by clicking the arrows at the side of the page, or by using the toolbar.
by clicking anywhere on the page.
by dragging the page around when zoomed in.
by clicking anywhere on the page when zoomed in.
web sites or send emails by clicking on hyperlinks.
Email this page to a friend
Search this issue
Index - jump to page or section
Archive - view past issues
Green Smart Magazine : 2009_new
recovery, solar collectors and heat shifters can make temperatures more even throughout the home simply using existing air in and around the home. Passive design can reduce this heat transfer, where the space between ceilings and floors are well insulated and where stair wells and open voids are sealed off through structural elements. Passive cooling Passive cooling maximises the efficiency of the building envelope by minimising the amount of heat gained from the external environment and improving air circulation. This can be achieved by: • positioning adequate-sized windows to utilise cooling breezes to maximise ventilation • reducing internal air path barriers -- such as incorrect placement of internal walls -- to increase natural ventilation • positioning a water feature near openings to maximise and direct cooling breezes • avoiding over-glazing on east- and west- facing façades and use effective shading to minimise heat gain • including a solar chimney for purging unwanted hot air • installing the levels of insulation recommended for your climate zone • incorporating internal thermal mass features in the appropriate climate zones • using light coloured roofs and walls to reflect solar radiation. In certain climate zones, mechanical cooling may still be required. Two different heating+cooling • purging heated air to outside and bringing in cooler air for circulation • low running costs and quiet systems for air movement • can be used on single- and multi-storey houses • can be designed to complement passive design features for maximum efficiency • easy to install during the construction stage, but can also be fitted into existing houses • power can be sourced from green power, photovoltaic panels, or mini-turbines. benefits of enabling air movement COMBINING FANS WITH EXHAUST SYSTEMS CAN HELP TO INCREASE AIR MOVEMENT BY PURGING HOT AIR AND DRAWING IN COOLER AIR FROM COOLER ENVIRONMENTS methods of cooling are geothermal heat pumps and air movement. Geothermal heat pumps (earth coupling) use heat exchange pipes that are drilled into the ground where the temperatures are relatively stable all year round. Bore holes (70mm wide) are drilled 15 or 30 metres into the ground and a continuous closed loop of copper piping is inserted and surrounded by a thermally conductive grout/cement. A refrigerant is circulated through copper pipes which act as the condenser for this geothermal airconditioner. Superheated gas is condensed into a liquid by the ground's heat capacity eliminating the stored latent heat. Significant energy savings (up to 75 per cent) are achieved by this direct exchange and it is also possible to heat your hot water for free in this mode! Inside the house, a geothermal heat pump cooling system appears just like any other airconditioner. Centrally controlled through a thermostat, the cooling is typically delivered through duct work and roof vents which couple to a refrigerant heat exchanger and fan. The heat exchanger is fed by the ground loops directly through a compressor. As well as ducted cooling, the geothermal heat pump can feed radiant wall panels or chilled beam ceiling coolers which circulate fluid through ceiling pipes much like in-slab floor heating. Enabling air movement can be an energy- efficient and effective means of increasing air circulation throughout the house, and can be supplemented with mechanical systems such as fans and exhaust outlets. Combining fans with exhaust systems can help to increase air movement by purging hot air and drawing in cooler air from cooler environments. For more information about these systems visit www.energycore.com.au or www.hrv.com.au gs Photo courtesy Third Ecology Photo courtesy Daran Constructions 74 greensmart 9 LEFT: Maximise ventilation through well-placed fans and windows ABOVE: A light-coloured finish will dramatically reduce a roof's heat absorption