Giacomini brings its approach to comfort to the UK

Shildon
The ability of an underfloor heating system to provide a comfortable environment and avoid the swings of temperature that would be harmful to exhibits at the National Railway Museum at Shildon is demonstrated by the recently installed Giacomini system.
Comfort technology based on radiant heating and cooling is more energy efficient than just controlling air temperature, according to a major Italian company, which is now bringing its underfloor heating technology to the UK.About half the heat exchange between a person and the surroundings is by radiation, but the provision of heating and comfort in buildings is generally addressed only by controlling air temperature. Not only is heating the air less effective than radiant heating, it is also less energy efficient — as Servilio Gioria, chief engineer with the research and development department of Italian company Giacomini explains. Delivering comfort Giacomini’s approach to delivering comfort in buildings is based on controlling the radiant temperature of large surfaces. Basically that means underfloor heating and chilled ceilings to deliver comfort cooling. Radiant heating has an established market in the UK for large spaces such as factories and warehouses, using radiant tubes or high-temperature plaques. Presented as underfloor heating, it is finding a growing market in residential properties and is also effective in many types of commercial premises. Giacomini has been involved in underfloor heating for many years, and has an enormous portfolio of installations in many countries. Now the UK is one of those countries, with the setting up earlier this year of a UK subsidiary to supply both components and fully installed systems. Based at Yate in Gloucestershire, Giacomini Sales (UK) has recently completed its first major installation — the National Railway Museum at Shildon in County Durham. The need of museum manager Dr George Muirhead is to preserve historic locomotives and rolling stock in an environment that is also comfortable for visitors. Underfloor heating for nearly 3000 m2 of floor area space reduces convection, maintains an even temperature and avoids the aesthetic problems associated with radiators or forced air units. Dr Muirhead explains that some of the exhibits are very susceptible to deterioration. ‘Some of the carriage interiors and roofing, which we have taken great care to preserve or restore to their original glory, are particularly fragile. It’s important to maintain a constant temperature that avoids excessive contraction and expansion and eliminates cold spots.’ For Chris Pritchard, managing director of Giacomini in the UK, this is a major project. He stresses the total capability of the company, which makes all the components needed — including manifolds, fittings, brackets, and plastics pipework. The company also offers a full design and installation service. Indeed, the philosophy of the parent company has long been not to sell products but to sell systems and engineering design. Two reasons Servilio Gioria highlights two reasons why radiant heating is more comfortable than convective heating — and one of them also explains why it is more energy efficient. First, the temperature distribution in a room with underfloor heating is much more even. At floor level and for a few centimetres above, a good design temperature is 22°C. The temperature than falls off and might be 16°C at ceiling level in a typical office space. (Fig. 1) In contrast, the temperature in the same room heated by a radiator at low level against a wall could be as high as 38°C close to the radiator, yet still leave a substantial area just above the floor at 14°C. The other factor that Servilio Gioria identifies is that people are sensitive to both air temperature and radiant temperature — in equal proportions.* To achieve comfort in spaces with large areas of cold surfaces, the air temperature has to be raised, which immediately increases ventilation heat losses. A rule of thumb is that underfloor heating requires an air temperature 2 K less than a convective system to achieve the same comfort. Chilled ceilings Just as underfloor heating provides an energy-efficient approach to space heating, so radiant cooling based on chilled ceilings, can also be a very efficient method of delivering comfort cooling. Servilio Gioria tells us that although Giacomini is not offering chilled-ceiling technology in the UK — for the time being at least — it is a major market for the company elsewhere in Europe and the USA. The equation below* is also the key to energy-efficient cooling. It implies that higher air temperatures can be tolerated if surface temperatures can be kept low. A detailed analysis of the benefits of heating and cooling using a radiant ceiling is provided in a guide from Giacomini ‘Understanding radiant ceilings for heating and cooling’. Dealing first with heating, Sr. Gioria considers a design temperature for heating of 21°C for an office space of around 60 m2. Much detailed calculation leads to a mean radiant temperature of 18°C without a radiant ceiling, so that an air temperature of 24° is required to achieve a comfort temperature of 21°C. With a radiant ceiling at 30°C, the mean radiant temperature is rather higher at 22°C, so that an air temperature of 20°C will achieve the required comfort temperature. This type of ceiling will be associated with a full air-conditioning system, including supplying air, and Sr. Gioria suggests that the energy required to heat that air without a radiant ceiling would be about 20% higher.
Fig. 1: The radiant heat delivered by an underfloor heating system produces much more uniform and comfortable conditions than a radiator.
He also considers the effect on cooling in the summer, noting that radiant cooling panels act only on the sensible component of the thermal load. More detailed calculation suggests a mean radiant temperature of 27°C without radiant cooling and 24°C with it. To achieve a comfort temperature of 25°C without radiant cooling would require an air temperature of 23°C, but as high as 26°C with radiant cooling. Factors Many factors need to be considered in assessing energy requirements. One is that lower volumes of cooled air might be required, reducing fan requirements. Overall, suggests Servilio Gioria, the overall cooling energy required might be reduced by 15 to 20%. Giacomini has a huge portfolio of such projects in Italy, Spain and the USA. The company’s task in the UK is to raise awareness. Chris Pritchard, managing director in the UK, describes Giacomini as ‘one of the world’s best-kept secrets. It was set up in 1951 and makes a vast range of plumbing components — many of them widely used in the UK under a series of own-brand names. Now Giacomini is moving towards becoming better known in the UK, initially for underfloor heating. To help better develop this market, the company has teamed up with boiler supplier MHS Boilers, providing a single source for underfloor heating contracts exploiting condensing boilers to maximise the energy-efficiency benefits of underfloor heating. Projects using Giacomini systems are starting to come through. It cannot be too long before the company’s radiant cooling systems start to reach the UK. Giacomini Sales (UK)_ Ltd is at Unit 3, Goodrich Close, Westerleigh Business Park, Yate BS7 5YS * Servilio Gioria’s argument is based on the ASHRAE principle that: Tc=Ta/2 + Tr/2 In contrast, the more widely accepted equation in Europe is: Tc=Ta/3 + 2Tr/3
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