R744 Refrigerant (CO₂): What It Is, Benefits, and Is It Right for Your System?

Are you looking for a refrigerant that can balance excellent performance and environmental protection? R744 (CO₂) is becoming a good choice. In this guide, you’ll learn what R744 is, why we use R744 refrigerant, and whether it’s a good choice for your system.

Table of Contents

What is R744?

R744 is known as carbon dioxide. It is the standard number for the refrigerant industry, developed according to the ISO 817 and ASHRAE naming system. It is pure carbon dioxide refrigerant with a content of up to 99.9%.

CO₂ is a colorless and odorless gas. It is heavier than air and has a volume concentration of 0.04% in the atmosphere. It has a Global Warming Potential (GWP) of 1 and an Ozone Depletion Potential (ODP) of 0, making it one of the most environmentally friendly options.

Before synthetic refrigerants dominated the market, CO₂ was widely used in marine refrigeration, breweries, and food storage systems. Many engineers today are rediscovering CO₂ because modern compressor technology now allows safer operation at high pressures.

Its impact is minimal compared to synthetic refrigerants. Because of this, R744 is claimed as a natural refrigerant. It’s commonly used in transcritical systems alongside refrigerants such as R134a or ammonia (R717).

Here are the key properties:

Properties	R744
Sublimation Point (1 atm)	-78.5 °C
Triple Point	−56.6°C / 5.2 bar
Critical Point	31°C
Global Warming Potential	1
Flammability Rating	A1 (Non Flammable)
Saturation Pressure (25°C)	6370 kPa gauge
Critical pressure	74 bar

Why are We Using R744 Refrigerant?

Sustainability

Because of global climate change, regulations are tightening worldwide. Policies like the Kyoto Protocol and F-Gas regulations are pushing businesses to move away from high-GWP refrigerants. These rules are to reduce the emissions of greenhouse gas, including CO₂, CH4, N2O, HFC, PFC, and SF6. They directly affect your system choices by limiting high-GWP refrigerants.

In 2006, the United Nations established strict laws on fluorinated gases (F-Gases) to regulate their emissions. In Europe, the F-Gas Regulation is one of the strongest drivers behind the adoption of CO₂ refrigeration systems. It sets up strict limits on the use of high-GWP refrigerants such as R404A and R134a. Depending on where you live, you may also face refrigerant taxes or restrictions on use.

Therefore, many businesses are turning to low-GWP refrigerants like R744. Here’s why R744 is a better long-term choice:

Refrigerant	Type	GWP (Global Warming Potential)
R134A	HFC	1430
R404A	HFC Blend	3920
R717	Natural	0
R744	Natural	1

Compared to other refrigerants, R744 has strong environmental performance and a small impact on global warming.

Safety

R744 is classified as A1 under ASHRAE standards. If it leaks, it has a small environmental impact when properly handled, a very low environmental impact, and doesn’t impact the ozone layer at all. It is a safe and reliable option for many applications.

Here’s how R744 is classified under safety standards:

Safety group	Lower toxicity	Higher toxicity
No flame propagation	A1	B1
Lower flammability	A2L	B2L
Flammable	A2	B2
High flammability	A3	B3

Cost of R744 Refrigeration Systems

The initial cost of a CO₂ system is more than that of traditional systems. You’ll need to invest more funds in equipment and system design in advance. Over time, CO₂ systems can reduce your energy costs. You can save costs through:

Reduce energy bills
No refrigerant taxes
Regulatory compliance

However, you should also take notes of:

Higher pipe thickness requirements
Stronger compressors and valves
Pressure-rated heat exchangers
Technician training costs
System monitoring investment

R744 vs R134a

If you’re deciding between R744 and R134a, here’s a quick comparison:

Properties	R744	R134a
Global Warming Potential	1	1430
Pressure	High	Moderate
Environmental Impact	Minimal	High
System Design	Specialized	Standard

Need help choosing the right CO₂ system? Contact us for a free consultation.

Six Advantages

R744 is gaining popularity for several key reasons:

High safety standards (A1 classification)
Excellent heat transfer performance
Strong energy efficiency
Environmentally friendly (low GWP)
Lower total cost of ownership over time
Non-corrosive

Six Disadvantages

Here are the limitations of R744 refrigerant:

Operates at significantly higher pressures than traditional refrigerants
Leaks are harder to detect since CO₂ is odorless
High system cost
Strict control of moisture, oil, and other pollutants is required
Requires specialized system design and trained technicians
Performance may drop in very hot climates without optimization

Applications

R744 has a wide range of applications in many fields, especially in commerce and industry. You’ll typically use R744 in applications like:

Transcritical supermarket rack systems
Low-temperature food processing lines
Transport refrigeration
Heat pump systems for hot water production
Mobile air conditioning

To Wrap Up

If your business is planning to phase out high-GWP refrigerants or expand refrigeration capacity in regulated markets, CO₂ refrigeration is no longer an experimental choice — it is becoming the industry standard.

If you’re planning a new system or upgrading an existing one, it’s worth considering. Talk to our team to find out if R744 is the right solution for your application.

FAQ

Is R744 compatible with R134a equipment?

No. The pressure of R744 operates ten times higher than that of R134a. R744 systems use specialized components designed to meet SAE and industry standards.

Where can you buy R744 refrigerant?

You can purchase R744 refrigerant from certified refrigerant distributors or HVAC and refrigeration suppliers.

Are there any safety concerns when using R744 refrigerant?

High concentrations of CO₂ can displace oxygen in enclosed spaces. Overexposure to CO₂ can cause symptoms ranging from drowsiness to asphyxiation in extreme cases.