detected by its odour , enabling one to be quickly cared for by professional trained technicians . Therefore don ’ t neglect to train your staff working in the environment and plant room .” |
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CAREL
t-Store is CAREL ’ s modular and scalable solution .
the water and a second circuit is cooled with this water to cool the water being used in the building . The possibility to get ammonia into the second circuit is thereby minimised ,” she adds .
Ammonia is produced in South Africa and is much cheaper than other refrigerants , with Sasol producing about 610 000 tons annually .
Döbelin lists bigger plants using ammonia as :
• Large cold stores used for export of fruit – citrus , apples and pears
• Decidua sub-tropical fruit uses exclusively ammonia
• Breweries
• Wineries
• The chicken industry uses ammonia for spiral and holding freezers
• Cold stores for holding imports and exports from other countries
• The food distribution industry uses ammonia for freezer holding rooms ( one plant was build and commissioned in 2015 in Johannesburg to hold 45 000 pallets of frozen goods )
• Abattoirs mainly use ammonia for large and smaller plant – for instance , City Deep slaughters 6 000 to 8 000 heads a day
• Using ammonia for freezing products in plate freezers
• The ice cream industry
• The fishing industry to produce flake and slush ice
• In gold mines flake and slush ice are also used
• Ice skating rinks
Döbelin describes the regulations in South Africa : “ The first Ammonia Safe Handling Course was demonstrated and implemented in 2004 at OTTC , which OTTC and ACRICSA
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developed and registered at SAQA to enable regulation and standards for ammonia in 2014 . The first assessment and cards were thereafter issued to the first participants . SARACCA is the official organisation for this regulation for South Africa
“ In October 2014 the regulations of our standards became law . They are regulated in South African National Standard ( SANS ) 1017 , the regulations being similar to those in the EU , but in some areas even stricter . Most of our pressure vessels have to be stress relieved ( post weld heat treatment ). Compulsory checks of all plants are in place with monthly , three monthly , annual and three yearly checks having to be done . These are to be carried out by trained persons with a license to work on ammonia plants and must be recorded in a compulsory logbook .”
“ The recordings and other compulsory checks are checked by AIA ( authorised inspections authority ) every three years , for example , by globally recognised testing and certification body TUV . Several institutes in South Africa are authorised to train technicians to obtain the required license .
“ Three levels are available and have to be renewed every three years :
• Level A : is the operator and cannot work on the plant
• Level B : is the person who can maintain and repair the plant
• Level C : is the designer , commissioning engineer and inspector
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Döbelin suggests the future of ammonia is bright as it is the best oldest and natural refrigerant . “ Most of the people are afraid of ammonia because it can be dangerous when one is exposed to it . In fact it is a very safe refrigerant because its self-alarming and even the smallest leak can be immediately |
R32 AND GLOBAL WARMING POTENTIAL
According to a White Paper 4 by Daikin Corporation on R32 , hydrofluorocarbons ( HFCs ), as the name suggests , are compounds containing hydrogen , fluorine and carbon . They are used for residential and commercial heating , ventilation , and air conditioning ( HVAC ) as refrigerants , by firefighters as a fire suppressant , and in aerosols as propellants . HFCs are also greenhouse gases often described in terms of their global warming potential ( GWP ), which is the tendency of a substance to persist in the environment while absorbing energy and , thus , retain higher energy and temperatures in the atmosphere .
GWP ratings for substances and material that contribute to the potential of global warming are developed by the Intergovernmental Panel on Climate Change ( IPCC ), a United Nations body responsible for assessing the science related to climate change . 1
GWP uses the same scale to evaluate all substances and materials , making comparisons of direct emissions of refrigerants easy . For example , R410A – a commonly used HFC refrigerant over the past two decades – has a GWP of 2088 , which suggests that each kilogram of R410A emitted to the atmosphere is equivalent to 2088 kilograms of CO 2 emissions . Different refrigerants have different GWPs :
R32 , or difluoromethane ( CH2F2 ), is an HFC refrigerant with a GWP of 675 , which is markedly lower than that of R410A and many other commonly used refrigerants . However , GWP is only one refrigerant property and not the only measure of a refrigerant ’ s environmental impact when employed in HVAC systems .
To estimate the total emissions-related effects of a refrigerant ’ s use in HVAC systems , environmental researchers often employ a methodology known as Life Cycle Climate Performance ( LCCP ) modelling . LCCP modelling estimates the total direct and indirect greenhouse gas emissions over an HVAC ’ s system ’ s lifetime , from manufacturing to disposal and recycling .
Put differently , an LCCP analysis considers a refrigerant ’ s physical properties and thermodynamic performance as well as the impacts of that refrigerant ’ s use in an HVAC system to estimate total CO 2 equivalent emissions over that HVAC system ’ s lifetime .
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Andrew Perks
Andrew Perks is a subject expert in ammonia refrigeration
R-32 ’ s properties can help HVAC engineers design systems that have a lower greenhouse gas emission impact than R410A . R-32 has greater latent heat capacity than R410A , which means that R-32 systems could be designed to achieve the same capacity performance by circulating less refrigerant at a lower flow rate through the compressor . A lower charge of R-32 refrigerant in comparison to R410A allows HVAC engineers the opportunity to design smaller compressors and coils .
These characteristics of R-32 help give engineers the tools they need to design R-32 systems with energy savings and a reduction in the material used . These indirect benefits can have a significant impact on the environment that are not accounted for in a GWP rating alone .
Daikin lab tests on rooftop systems equipped with inverter-driven compressors and water-cooled chillers found that fullload and part-load efficiency rating metrics improved by up to 12 % by using R-32 as compared to R410A . Daikin engineers have also found that R-32 can be used in heat pump and cooling applications and extreme cold and hot climates with improved performance over R-410A . According to the EIA projections , 94 % of the required energy for operating air conditioning systems was provided using electricity from nonrenewable sources . CLA
REFERENCES
1 . Previous issues of Cold Link Africa – contributor Andrew Perks 2 . CAREL media release 3 . Open Trade Training Centre ( OTTC ) 4 . White Paper by Daikin Corporation on R32
Regrigerant – 32Reasons . com
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