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Thermal test chamber – a step towards food safety

Thermal test chamber – a step towards food safety

By John Ackermann
The culmination of four years of hard work resulted in a newly launched test chamber for refrigerated vehicles (the first in Africa), which was officially transferred to the South African Bureau of Standards (SABS) on 23 May 2017.

The project was made possible by various stakeholders in the cold chain industry, who were able to see the finished chamber for the first time during the final steering committee meeting.

The project was implemented from April 2013 to May 2017 and was commissioned by the German Ministry for the Environment, Nature Conservation, Building and Nuclear Safety (BMUB). The expected accumulated emis¬sions savings potential amounts to two million tons CO2-equivalent by 2030.

“At a time when ‘green’ intelligence and the labelling of carbon footprint is creeping into the South African economy and the creation of job opportunities, the Department of Trade and Industry (dti) welcomed the partnerships with the GIZ refrigerated distribution project,” said Gerhard Fourie, chief director green industries (dti), in his welcoming address.

He went on to tell those at the opening of the SABS vehicle thermal test chamber that any improvement in the energy efficiency of the transportation of perishables is an improvement in the bottom line of life. “We all depend on perishable foodstuffs for a healthy lifestyle and the GIZ project is a giant step towards sustainability in that direction,” he said.

In October 2011, GIZ started the groundwork of a project that would mitigate the carbon emissions from the transportation of temperature-sensitive perishables in South Africa. The project — funded by the German Ministry for the Environment, Nature Conservation, Building, and Nuclear Safety as part of the International Climate Initiative (IKI) — would partner with the South African government (the dti, the Department of Environmental Affairs, the Department of Transport, and others), and trade associations.

After collaboration with role players and trade associations, a chamber to test the thermal performance of refrigerated vehicles used in the transportation of perishables was agreed upon as an important element of the GIZ project.

Following a transparent procurement process of public tenders and engagement with all role players, the chamber was completed and officially opened on 23 May 2017.

To ensure consistency and the accuracy of tests done in the chamber, a standard — SABS 1744 — has been drafted and published.

Joost Schmallenbach, head of the Political Department in the German Embassy, added to Fourie’s views. “Although not a scientist, it makes good sense to me to optimise the performance of refrigerated vehicles with the least energy usage and to safeguard the food that we eat. The German government invested EUR3.5-million towards the refrigerated transport project in South Africa and is one of 514 projects done worldwide to mitigate climate change.” Although one of many similar projects, he pointed out that small changes done over time lead to big change and impact positively on the economy in the long term.

The vehicle thermal test chamber is the latest addition to the many test stations and laboratories at the extensive facilities and head office of the SABS in Groenkloof, Pretoria. The unveiling of the chamber was welcomed by Amamda Geabashe, executive testing (SABS). “Our staff has enjoyed a close collaboration with the GIZ-appointed consultants, Cemafroid in France, to ensure that the chamber is operated according to international standards. The testing of refrigerated road vehicles is new to the SABS and we welcome a close collaboration with industry role players to maximise the benefit of this important investment.”

Cemafroid was afforded the consultancy services for the test chamber and provided exchange opportunities in terms of design, implementation, commissioning, and training. SABS personnel were extensively trained at the SABS and at Cemafroid in Paris. The staff was declared competent by Cemafroid to carry out all relevant tests. An Interlab comparison between Cemafroid and the SABS was carried out successfully.

‘Mans’ Rehaman, national chair of the South African Vehicle and Body Builders’ Association (SAVABA), thanked the GIZ for the confidence shown in South Africa and the investment made in the local body building industry. “The visits by overseas body builders and the transfer in manufacturing technology will go a long way towards setting new manufacturing standards.”

A long time coming
A chamber to test the thermal performance of road vehicles of maximum legal length has been mooted in South Africa since the late 1980s. A chamber similar to those in Europe was high on the agenda when the South African Refrigerated Distribution Association (SARDA) was founded in June 1990. The SARDA code of practice states: “Implementing the cold chain in the distribution of perishable products published in September 1993, the heat leakage rate for refrigerated vehicles was recommended as 0.4W/m²-°K.”

After two visits to South Africa by Robert Heap, John Ackermann of SARDA went to view the Shipowners Refrigerated Cargo Research Association (SRCRA) test chamber at Cambridge, UK, in 1992, with the intention of a transfer of technology to establish a chamber In Cape Town. “The lack of funding shelved the building of a chamber and was only revived when GIZ started their project in South Africa in 2011,” Ackermann recalled at the unveiling of the SABS chamber.

Maintaining the cold chain
Speaking with a passion for the cold chain industry, Ackermann continued: “All too often there is a misconception about the importance of low heat leakage rates of refrigerated vehicles for long distance transport or the local distribution of perishables. It all revolves around energy usage, low carbon emissions, and food safety.” The higher the heat leakage, the more energy (diesel or grid power) is required to maintain temperature. Admittedly, if the heat leakage rate is high, all that is needed is a refrigeration unit with a higher cooling capacity — but with a higher fuel bill and larger carbon footprint. However, in the event of the refrigeration system failing or the system being switched off for whatever reason, the higher the heat leakage rate will be because of poor insulation, body manufacturing defects, or poor maintenance. The increase in cargo temperature will be quicker, too. Temperature variations influence food safety, which is of prime concern to everyone, including each person at the opening celebration and their family members.

The export of perishables is a major contributor to the economy of South Africa and relies heavily on refrigerated vehicles and reefer containers able to maintain cargo temperatures at optimum levels until the destination in Europe, the Far East, or Africa is reached. Refrigerated transport of the best performance also plays an important role in the distribution of pharmaceuticals and vaccines across Africa. Vaccines are temperature sensitive and run the risk of being ineffective if subjected to high temperatures during the distribution chain.

The unveiling of the SABS thermal test chamber has been recorded as a milestone and the beginning of a new era in refrigerated transport in South Africa.

The chamber at the SABS is a step in the right direction and is in keeping with the technological advancement being made in every aspect of refrigerated transport. “A test in a chamber is the only foolproof method to quantify the heat leakage rate of a new or used refrigerated vehicle,” said Ackermann during his speech. Random sample testing of the vehicles presently operating on South Africa’s highways will indicate how well equipped they are for their present duties, which often vary from chilled loads one way and frozen on a return trip. GIZ deserves all the praise for the bold step of investing so much in the local refrigerated transport industry.

Upping quality and performance
Transporters and body builders are urged to make full use of the chamber, not because of legislation, but to benchmark their quality standards and performance. Every litre of diesel saved to maintain temperatures improves profitability and reduces carbon emissions for the good of humankind.

To ensure consistency and the accuracy of tests done in the chamber, a standard — SABS 1744 — has been drafted and published. Enforcement of this standard will also ensure that any locally tested vehicle can safely be sold to foreign buyers with the assurance that the thermal performance meets international standards.

Introducing R290
The conversion of a transport refrigeration unit charged with R404A (GWP 3260) to a natural refrigerant R290 (GWP 3) was another element of the GIZ project. A locally produced Transfrig model MT450 unit was chosen for the pilot project. Bill Wilson, technical director of Transfrig, presented an overview of the project and the potential commercial benefits.

The refrigerant charge of the unit was reduced from 3.5kg to only 600g, the coefficient of performance (COP) improved between 25% and 30% (depending on the duty), and some of the piping reduced from 10mm to 7mm (evaporator) and from 10mm to 5mm in the condenser.

Being a class A3 refrigerant with a high level of flammability, the biggest challenge was to meet all the requirements to prevent an explosion. The tests were extensive and inclusive for all possibilities of leakage from the system.

The testing and design changes were done with the guidance of consultant Daniel Colbourne of the UK.

The unit is undergoing field trials on a 4m body for the local distribution of ice cream in Johannesburg. The performance thus far is encouraging, which indicates that the unit could become a standard production model.

Open for business
As of 23 May 2017, the thermal chamber was handed over by the German Embassy to the SABS. On opening the 5m-high doors of the chamber, Herman Strauss, senior manager of the SABS, was keen to explain the layout and functioning of the chamber.

“For the commissioning of the chamber, a sample body, which had been tested in the Cemafroid chamber in France, was tested in our chamber. The results were almost exact; in fact, our time to achieve stable conditions was slightly better than those in France,” he said.

The chamber is now fully commissioned and ready to accept vehicles for testing. The chamber will be operated by Constant Pretorius, with the measurements and calibration of instruments done by registered petrologist, Joshua Msimanga.

Getting tested
When asked, Pretorius indicated the charges for testing. “The charge for a test to determine the K factor is estimated at R45 000, and the time required will vary from two to five days. My advice is that interested parties contact me and I will discuss the tests and charges in detail.”

A new era
The unveiling of the SABS thermal test chamber has been recorded as a milestone and the beginning of a new era in refrigerated transport in South Africa. The industry salutes GIZ on such a magnanimous initiative to reduce the carbon footprint of refrigerated transport in South Africa.

Click below to read the July/August 2017 issue of Cold Link Africa

CLA JulAug 2017


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