How Do Heat Pump Water Heaters Work?

The recent trends in home energy in Australia clearly reflect a shift. The number of households giving up on their electric or gas water heaters is increasing every day.

What are they opting for instead? Heat pump water heaters.

Why are people switching to heat pump water heaters?

It’s a valid question with a very straightforward answer. People want lower power bills, greener choices, and technology that actually makes sense for the future.

That’s precisely why!

Just think about it: most of the energy consumed by a household, especially in cold regions, is used for water heaters. While you enjoy the hot water, the energy being wasted by a typical electric heater goes unnoticed.

Such energy-wasting electric water heaters, consequently, raise your electricity bills in a very subtle manner. 

A heat pump water heater can significantly reduce those expenses, often by as much as 60%. This represents a long-term change in the way we handle energy, not just a small saving.

Savings, however, represent only one aspect of this switch. There are others, too:

• Greenhouse gas emissions are reduced when power is used less. This is a huge triumph for homeowners who care about the environment.
• Installing energy-efficient technologies can now result in tax credits or refunds in several regions of Australia. This implies that you save money not only today but also in the future.
• Houses with heat pump systems are probably going to be more valuable in the long run as energy regulations change. So, this shift today helps with future-proofing.

The Basic Working Principle of a Heat Pump Water Heater 

To understand the cost savings with heat pumps better, we must also understand how the heat pump water heating system operates and what distinguishes it from traditional water heaters.

This new, trending system that keeps your showers warm on chilly mornings doesn’t create heat like the traditional water heaters do. 

In simple words, without any technical details, it would suffice to say that heat pump water heaters use electricity to move around the surrounding heat rather than generating more heat.

For a more technical understanding, however, you may compare it to a refrigerator in reverse.

Much like a refrigerator that transmits heat from inside the appliance to its surroundings, a heat pump uses a fan and a compressor to use heat from the surrounding air to heat the water tank.

Key Components of Heat Pump Water Heater

It might help to know the parts inside a heat pump water heating system in order to match it with the step-by-step process and understand how it actually works. The following are the key components:

Fan

The unit has a fan integrated into the system, which is used to draw in air from the surroundings and begin the entire process. If there is no air intake, there is no heat to be extracted. The built-in fan, therefore, ensures a constant airflow over the evaporator coils.

Evaporator coil 

It is filled with a special refrigerant that absorbs the heat from the warm air that passes over it. It is designed to capture even small amounts of heat energy from the air.

Compressor

The refrigerant moves into the compressor once it absorbs the heat and is squeezed by the compressor, such that the pressure and temperature rise. Compressing the refrigerant turns low-grade warmth into usable heat energy that can easily heat up the water.

Condenser coil

The condenser coil is what the hot refrigerant then flows through. This condenser coil usually wraps around the tank or runs inside it. It is also called the heat exchanger because it helps transfer heat from the refrigerant to the water.

Step-by-step working principle of a heat pump

Let’s see how the heat pump system components work together to produce hot water efficiently.

Step 1:

The exhaust fan absorbs hot air from the environment. The exhaust fan uses electricity and must run continuously to absorb heat from the surrounding air.

Step 2:

The exhaust fan absorbs and then transfers heat to the refrigerant. The refrigerant compresses the heat collected from the surrounding air. Because the heat collected from outside is less than 30°F, compressing the heat increases the temperature. This process continues until the heat reaches the temperature that produces hot water at the desired level. Consider this to be the opposite of the process that a refrigerator employs.

Step 3:

The heat transfers to the tank unit after the system compresses it. The tank stores water. The heat then converts this water to hot water.

Step 4:

A heat pump normally heats water up to 55°F. You can manually set a temperature above 55°F. When you set a higher temperature, the electric backup coil automatically starts and heats the water as specified. The coil stops working again when the water reaches the specified temperature.

Operating Conditions for heat pump water heater

A heat pump water heater’s performance is significantly dependent on its environment, much like any other technology. It is, therefore, important to understand the operating conditions for your system if you want to get the best out of it.

Suitability of the climate:

The ideal operating temperatures for heat pump water heaters are mild to warm, usually between 40°F and 90°F (5°C and 32°C).

Although efficiency may decrease in colder climates, modern versions can still operate in cooler air.

This is exactly why a lot of units are built as hybrids, automatically switching to conventional electric heating when more assistance is required.

Space requirements:

Heat pump water heaters require greater breathing room than conventional tanks because they suck air in and expel cooled air. A well-ventilated area, like a utility room, garage, or basement, guarantees optimal system performance.

FAQs: Heat Pump Water Heater Working Mechanism