Domestic Energy Conservation Methods Flashcards
LED (Light emitting diode)
These are very energy-efficient lights.
Building orientation for solar gains
elongated walls with many windows on south facing walls (in the northern hemisphere)
Surface area to volume ratio of a building
low surface to volume ratio will reduce heat losses (more spherical or cube shaped building reduce surface area)
Passive solar heating
building heating through orientation and large windows on south facing walls (in the northern hemisphere)
The use of high thermal mass materials
High thermal mass materials reduce temperature extremes, they absorb heat slowly at times of overheating and emit heat at times of cold. Examples of materials include concrete and water.
Low embodied energy building materials
embodied energy can be reduced by reducing the amount of cement and concrete. Alternative to concrete - limecrete. Alternative to cement - Lime mortar. Rammed earth as an alternative to concrete block walls.
Earth sheltered buildings
sinking part of the building into the ground reduces heat losses as the ground is usually warmer than above ground air.
Home insulation
mineral wool, polystyrene, natural wool, shredded paper. Use of insulation reduces heat loss.
Factors that affect heat loss from a building
temperature gradient (difference between indoor and outdoor temperature), thermal conductivity or thermal resistance of the external walls, loss of warm air from inside, chill effect caused by wind and rain.
Window glazing
reduces heat loss via convection. Double, Triple or Quadruple glazing may contain air, argon, krypton, xenon (reducing U value) or a vacuum.
Low emissivity glass, low e-glass
has a surface coating that reflects infrared energy back into the building
U value
A measure of the rate of heat transfer of a material, measured in watts per square metre celsius. The lower the U-value, the better the material is as a heat insulator.
Thermal Conductivity
a measure of how well a material conducts energy when it is heated (and therefore how quickly it will lose heat). Material with high thermal conductivity would be a bad insulator.
Thermal Resistance
a measure of how difficult it is for heat to be conducted. A material with high thermal resistance would be a good insulator
Heat exchangers for ventilation systems
Warm stale air leaves the house, cold fresh air enters. Heat from the air leaving is passed into cool air entering in order to allow heat transfer between the two. Incoming air is usually contained in a long thin pipe made of a good conductor to increase the rate of heat transfer.
Automatic ventilation
thermostatically controlled screen and window openings to allow for cooling in time of excessive heat.
Occupancy sensors
detect movement and sources of IR (heat) and turn off lights and heating in the absence of movement/heat. Or the opposite, turn on lights and heating when detecting movement or heat.
Programmable thermostats
different temperatures can be set in different rooms at different times. Heating will turn off when the set temperature is reached.
Hot water storage
If water is heated some time before use it should be stored in a well insulated tank, ie. made of material with low conductivity and high thermal resistivity.
Heating water as required (combi boiler)
A combination boiler heats water as required, on demand. Only the hot water required is heated avoiding energy wastage.
Smart/remote heating systems
heating systems can be operated remotely through a mobile app, for example only turned on as occupants are making their way home.
Conserving domestic energy through human behaviour
turning off lights, turning down thermostats for space heating, turning off appliances rather than leaving on standby, taking showers rather than baths, only heat required water e.g. one cup kettle, installing radiator thermostats.
Improved efficiency of appliances
Buy appliances with the highest efficiency rating, swap incandescent bulbs for LED, ovens with well sealed triple glazed door, low energy fridge with more efficient compressor. LED screens use less energy than Plasma and cathode ray tubes, dishwashers with lower water use.
Limecrete
An alternative to concrete that has a much lower embodied energy because it uses calcium hydroxide rather than cement.
Rammed earth
A wall construction method where materials such as clay, soil, straw and sand are compacted. Because no cement is used it has a low embodied energy.
