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Making life easier D


evelopments in gas condensing boilers are simplifying installation and commissioning, as well as improving efficiency and


reliability. Christian Engelke, technical director of Viessmann UK, explains how. Although gas condensing boiler technology is now very familiar, it is constantly evolving. Recent product innovations have made installation, commissioning and maintenance even more easy for professional installers and engineers, at the same time as delivering better energy efficiency, durability, and reliability to end users. Here’s an introduction to five technical features well worth looking for.


Push-fit connection A new casing concept and an innovative tool-free push-fit system have now made it possible to ready a boiler for operation in just five simple steps. By installing the boiler on the bracket of an installation jig, all heating water and DHW pipes are already securely connected to the network without the need for clamps or soldering and the only threaded fitting necessary is in the gas connection.


Automatic flue gas adaption This is another clever feature to ensure optimum performance under certain ambient air pressure or air flow conditions. The air flow into the boiler


varies due to ambient air temperature or long flue runs, or even as a result of adverse wind conditions that prevent the boiler from running at its desired output. The new sensor detects those fluctuations and adjusts the fan speed accordingly. This ensures the boiler always runs at 100% when required. Conventional boilers, on the other hand, may drop the heat output by up to 15%.


Taking control


The benefits of high modulation ratios are well known. In our case, the Vitodens 200-W is able to modulate down to 1.8 kW achieving a turn-down ratio of 1:20. This was achieved with a new automatic combustion controller. The advantages are huge, achieving fewer burner starts thus better efficiency and lower emissions. This also makes the boiler virtually silent and more compatible for low energy homes. It simplifies the commissioning process by removing the need to make combustion-related settings manually. It also removes the need to manually change the gas valve or gas injector if the boiler has to be changed over from natural gas to LPG. Self- calibrating combustion control benefits the end user too, because it automatically adjusts the gas/air mixture to compensate for the fluctuations in gas quality that can negatively affect a boiler’s efficiency and reliability. This is becoming more desirable in the UK,


BOILERS


where the majority of natural gas is now imported or supplemented by LNG gas.


Dynamic pause time optimisation With the old-school approach of defined pause times, a burner remains off after each operating cycle until a minimum time period has elapsed and the boiler water temperature has fallen below a predefined limit. With dynamic pause time optimisation, however, an algorithm evaluates the rate at which the boiler water temperature increases during the switching interval, then matches pause times to this. This results in a reduced number of cycles and pre- purge phases, extended burner runtimes during spring and autumn, and lower standby losses due to low average boiler water temperatures, bringing an improvement in efficiency.


Smart energy management The integral control units of domestic boilers are beginning to give information detailed enough to help control energy consumption. An example of this is the five-inch touchscreen of the Vitotronic control unit in the Vitodens 200 series, which provides continuous information about gas consumption and boiler power. This can also display information about solar yields and DHW cylinder loading status, temperature stratification, and temperature curves. Historic data is retrievable, so information can be used to modify user habits and energy consumption.


EnergyMatters M


Getting warmer – give London renters an energy break


any London homes are leaky and hard to heat. Improving them would help meet carbon reduction targets - they produce


over a third of the city’s greenhouse gas emissions, 13.4 million tonnes of CO2 in 2014. The private rented sector is particularly difficult, as landlords are often not keen to improve energy efficiency standards, sometimes because they don’t know about easy improvements. The London Assembly Environment Committee


recently launched its report, ‘Getting Warmer’ examining what can be done to reduce domestic carbon emissions and fuel poverty in the capital.


The report found the following: • At least one in five Londoners has a pre-payment meter for gas and/or electricity. The best energy tariffs are not available to these customers. • In December 2016, Ofgem found that there were more than 1.7 million customers with a particular supplier who could save over £260 a year by


switching to the cheapest tariff from that same supplier.


• After having a smart meter installed, eight in 10 people take steps to reduce their energy usage. • Small private landlords may have limited awareness of what practical steps they can take to improve efficiency. • There is also an issue of limited enforcement in the private rented sector.


It recommended the following: • Supporting improvements in the rented sector, with clear advice to small landlords on energy efficiency and how to achieve it, plus support for councils on enforcement of private landlords’ energy efficiency obligations. • A consultation on clearer regulations for the private rented sector with a view to improving energy efficiency and affordable warmth. • Working with boroughs and other large landlords to promote the rollout of smart meters


in rented housing, for example when a property changes tenants.


• Supporting people to move off pre-payment meters where it is in their interests, or offer pre- payment tariffs at the same price as credit. • Investigating the feasibility of, and setting up if possible, a finance provider (within or alongside the Energy for Londoners Company) to provide a version of the Green Deal in London, ideally offering lower interest rates than commercial loans. Environment Committee chair, Leonie Cooper


AM, said: “London has found energy improvements particularly challenging. It has always got less than its fair share of available funding under the national schemes, and so less work has been carried out. This lack of energy improvement work has contributed to London’s recent huge rises in fuel poverty. Landlords should be supported to improve


their properties – this will help those renters who struggle to pay rising energy prices.”


www.heatingandventilating.net


July 2017


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