Passive solar water heating

Pressure Relief Valve Solar Water Heater

Ample supplies of hot, clean water ' on tap' are a basic signifier of an advanced society. Ever since ancient times the heating and distribution of domestic hot water DHW has been central to a civilised lifestyle - even if only the rich could enjoy the convenience and comfort that DHW can provide. Over the last century or so, fossil-fuelled DHW systems have become the norm, and the last 50 years in particular has seen DHW usage rocket. Daily power showers have replaced the weekly bath in water...

Energy stores

Sphere Tank Hydrocarbon Transfer Pump

Most alternative energy sources are inherently variable and unpredictable. Solar and wind power are the worst offenders in this respect, while being in many ways the most convenient and cost-effective. Technologies based on wind and solar power, therefore, have to cope with a widely fluctuating energy input that rarely matches demand for more than short periods. A practical alternative energy system must be able to smooth out any mismatches that occur without an overdependence on back-up...

Introduction

Sterling Motor Solar Energy

Modern buildings need heat and electrical energy to perform their design functions. Even today, with climate change widely acknowledged as the greatest threat to human civilisation in its entire history, buildings are being designed and constructed which are, and will continue to be, totally dependent on national energy grids. These grids are still, and for a long time will continue to be, almost totally dependent on fossil fuels. Thanks to political inertia, vested interests and endemic...

Active solar water heating

As described in Chapter 2, passive solar water heating systems have the merits of simplicity and are usually reliable. These benefits, however, come at a price. The systems are inflexible in that they need the hot water storage or heat exchanger to be positioned above the solar collectors, and they are difficult to integrate with other forms of alternative energy technologies. Water-based active solar water heating systems use pumps to circulate the heat collection fluid between solar collector...

Holiday Home at Rock North Cornwall

Thermal Mass Vented

High thermal mass, the control of solar gain and water heating by a combination of solar and ground source energy are featured on this new build project in south-west England. By English standards Radoon, a two-storey house overlooking the estuary of the River Camel in Cornwall, is a large dwelling, with six double bedrooms in its 323 m2 of floor area. The original Radoon was built in the 1920s using concrete blocks made with sand from the local beach. By the turn of the century the concrete...

Manchester College of Art and Technology

Facade Solar Cladding

Active rainscreen cladding made up of solar photovoltaic cells is a prominent feature on this award-winning development. For generations of Manchester citizens the imposing Victorian public baths at Harpurhey were a local landmark. The Grade II listed structure finally closed in 2001 after serious structural defects were discovered and judged to be uneconomic to repair. In 2004, however, work began on an imaginative redevelopment of the site, aimed at providing new facilities for the Manchester...

Combining technologies

Passive Solar And Low Energy Strategies

Meeting a significant percentage of a building's energy needs with microgeneration is usually best accomplished with a mixture of compatible technologies. Even a low technology approach might, at the very least, involve windcatchers, passive solar air and DHW heating and a rock bin thermal store. Over-complexity is a perceptible risk with a higher technology approach nevertheless, phase change materials, ground source heat pumps, advanced active solar water heating, several forms of solar...

Photovoltaics

Rooftop Dual Axis Solar Tracker

There is a seductive simplicity about solar photovoltaic PV technology. No complex machinery is needed, no fossil fuels, power stations or electricity pylons, no energy is wasted in cooling towers or distribution networks. A classic solar PV installation has no moving parts. It is silent, unobtrusive and needs little maintenance. PV cells can be integrated into elegant fa ades without architectural embarrassment. A PV installation can take up much less space than its solar air or water heating...

Manchester Civil Justice Centre

Civil Court Building Manchester

A unique combination of natural ventilation and daylighting coupled with the use of aquifer water cooling helps cut energy costs by more than 20 for this landmark public building. Described as a 'fourteen-storey filing cabinet', the 110 million, 35,212m2 gross Manchester Civil Justice Centre is the largest court building to be developed in the UK Cantilevered courtrooms are a distinctive feature of the Manchester Civil Justice Centre Reproduced with permission from Mott MacDonald Cantilevered...

Drake Landing Solar Community

Solar Pex Collector

Situated in Okotoks, Alberta, Canada at a latitude of 51 N, the Drake Landing Solar Community DLSC is claimed to be the first major use of high temperature seasonal borehole thermal energy storage in North America. The energy comes from an active indirect solar water heating system using flat plate solar collectors which harvest enough energy to provide 90 of the annual space heating and 60 of DHW needs for the 52 individual dwellings on the site, even throughout long winters where temperatures...

The Stornoway Waterwheel

Waterwheel Overshot System

A modern version of the classic overshot waterwheel is at the centre of an imaginative restoration project in the Outer Hebrides. Back in the early nineteenth century, the subsistence economy of western Scottish islands like Lewis was based on a plethora of small vertical axis or 'Norse' waterwheels. These powered the grindstones that ground the barley and oatmeal which formed the staple diet of the locals - wheat was unsuited to the infertile, acid soils and cool, damp climate of the Hebridean...

Air ground and water source energy

Underfloor Ducted Air Conditioning

Heat is not the same thing as temperature. The water in a stream or well, the soil a few metres below ground level, even the ambient air, might be significantly cooler than the desirable temperature for domestic hot water or space heating use - but they still contain heat energy. If the heat from a large volume of lower temperature water, soil or air can be extracted then transferred to a much smaller volume of water or air, the temperature of the receiving water or air will be raised, even if...

Cogeneration trigeneration and beyond

Stirling Engine 55kw

Generating the electricity that the modern world depends on by burning hydrocarbons can be a very inefficient process. This is particularly the case where the electricity is generated in large power stations then transmitted long distances to the consumer. National electricity grids may be very convenient, for producer and consumer alike, but as little as one-third of the chemical energy in the fuels burned actually arrives in the form of electrical power. This applies to both fossil fuels and...

Aaaaaaaaa

Typical underfloor heating arrangement Reproduced with permission from Nu-Heat, UK heating in general usually needs a less sophisticated electronic controller than a radiator-based system, simply because it involves much greater thermal masses and, therefore, much slower changes in temperature. DHW supplies can become more reliable if a so-called triple function system is specified. This uses a dedicated second internal refrigerant to water heat exchanger to supply heat to the DHW tank thermal...

Passive solar space heating

Manual Operated Air Dampers Air Handlers

As global warming becomes more obvious, the need for space heating in most developed countries will decrease, even as the need for space cooling increases see Chapter 8 . Nevertheless, for many years to come the energy required to keep buildings comfortable for their occupants during the depths of winter will still be a sizeable fraction of the world's energy needs. In Europe currently this fraction is estimated at more than 12 . Even with enhanced standards for insulation and increasingly...

Smallscale hydropower

Pelton Shoot Head Penstock Forebay

In many ways hydropower is the ideal alternative energy source. Its delivery is much more reliable, consistent and predictable than wind or solar energy. Modern turbines can extract up to 90 of the kinetic and potential energy in the water that passes through them -although an overall efficiency of 70 is more typical for small installations. More power is usually available during the wet winter months than in the summer, a supply profile that more closely matches normal demand. Unlike some...

Active solar space heating

Thermosyphoning

Adding pumps or fans to passive solar water or air heating systems can greatly increase their overall efficiency and sophistication, at the expense of greater capital and running costs and lower reliability. Active solar space heating systems can take full advantage of thermal store possibilities to significantly reduce the need for back-up space heating. More solar heat can be utilised for longer periods, and extremes of temperature can be mitigated more effectively. Active solar water space...

Biomass heating

Biomass Combustion Systems

For many millennia, the main source of energy was biomass, complex hydrocarbons produced by living organisms. Heat came from wood, charcoal, peat, bamboo, animal dung and bones, burnt in open fires and primitive kilns and furnaces. Natural oils, waxes and tallows gave light. Oils were pressed from seeds or nuts or rendered from whale or seal blubber, waxes were plundered from beehives or extracted from berries tallow came from the carcases of cattle. The Romans had a very effective form of...

Passive cooling options

Windcatcher Qanat

As the climate warms, the demand for environmental cooling will inevitably increase. It would increase anyway in developed countries the acceptable ' comfort zone' inside buildings is becoming narrower. Occupants are less and less willing to modify their clothing and habits in response to seasonal changes. Fifty years ago clerical staff thought nothing of wearing woollen underwear to the office, where men would work in three-piece suits, collar and tie for most of the year. In the height of...

Wind power

Wind Turbines Cause Global Warming

Mankind has been harnessing the wind for more than two millennia. Windmills have ground grain, drained marshes, sawn timber, and even heated water by churning. The first windmill specifically designed to generate electricity was erected in Ohio in 1888, and in 1931 a 100 kW wind turbine in Yalta, in the former USSR, began feeding power into the local 6.3kV grid. Wind farms are now seen as the quickest and easiest route to reducing dependency on fossil fuels for national electricity generation....

Active cooling options

Parabolic Trough Plant

Passive cooling systems, like passive space heating systems, have many attractive features, not least simplicity, cost and reliability. They also have serious limitations. Windcatchers, solar chimneys and the stack effect on their own can never ensure that stale warm air is always extracted from every nook and cranny of every building and that cool fresh air always replaces it at a rate which significantly improves occupant comfort. Larger buildings with complex floor plans that depend entirely...

Pyrolisation gasification and anaerobic digestion

Pyrolysis Process Making Charcoal

Even when a particular biomass material is suitable for straightforward burning as described in Chapter 7, this will not necessarily be the most efficient way of recovering the embodied energy of the biomass. Materials with naturally high moisture content in particular may well contain significant amounts of hydrocarbons and other organic materials but drying them to a state in which they could be fed directly into a boiler is rarely either practical or economic. However, alternative...