Jan 6 2009
The world's energy consumption is expected to increase by 50% from 2005 to 2030 according to a new report from the US Energy Information Agency. With high targets to reduce carbon emissions OEMs are under increased pressure to design products that supply and deliver energy in the most efficient way.
They are also increasingly being tasked with designing technology to monitor energy usage more effectively, such as SMART metering, which enables consumers to be more aware of their energy usage. SMART metering is fast becoming recognised as an important way to increase energy efficiency and in some instances it is becoming a Government legislated requirement. For example, the UK Government has announced it wants SMART meters to be rolled-out to all domestic customers by 2020 and larger business customers over five years from early 2009.
Another way to increase efficiency is through the long-term installation of central and district heating systems. Flowmeters and pumps used in these systems are just some of the products where OEMs are using ceramic because of their excellent electrical and mechanical properties.
This article investigates district heating and the technologies available for metering and pumping, including ultrasonic flowmeters and heat meters that are now widely used in the industrial and building sectors for monitoring hot water systems and energy efficiency monitoring. Their simplicity and reliability has seen their widespread adoption throughout the world as an accurate and reliable method of quantifying heat energy consumption.
District Heating
District heating is a system whereby heat is generated in one central location and distributed throughout residential, commercial and industrial buildings, rather than each individual building having its own heat system and boiler.
These are widely used throughout Europe. Ninety-five percent of heating in Iceland originates from district heating, 60% in Denmark, 50% in Finland, 12% in Germany and only 1% in the UK.
In Denmark there are many schemes and the district heating system in Copenhagen is one of the world's largest, supplying heat for a floor area of around 50 million square metres. The transmission system connects four CHP plants, four waste incinerators and more than 50 peak load boiler plants to more than 20 distribution companies with a total heat production of around 30,000TJ.
The benefits of combined heat and power (CHP) used in district heating are impressive and widely acknowledged. CHP's high energy efficiency levels cut energy costs for UK businesses, increasing their competitive edge. Community Heating schemes using CHP take disadvantaged people out of fuel poverty, providing affordable warmth and cheaper electricity from a secure, local source, supporting sustainable community development. And CHP reduces carbon emissions substantially, playing a vital part in combating climate change.
Flowmeters are used to determine how much heat and gas each home and business is using and pumps are used to circulate the hot water.
Meters
A gas meter can be designed using one of a number of technologies to measure the volume of fluid that has passed through a pipe and been used by a residential, commercial or industrial building.
There are various types of flow meter, for example those that measure flow by differential pressure (orifice), positive displacement (rotating, diaphragm), velocity (turbine, ultrasonic) and mass (coriolis).
Ultrasonic Meters
Ultrasonic meters work by calculating the flow as a measurement of time of flight of a sound wave through the fluid. The meters have transducers mounted on each side of the pipe.
Designers striving to achieve greater accuracy are using piezoelectric ceramic materials such as Morgan Technical Ceramics' materials which have excellent strength properties and can withstand the high pressures that are present in some applications. Furthermore stability of the piezo materials is critical to ensure accurate measurement across the whole spectrum of ambient conditions that a meter is typically exposed to. The company typically manufactures piezo ceramic discs with a range of different electrodes to meet the specific environmental requirements to very tight frequency tolerance to ensure optimum matching between receiver (Rx) and transmitter (Tx) transducers.
An inherent property of the piezoelectric ceramic material means that when an electrical signal is passed to the ceramic it will develop strain. When this occurs at high frequency it generates a sound wave. Conversely, when a sound wave comes into contact with the ceramic it will come under stress and produce an electrical signal. The flow rate can be measured by calculating the time from transmission of a pulse to the time of receiving the echo.
The meter is set up so the sound waves travelling between the transducers are typically at a 45 degree angle to the direction of liquid flow. The speed of the signal travelling between the transducers increases or decreases with the direction of transmission and the velocity of the liquid being measured. A third ultrasonic transducer can de used to measure the time of flight between a known distance target to calculate the exact speed of sound of the liquid or gas to make measurement even more accurate.
As there are no moving parts the meters are not subjected to wear and are more reliable than alternative meters. The electrical output from this metering technology is inherently more suitable for SMART metering, making this an enabling technology to meet upcoming legislation.
Pumps
Circulator pumps are used in central and district heating systems and domestic service systems to circulate hot water. They need to be able to run quietly and consistently for long operational periods - often up to 5,000 hours a year.
Morgan Technical Ceramics produces a range of alumina ceramics from which shafts and bearings are manufactured. They have a near-diamond hardness which makes them extremely resistant against abrasive wear and as a result increases the pump efficiency. These are incorporated during the design phase, specifically to combat the arduous environments involving abrasive particles and corrosive fluids, in which these pumps can operate.
Morgan Technical Ceramics prides itself in being able to maintain exacting dimensional tolerances enabling low noise levels to be achieved and minimising energy consumption. This leads to increased pump life and an opportunity to extend warranty periods.
Conclusion
While district heating schemes are a long-term solution to improving energy efficiencies, there are many products in the energy supply chain where efficiencies can be made in the short-term. Governments around the world are recognising the benefits of SMART metering, which will enable consumers to be more aware of their energy usage and monitor it more effectively.
Through looking at component materials OEMs can design products which lead to increased efficiency of measuring energy consumption and supply. Ceramic's excellent electrical and mechanical properties make it an ideal material.
Source: Morgan Technical Ceramics
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