Can HC Replace HCFC/HFC in Unitary A/C Applications?

On 10 April UNEP OzonAction organised the first of its webinars in the “RefTalk” series, titled, “Can HC Replace HCFC/HFC in Unitary A/C Applications?” Presentations from UNIDO, Chinese Government representatives and university researchers were followed by a Q&A during which hydrocarbons21.com asked panellists about the anticipated future success of R290 room air conditioners (RAC). Part 1 of our reporting looks at presentations by Ole Nielsen and Tingxun Li.

The newly launched UNEP OzonAction “RefTalk” series aims to present in depth the new commercially or potentially available refrigerants in different sectors. The aim of this webinar series is to provide a platform to share expertise, engaging with participants worldwide, in an informal atmosphere.

Mr. Atul Bagai, Regional Network Coordinator, OzonAction, UNEP CAP ROAP, introduced the webinar on hydrocarbons (HC) saying, “The topic that has been chosen today is a very interesting one, and in fact a very timely one, especially for the Article 5 Country Ozone Officers and also for the industry, for end use level and servicing sector. From all perspectives this is going to be a very hot topic.”

Hydrocarbons as Alternatives to HCFC-22 - A cool solution? Mr. Ole Nielsen, United Nations Industrial Development Organization (UNIDO)

Mr Nielsen spoke about the 20-year history of HCs, which began with Greenfreeze, evidence that HCs can be used to replace HCFC/HFCs in certain applications. He emphasised however, the fact that an HC room air conditioner production line is very different from a domestic refrigeration HC assembly line. Therefore it is not possible to simply replicate the experience of introducing HCs in the domestic refrigeration sector.

During his presentation Mr Ole emphasised the importance of training, and that technicians need to understand safety procedures when working with HCs. In particular he stressed the need to consider the following:

Proper service tools for HCs are needed, such a venting hose instead of a recovery machine. The question is what size should this venting hose be?
HC leak detector to monitor flammable atmospheres are needed.
HC purity - while high purity is manageable in a production setting, service technicians may choose lower purity. What is the impact of this, and can we accept 97.5% purity instead of 99.5% purity?

In Mr Ole’s view China has taken a very progressive step in deciding to focus on HCs as a replacement of R22 in unitary HCs. The substantial technical assistance component (TA) of the Chinese HCFC phase out management plan (HPMP) could help the whole world in moving forward in implementing HCs.

Can R290 replace R22 unitary AC? Dr. Tingxun Li,Associate Professor, San Yat-sen University, Guangzhou, China

Flammable refrigerants can now be used safely in unitary A/Cs. Moreover, according to published test results presented by Dr. Tingxun Li, R290 is 5-15% higher in efficiency than R22.

But the question remains, is R290 dangerous? In order to assess the risk and answer this question Dr. Tingxun Li says three other questions need to be answered first:

Although R290 is flammable does that mean an AC with R290 is flammable too?
Does an AC that is flammable mean that R290 will be ignited?
If the AC R290 is ignited, must there be an explosion?

According to Dr. Tingxun Li in general people confuse the risk attributed with flammable refrigerants with the risk posed by a flmammable refrigerant AC, which are not one and the same.

Across the world 500 million HC fridges/freezers are in use, with an ignition frequency of about 1x 10^-8 per year. If HC fridges are accepted, are ACs with R290 as safe as an HC fridge/freezer? According to testing by Tian Jing Fire Research Institute in China, the answer is yes.

The Tian Jing fires test had R290 leak from AC units and ignite. Conclusions for the testing were:

R290 AC indoor unit is hard to ignite
When AC is on fire the maximum heat flux is about 3kW/m²
The highest tempeature reached is about 200°C
There is no explosion, the most dangerous is the smoke from the burning plastic

About UNEP OzonAction

The UNEP DTIE OzonAction Branch assists developing countries and countries with economies in transition (CEITs) to enable them to achieve and sustain compliance with the Montreal Protocol. With the programme's assistance, countries are able to make informed decisions about alternative technologies and ozone-friendly policies.