What Type of Compressor is Good for a Heat Pump?

Did you know in 2019, in the UK, there were more than 239,000 people used heat pumps in their homes? The figure has continuously over the years. Heat pumps are undoubtedly the best option if you don't want your home to turn into an oven during summer or a fridge during winter.

These incredible appliances effectively regulate temperatures to ensure you are comfortable in any season. But have you ever thought about the different types of heat pumps available in the market? 

Well, compressors determine the efficiency of a heat pump, which makes it necessary to understand the type used in its manufacture before making a purchase.

Stick along for a detailed insight into everything you need to know about the different types of compressors used in heat pumps and how to choose the best option.

But first!

What is a Heat Pump?

It is a home appliance device specially designed to move heat to a room during the cold season and cold air in the hot season. Technically, heat pumps are designed with inverters that function like refrigerants or heaters- depending on your needs. 

 The technology integrated into these devices eliminates the need for separate air conditioners or heating systems. Besides, they are also quite energy efficient compared to most traditional HVAC systems. 

Even when temperatures go down to -20°C, a good heat pump can maintain a steady 21°C or 90% of the warmth you are used to having in your home. 

How About a Compressor?

Compressors play a critical role in a heat pump's operation. It is responsible for pumping the refrigerant gas through the system and creating the pressure difference needed for the heat transfer. These devices are located in the heat pump's outdoor unit and are driven by an electric motor.

Technically, when the heat pump is in heating mode, the compressor takes in the low-pressure, low-temperature refrigerant gas from the outdoor unit's evaporator coil and compresses it to a high-pressure, high-temperature gas. 

The high-pressure gas is then sent to the indoor unit's condenser coil, releasing heat to warm the indoor air. After releasing its heat, the refrigerant gas is cooled and condensed back into a liquid by the indoor unit's fan.

Types of Compressor Heat Pumps

There is quite a wide range of compressors used in heat pumps. However, most typical mainstream models today fall within the categories below. 

Reciprocating Compressors

Reciprocating compressors are the most common type used in numerous heat pump models. They work by compressing the refrigerant gas and moving it through the heat pump system to transfer heat from one place to another. 

During the heating cycle, the gas typically absorbs the heat from the air or ground outside the building and releases it in the room. In the cooling cycle, the process is reversed, and the refrigerant absorbs heat from inside the building and releases it outside.

It takes the low-pressure/low-temperature refrigerant gas from the indoor unit's evaporator coil and compresses it to a high-pressure/high-temperature gas. This high-pressure gas is then sent to the outdoor unit's condenser coil, releasing heat into the outdoor air.

After releasing its heat, the refrigerant gas is cooled and condensed back into a liquid by the outdoor unit's fan, and the process repeats itself. It is an essential cycle that ensures you get the required temperature in your home.

Scroll Compressors

Scroll compressors are known for their high efficiency, quiet operation and reliability. It is because it uses two interleaving spiral-shaped scrolls or plates to compress the refrigerant gas. The devices are located in the outdoor unit, usually outside the house. 

During the heating cycle, the compressor takes the low-temperature refrigerant gas from the outdoor unit's evaporator coil and compresses it to a high-temperature gas. The gas is then sent to the indoor unit's condenser coil, where it releases its heat to warm up the indoor air.

After releasing its heat, the refrigerant gas is cooled and condensed back into a liquid by the indoor unit's fan. During the cooling cycle, the process is reversed. The compressor takes in the low-pressure, low-temperature refrigerant gas from the indoor unit's evaporator coil and compresses it to a high-pressure gas.

Scroll compressors have several advantages over other compressors, such as reciprocating compressors. They have fewer moving parts, which reduces the chances of a mechanical failure. Besides, they are also quieter. Apart from that, they are also more energy efficient and can provide better temperature control compared to other types of compressors.

Screw Compressors

These compressors are commonly used in larger commercial and industrial heat pump systems due to their high efficiency and reliability. They use two rotors with helical lobes that rotate and compress the refrigerant gas as it passes through the compressor.

Like most compressors, screw compressors are located in the outdoor unit and driven by an electric motor. During the cold season, the compressor generates warmth by heating the low-temperature refrigerant gas from the outdoor unit's evaporator coil and compressing it to a high-temperature gas. 

The high-pressure gas is then sent to the indoor unit's condenser coil, releasing its heat to warm up the air in your room. After the heat is released, the refrigerant gas is cooled and condensed back into a liquid by the fan in your indoor unit. 

The process is reversed during the hot season. Note that screw compressors have several advantages over scroll or reciprocating compressors. They are highly efficient and can provide a large volume of refrigerant gas with relatively low power input. Screw compressors are also reliable and require minimal maintenance, making them an ideal choice for large-scale heat pump systems.

Centrifugal Compressors

Centrifugal compressors are the perfect option if you are looking for a high-efficiency heat pump for use in large commercial or industrial applications. They use a rapidly spinning impeller to accelerate and compress the refrigerant gas, resulting in a high-pressure gas that can be used for heating or cooling.

While they may be more expensive than other compressors, they can handle large gas volumes with minimal maintenance requirements. During the heating cycle, the compressor takes in the low-temperature refrigerant gas from the outdoor unit's evaporator coil and accelerates it with the rapidly spinning impeller. 

This accelerated gas is then directed to a diffuser, which converts its kinetic energy into pressure, resulting in a high-temperature gas. The gas is then sent to the indoor unit's condenser coil, where it releases its heat to warm up the indoor air.

During the cooling cycle, the process is reversed. One of the best things about centrifugal compressors is that they are relatively quiet and require minimal maintenance. Although they are a bit more expensive than other compressors and may require specialized installation and maintenance procedures, they are quite effective in large-scale applications.

Rotary Air Conditioning Compressors

These compressors are the ideal option for anyone looking for compressors for use in residential and commercial heat pump systems. Their efficient operation and compact size make them the perfect choice. They use rotating vanes or blades to compress the refrigerant gas and can provide high-pressure output with low vibration and noise levels. 

While they may not be suitable for larger-scale systems, they are an excellent option for small-scale heat pump models. They function almost similarly to other compressors. During the cooling cycle, the compressor takes the low-temperature refrigerant gas from the indoor unit's evaporator coil and compresses it to a high-temperature gas. 

The gas is then sent to the outdoor unit's condenser coil, releasing heat to the outdoor air. Finally, the outdoor unit's fan cools the refrigerant gas and condenses it into liquid. The best thing about rotary air conditioning compressors is that they are compact and lightweight, making them an ideal choice for small-scale heat pump systems. 

They also operate with low vibration and noise levels and require minimal maintenance. The only downside is that they may not be suitable for larger heat pump systems that require high-volume output.

What Type of Compressor is Good for a Heat Pump?

The best type of compressor will depend on the type and size of your heat pump, the operating conditions, or the desired heating and cooling capacities. Technically, each type of compressor has advantages and disadvantages, and the choice of the compressor will depend on the system's specific needs.

For instance, Reciprocating compressors are a popular choice for small to medium-sized heat pump systems, as they are efficient and relatively inexpensive. However, they may not be suitable for larger systems or those that require high output capacity.

On the other hand, Scroll compressors are also a good option for small to medium-sized heat pump systems, as they are compact, efficient, and have low noise levels. They may be unsuitable for larger systems or those requiring high output capacity.

Screw compressors are often used in larger commercial or industrial heat pump systems, as they can provide high output capacity and are highly efficient. However, they can be expensive and require more maintenance than other compressor types.

Centrifugal compressors are an excellent option for large-scale heat pump systems that require high-volume output at high-pressure ratios. However, they are generally more expensive and may require more maintenance than other compressor types.

Rotary compressors are popular for residential and commercial heat pump systems due to their efficient operation and compact size. They are a good option for small-scale systems but may not be suitable for larger systems or those that require high output capacity.

Final Thoughts

Compressors in heat pumps are undoubtedly the most critical components that ensure you get the required warmth or cool air to keep you comfortable in the different seasons. Now that you know the different types of heat pump compressors, it will be possible to pick the right option that suits you best based on your preference. 

At SPRSUN, we pride ourselves as a world-class company that provides quality heat pump solutions to our clients. Contact us for all your heat pump needs, and let us ensure your home always gets the required temperature.