Heating the buildings is a requirement for a comfortable living. However, traditional heating methods have an adverse effect on the environment by increased carbon emissions. Hence it is important that we explore alternative heating schemes or strategies.
The basic principle is to reduce our dependence upon traditional petroleum-based fuels. Such strategies can not only help the environment but help to reduce the cost of heating.
To introduce any alternative methods in existing buildings is challenging due to the age and fabric of such buildings and due to the potential cost involved. New-build properties offer more choices where such alternatives can be designed and are more cost effective.
Alternative strategies are discussed below. These can be applied to the design or a new building or upgrading an existing one. It is a good idea to mix-and-match the approaches to arrive at the best possible and environment friendly solution.
We can design our homes in a way that makes the best use of heat radiated by the sun. This approach sometimes referred to as passive solar heating includes ideas such as south-facing windows, using materials that retain heat and planting tress strategically to provide shade during the summer.
The other way to utilize solar energy is called active solar heating. We can replace our traditional heating equipment with solar collectors, heat pumps and storage tanks. The energy source, sun, is obviously a renewable source. We can use solar panels and photovoltaic modules as collectors.
Ground Source Heat Pumps
There is a considerable amount of heat contained within the earth. In geothermal heating, we extract and use this energy for heating purposes. We can push a fluid down the ground to an appropriate depth. Fluid extracts heat from the ground. The fluid is then transferred to the building using underground pipes. A heat exchanger takes the out from the fluid which is distributed within the building.
Again, the source, earth, is renewable. Geothermal systems are believed to works well on the existing properties as a retrofit.
Air source heat pumps
These absorb heat from the outside air rather than the ground and are classified as either air-to-air or air-to-water. These pumps are energy efficient, low-maintenance and rely upon a renewable source
Air-to-air heat pumps are used to provide heat directly inside a building. The system consists of an ‘external’ unit used to extract heat which can then be distributed inside a building. The system is unlikely to provide hot water.
Air-to-water heat pumps are suited where low temperature heating is required over longer periods of time such as under floor heating.
Wood Pellet Boilers and Stoves
We can use wood pellets for both hot water and in the stoves. These are a cheap alternative to the traditional gas or oil-based boilers and stoves. The burning efficiency is good which means that these use most of the fuel leaving a small amount of ash which does not need to be cleaned daily.
These are considered as carbon neutral as the amount of carbon dioxide generated during burning is almost the same if this wood was allowed to decay in the forest.
If roof a building is covered with earth, it dramatically improves its thermal properties. Building can retain heat during winter and be cooler in the summer. The term green roof (sod roof, living roof, etc) refers to a roof covered with vegetation. It consists of layers of soil and water proofing material besides other components.
Community or District Heating
This consists of a central boiler and a pipe distribution system to cater for a number of buildings. Each building has a heat exchanger. The system has been implemented in Scandinavia where it serves on an extensive scale.
It can use biomass and other renewable sources of energy having low-carbon content and can be implemented at a comparatively low cost. Other Strategies Instead of hating large areas through central heating, we can use space heaters which are self-contained device for heating an enclosed area or a small space
Density of a material determines its capacity to store heat. Such materials heat up slowly, and then give out that heat gradually. Buildings made of brick, concrete and stone have a high thermal mass or thermal capacity. Buildings with a high thermal mass take a long time to heat up but also take a long time to cool down and hence has a very steady internal temperature which means we can have small boilers in the house which can raise the temperature gradually and then turning themselves off for sustained periods.
The resources listed below contain a more detailed explanation of alternative heating strategies and district heating systems. These have self explanatory titles which will help you understand the concepts and their application. Some case studies are also included.