My interest in renewable energy stems from the fact that I am planning to build a house from scratch in the very near future. As a new construction it will give me a clean slate to work with. I would like to incorporate as much renewable energy technology as I can in this house. In fact I want to have an off the grid house.
As I will be building the house from scratch I will be able to incorporate the full spectrum of renewable energy in the design of the house from the low-tech to the high-tech.
Passive energy is a “low-tech” approach. When constructing or remodeling a house, a bit of advance planning will yield a considerable amount of possibilities to use solar energy to both heat of cool your home.
The running costs of a building can be reduced if the reliance on mechanical or electrical heating, cooling and lighting can be reduced.
Passive solar energy cannot be tacked on to a building. Passive solar energy is not an addition to a house that can be added later or at the end of the building process. It is therefore essential to consider the possibilities for passive solar energy right from the start of the building process i.e. at the planning stages.
Passive solar energy system must be incorporated into and form an integral part of an energy efficient building and landscape.
The field of passive solar energy involves building design and the placement of appropriate building components to make the best use of sunlight for day lighting, passive heating and/or passive cooling. Besides saving energy, a primary benefit of passive solar is improved comfort for the occupants.
Passive solar energy is a resource that does not require machinery. If properly designed, buildings can use daylight year-round to capture the sun’s heat in the winter and minimize it in the summer. Buildings designed in such a way utilize passive solar energy to help heat, cool, or light them.
Your energy requirements can be reduced considerably through the use of passive solar design, better insulation and energy efficient appliances. The amount of energy saved will naturally vary on the architectural design of the house, the landscaping surrounding it, and the efficiency of the appliances including the illumination.
Many passive solar heating design features also provide day lighting. The use of natural sunlight to light up or brighten a building’s interior is known as day lighting. An open floor plan allows the light to reach throughout the building. This can result in substantial savings on electric bills, and not only provides a higher quality of light, but improves productivity and health. Combining natural day lighting with natural ventilation strategies can considerably reduce energy consumption, making a significant contribution to a sustainable building design.
The most common building component used in passive solar energy is the windows. Over a year, most windows loose more energy than they gain. Advanced windows systems can actually be net energy suppliers, with better net annual energy performance than the most tightly insulated wall.
Advanced windows systems use a combination of double or triple glazings, low-emissive coatings, argon or krypton gas fill, and transparent insulation. Choosing an advanced window system and placing most of them to face southwards can reduce your annual heating load considerably. Studies have shown that houses designed using such passive solar concepts can require less than half the heating energy of the same house using conventional windows with random window orientation.
In winter, when the external temperature cools down in the evening, the thermal mass will radiate that absorbed heat into the rooms. Proper design and selection of shading devices can also result in reduced cooling loads in the summer. Apart from shading devices a passive solar cooling device such as the thermal chimney can be used to help cool down a house. It is of a similar design to that of a smoke chimney but instead of smoke it vents hot air out of the house through the roof.
Another approach for getting more solar energy into your home is to build small additions, sometimes referred to as sun rooms, which are designed to maximize solar intake. If the ventilation for these additions is properly designed the incoming energy not only provide heat to the sun room itself, but can be extended via convection or forced air systems to help heat the rest of your home.
A significant challenge for the next generation of modern dwellings is the integration of advanced window technologies, superior day lighting and passive solar heating for buildings in cold climates. New technology developments, in particular with advanced windows and airtight envelopes, make many older passive solar “rules-of-thumb” obsolete, and require the use of energy performance analysis tools.
The use of environmental modelling, a new and invaluable design tool that provides a detailed computer analysis of the internal environment with predictions of temperature, airflow, CO2 concentrations and daylight levels will help in designing more energy efficient houses.
With a bit of planning, passive solar energy design can reduce your energy requirements which also reduces the amount of energy your micro-solar and wind power plant has to produce.
