A reverse cycle air-conditioner is a heat pump that can keep you:
- cool in the summer, and
- warm in the winter.
When used as a heater on a cold day, heat pumps draw heat from the cold outside air and pump it into your house. Modern heat pumps do this very efficiently. As heaters, they can:
- use one unit of energy to run electric pumps and fans, and
- deliver from 3 to 6 units of energy to warm the air in your house, energy gathered from the sun-warmed but cold-feeling air outside your house.
You get lots of energy by using a little energy. That’s super efficiency.
You can have the electricity powering the heat pump come from renewables by buying accredited Green Power or using your own rooftop solar panels.
This post is mostly presentation slides created by Tim Forcey, a BZE author, energy advisor, and author of many publications on this topic.
It is about heat pumps, including:
- how they work,
- how much cheaper they can be compared with gas heating,
- links to further reading, and
- several case studies.
Why is this presentation needed?
1). Save money! Many Australians are unaware that when they installed a reverse-cycle air conditioner to keep their home cool during a few days in summer, they also installed a space-heater than can heat their home more cheaply than gas for months-on-end in winter.
2). Heat with renewable energy! Many Australians don’t realise that the heat coming out of a reverse-cycle air conditioner (known elsewhere in the world as a heat pump) can be from 50% to 100% renewable energy.
Overseas, reverse-cycle air conditioners are called heat pumps.
USA: “Affordable heating is an emergency issue for low income earners, and heat pumps are one of the most efficient means to produce energy for heating”.
UK: “The Renewable Heat Incentive pays more than 22,000 home owners a combined £125m for running green heating systems such as heat pumps.”
NZ: “The Mayfield School principal said about $129,000 would be spent on the “long overdue” refurbishment of a toilet block and replacing the coal boiler heating system with heat pumps.”
Tasmania: “Gas appliances have an average efficiency rate of 80% compared to some electrical appliances (such as heat pumps) that can have an efficiency rate of 300%.” (Aurora Energy)
So why are we talking about heat pumps, when we are meant to be talking about reverse-cycle air conditioners?
“Heat pump” is a term used in Canada, the USA, the UK, New Zealand, and Tasmania – instead of “reverse-cycle air conditioner”.
A heat pump does not aim to create heat.
It uses the refrigerant cycle to move heat from a cold place to a hot place – in the direction opposite to natural heat flow.
Technically, fridges are also heat pumps.
Heat pumps are all around us!
See the following examples…
The HEATULATOR: a simple-spreadsheet heating- comparison calculator for all homes.
Inputs: Electricity price, gas price, and efficiencies/effectiveness of gas and electric heating systems.
Output: The ratio of heating-with-gas divided by heating-with-electricity.
A result > 1 means using electric heat pump(s) are cheaper than using gas.
Tim recognises the following individuals and people at the following organisations who have added to his knowledge of heat pumps and home heating:
- The University of Melbourne Energy Institute (MEI),
- The Alternative Technology Association (ATA),
- Positive Charge,
- Matthew Wright (Pure Electric and University of Melbourne),
- Alan Pears (RMIT and ATA),
- Richard Keech of Beyond Zero Emissions (BZE),
- Everyone at https://www.facebook.com/groups/996387660405677/