Commercial heating
www.heatingandventilating.net
Role for gas in climate challenge
Gas-fired technologies will remain central to the industry’s response to the UK’s climate change and air quality strategies, says Liam Elmore, Lochinvar sales director
T
he government’s commitment to a net zero carbon economy by 2050 will not mean abandoning gas any time soon. In fact, gas-
fired products will be essential as end users look for practical and cost-effective ways of managing the transition and turning the government’s vision into reality. Gas-fired systems will also be crucial in meeting
our parallel obligation to improve air quality by keeping NOx emissions in check.
The hybrid approach is one of the most practical ways of addresssing the challenge of minimising carbon emissions
High efficiency gas-fired products will underpin
many hybrid solutions that will often be the most cost-effective and practical way to meet performance targets and, because they can be deployed at a lower capital cost than a fully renewable option, they can deliver a faster return on investment. The hybrid approach of combining conventional
and renewable technologies is also one of the most practical ways of addressing the significant challenge of minimising carbon emissions from existing buildings. 80% of the buildings that will be with us when we arrive at our 2050 destination are already built and, in many cases, it would be financially challenging to retrofit to renewable only or all-electric heating and hot water systems. Therefore, the ability to upgrade conventional systems to low carbon equivalents will be a major step towards the net zero goal. The replacement of gas-fired boilers with heat pumps in a care home for example, is likely to mean a complete system redesign as existing radiators
November 2019
would not be suitable for the low-grade heat produced by the likes of heat pumps. Heat pumps are also significantly more expensive than gas-fired boilers and such a system redesign would involve a further substantial increase in capital cost, not to mention the considerable disruption to the residents and management.
Challenge
We must also be mindful of another serious challenge for building services engineers – the need to minimise air pollutants. Again, gas-fired systems have a big part to play and this has been a major priority for our product development teams at Lochinvar. NOx emissions from Lochinvar’s new EFB gas-
fired condensing range are lower than 24mg/kWh, which the company believes to be the lowest level produced by any commercial wall hung boiler currently available on the UK market. As a result, all EFB models qualify for the maximum two credits awarded for air quality on BREEAM-rated projects. These new boilers are also supported by a ‘Five
plus Five’ warranty that covers the heat exchanger, which will be replaced free of charge in the first five years of operating life in the event of a manufacturer’s fault. Thereafter the warranty moves onto a sliding scale where 60% of the cost of replacement will be covered in the sixth year; 40% in years seven and eight, so on down to 20% in the ninth and tenth. This latest addition to the extensive Lochinvar
boiler range has four models offering outputs from 85 to 151kW driven by high efficiency condensing technology. The heat exchanger is constructed from high quality stainless steel, which has excellent resistance to corrosion and will operate at working pressures of up to six bar. Up to sixteen of these boilers can be installed in a
cascade system to provide maximum flexibility and operating reliability in larger projects. EFB cascade mounting frame assemblies are also lower than 1.8m in height, which is very helpful for both installation
and maintenance, particularly in plant rooms with restricted height and access. All four models have integral controls, which include cascade operation, with or without BMS connection. They will manage the cascade system, boiler operation and pumps as well as the cylinder temperature. Direct gas-fired water heaters (DGFWHs) will also
remain a significant technology. They can satisfy the high hot water demands of a wide range of buildings – including hotels and hospitals – in a highly efficient way as they are designed on the principles of low storage with fast recovery of hot water.
Volumes
Unlike DGFWHs, current technology heat pumps do not have the ability to provide high volumes of hot water in a short period of time, and therefore a substantial increase in hot water storage for buildings like hotels, schools and leisure centres would be required. A circulating-type DGFWH can often meet the estimated hot water demand from a single water heater, but many commercial buildings would almost certainly want stand-by to ensure no disruption to hot water supply. Two water heaters working in tandem would
provide that security of supply and would also be capable of providing up to 20,000 litres per hour with just 700 litres held in storage. DGFWHs can also be integrated with renewables
or low carbon technologies, such as heat pumps and solar thermal, which can be used to provide pre-heated water. This kind of innovation will continue to underpin
the UK’s longer term net zero carbon goals by ensuring building services contractors and end users have the flexibility to address each project on its merits. They can then respond with appropriate and practical solutions that minimise NOx while also keeping us on our road towards net zero carbon.
www.heatingandventilating.net
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