Middlewich railway station served the salt-producing town of Middlewich in Cheshire between 1868 and 1960. Regular passenger trains stopped using the station in 1960, followed by freight trains in 1967, which is when it finally closed. Within weeks the Old Station House, a single storey building, was bought and converted into a small three-bedroom private residence.
In April 2021, Colin Biggins, Managing Director and founder of building firm Project Construction, bought the house and began a full-scale eco-renovation.
The first thing Colin did was to expand the property: he removed the roof and added a storey, which doubled the size of the property. Now the property had five bedrooms, of which three are en-suite, with the master featuring a 7m x 6m walk-in wardrobe, a large family breakfast room, and an L-shaped lounge.
Aware that energy prices were rising (although not to the levels they are today), he wanted to ensure his property had a heating system that would deliver long-term efficiency and low carbon emissions. His starting point was insulation. He wanted the best thermal performance and decided on spray foam insulation for the pitched roof. Green Horizon Energy Solutions, from Stockport, took just one day to apply the foam to a dept of 170mm.
He then contacted Aqua Plumbing & Heating, based in Wigan, to design the heating system. His brief to heating engineer Danny Martin was simple: “I want a low maintenance system that’s economical to run, and will give my family and me warmth when we want it and endless hot water.”
Colin had already purchased a Regal 28kW log burner from the Fireplace Warehouse, so Danny would need to factor that into the design.
To provide the most eco-friendly and cost effective heating solution, the design would incorporate a thermal store, overheat protection, automatic cross-over controls, and a gas combi boiler.
First Danny contacted World Heat Cylinders for a custom-made 300l open-vented, slimline cylinder with a gravity circuit, a mains pressure reverse hot water coil, and a thermal blending valve to prevent scalding. As the log burner uses gravity to move the hot central heating water, Danny positioned the thermal store in a cupboard in the loft bedroom that had an external wall; the perfect location for a small plant room.
Danny wanted to ensure that noise was not an issue in the property and selected the Intergas Eco RF36 as it’s very quiet, even when it’s operating at full rate.
Lack of operating noise wasn’t the only reason for choosing Intergas: “Intergas boilers are unique in their ability to receive pre-heated hot water, and by using an Intergas clip on the pipe temperature sensor, the boiler will only fire up if the water temperature is below 50°C, and will only top up what is needed,” explained Danny.
“This is a great way to save energy, save money, and lower carbon emissions. Most other boilers have a plastic hydro block design and a really low maximum input temperature, otherwise they would warp and leak fairly quickly.”
Danny also set the flow temperature on the boiler to around 40°C for heating and 60°C for hot water, to achieve further energy savings.
Regular disinfection of any thermal store is critical, so once a week the electric immersion heater will take the thermal store above 60°C to remove any bacteria.
Next, Danny had to connect the two separate heat sources – the open vented log burner and the sealed gas boiler – which, with an off-the-shelf plate heat exchanger and a low loss header, was easily achieved. Danny said that although the Intergas Eco RF can be used on an open-vented system, with the boiler being located in the loft bedroom, there wasn’t the minimum height above it to the feed and expansion tank to prevent it pumping over.
The answer was to fit a plate heat exchanger to keep the pressurised boiler circuit and the log burner separate; Danny could have fitted an additional coil to the thermal store and have the boiler heat it, but this would have meant heating an extra 300l, instead of just the radiator circuit – and it worked really well, all he had to do was alter the pump speed in the boiler settings.
With safety in mind, Danny used a large cast iron school radiator for the gravity heat sink, and dual-redundancy, hard-wired Honeywell controls to ensure the log burner is always priority.
As the pipe thermostats and cylinder thermostats interlock, all Colin needs to do is light the fire and sit back; the controls will automatically switch the boiler off once the thermal store has reached 40°C and the system will push to the radiators. Once the fire has gone out, the boiler will cut back in if the room stat is calling for heat.
This complex installation took three days to complete and Colin’s a happy homeowner: “I’m really happy with the heating design and installation, and would fully recommend to anyone wanting to save energy, to go down this route. You’ll need to use a highly competent contractor as I did.”
The entire Old Station House, including its three metre-high loft rooms, which are not heated, are always warm. As for hot water on demand, the Eco RF and the thermal store have got it covered in an energy efficient manner.
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