Domestic Renewables

The use of renewable energy sources in the domestic home is something that has been available for years. The advantages of recycling rubbish, and composting old scraps of food is something that is as old as the hills. It is only recently however that the technology and public grants and incentives have coincided to allow domestic renewable energy gathering on an industrial scale.

The only chance that domestic users of renewable energies will be able to improve their home is by the adoption of a small number of technologies. We are not going to be using Geothermal vents to heat our homes in any thing other than unique situations. Also, the chances of using fusion technology to extract molecular energy from water in a machine under the stairs is decades away, if at all. The main technologies that a domestic house dweller will be using to power and heat their homes will fall out of the list below:

• Air Source Heat Pump
• Ground Source Heat Pump
• Solar Water Heating Systems
• Microgeneration – Solar (Photovoltaic) Energy Collection
• Microgeneration – Wind Turbines
• Rainwater collection
• Grey Water recycling

Air Source Heat Pump

The Air Source Heat Pump is similar to the Ground Source Heat Pump as described below. The only difference is that the system uses the temperature of the air to provide heating / cooling as appropriate. The major difference is that the temperature capture is having to cope with variable temperatures in the air, so has to work harder to achieve the same aims as a GSHP.

Ground Source Heat Pump

As you dig in your garden, below a certain depth, the temperature of the ground is a constant non-freezing temperature.  Using a Ground Source Heat Pump (GSHP), this temperature of approximately 12-15C can provide latent heat into the home. Good insulation is required as the temperatures are relatively low, but the output power to required input power (to drive the heat pump) is of the order of 3 times.

This energy, when combined with a cluster of alternative heating solutions in the home can reduce power bills significantly. It is possible to reverse the system, so that in the summer months the GSHP can be used to cool the home as well.

Solar Water Heating Systems

Solar water heating is a technology that has been with us for years. The principles that we use to heat water from the sun are the same principles that heat greenhouses in winter and make them unbearable in summer.

Broadly the concept is that water is run through piping, itself running through a sun-trap. In many cases this sun-trap is a box frame that is coated with heat absorbing paint, and behind a screen which also traps the heat. As the water enters this frame it absorbs the heat collected and it warms up. The water can then be pumped into a tank (normally on the roof, or in the loft) for use at a later stage.

Heating such as this can reduce your heating bills as the water doesn’t have to be heated at all / as much to provide you with a ready supply of hot water.

Microgeneration – Solar (Photovoltaic) Energy Collection

Perhaps the renewable uppermost in most people’s minds is the use of solar panels to generate electricity for the home. A solar panel works by converting photons of energy (sun rays) into an electrical charge. This charge can then be stored in large batteries or directly used for supporting the electrical load of the property. If an excess of electrical charge is produced, then the surplus can be transmitted back to the National Grid and a payment to the householder is made.

Installation of solar panels is normally done by attaching them to roof supports. This removes the need for extra structure that may be cumbersome and make installation inefficient. It is necessary to position solar panels in a suitable orientation to maximise their exposure to the sun. Traditionally a South/Southwest-facing roof will accumulate the most of the suns rays.

Microgeneration – Wind Turbines

Does the wind blow near you? Is the air unobstructed as it channels itself across your garden? With that in mind it maybe possible to extract energy from the wind and use it to power your house.

The rotation of the blades due to the wind, energises a motor that generates electricity that can be wired into either your home or the local grid. They come in all sizes and power ratings, making selection important for the domestic dweller. It might also be that due to the local wind speed averages, that a wind turbine is not appropriate for a particular location as many wind turbines require a minimum wind speed for power generation.

Rainwater collection

Rainwater collection is possibly the simplest of the renewable technologies. It harvests the naturally falling rainwater through guttering and drainage pipes into a large storage tank. Adding a pump allows the collected water to be supplied into the home which will supplement the water already being supplied by the Water Company. It is likely that the best usage of this water will be the toilet and the washing machine as standards for drinking water need to be maintained.

Grey Water recycling

Grey water is the water that goes down the drain when you’ve finished doing the washing up. It’s also the water that the washing machine uses to clean your clothes. The thing is that normally this water will end up going back out into the wider sewerage system, never to be used again until the Water Company processes it.

In the average household, about  1/3 of the water is used for toilet flushing, the remainder of the grey water comes from baths, showers, hand basins and washing machines. As a reusable resource, there is only a little treatment that needs to be done in order to bring it to a standard that can be used for toilet flushing. Additionally, it can be collected to water gardens and other external areas, though it must be treated as soap & detergents can break soil down.

Care must be taken to ensure that contaminants such as soap and bleach are contained and not stored for any great length of time as this encourages bacteria to develop and render your efforts useless.

Grey Water recycling is very useful in an age where water availability is becoming critical and the rise in housing stock, along with population growth is putting pressure on the water table and the resources that it supplies.

In Summary

These are all activities that can be attempted by most homeowners. There will be times when a little help is needed, particularly where electrical or plumbing connections are made, but there is a lot of scope to undertake all sorts of renewable energy upgrades to domestic homes and dwellings.

Will blogs from Envirotechguru – For all your green and renewable needs on a regular basis, with the intention of helping you discover a more environmental way of extracting energy from the Earth.

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