Cold storage
Cold storage

Cold storage

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TL;DR

  • Keeping things cold requires a lot of energy, and the cold storage industry is experiencing unprecedented growth between the increasing demand for fresh food and the development of new vaccines. These are vital products, so while the cold chain needs to optimize energy consumption and reduce emissions, service reliability is absolutely crucial.
  • Most cold storage warehouses are decades old and pieced together by multiple contractors (plumbers, electricians, etc.) using systems that are not optimized to work together.
  • System analytics and predictive maintenance for cold storage optimization can slash energy consumption while increasing system reliability and increasing the lifespan of high-cost equipment.

Cold storage

Refrigeration is necessary for storing and transporting food and pharmaceuticals but is also used in data centers, research facilities, and sports arenas. It keeps our food fresh, prevents computer servers from overheating, and enables nuclear research.

The Covid-19 pandemic changed the world in many ways, one of which is the astronomical growth in online grocery shopping. Monthly consumer spending on online groceries has doubled since before the pandemic, and that level of convenience has become the new normal for many shoppers. In the US in 2020, 79% of shoppers were ordering their groceries online, up from 19% the year before.

Cold storage applications vary from items that need to stay chilled, like fruits and veggies, all the way to “ultracold” storage for medicines and vaccines. These facilities represent a significant investment, and a new cold storage warehouse can cost around twice as much to construct as a regular warehouse. Cooling processes alone can account for 60-70% of the electricity demands, with frozen warehouses using 30% more electricity than chilled (per capacity unit).

Source:
Source: My Climate Journey

Refrigerants

Refrigerants seem to involve a lot of trial and error, at the unfortunate expense of the environment in most cases. Chlorofluorocarbons (CFCs) were developed in response to early refrigerants that killed people when they leaked. Chemists succeeded in creating safe substances to use around people, but they also created something that was also destroying the ozone layer. To our credit, once it was discovered that CFCs were eating away the ozone layer, the world quickly came together to ban them.

Hydrofluorocarbons (HFCs) were developed to replace CFCs and be safe for the ozone layer, but it turns out that one molecule of HFC can absorb thousands of times more heat than a molecule of CO2 (depending on the formula, up to almost 15,000 times more!). So now, the EU and the US are also working to phase out HFCs.

What are the other options?

  • Hydrofluoroolefins (HFOs): The latest generation in fluorine refrigerants, HFOs have a low global warming potential and do not damage the ozone layer. It is important to know that HFOs in the atmosphere will break down into something called trifluoroacetate (TFA), which will eventually end up in water bodies (not good for aquatic organisms) and is impossible to remove via current water treatment technology.
  • Natural refrigerants: The idea here is only to use substances that occur in nature (propane, ammonia, CO2) as refrigerants to avoid making more mistakes that will be difficult to reverse. The benefit of using substances already found in nature is that we already know what those impacts will be and can take appropriate measures to mitigate them.

Climate impact

The entire RAC sector (refrigeration and air conditioning) accounts for about 10% of global emissions and uses 17% of global electricity. In developing countries, cooling can consume as much as 30% of all electricity used. The demand for electricity in the cooling sector is expected to triple by 2050.

The cold chain as a whole (storage and transportation) is estimated to be responsible for about 2.5% between energy consumption and refrigerant emissions (from leakage and improper end-of-life disposal). Energy use is the largest source of emissions, accounting for about 70%.

  • The percent of global emissions from cold storage jumps to 4% if food loss is included.
  • Within the food industry, refrigeration accounts for about 60 to 70% of electrical energy consumed.

The market

The cold chain market (storage, transport, and distribution) was been valued at $232 billion in 2021 and is expected to grow to $583 billion by 2030. Global capacity for cold storage grew by 16.7% from 2018 to 2020, reaching 716 million m3.

  • Largest unmet markets: Mexico, Brazil, and China

Within the cooling sector, industrial refrigeration experienced the highest growth (5.1%) between 2018-2020, with transport refrigeration following closely behind (4.8%).

Source:
Source: UNEP & FAO, 2022

Challenges

Cold storage warehouses are usually pieced together by multiple suppliers and specialized workers—they require plumbing, electricity, ventilation, and insulation. When all of the various components come together, those systems are usually not optimized to work together. This places unnecessary strain on high-cost items like refrigeration compressors, greatly reducing their lifespan and increasing the electricity demands of the system as a whole.

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The average cold storage facility is 42 years old, and 78% of cold storage facilities in the US were built prior to 2000.

Ensuring reliability

A lack of proper refrigeration can lead to food loss and even death when we’re talking about the loss of vaccines and medicines. Think of the cold chain as a bridge that connects perishable items to consumers. If there is a problem with the bridge, fewer of those perishable items will make it across.

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The amount of food lost due to a lack of effective refrigeration is estimated to be 526 million tonnes yearly, or enough to feed one billion people.

Vaccines are an example of a product that has very strict temperature control requirements. Depending on the vaccine, those requirements range from -80°C to 8°C, with usually narrow windows, and the situation can quickly become problematic if temperature control fails, even for short periods of time. mRNA vaccines, like the Covid-19 vaccines, require these ultracold storage solutions, and this puts much higher demands on already stressed systems. A single ultracold (or ultralow) freezer consumes as much energy as an entire average home does, with some research facilities and hospitals operating hundreds of them at a time.

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Up to 50% of vaccines are wasted every year, and according to the World Health Organization, this is largely because of failures within the cold chain system, or a lack of access to adequate cold storage.

Fire prevention

Maybe not obvious at first, since fire isn’t the first thing that comes to mind when considering low temperatures, but cold storage facilities always have a fire risk because the air inside is so dry. Furthermore, once a fire has started, the thick insulation and walls will keep the heat and smoke trapped inside. A standard sprinkler system won’t cut it here. Fire detection and prevention systems must be able to withstand and work at extreme temperatures.

Opportunities

One refrigerated warehouse consumes an average of 24.9 kWh of electricity per square foot, versus 6.1 kWh for non-cold storage facilities. The typical cold storage facility is between 150,000–400,000 sq ft meaning an electricity use of 3,735,000–9,960,000 kWh per year.

Potential savings:

  • 17% consumption reduction: 635,000–1,700,000 kWh/year
  • 40% consumption reduction: 1,500,000–4,000,000 kWh/year
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4,000,000 kWh ≈ 1,500 tonnes CO2* *based on average US electricity generation estimates

Software based solutions

  • System analytics:
    • Addressing temperature control in large storage facilities (>100 m3) has an average payback of fewer than two years.
    • Load management has been estimated to reduce the electrical consumption of refrigeration compressors by 17%. It can extend the life of the machines by reducing their overall operating time without compromising temperature requirements.
    • Predictive maintenance: Collecting data about when, why, and where failures and abnormalities occur (and how temperatures fluctuate in relation) can be used to inform predictive models and prevent those issues before they occur. Moving away from purely reactive maintenance can reduce or potentially even eliminate downtime, preventing loss of stocks and reducing costs.
  • Logistics management: Optimizing delivery routes can help reduce the travel time for cold storage products.

Retrofitting

A survey of 38 cold food stores across Europe showed that significant energy savings could be achieved by optimizing usage and repairing/retrofitting equipment: on average, 28% but up to 72%. 54% of the issues found had paybacks of less than one year, and 83% had paybacks of less than five years.

New cooling methods

  • Magnetic refrigeration: Certain metals will increase in temperature when a magnetic field is applied—this is called the magnetocaloric effect. Once that magnetic field is removed, the metal will cool down again. Liquid can be used to carry away the excess heat that was generated while the magnetic field was applied, and then when the field is removed, the material will cool enough to be used as a coolant.
  • Ionocaloric cooling: When a solid material melts, it absorbs heat from its surroundings. In ionocaloric cooling, an electric current causes a flow of ions that drive a phase change from solid to liquid - absorbing heat and cooling the surroundings. Because the material is in liquid form, it can easily be pumped away. When the current is removed, the material returns to liquid form, and the heat is released.
    • Using CO2 captured from the atmosphere can be used to create the cooling material.

Resources

Last updated: June 2023