There has been increased regulatory pressure for refrigerants, especially in the HVAC industry. The stakeholders are in search of the perfect balance between safety and efficiency while minding the impact on the ozone layer as well as global warming. Currently, all the commercially available refrigerants are facing policy pressure thus the reason for development of alternative refrigerants.
Some of the proposed alternatives include next generation refrigerants with properties similar to HFCs and HCFCs, are olefin-based but have a very minimal impact with the environment. R-1234yf is the first commercially available refrigerant alternative which was introduced to replace those being used in the automotive industry. It is a good beginning of the acceptance of these alternatives into the HVAC industry and many more niches.
Non-Fluorinated Alternative Refrigerants
When looking for the best refrigerant alternatives, all the stakeholders including the manufacturers and the public should balance the environmental concerns such as leakage rates, ozone depletion and global warming together with other concerns such as performance, safety and energy efficiency. Some of the considerations include ammonia, Carbon monoxide and hydrocarbons. Non-fluorinated refrigerants are also referred to as natural refrigerants, have a few desirable characteristics such as vapor compression cooling.
However, the HVAC industry prefers using fluorocarbon refrigerants since they have a notable balance of efficiency, no negative environmental impact and also improved safety. Note that, most of the refrigerants that have been in use for a long time actually have a GWP lower than these alternatives. Over the next few years, there should be increased usage of the natural refrigerants, especially where their unique benefits are appreciated including low temperature refrigeration needs.
Handling Flammability Issues
With the fluorocarbons currently in use in the HVAC industry, there is no challenge with looking for non-flammable refrigerant solutions. However, with the passing of time, with the industry changing to olefin-based refrigerants, the challenge comes in when trying to incorporate slightly flammable refrigerant options. There are guidelines in place on how to use refrigerants that have been classified as slightly flammable safely.
As a matter of fact, a new classification was introduced for flammability ratings (2L), that covers most of the newly introduced refrigerant options. The new refrigerants are very difficult or impossible to ignite at room temperature. To do so, there are servicing techniques in use to ignite them. Flammability might be a simple subject but it has a lot of nuances. There are a few metrics in place to determine flammability with the most important ones being the burning velocity and minimum ignition energy.
- The minimum ignition energy refers to the amount of energy required to ignite the refrigerant at room temperature. If it has a higher number, the refrigerant will be tough to ignite.
- The burning velocity is the rate the refrigerant will burn when it is ignited. If it has a slow flame, it has a reduced risk.
As per research most refrigerants in the 2L classification are difficult to ignite and have a very low burn velocity. Those olefin-based options are non-flammable or have very low 2L refrigerants.
High And Low Pressure Challenges For Next Gen Refrigerants
Since the introduction of refrigerants, the industry has adopted various options to address various uses and types of compressors. With the refrigerant alternatives, it’s going to be challenging to determine low GWP, especially for those with high operating pressure. Some replacements provide low GWP with efficiency and non-flammability rating. However, with medium pressure alternatives, there is more of a challenge.
The non-flammable alternative blends such as olefin-based refrigerants will be introduced with GWP values going below 500. However, it might be tough to maintain slightly flammable levels while improving performance. A few 2L rated refrigerants such as R-1234e are in consideration to balance performance and safety among the medium pressure alternatives. The R-410A, is a high pressure alternative being offered by manufacturers, will be slightly flammable. There is continued research to determine non-flammable blends for the adverse applications.
There are some options available such as propane which is being used for a few applications but there are safety concerns thus it is limited to low charge applications, including domestic refrigerators. One advantage is that most of these refrigerant alternatives show improved performance and efficiency, so the results are quite promising.
How To Manage The Risk With The New Changes
With the constant changes in the regulations of refrigerants, there is a lot of risk when it comes to choosing the right refrigerants. To minimize that risk, we need to understand it. First, you can evaluate the current cost over the total lifetime of the equipment, you will understand the risk of choosing an entirely new refrigerant. For most refrigerants, using them for a lifetime, at least 88% of the costs incurred will come from energy consumption.
By understanding the major costs over the lifetime of the refrigerant, you need to find ways to minimize the risk of getting a new one. Here are some useful tips to consider.
- Start by using the least amount of refrigerant to minimize the refrigerant charge.
- Monitor, track and repair any leaks in the system. Proper maintenance of the system is important to avoid any leaks and identify them once they happen.
- Make sure the performance is at its peak by maintaining the system regularly.
By comparing the overall life cycle cost of the chiller, the refrigerant is the smallest expenditure you will incur. With these tips, you can even reduce the cost to make it as little as possible.
With the societal demands, the HVAC industry has been forced to introduce alternative refrigerants with their own opportunities and challenges. Since the last change, there was reliability and efficiency but the new changes will reduce the environmental impact. While maintaining safety, the challenges will result from balancing performance and the emissions. The HVAC industry will be forced to choose the next generation refrigerants to determine the global warming potential and ozone depletion impact to guarantee the safest operations and applications in various areas. With enough research, there should be enough refrigerants to move us into the next phase.