Heating up

Warm air can be efficiently piped throughout the house through vents.

Changes in the way that heating and hot water requirements are met in domestic properties is leading to a new wave of technological solutions according to Chris Yates of Johnson & Starley.
The overall level of energy consumed in the UK is some 1,500tWh, and heat energy accounts for almost half of this figure. The domestic sector uses over half of the heat energy (385tWh) and exceeds the combined total of both the commercial and industrial sectors. The importance of developing new heating technologies to address this situation cannot therefore be underestimated.
The heating products, systems and technologies that have come forward cover many different areas of heating and hot water generation. With condensing boilers, the integration of passive flue gas heat recovery (PFGHR) into the primary heat exchanger and within a standard size combi boiler cabinet, is a major step forward.
For example, the QuanTec HR28C new generation of super efficiency condensing combi boiler saves space – especially height – over external add-on PFGHR components, and, in hot water mode, it can reduce gas consumption by a further 12% and CO2 emissions by 0.5 tonnes per year compared to other condensing combi boilers.
This latest advance in technology comes at an affordable price, with the small cost premium over normal condensing combi boilers being paid back within an estimated three years.
Until now, the SEDBUK classifications for combi boilers had not revealed or even included the Domestic Hot Water (DHW) efficiency levels – and on most condensing combis, the DHW efficiency is surprisingly low in comparison to the control heating side of a combi (the only side previously scored by SEDBUK).
Now however, within the latest SEDBUK database, a combi boiler’s hot water efficiencies finally are taken into account.
This new generation of high efficiency combi-plus boiler naturally reduces plume as flue gases exit at only circa 19°C when in DHW mode and reduces NOx to only 30 mg/KWh. If the current estimated field population of ordinary condensing combi boilers (estimated at circa 7.35 million) was replaced by this new generation combi-plus, it would reduce CO2 emissions by up to 3.7 million tonnes per annum and fuel savings by up to approximately £850 million per annum.
Many opportunities exist to upgrade older houses and flats where multi-point water heaters are used and where space heating is electric, solid fuel or partial gas-fired heating. Replacing these fragmented systems is now far easier, especially in flats. For example, the installation of an Aquair HIU heating interface unit, linked to a domestic high efficiency combi boiler, is an efficient and cost effective solution. It saves space and gives substantial savings in CO2 emissions – in every case it reduces gas consumption.
For warm air central heating, new condensing technology has the facility to provide both space heating and domestic hot water (DHW). Existing warm air heaters with a DHW facility typically have a 3.5kW output (some up to 6kW) circulator water heater fitted within the warm air heater cabinet. The circulator water heater has its own burner and controls but shares the same flue system as the warm air heater to evacuate the products of combustion.
“Another major benefit of warm air heating is the rapid initial heat-up period – substantially less than half that of wet systems.”
To enable two separate condensing appliances in the same footprint is not practicable but a solution has been developed through Johnson & Starley’s new WarmCair. It uses one heat source to provide both the central heating and DHW but manages to maintain their independent usage patterns. This product has also included features that will meet the requirements of on-going and future requirements of the ErP Directives for warm air heaters and domestic hot water production.
Typically, standard efficiency combined appliances have been produced where the domestic hot water requirements are a limiting factor. This is because 3.5kW of water heating capacity would not be sufficient to meet the demand or recovery time required in larger dwellings.
With the WarmCair range, the heat available for DHW is increased significantly and will not only meet the requirements of all existing installed combined appliances but will cater for much higher domestic hot water demands in new-build dwellings. Since WarmCair heaters are fully modulating in both space heating and hot water modes, the required amount of heat is delivered to match the demand.
Another major benefit of warm air is the rapid initial heat up period. It is substantially less than half of that of wet systems, permitting certain life-style options which are not easily achieved in properties with traditional wet heating systems. These can also lead to additional savings in fuel consumption, while intelligent controls allow users to manage and control their usage of their Warm Air system carefully.
To carry out an installation, a Gas Safe registered installer will require the core gas CCN1 and a minimum DAH1 as is currently required to work on an existing warm air heater with an integral domestic hot water heater. All gas operatives will also need CPA1 to carry out a combustion performance analysis.
In another energy efficiency led development, WarmCair has the potential to be coupled with other decentralised heat sources, such as heat pump systems and district heating systems/networks. Renewable decentralised heat sources can be highly efficient when supplying heat energy to suitable dwellings through a quality insulated distribution system, particularly in new build situations.
Warm air central heating via a Heating Interface Unit (HIU), with DHW, is an efficient and cost effective way of heating dwellings on both existing and new systems. In the affordable housing sector, space saving through the absence of radiators is a significant benefit.
In terms of installation, today’s warm air central heating systems are adaptable to all types of new and refurbished accommodation from small flats to large new-build housing. An installer can fit a replacement warm air system typically in less than one day and the possibility to undertake several jobs in a short period increases the potential for good returns.
For local authorities, warm air systems can represent best value through low life cycle costing. They are also fully compliant with Part L of the Building Regulations.
Air quality has also become a major issue, but not just keeping the air clean. The higher levels of insulation, now an integral element of new House building design, and the increase in air tightness has led to issues with condensation, mould growth and an attack on the very fabric of the building. Opening a window to replace stale air and remove condensation wastes energy. The need to find a viable and effective solution is resulting in major growth in the market for integrated warm air and heat recovery systems.
[author image=”https://www.installeronline.co.uk/wp-content/uploads/2013/09/Chris-Yates.jpg” ]Chris Yates joined Johnson & Starley in July 2013 from the Heating and Hotwater Industry Council (HHIC) where he had been Deputy Director for the previous four years. With a background in general management in the H&V industry, he is a member of several Industry Associations, Professional Committees and Standards Boards, and has worked closely with government departments[/author]