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Featured Article
| Shifting ground |
Unless greenhouse gas emissions from land are tackled, any efforts to reduce emissions from buildings may fall short in attempting to stave off the worst consequences of climate change. Richard Douthwaite explains how, with a little ingenuity, techniques can be applied to dramatically reduce land emissions whilst simultaneously providing new raw material streams and energy source
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Official magazine of Easca  |
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Taking control |
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Tuesday, 17 March 2009 |
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Page 4 of 5
Comeragh Controls’ discretely wired TRV on a radiator in David Kirwan’s home
According to Eurotech’s calculations, this kind of precision can deliver savings of “at least 30 per cent”. Their Eurosmart systems are not however restricted to either un- derfloor or new build scenarios but can work perfectly with all legacy systems and with retrofits. “Take a common situation now where someone has put in a backboiler and they also have maybe a gas boiler and a solar panel. When the backboiler is lit, a sensor at the boiler picks this up, and the system will turn off the gas boiler and run the pump for the back boiler and use that energy instead of using the boiler…Stuff like that happens in the background without the customer worrying about it. It operates all of the devices in the heating system.” Eurotech’s system also has a ‘reduce temperature’ facility which drops rooms to a preset background temperature when not in use. This is particularly valuable with geothermal systems, because it allows a low grade heat be retained in the thermal mass of the building, making it much easier, faster and cheaper to bring the space back up to temperature when required. Weather compensation, an additional feature of Duffy’s system, also works particularly well with underfloor systems because it removes the risk of overheating in milder conditions. One thing Duffy is keen to emphasise is the essential role of any control system in tying diverse energy sources together seamlessly. “A control system must integrate with everything that is influencing heating in the house. Every mechanical item must be controlled by one central system, not by bits and pieces of timeclocks and thermostats and a whole lot of different things strung together. You’ve got to have a centralised control system with the intelligence to deliver the right temperature at the right time.”
Martin Carey of Comeragh Controls in Tipperary says that their system takes zoning to the nth degree, and instead of the conventional three zones – for living quarters, sleeping quarters and domestic hot water – they set up a separate zone for each room in the house. “With the three zone system that’s on the market at the minute, you can get on average 15 per cent savings, whereas ours will deliver about a 47 per cent improvement.”
“It’s not rocket science. Say a standard radiator produces 2kW per hour. If you’ve ten radiators in your house, between them they’re consuming about 20kWh between them. They’ll have a flow temperature into them from your boiler of about 70 degrees and a return temperature of 50 degrees. If you’ve no control in the room, they will continue to give off heat, irrespective of whether your house is insulated or not. It’s only when you turn off your boiler, or only when you turn off those zones that they stop using heat, irrespective of what else is going on…so what we say is, using this system, you turn on the radiators you need. So for example, if, out of your ten rooms, two of your radiators are on, instead of using 20kW, you’re using 4kW. There’s significant straight savings right there.”
The Comeragh Controls system is operated from a central electronic console, while room thermostats can override the programme temporarily if more or less heat is needed. “The thermostat functions like a light switch. You can go to your thermostat and say you want your zone to come in for one hour, two hours or three hours. That overrides whatever the schedule is. So you have a generalised schedule for the whole house but that’s only a general thing…you can walk into a room at any stage and activate it or deactivate it.” Carey estimates a payback period of between four and six years. The system itself is highly configurable and will integrate with all and any pre-existing systems. “Irrespective of what kind of heat source they’re using, we can configure it so that the system selects the heat source that’s cheapest at any one time.” It’s interesting to note that the DEAP software which generates building energy ratings will only credit up to three zones, so that any house with a Comeragh Controls system will almost certainly be more energy efficient that its BER suggests. “That’s a real bone of contention for us.” says Carey.
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