Active district solar heating

Flat plate or evacuated tube solar heating collectors are a well-established technology for individual buildings, especially at the domestic scale. The next development is likely to Figure 2.8 Mechanical circulation solar thermal system with back-up boiler (courtesy of Renewable Energy World, March-April 2004) Figure 2.8 Mechanical circulation solar thermal system with back-up boiler (courtesy of Renewable Energy World, March-April 2004) be the scaling up of this technology to help meet heating...

The road ahead

There are two approaches to the adoption of hydrogen as the prime energy carrier of the future. The first is to extract hydrogen from a readily available fuel like natural gas or petrol. As stated earlier, this is done by a reformer unit. The sage of the green movement, Amory Lovins, claims that a reformer the size of a water heater 'can produce enough hydrogen to serve the fuel cells in dozens of cars'. The great advantage of this approach is that there already exists the infrastructure for...

Combined heat and power CHP

From time to time reference has been made in the text to CHP. Since there seems to be strong EU and UK government support for this system of energy distribution it calls for special consideration. First, electricity generation in the UK is the largest single contributor to CO2 emissions, amounting to 26 of the total. Many buildings are responsible for more CO2 from the electricity they use than from the fuel for the boilers providing hot water and space heating. At the same time the heat from...

Stirling combined heat and power

The alternative system that is already on the market is a micro-CHP (combined heat and power) unit based on the Stirling engine. The UK government is increasingly promoting micro-CHP as part of its strategy to reduce CO2 emissions, especially in the domestic sector. It is interesting how two nineteenth century technologies, the fuel cell and the Stirling engine, are only now coming into their own. Invented by Robert Stirling in 1816, the eponymous machine is an 'external combustion engine'...

Building integrated systems

There is increasing interest in the way that the design of buildings can incorporate renewable technologies including wind turbines. Up to now such machines have been regarded as an adjunct to buildings but a concept patented by Altechnica of Milton Keynes demonstrates how multiple turbines can become a feature of the design. The system is designed to be mounted on the ridge of a roof or at the apex of a curved roof section. Rotors are incorporated in a cage-like structure which is capped with...

Smallscale hydro

Hydropower has a history going back at least 2000 years. The Doomsday book records 5000 waterwheels. One of the earliest hydroelectric schemes and first in the world to power a private home was installed by the First Lord Armstrong in the 1880s at Cragside in Northumberland. This means, of course, that it is not exactly at the cutting edge of progress. The expansion of the National Grid sounded the death knell for many small hydroschemes. However, it is increasingly now being perceived as an...

Airsourced air heat pumps

Instead of drawing warmth or coolth from a ground or water source, in warmer climes it is possible for the external source to be the air. In cooling mode the compressor pumps refrigerant to the outside coil where it condenses into a liquid. The air flowing across the coil removes heat from the refrigerant. It is then transported to the inside coil where it picks up heat from the interior of the building. Internal air is blown across the inside coil where the liquid refrigerant evaporates giving...

Tidal currents

Alderney Tidal Currents

Whereas the tidal fence is appropriate for capturing fast tidal flow between land masses like an estuary or well-defined channel, other technologies can exploit the energy content of tidal currents that oscillate along coasts. These have to be distinguished from large ocean movements like the Gulf Stream, which are thermodynamic phenomena. Horizontal-axis underwater turbines are the favoured technology for offshore tidal currents. They are similar to wind turbines but water has an energy...

Sky Zed

Tower blocks are usually regarded as the antithesis of green building. Bill Dunster Architects have tackled this perception head-on with the concept design for a zero energy tower. The argument is that urban densities will have to increase which will make some high-rise development inevitable, therefore the task is to exploit their height and floor plate to make them net sources of power. The tower could form the focal point of a larger low-rise housing complex on the lines of BedZED (see...

Contents

1 Climate change and sustainable energy The 2005 Prince Philip 1 Lecture at the Royal Society of Arts by Sir John Houghton CBE FRS The Intergovernmental Panel on Climate Change (IPCC) 5 3 Low energy techniques for cooling 31 Groundwater aquifer cooling and warming 31 Desiccant dehumidification and evaporative cooling 36 Solar-assisted desiccant dehumidification with air conditioning 37 Types of small-scale wind turbine 54 Monolithic tandem concentrator cells 70 Photovoltaics cost projections 72...

Acknowledgements

I am indebted to the researchers and construction professionals who readily gave permission for the inclusion of their work in the text. These include Dr Koen Steemers of Cambridge Architectural Research, Arup Associates for BedZED diagrams, Christopher John Hancock for the images of Malmo, Jeremy Stacy Architects for the Council Offices, King's Lynn, Fielden Clegg Bradley for the National Trust Offices, Swindon, XCO2 for the triple helix wind generator image and Pilkington plc for the image of...

Hydrogen the agent of social reform

At present consumers of energy in developed countries are reliant on either an extensive grid of wires or pipes for gas. Both are wasteful of energy and costly in terms of maintenance (Fig. 7.6). Figure 7.6 The National Grid for the UK and Ireland including the inter-connectors with Ireland and the continent Figure 7.6 The National Grid for the UK and Ireland including the inter-connectors with Ireland and the continent One of the most persuasive of hydrogen apologists is Jeremy Rifkin,...

Mode of operation of geothermal heat pumps

In the cooling mode a GHP is transformed into a refrigerator. Water circulating in the earth loop is warmer than the surrounding ground. It therefore releases heat to the ground, cooling in the process. The cooled water then passes through a heat exchanger in the heat pump. Within the heat exchanger refrigerant, gas heated by a compressor releases its heat to the water, which then begins its travel to release heat to the ground. The refrigerant, having released its heat energy, becomes a cold...

Malmo city of the future

Malmo Bo01

The development on the waterfront of this southern city in Sweden was given its initial impetus by exhibition Bo01, masterminded by Professor Klas Tham and aimed at promoting sustainable urban development. The significance of this project is that it seeks to reconcile the goals of sustainable design with the demands of the market. Malmo is set to experience a renaissance in its fortunes with the completion of the Oresund Bridge linking it to Denmark. This project represents an emphatic...

STM 4Piston Double Acting Stirling Cycle Engine

Www Stmpower Com Stirling

Figure 9.6 Axial configuration of cylinders (courtesy of STM Power) Beta Stirling Engine Figure 9.6 Axial configuration of cylinders (courtesy of STM Power) Beta Stirling Engine This has a single power piston in the same cylinder and on the same shaft as a displacer piston. The latter is a loose fit piston which serves to move the working gas from the hot zone to the cold heat exchanger. As the working gas is pushed to the hot zone of the cylinder it expands and pushes down the power piston. At...

Free piston Stirling engines FPSE

Stirling Alternator

The second main category of Stirling engine is a version in which the piston floats freely within a hermetically sealed cylinder thus without an external linkage to drive a generator. This elegant development of the Stirling principle is even more silent than the previous examples and is ideal for domestic use. Sunpower Inc., a US company, plans to introduce a system to the UK in 2007 which is based on a Stirling engine which incorporates an alternator within the cylinder which produces 1 kW of...

Types of smallscale wind turbine

Vertical Wind Turbine Blade Design

Most small systems have a direct-drive permanent-magnet generator which limits mechanical transmission losses. Systems under 2 kW usually have a 24-48 V capacity aimed at battery charging or a DC circuit rather than having grid compatibility. Up to the present, horizontal-axis machines are much more in evidence than the vertical-axis type, even at this scale. These machines have efficient braking systems for when wind speed is excessive. Some even tip backwards in high winds, adopting the...