10 April 2017

Switching to low GWP refrigerants

A-Gas Refrigerant Product Manager Roger Smith explains how moving from high GWP gases can be made easy for installers and end users. 

The challenge facing installers and end users is to make the switch from high GWP refrigerants to low GWP alternatives as easy as possible. The stepdowns driven by the F-Gas Regulations mean that we are only nine months away from 2018 and a 37 per cent reduction in the supply of virgin HFCs (on a CO2 equivalent basis).

Next year it’s predicted that the shortfall in the availability of virgin refrigerants will have a significant impact on the industry. The good news is that the major players in the supermarket sector are facing up to this already. With the end users forcing the pace, engineers are looking to replace high GWP refrigerants with low GWP options. 

On the face of it making the switch from a high GWP refrigerant to a low GWP alternative can seem a daunting task. For most installers their first thoughts will be focused on how they can achieve the same kind of cooling capacity as the current refrigerant in use.

How much power will be needed to get the same or improved efficiencies is another question which will dominate. What about the seals and the control systems? How much will it cost to complete the upgrade? These are key questions which understandably will need to be answered and acted upon.

But help is on hand to assist installers and end users to solve these tricky problems. The first – and most important move – is to get in contact with your refrigerant supplier. They will have the expertise to ensure that you make the right choice of low GWP refrigerant replacement.

To help with these issues A-Gas has introduced an online refrigeration selection form, Refrigerant Suggestions. It’s easy to use and all you have to do is visit the A-Gas website Refrigerant Suggestions and complete the form.

A-Gas technical experts will then be in contact to suggest which low GWP refrigerant options are available to match the system you are looking to convert. There is a sample report to download that will provide you with an indication of the changes to the system needed. Included in this is cooling duty, power requirements, charge sizes and other key elements.

But before we get to this stage we want to know the core details about the job. For example, is it an air conditioning system, a chiller or a cold room you are working on? What type of condenser does it have? Which refrigerant is being used? Expansion devices and the type of compressor being employed will also have a significant influence on the type of refrigerant that can be suggested as a low GWP alternative.

Other essential information will be the evaporating and condensing temperatures. If you know the superheat and the sub-cooling figures that’s a real bonus for us but if you don’t we can still help. The selection criteria from system to system will differ and what we can do is look at the alternatives available and suggest the ones which apply to the needs of your system.

We can carry out modelling on how the new low GWP refrigerant will perform and this will provide you with an enhanced appreciation of the options available.

We treat each inquiry individually rather than make broad-based assumptions. A typical question will be: I’ve a R404A-based refrigeration system and I want to keep it going? Or I’ve a chiller running on R134a what can I use in there? In these instances we can also draw on our expertise in the market place. Other users may have already made the much the same switch and we can highlight the advantages of a particular refrigerant or warn about the pitfalls of using another.

New products are appearing on the market all the time and we include them in our scenarios. From the cooling duty we can calculate the power consumption and this is something the A-Gas technical team will consider for every single alternative refrigerant. This means that when we present the report sheet to you we can reveal how the system is currently operating and then evaluate how each of the alternative low GWP refrigerants will perform in the system.

The A-Gas technical team will also look at how the condenser will have to perform. It maybe that one refrigerant works beautifully within the parameters given by the customer but when the calculations are completed for the low GWP gas the condenser will be 20 per cent too small.

Our report table for the customer is colour coded and what you should be looking for is how much green we have in there. We have set up the cells in the table to automatically tell us that we have the right match for the system. In simple terms: an increasing COP with a better cooling capacity or a decrease in cooling capacity with an increase in COP. If there is a decrease in COP then it is shown up as red but an increase shows up as green.  If it’s the same, it stays the same colour.

Elsewhere on a technical note, if the mass flow rate goes up too much then you may not get enough flow through the main liquid line or back up the vapour line – even through the expansion device – without a lot of changes, then you will have further problems in making the switch. So, a broad base view on the new refrigerant and its operational parameters is presented to the customer. 

Our online refrigerant suggestion service provides a wealth of information and a full breakdown of practical, evidential data. It is fair to say that making the switch can be very technical for even the most experienced installer, so to help further A-Gas has a picture-based advice to explain how it all works.

At A-Gas we believe that our new online refrigeration suggestion form will make a difference and help lighten the load when you change to a low GWP refrigerant. With the benefit of this expertise you will be in a better position to make the right decision but with the greenest option at the forefront.

As seen on the ACR News.