Blog 139 - ‘FRIDGE SYSTEMS // THEN AND NOW // MONTREAL AND KYOTO PROTOCOLS - Part I

Sometimes it is necessary for us to reflect on where we were, where we are and where we are going. This article explores some of the aspects of refrigeration.

The cold rooms on board a ship are the main sustenance islands for unspoilt provisions of vegetables, meat, fish, diary products etc for long voyages. Present day practice is to stock up on long lasting provisions in the cheapest ports and pick up fresh provisions - vegetables, fruits, meat, fish, eggs etc - at intermediate ports. So, an efficient ‘fridge cooling system is needed to preserve the items, with rooms set at different temperatures.

During sailing ship days, there was no electricity nor any refrigeration available on board to preserve food. The sailors of those days used a variety of methods to keep their provisions from rotting, at least tried to stem the rot for as long as possible. That they failed more times than succeeded is now history, given the very long voyages of months, the scurvy attacks on sailors, the delirium that sometimes comes with not eating fresh produce for long periods and the problems that are associated with eating rotting meat.

Their forays into uncharted islands to store themselves up with fresh produce, fresh game and fresh water are the stories of legends, especially when they met the residents of settlements, sometimes friendly, sometimes hostile.

To preserve their food when they left their home port, ‘Google’ tells me that Sailors preserved food on ships using a variety of methods, including: 

• Salting

• Meat was stored in barrels of salt and brine to dehydrate bacteria and prevent it from growing. One early method of salting was corning, where large grains of salt were rubbed into the meat. Salted meat was often called "junk" or "salt horse". 

• Pickling

• Fruit and vegetables were stored in sealed containers of acidic liquids like vinegar or sour whey to prevent bacteria from growing. 

• Storing in barrels

• Food was stored in wooden barrels or casks. 

• Selecting long-lasting foods

• Ships carried foods that could last a long time, such as biscuits, dried beans, salted beef, flour, raisins, rice, hard cheeses, and molasses. 

Food on ships could quickly spoil and become infested with pests like weevils, maggots, cockroaches, and rat droppings. 

Semi-perishables were stored in a cool, dry, dark place, and their other foods were either canned, jarred, bottled, salted, smoked, fermented or dehydrated.

The advent of ice factories ashore gave a fillip to the preservation process, by increasing the life of perishables during the voyages.

Of course, the catchment of fresh sea food while at sea, gave a boost to the health, culinary and gastronomic morale on board.

The words ‘victuals’ (pronounced ‘vittles’) and ‘victualling’ (pronounced ‘vittualling’ are, even now, a part and parcel of maritime lexicon. The word "victuals" comes from the Late Latin plural noun victualia, which means - surprise, surprise -  "provisions".

It is known that, as early as 1560, sailors were given their ‘victualling allowance’ or rations of “biscuits, beer, salted beef, fish, butter, and cheese and by 1588 they had added bacon and peas to the menu”.

The modern seafarer is very well aware of the word ‘victualling’, as ‘victualling allowance’ is part of the lexicon of contracts signed between ship owners and Seafarers’ Unions. Strict orders were given by the Ship Owner or Manager to the Master of each vessel that he is not to exceed a certain amount per day per seaman. At the fag end of my sailing days, this allowance amounted to (about) US$ 9 per person per day.

For a long period of time, this ‘victualling amount’ given to each member of the crew was sacrosanct, beyond the clutches of the Owner or Management Company. What to do with the amount - in terms of buying provisions for the ship - was the exclusive preserve of the Master and Chief Steward on board. But, in recent years, this monies has been usurped by some unscrupulous Management Company higher ups, flying Flags of Convenience, to the detriment of quality of food on board.

The Master’s power and prerogatives have been trampled upon a hundred times over, in order to line their own pockets.

Of course, even with a Master having exclusive rights to the allowance, it is not unheard of to see that a few Masters dipping their hands into the till and making off with a good bit of money, thereby hitting the very stomachs of the sailors they are to feed and protect.

With mechanised machinery came refrigerated machinery. Surprisingly, various refrigerated systems were introduced more to carry carcasses of meat rather than preserving the food for the seafarer - as early as the 1870s. 

1876 - The ship ‘Eboe’ had a methyl-ether refrigerating plant.

1879 on  ‘Bell Coleman’ Dense Air Machine became a popular refrigerating plant.

1890 - The J & E Hall company installed the first marine CO2 refrigerator system on the Nelson Line ship Highland Chief. (I still remember my first ship in 1970 - it had a J&E Hall R-22 ‘Fridge Compressor).

1929 - The entire ‘fridge scenario changed. Till then, most domestic ‘fridges (used at home) were using toxic gases, either ammonia (NH3), methyl chloride (CH3Cl) or Sulphur Dioxide (SO2) as refrigerants. During that decade, several fatalities had occurred to the general public due to inhalation of leaked, toxic, gases and there was a hue and cry. Some of the top companies of that period, Frigidaire, Du Pont and General Motors came together to research this. In 1928, two scientists developed a compound gas which they called Freon.

Freon represents several Chlorofluorocarbons (CFCs).

“Freon represents several different chlorofluorocarbons, or CFCs, which are used in commerce and industry. They are a group of organic compounds containing the elements carbon and fluorine, and, in many cases, chlorine and hydrogen. CFCs are colorless, odorless, nonflammable, noncorrosive gases or liquids and highly stable compounds that were used as propellants in spray cans and in refrigeration units. They are several organic compounds composed of carbon, fluorine, chlorine, and hydrogen. CFCs are manufactured under the trade name Freon.”

The Fridge and Cooling Industry merrily settled itself to using CFCs as refrigerants.

40 to 50 years later, scientists - this time chemists - Mario Molina and Sherwood Rowland (1974) found and proved that the CFCs were the direct cause of depletion of the ozone layer, which alerted all scientific bodies and the UN. In 1995, Rowland, Molina, and atmospheric chemist Paul J. Crutzen shared the Nobel Prize in Chemistry for their work.

The ozone layer protects the Earth from the sun's harmful UV-B radiation. The discovery of the ozone hole also showed how quickly human activity can negatively impact the planet.

“Sherwood Rowland and Mario J. Molina discovered that chlorofluorocarbons (CFCs) could deplete Earth's atmospheric ozone layer, which blocks the sun's damaging ultraviolet rays. When the scientists reported their findings in 1974, CFCs were widely used as refrigerant gases and as propellants in aerosol sprays.”

From Wikipedia: “Ozone depletion consists of two related events observed since the late 1970s: a steady lowering of about four percent in the total amount of ozone in Earth's atmosphere, and a much larger springtime decrease in stratospheric ozone (the ozone layer) around Earth's polar regions. The latter phenomenon is referred to as the ozone hole. There are also springtime polar tropospheric ozone depletion events in addition to these stratospheric events.

The main causes of ozone depletion and the ozone hole are manufactured chemicals, especially manufactured halocarbon refrigerants, solvents, propellants, and foam-blowing agents (chlorofluorocarbons (CFCs), HCFCs, halons), referred to as Ozone Depleting Substances (ODS). These compounds are transported into the stratosphere by turbulent mixing after being emitted from the surface, mixing much faster than the molecules can settle. Once in the stratosphere, they release atoms from the halogen group through photodissociation, which catalyze the breakdown of ozone (O3) into oxygen (O2). Both types of ozone depletion were observed to increase as emissions of halocarbons increased.

Increased cancer risks and other negative effects were predicted with the ozone depletion and the entry of more concentrated UV radiation through the ozone hole created by CFC emissions”. 

The medical fraternity predicted an increase of skin cancer, sun burn, blindness, cataracts, as well as being harmful to plants and animals.

The long and the short of it - Ozone provides the shield needed for humans.

CFCs destroy the ozone, hence has to go.

The Montreal Protocol on Substances That Deplete the Ozone Layer is an international treaty designed to protect the ozone layer by phasing out the production of numerous substances that are responsible for ozone depletion. It was agreed on 16 September 1987, and entered into force on 1 January 1989. Since then, it has undergone nine revisions, last in 2016. Even then, the ozone depletion due to the ozone hole in the North Pole is calculated to regain its 1980 levels only by about 2040, whereas the ozone hole over the Antarctica is expected to reach those levels only by 2066.

In actuality, this signing of the Montreal Protocol in 1987 and its strict implementation in 1989 is one of those rare occasions when the world, in unison, agreed on quickly acting before more damage can be done to an already vulnerable and susceptible environment.

It is necessary to now go into more details of the Montreal Protocol, as it affected our lifestyle, our working lifestyle as well as our living lifestyle. 

Some examples of Ozone Depleting Substances (ODS) include:

• Chlorofluorocarbons (CFCs)

• Halons

• Carbon tetrachloride (CCl4)

• Methyl chloroform (CH3CCl3)

• Hydrobromofluorocarbons (HBFCs)

• Hydrochlorofluorocarbons (HCFCs)

• Methyl bromide (CH3Br)

• Bromochloromethane (CH2BrCl) 

ODS are stable in the troposphere, but break down in the stratosphere when exposed to intense ultraviolet light

The distribution of atmospheric ozone in partial pressure as a function of altitude (Wikipedia)

Humanity has, by now, become accustomed to refrigerated foods. So, what is the alternative to CFCs?

There emerged two alternatives.

Hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs) are two chemical classes that are used as alternatives to chlorofluorocarbons (CFCs).

Here also there was a catch.

HCFCs contain small amounts of chlorine and have a lower ozone depletion potential. So, a compromise was reached. As a temporary measure, HCFCs can be used. The more advanced countries are mandated to cease using HCFCs by 2030 and the less advanced countries by 2040.

HFCs - One of the most widely-used replacements for CFCs is a chemically-similar group called HFCs (Hydro-Fluoro-Carbons). These compounds contain hydrogen atoms rather than chlorine, and are often marketed as 'environmentally-friendly' due to their negligible contribution to ozone layer depletion.

Controversially, although HFCs do not contain chlorine and do not contribute to ozone depletion in the stratosphere, some of the HFCs contribute to the green house gases that form part of the much touted ‘global warming’. 

Evidence of Global Warming was picturised in FB as under:

The Kyoto Protocol has emphasised a reduction in the use those HFCs.

Carbon Dioxide CO2 is also an alternative.

The common refrigerants used today are

R 134a and R 32 (HFCs)

R 407c - a blend of R 134a, R 125 and R 32

R 410a - A refrigerant with good thermodynamic properties and higher energy efficiency than R-22

R 454b - A blend of R-32 and R-1234yf, with a lower global warming potential (GWP) than previous refrigerants.

This begs the question - are HFCs and HCFCs as efficient, less efficient or more efficient than CFCs when used in the refrigeration cycle?

 HFCs and HCFCs are more efficient than CFCs for refrigeration on board because they are more thermodynamically efficient and have a lower ozone depletion potential (ODP) and global warming potential:

HFCs

HFCs have excellent thermodynamic properties, which means they can absorb and release heat efficiently. This results in better energy efficiency and, although the gas itself is costly, it has lower operating costs.

HCFCs

HCFCs contain hydrogen, which makes them less stable than CFCs and more easily broken down in the atmosphere. This results in a lower ODP and global warming potential than CFCs.

CFCs

CFCs were inexpensive to mass-produce and performed similarly to the natural refrigerants they replaced. However, they contribute to the destruction of stratospheric ozone.

AMMONIA

Ammonia is another alternative to CFCs and HCFCs. It has a low price per kg, low specific weight, and a low indirect CO2 footprint. However, it is poisonous when accumulated in high concentrations, has a distinctive smell, and is lighter than air.

So, in fact, the refrigerant gases in use today are more expensive but more sustainable - as far as earth is concerned.

In today’s world of environment consciousness, two operative words or, more accurately, two acronyms - ODS (Ozone Depleting Substances) and GWP (Global Warming Potential) are regularly bandied about.

While Global Warming Potential and Green House Gases are intimately linked, there are many sceptics who retort that GWP and Green House Gases are the playthings of the rich, the more advanced countries. They opine that the imposition of the cost of the tools needed for such environmental control are, mostly, manufactured in the advanced nations and are being deliberately foisted on the less developed countries, more as a money making scheme than an environmental improvement. Those countries have usurped the Kyoto Protocol and taken the amendments hostage to the detriment of the poorer countries. There are numerous controversies that need to be sorted out, that need to be bolstered by scientific facts.

On the other hand, the Montreal Protocol on ODS has seen quick - or as quick as they possibly can - implementation of the clauses and later amendments, because all member countries immediately recognised the potential for disaster if the world did not pay heed to the widening of the ozone hole in the stratosphere. Even with quick implementation and all the nation states co-operating, the damage to ozone layer is such that, to even regain the 1980 status, the earliest predicted year is 2040 over the North Pole and 2060 or thereabouts over the South Pole. To regain 1920 status will, likely, take till the end of the century, were we to continue to pay the price till then and lay emphasis on the cautionary measures now in place.

One of the beneficial fallouts of the implementation of the ISO (International Organisation for Standardization) clauses is that each industry started policing itself to improve standards, to improve quality, whether in the product or in the service and improve the quality of its qualified work force by systematised training and certification. (As far as the Marine Industry is concerned STCW (Standards of Training, Certification and Watch Keeping) is a prime example.

Similarly, the Refrigeration Industry has taken upon itself the task of regulating the Industry, researching, setting standards and policing itself with the mandatory audits by an outside, qualified, source, much akin to the Classification Societies of the Marine Industry.

Quite a bit of the material that I present below has been quelled from “Danfoss” website, as they seem to have a very resonant way of bringing to light the mysteries behind ODS and GWP.

One of the (newly) qualifying ISO Standards that the Refrigeration Industry has set upon itself is ISO 5149-1:2014 for Refrigerating Systems and Heat Pumps.

“ISO 5149-1:2014 specifies the requirements for the safety of persons and property, provides guidance for the protection of the environment, and establishes procedures for the operation, maintenance, and repair of refrigerating systems and the recovery of refrigerants.

ISO 5149-1:2014 specifies the classification and selection criteria applicable to the refrigerating systems and heat pumps. These classification and selection criteria are used in ISO 5149‑2, ISO 5149‑3, and ISO 5149‑4.

ISO 5149-1:2014 applies to: a) refrigerating systems, stationary or mobile, of all sizes including heat pumps; b) secondary cooling or heating systems; c) the location of the refrigerating systems; and d) replaced parts and added components after adoption of this part of ISO 5149 if they are not identical in function and in the capacity.”

There are several other statutes, which I will not go into - this being the primary one. Of course, being ten years old, several amendments have come into play, the essence is in 5149-1.

The ISO / DIS 5149-1 is presently under development and will entirely replace 5149-1:2014 shortly. This includes several sustainable development goals.

What did ISO 5149-1:2014 achieve or propose to achieve?

Introduction of refrigerant gases that 

Are Non Toxic - achieved after 1929 itself, with the introduction of Freon family of gases. 

Are Non flammable or Mildly flammable (without posing any risks) 

Is not of the family of gases that are Ozone Depleting Substances (Montreal Protocol)

Is not of the family of gases that have Global warming Potential.

Refrigerants were classed under the following headings:

Courtesy: Danfoss

Non-toxic and mildly flammable, A2L refrigerants are gaining traction as a relatively easy way to further reduce global warming potential (GWP).

With the cooling industry successfully phasing down the use of higher GWP refrigerants, countless applications are now benefiting from refrigerants that are kinder to the environment. Now, the next step is to go further, and achieve ultra-low GWP.

Natural refrigerants like R290 and CO2 are being used for a wide range of applications. But for installers looking for a cost-effective option that maintains a conventional system design, A2L refrigerants are an excellent choice—offering a GWP saving of 90% and more.

Most of the refrigerants that has come into use recently have the A2L Classification, meaning ‘mildly flammable’.

‘Mildly Flammable’ means A2L refrigerants need at least 1,000 times more energy to ignite than most A3-class flammable refrigerants.

It means that A2L refrigerants are unlikely to ignite from a discarded cigarette or a space heater. Even naked flames struggle to ignite A2L refrigerants under test conditions.

What’s more, the “L” means they have a low burning velocity. So, even in the event of ignition, the flame will likely burn slowly and self-extinguish

Refrigerants need a certain concentration in air to generate a flammable mixture. The lowest flammable concentration is the lower flammability limit (LFL).

For A2L refrigerants, the LFL is greater than 100g/m3; typically, it’s above 300g/m3.

A2L has lower flammability and toxicity compared to other classifications—making it the second safest refrigerant category.

A - Non Toxic

2 - Flammable

L - Low Burning Velocity

The primary benefit is on the GWP level. When compared to a popular refrigerant like R134a, an A2L refrigerant like the R1234yf offers up to 99% reduction in GWP. The very low or ultra-low GWP level makes A2Ls an attractive choice as regulations tighten further. They are also relatively easy to use.

The disadvantage is that they cannot be used in a retrofit. The whole plant will need to be renewed, making it the ideal choice for new buildings.

A2L refrigerants offer better performance and efficiency than many A1 and natural refrigerants—making them a versatile choice when used with the correct components and pipe sizes.

Blend refrigerants combining hydrofluorocarbons and hydrocarbons are good substitutes to decrease the flammability of hydrocarbons while reducing the global warming potential of hydrofluorocarbons. Four hydrofluorocarbon/hydrocarbon blends (R134a/R290, R134a/R600, R134a/R600a, and R134a/R1270)

Typical Schematic Diagram of Plant using HFCs

Below is a typical base layout of an older type refrigeration system. I am of the opinion that the same principles will apply to the newer gases. What will, likely, be different are the pressures and temperatures at each point in the system.

AR