See you at the SAIRAC Dreosti Memorial Lectures

Dr Guido Dreosti

Dr DreositDr Guido Dreosti, founding president of SAIRAC.  Died 7 September 1997 at the age of 92.

At the inaugural meeting of the South African Institute of Refrigeration held at Hotel Bordeaux in Cape Town on 17 July 1951, Dr Guido Dreosti was elected the founding president. The initial membership was 41, with Dr Dreosti being allotted membership number 1. He was president for the first five years and again in 1957/58 and 1962/63.

In 1962, the institute widened its scope to include air conditioning and became the South African Institute of Refrigeration and Air Conditioning (SAIRAC). Since 1951, until February 2019, 4 538 persons have joined SAIRAC.

Dr Dreosti was a true scientist and had a wide range of interests pertaining to the food industry, particularly fish and fruit and its preservation by means of refrigeration. His qualifications had an engineering flavour to them and culminated with a doctorate in engineering physics from the University of Utrecht in Holland in 1930.

Milestones in his career include:

  • Research into the pre-cooling of fruit for the South African export industry from 1930 to 1940.
  • Director of the Fishing Research Institute, Cape Town.
  • Technical adviser to the Perishable Products Export Control Board (PPECB).
  • Research professor at the University of Cape Town.

Dr Dreosti published over 300 papers on subjects in the fields of refrigeration, dehydration, canning, and so forth. He made a lasting and valuable impact on humankind and left the world a better place.

SAIRAC launched the Dreosti Memorial Lecture in 1998 in memory of and to honour the outstanding achievements and leadership of its founder. The Dreosti lecture exemplifies the objective of SAIRAC to promote the unrestricted dissemination of knowledge and information.

Design, maintenance, and conversion of systems to R290 as an alternative refrigerant with very low GWP and as practical as R22 

Few would argue against an urgent reduction of whatever contributes towards global warming. With much relevant, factual evidence of a global increase in average temperatures, the causes of this trend need to be addressed.

Dr HasseDr Volkmar Hasse.

Many synthetic refrigerants are a major contributing factor towards stratospheric ozone depletion in some cases, as well as having major global warming potential (GWP) when allowed to escape from refrigeration or air-conditioning systems. Some systems may be ‘greener’ in terms of energy consumed to operate but with a refrigerant that is harmful to the environment, or vice versa. How does one evaluate each solution and compare with others?

To aid the evaluation, a standardised method of calculation was developed to calculate the potential impact of a system at the design stage. This is known as the total equivalent warming impact (TEWI) index.

Consider the huge numbers of applications making use of R22 currently. Is it feasible to replace all these applications with CO2 as refrigerant? It is possible, but economic and practical factors need to be considered.

CO2 (R744) is an alternative and a very good one at that. It does require a high level of skill to build the systems and operate it safely. Being an alternative, it means replacing an existing R22 installation completely.

What if it were possible to replace the R22 with an alternative refrigerant without changing the entire installation? With some minor modifications to existing R22 systems, this is indeed possible. We are able to see this from global research and applications — R290 can indeed be used to retrofit R22 systems.

This application of R290 is not new. With the discovery that CFCs like R11 and R12 were contributing handsomely to the stratospheric ozone depletion, alternative synthetic refrigerants were developed with a much lower ozone depletion potential (ODP) to lower the environmental impact. (R22 being a primary example — but R22 still has a small ODP.) In some cases, the shift to hydrocarbons (HC) was made decades ago. Looking specifically at domestic appliances and light commercial refrigeration systems, most of these systems are produced today using R290 or R600a as refrigerant.

Yes, there absolutely are matters that need to be resolved to reduce risks when it comes to the flammability of R290. Others have done so to a large extent already for us to learn from and expand upon.

From the lectures to be presented by Dr Hasse, detailing all aspects around the use of R290, we trust you will be in a position to benefit from the relevant information and to equip you in the design, maintenance, and potential conversions of systems to R290 as an alternative with a very low GWP and as practical as the currently used refrigerants in many ways.

Dr Hasse retired in February 2018. His last position held was senior programme director, GIZ: Low Carbon Urban Development Programme, China.

His strengths and competencies

Obtaining a PhD in Applied Biology from the University of Giessen, Dr Hasse’s career span nearly 40 years (1978–2017) as government advisor in several German economic cooperation partner countries through international cooperation projects in the role of:

  • Negotiation and implementation of sustainable environment measures, including technology transfer and applied integrated environmental protection projects.
  • Advice to transfer environmentally friendly technologies, including related policies and regulation, and economic aspects for urban and industrial climate protection, on substances that deplete the stratospheric ozone layer, and in agricultural pollution prevention.
  • Energy management systems for greenhouse gas emission avoidance in industrial and urban environments and ozone friendly technologies in the sectors of refrigeration, air conditioning, and insulation foam production.
  • Specific experience in agriculture in plant production, horticulture, plant protection, soil and irrigation management, agricultural pesticide management, biological pest control, and agricultural biodiversity.

This included an eight-year period leading and managing a complex global environmental programme (German bilateral contribution to the Montreal Protocol on Substances that Deplete the Stratospheric Ozone Layer) with 40 partner countries, over 160 individual projects, and total funding exceeding EUR70-million. He made contributions to international environmental agreements on stratospheric ozone layer and global climate protection, his responsibilities covering policy, advice, capacity building, and technology transfer.

His background also covers a 20-year period of experience with advising Chinese policymakers on technology transfer energy management in urban and industrial applications; and in environmentally friendly technologies for the refrigeration, building insulation foam, and agricultural sectors. In addition, he successfully negotiated a variety of key policies and projects.

Dr Hasse enjoyed more than a decade of multilateral cooperation with the United Nations and cooperation with national governments, including China, India, Brazil, Iran, Thailand, Egypt, South Africa, and Kenya, as well as many smaller partner countries.

Book your spot
To attend any of the four events, visit and complete the entry form to be returned to the SAIRAC national secretary, Marlene Gamble at There is no entry fee and a cash bar will be available.

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