WATER


Hospital and healthcare premises face unique challenges when it comes to ensuring a reliable, safe and more


sustainable domestic hot water supply. Andy Green, technical director at Baxi, looks at some of the options


boiler plant and calorifier provide both heating and hot water, separating out the hot water is an advisable first step. Upgrading existing non-condensing direct-fired water heaters to more energy-efficient models is another relatively cost- effective step that will reduce energy-related emissions and costs. 2. Heat pumps: The drive


towards decarbonisation and electrification of heat (including hot water) means that the favoured approach today will likely be to install heat pumps. High temperature heat


T


he NHS is committed to reaching Net Zero from its directly controlled emissions by


2040, with a target of an 80% reduction in emissions between 2028 and 2032. With emissions from hot water and space heating systems alone accounting for 80% of NHS emissions, this will likely be an area to address. But with a huge variety of building types and


heating systems across the one estate, it is no small challenge. Furthermore, hygiene-critical environments bring particular considerations. First is the need to ensure a reliable, sufficient and safe hot water service as healthcare premises depend on water to maintain a hygienic and comfortable environment for patients and staff. Related to this is the need to implement


measures to prevent the build up of waterborne pathogens, mostly related to the control of legionella bacteria, in the hot water system. To reduce the risk of legionella, the Health and Safety Executive (HSE) advises that domestic hot water (DHW) should be stored at least at 60˚C and distributed so that it reaches 55˚C in healthcare premises. As the risk of patient scalding or burning


increases when water temperatures are too high, temperature control needs to be provided at hot water outlets to protect patient safety.


DRIVING DOWN EMISSIONS So what opportunities are there to drive down emissions related to the hot water system while continuing to prioritise patient safety? 1. Energy efficiency: The first consideration,


particularly in existing buildings, should always be to reduce energy demand. Quick wins include low volume shower heads to save water usage and energy for heating water, and pipework lagging to reduce heat losses. In buildings where a central


www.essmag.co.uk


pumps, coming soon to our Remeha range, are able to deliver the high flow temperature required to meet the desired hot water temperature. This removes the need for an alternative technology to achieve the required 60˚C or higher storage temperature, bringing greater design flexibility. However, it should be noted that the coefficiency of performance of heat pumps falls off at higher temperatures. Using lower temperature air source heat pumps


with direct electric water heaters would maintain the higher efficiencies but involve much higher volumes of stored domestic hot water. Potential issues relating to available space and the weight of the larger cylinders should be considered – particularly when dealing with roof top or non- basement plant rooms. Additional forms of legionella control within the larger volumes of stored water will also need to be managed. 3. Multivalent approach: On refurbishment projects where the natural gas supply might be maintained, a multivalent approach using air source heat pumps to preheat direct gas-fired water heaters (DGFWH) should not be overlooked. High efficiency DGFWH – especially those like the Andrews MAXXflo EVO, which come with anti-legionella functions as standard, have many advantages. These include considerably reduced storage compared with other systems, more straightforward legionella control, and reduced recovery times and capital expenditure. 4. Point of use water heaters: A further


consideration in hospitals and healthcare premises


https://www.remeha.co.uk/products/heat-pumps/e-hp-aw-air-source-heat-pump https://www.andrewswaterheaters.co.uk/products/condensing-water-heaters/maxxflo-evo https://www.heatraesadia.com/products/cylinders-and-hot-water/unvented-calorifiers/ megaflo-commercial-flexistor


is the inclusion of point-of-use water heaters, which could be fed by solar PV, for the immediate production of safe hot water. Installing apoint-of-use water heater that incorporates anti-legionella functionality will ensure that water is adequately stored, cycled and distributed.


Andy Green


FINDING THE RIGHT SOLUTION When it comes to DHW generation, there may be numerous options for energy managers, but not all will be suitable for each project. Converting older hospitals that use gas-powered steam or high temperature water heating systems to a low-carbon solution, for example, will typically need to be carried out in several stages. The most appropriate of these will depend on the stage your hospital is at on the decarbonisation pathway, the building type and hot water system. And, of course, the budget. Our expert Public Health technical sales team


works with energy and facilities managers to understand your unique requirements and arrive at the most appropriate solution on a project-by-project basis. Working together, we can help you plan your Net Zero pathway, all the while prioritising a safe, reliable and efficient hot water service.


Baxi www.baxi.co.uk


A multivalent approach may be the right solution


ENERGY & SUSTAINABILITY SOLUTIONS - Spring 2023


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