After a comprehensive tendering process when the Co-Op Facilities Management team, headed by Brendan Laing, examined numerous options, they decided on a system based around two high efficiency ATAG XL140 gas-fired boilers supplied by ATAG Commercial and installed by main contractors for the work, Climate Heating & Plumbing Services.
‘The Co-Op has traded on its ‘ethical’ credentials for many years, investing in renewable energy and in reducing its carbon emissions’, said Brendan Laing, ‘The ATAG boilers more than met our requirements and will help us reduce our energy costs for many years to come.’
The store’s old system comprised a warm air unit mounted in the ceiling void serving the check out area, an electric door curtain over the main entrance, and a combined, gas-fired and DX air handling unit serving the main store area. Hot water was provided by a direct cylinder with two 6kW immersion heaters. Difficult access for servicing these various system elements resulted in high maintenance costs while overall system Inefficiencies meant ballooning energy costs.
Reflecting its Dutch energy saving heritage and featuring ATAG’s tried and tested 316 stainless steel heat exchanger technology currently used throughout their boiler range, the XL140 gives a class leading efficiency of 109.3% (EN677) achieved through seamless upwards modulation. NOx emissions have been reduced to below 30ppm, which ATAG believe is the lowest in its class.
The boilers will deliver hot water to a new LPHW air-handling system serving the main store area and a new LPHW warm air door curtain above the main entrance. An ATAG 700 litre capacity unvented indirect system has replaced the old inefficient hot water system. Modifications were made to existing ductwork and also to pipework to provide a pumped secondary return with thermostatic mixing valves fitted to all outlets, bringing further energy savings. The two boilers are frame-mounted in-line and come complete with loss header, pressure unit and expansion vessel.
To enable the store’s management to monitor the heating and hot water systems performance and make adjustments where necessary, an RDM (Remote Device Monitor) control system was installed.
‘Initial feedback from our monitoring system indicates a 12% reduction in the store’s energy running costs,’ said Delivery Project Manager, Nick Cairns MEI. ‘With the benefits of a new reliable, highly effective and on-line system with lower reactive maintenance requirements, we expect system payback in just over 5 years.’
The XL140 has an output of 130.9kW and can be configured in multiples of up to 8 units to give a maximum output of 960kW. The boilers can be either wall or frame mounted in line (2-8 boilers) or frame mounted back to back (3-8 boilers) for simplicity of installation. A major feature of the XL range is the fact that the maximum output can be achieved in the smallest possible footprint of only 2.7m².
For total siting flexibility all XL models come with a variety of flue options and include an in-built fully modulating, low energy, ’A’ rated pump and ‘A’ brand components designed to maximise efficiencies while further reducing emissions.