Reverse Cycle Heating Benefits - Ford & Doonan

Summary of Benefits:

  • Cheapest Form of Heating to Run
  • Environmentally Friendly
  • Cools your home in summer

  • Safest form of heating for your family
  • Fastest way to heat your home
  • Easy to install

Why is reverse cycle an efficient form of heating?

The refrigeration cooling cycle is reversed so the indoor unit dissipates heat and the outdoor unit absorbs the outside air’s heat and becomes cold in the process.

This process creates a highly efficient heating source at a low running cost.

If we compare reverse cycle to electric element heating the usage is as follows:

Element (or Resistive) Heating- 1kw of electrical energy creates 1 kW of heat

Reverse Cycle Heating – 1kw of electrical energy creates typically 3 kW of heat

The additional energy created is due to a combination of

  • The heat of compression: the refrigerant gas is recirculated inside the outdoor unit’s compressor. The process of compressing a cool refrigerant gas into a high pressure hot gas generates heat (energy) and this is captured in the refrigerant gas and transferred to the indoor unit where air passed across the heat exchanger and dissipates the heat.
  • The refrigeration cycle: the process or cycle itself is highly efficient due to the characteristics of the refrigerant and its ability to transfer heat (energy)

This is a very fast method of heating

All reverse cycle units, be they ducted or smaller room air conditioners, have a fan within the indoor unit. This fan circulates the warm air (cool in summer) at considerable volume which typically results in six to seven air changes within a room per hour.

This air flow rate is very efficient at distributing the warm air around the entire room and does not rely on convection or conduction like many gas heaters. This high air change rate speeds up the warming of a room and within just a few you will feel and appreciate the comfort.

It is a fast method of heating

All reverse cycle units, be it a ducted or smaller room air conditioner, have a fan within the indoor unit. This fan circulates the warm air (cool in summer) at quite a volume, typically 6-7 room air changes per hour. This air flow rate very efficiently distributes the warm air around the entire room and does not rely on convection, or conduction like many gas heaters. This high air change rate speeds up the warming of a room and can take as little a few minutes and you’ll feel the comfort.

Reverse Cycle is a healthy Choice: no oxygen burnt or carbon monoxide produced

Unlike gas heaters and fire places, reverse cycle does not contain any open flame or combustion of any kind. This results in the room air not having being reduced of any oxygen during the heating process. Have you ever wondered why sitting in a room with gas heating can make you sleepy? The reason is the gas heater is burning oxygen and unless a fresh air supply is maintained into the room, the oxygen levels will slowly reduce and that sleepy feeling will increase

The combustion process of gas heaters also produces carbon monoxide, which is especially a challenge with portable and un-flued heaters. Carbon monoxide is very poisonous and there have been cases of people falling asleep with their heater on and failing to wake up.

The Refrigeration Cycle Explained in detail

The system uses a refrigerant (which exists as a gas at low pressure and as a liquid under compression) which is compressed and liquefied, allowed to cool in a condenser, and then allowed to expand in a controlled way (through an expansion valve) to become a gas in an evaporator (the expansion is accompanied by a strong cooling effect). In this operation the condenser becomes warm and expels heat.

The principle is the same as that used in a normal refrigerator which “moves” heat from the inside of a refrigerator to the outside. In the case of an air conditioner when in cooling mode, the heat is removed from the room being cooled and pushed outside through the refrigeration system. Similarly, if the unit can operate in “reverse” (called heating mode or reverse cycle), the process runs backwards and the energy is collected from outside and moved inside to the room being heated. In most cases, air conditioners are more efficient when operating in heating mode as the energy used to compress the refrigerant can also contribute to the net heating output.

How Does Reverse Cycle compare to Gas?

Small room – 10–20 square metres
Suitable heater type Running cost / 500 hours
Small gas (1.5kW) $212.50
Portable electric heater (2.4kW) $312.50
Small reverse-cycle air con (3.5kW) $113.83
Medium room – 35 square metres
Suitable heater type Running cost / 500 hours
Medium gas (3.5kW) $300.00
Medium reverse-cycle air con (6.0kW) $226.07
Large area – 60 square metres
Suitable heater type Running cost / 500 hours
Large gas (7kW) $412.50
Large reverse-cycle air con (8.5kW) $335.50

Heater types based on moderate climate. Running costs based on 500 hours at 6 hours per day over 12 weeks of winter. Rates and comparisons a guide only.

What does Capacity Output mean?

The measure of energy service for an air conditioner is the rated cooling and/or heating capacity of the air conditioner, usually specified in kilowatts (kW) (some product brochures use British Thermal Units or BTUs, although this is not common). Some retailers may use compressor ‘horsepower’, although this has no meaning in terms of the unit’s capability. These rated values are as declared by the manufacturers under the test conditions defined in the Australian/New Zealand Standard (which is based on the relevant international standard). The heating capacity of a reverse cycle air conditioner is the heat that can be put into a room. Similarly, the cooling capacity is the heat that can be removed from a room. The cooling capacity is made up of the sensible component (usually the majority of the capacity) which relates to the actual temperature reduction (cooling) of the air, plus the latent component, which is a measure of the de-humidification effect of the indoor air. Latent cooling capacity is sometimes expressed as moisture removal capacity in litres or kg of water per hour (1 kg per hour of moisture removal is equal to 683 Watts latent capacity).

What is an ‘inverter” air conditioner?

An inverter model means that the compressor is powered by a variable speed drive or ‘inverter’, which enables the compressor to run at a range of speeds from slow to fast, to match the output required. These are now the most common type of air conditioner. Previously the majority of products had fixed speed compressors which could only run at a constant speed. In order to vary their capacity they have to switch on and off at different intervals. Inverters are a sophisticated piece of technology which improve the performance and energy efficiency of air conditioners under normal use.

Comparing Reverse cycle air conditions

All air conditioners are required to display strictly regulated efficiency data.

This is typically their capacity or output which is measured in watts or kilowatts.

Their power input is the amount of energy or electrically they consume to deliver this capacity under certain conditions (outside air temperature and humidity)

These two pieces of data are used to produce the COP; the Co-efficient of Performance.

Example:
Capacity 5KW (5000 watts)

Power Input 1.75KW (1750 watts)

COP= 5/1.75 = 2.85

The smaller sized wall split type air conditioners also are required to display their energy label or star rating. This is a more simplified rating system for consumers and is in effect the same as the COP rating

Another rating form is the EER; the Energy Efficiency Rating.

No matter which rating system you use, it is important you are comparing the same rating system between each model of air conditioner you are considering.

The heater types above are based on being operated in a moderate climate. The running cost is based on 500 hours at 6 hours per day over 12 weeks of winter. The rates and comparisons are a guide only.

FAQ

How does the Refrigeration Cycle work?

The system uses a refrigerant (which exists as a gas at low pressure and as a liquid under compression) which is compressed and liquefied, allowed to cool in a condenser and then allowed to expand in a controlled fashion through an expansion valve to become a gas in an evaporator. This expansion is accompanied by a strong cooling effect. In this operation the condenser becomes warm and expels heat.

The principle is the same as that used in a normal refrigerator which moves heat from the inside of a refrigerator to the outside. In the case of an air conditioner when in cooling mode, the heat is removed from being cooled and pushed outside through the refrigeration system.

Similarly if the unit can operate in “reverse”, called the heating or reverse cycle mode, the process runs backwards and the energy is collected from outside and moved inside to the room being heated. In the majority of cases air conditioners are more efficient when operating in heating mode as the energy used to compress the refrigerant can also contribute to the net heating output.

What does Capacity Output mean?

The measure of energy service for an air conditioner is the rated cooling and/or heating capacity of the air conditioner, usually specified in kilowatts (kW) (some product brochures use British Thermal Units or BTUs, although this is not common). Some retailers may use compressor ‘horsepower’, although this has no meaning in terms of the unit’s capability. These rated values are as declared by the manufacturers under the test conditions defined in the Australian/New Zealand Standard (which is based on the relevant international standard).

The heating capacity of a reverse cycle air conditioner is the heat that can be put into a room. Similarly, the cooling capacity is the heat that can be removed from a room. The cooling capacity is made up of the sensible component (usually the majority of the capacity) which relates to the actual temperature reduction (cooling) of the air, plus the latent component, which is a measure of the de-humidification effect of the indoor air. Latent cooling capacity is sometimes expressed as moisture removal capacity in litres or kg of water per hour (1 kg per hour of moisture removal is equal to 683 Watts latent capacity).

What is an ‘inverter” air conditioner?

An inverter model means that the compressor is powered by a variable speed drive or ‘inverter’, which enables the compressor to run at a range of speeds from slow to fast, to match the output required. These are now the most common type of air conditioner.

Previously the majority of products had fixed speed compressors which could only run at a constant speed. In order to vary their capacity they have to switch on and off at different intervals. Inverters are a sophisticated piece of technology which improve the performance and energy efficiency of air conditioners under normal use

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