In low energy buildings, the energy from occupants alone can keep rooms warm throughout winter. In summer though this same energy can cause a problem. This ‘occupation energy’ from people living or working in a building then leads to overheating. Hausmate can help prevent overheating by both slowing the process of heat gain via passive cooling and through purge ventilation.
Slowing heat gain
Hausmate can close shutters, blinds and curtains to provide shading to limit the solar energy absorbed by the building ie; passive solar gain. Shutters are more effective than blinds as the solar energy is reflect before it passes through the windows and is turned into heat. Hausmate can close the shutters or blinds at the times of the day when the sun shines into the room and when the ambient light level is high, this means that the rest of the building stays well lit and shutters/blinds will not close on an overcast day.
When the building is overheated Hausmate can purge the heat: opening windows, vents and fans to create cross drafts and/or a chimney effect known as passive stack to help cool the building.
Under Part F of the building regulations it must be possible to vent rapidly, for instance when the toast is burnt or while painting a room. This is known as purge ventilation and is normally achieved by opening a window.
Purge ventilation can also be used to help cool a building with windows or with high volume vents being used to allow large volume of air through the property. This high volume ventilation becomes particularly important when looking to passively cool a building. Passive cooling is the dissipation of heat in a building with nil or low energy consumption. It is typically achieved by with cross ventilation or creating a passive stack.
Excess heat can be absorbed by the thermal mass of the building (typically brick walls or concrete floors). This is why a solidly built building can feel cooler than the surrounding air temperature on a summer day. However if this heat is not released over time the building will warm up. By passing high volumes of cooler (night time) air through the building, the heat can be released. Hausmate can control this cooling, either by creating cross ventilation by opening windows on either side of the building, or creating a passive stack. Passive stack ventilation occurs when Hausmate opens both high and low level vents or windows. The warmer air in the house will rise up and out of the window to be replaced by the cooler air coming in at a lower level. This will help cool the building. It is also possible to complement this passive cooling using active air conditioning.
Overheating can be an issue in any building but can be a particular problem in low energy buildings.