Energy, Environment and Sustainability Group

Off-grid cooling for postharvest food loss reduction In the developing world: review

Rupert Blackstone, Chair, Energy, Environment and Sustainability Group

Credit-Mandy Zammit
Credit-Mandy Zammit

Our Chairman, Rupert Blackstone, gives more details of this recent event and describes a new method of vacuum cooling which greatly extends the life of the produce.

The event was held on 12 April 2018 by Sean Roche, Managing Director of Liverpool based Inviro Choice Ltd and Zaid Bani Hani, Renewable Energy Student at the Renewable Energy Group at Exeter University’s Cornwall Campus, in association with the IMechE's Food and Drink Engineering Committee and the IMechE Energy, Environment and Sustainability Group.

aid spoke about how an innovative collaboration between Inviro Choice and Exeter University resulted in a viable off-grid solution for minimising postharvest food loss reduction in less industrialised countries.

Although hunger has been a rapidly shrinking problem of recent years, post-harvest food loss is one of the most pressing issues just about to hit the world. Post-harvest food loss reduction is a significant challenge for farmers and growers in the developing economies of the world, where spoilage of produce can lead to as much as 50% of harvested food not reaching the marketplace. This is not only a tragedy for the producers themselves, who suffer from reduced income and lost business opportunities as a result, but also an environmental and resource issue in terms of unnecessary greenhouse gas emissions and wasted agricultural inputs of energy, water and land.

Many less industrially developed countries are located in tropical and sub-tropical regions where the production of perishable produce, such as fruits and vegetables, represents a substantial proportion of food production.

Cooling such produce to an optimum temperature immediately upon harvest is crucial in ensuring that food entering the supply chain has the best chance of maintaining shelf life for as long as possible. This is particularly important where ambient temperatures are high. For example, a one hour delay in removing field heat from produce harvested at about 35°C can lead to a one day reduction in shelf life. Technology for postharvest cooling is available but typically relies on grid electricity or diesel gen-set supplied power to operate. These units are typically very energy inefficient (being based across the industry on a 1950s/60s design). In a world where 1.2 billion, mostly rural-based, people have no access to reliable grid supplied electricity the provision of alternative off-grid solutions is essential. This is particularly important in the case of less industrially developed counties, where diesel gen-sets are an unsustainable solution due to high costs, unreliable fuel sourcing and fuel price volatility, as well as their potential environmental impact through greenhouse gas and other emissions.

Inviro Choice has for many years manufactured vacuum coolers for heat removal from produce at point of harvest, but these units have been powered from the grid or diesel gen-sets. Sean and Zaid explained how Inviro Choice and Exeter University had worked together to develop an off-grid, solar powered, improved efficiency (70% better) machine with onboard energy storage and water production as a side benefit to help producers in less industrially developed countries around the world. Avoidance of food waste also means avoidance of waste of the water that is associated with the cultivation of that food.

Vacuum cooling is the first stage of the cold chain. The vacuum drops down the pressure so water boils off from the product, with the transfer of latent heat for the phase change providing the cooling effect. Sean Roche explained that the Inviro Choice vacuum cooling can reduce post-harvest loss by up to 100% and can extend shelf life by more than any other cooling, in particular due to the high rate of cooling compared to alternatives. The collaboration with Exeter University was with a view to increasing affordability through economy of scale and also to increase energy efficiency. The lifecycle costing that was presented by Sean and Zaid showed significant economic advantages compared with  the alternatives. The first pilot of the ‘Eco’ off grid range is to go out to Kenya this year. Inviro Choice is seeking funding or investment to increase the roll-out of its systems.

The thinking behind the work that was presented is very much in line with the Institution's 'Tank of Cold: Cleantech Leapfrog for a More Food Secure World' report.

A good account was given not only of the technical challenges encountered and the solutions developed, but also the commercial and humanitarian plans that the company has for future deployment.

This event was held in association with the IMechE's Food and Drink Engineering Committee and the IMechE Energy, Environment and Sustainability Group on the 12th April 2018 by Sean Roche, Managing Director of Liverpool based Inviro Choice Ltd and Zaid Bani Hani, Renewable Energy Student at the Renewable Energy Group at Exeter University’s Cornwall Campus.

Sean and Zaid spoke about how an innovative collaboration between Inviro Choice and Exeter University resulted in a viable off-grid solution for minimising postharvest food loss reduction in less industrialised countries.

Although hunger has been a rapidly shrinking problem of recent years, post-harvest food loss is one of the most pressing issues just about to hit the world. Post-harvest food loss reduction is a significant challenge for farmers and growers in the developing economies of the world, where spoilage of produce can lead to as much as 50% of harvested food not reaching the marketplace. This is not only a tragedy for the producers themselves, who suffer from reduced income and lost business opportunities as a result, but also an environmental and resource issue in terms of unnecessary greenhouse gas emissions and wasted agricultural inputs of energy, water and land.

Many less industrially developed countries are located in tropical and sub-tropical regions where the production of perishable produce, such as fruits and vegetables, represents a substantial proportion of food production.

Cooling such produce to an optimum temperature immediately upon harvest is crucial in ensuring that food entering the supply chain has the best chance of maintaining shelf life for as long as possible. This is particularly important where ambient temperatures are high. For example, a one hour delay in removing field heat from produce harvested at about 35°C can lead to a one day reduction in shelf life. Technology for postharvest cooling is available but typically relies on grid electricity or diesel gen-set supplied power to operate. These units are typically very energy inefficient (being based across the industry on a 1950s/60s design). In a world where 1.2 billion, mostly rural-based, people have no access to reliable grid supplied electricity the provision of alternative off-grid solutions is essential. This is particularly important in the case of less industrially developed counties, where diesel gen-sets are an unsustainable solution due to high costs, unreliable fuel sourcing and fuel price volatility, as well as their potential environmental impact through greenhouse gas and other emissions.

Inviro Choice has for many years manufactured vacuum coolers for heat removal from produce at point of harvest, but these units have been powered from the grid or diesel gen-sets. Sean and Zaid explained how Inviro Choice and Exeter University had worked together to develop an off-grid, solar powered, improved efficiency (70% better) machine with onboard energy storage and water production as a side benefit to help producers in less industrially developed countries around the world. Avoidance of food waste also means avoidance of waste of the water that is associated with the cultivation of that food.

Vacuum cooling is the first stage of the cold chain. The vacuum drops down the pressure so water boils off from the product, with the transfer of latent heat for the phase change providing the cooling effect. Sean Roche explained that the Inviro Choice vacuum cooling can reduce post-harvest loss by up to 100% and can extend shelf life by more than any other cooling, in particular due to the high rate of cooling compared to alternatives. The collaboration with Exeter University was with a view to increasing affordability through economy of scale and also to increase energy efficiency. The lifecycle costing that was presented by Sean and Zaid showed significant economic advantages compared with  the alternatives. The first pilot of the ‘Eco’ off grid range is to go out to Kenya this year. Inviro Choice is seeking funding or investment to increase the roll-out of its systems.

The thinking behind the work that was presented is very much in line with the Institution's 'Tank of Cold: Cleantech Leapfrog for a More Food Secure World' report.

A good account was given not only of the technical challenges encountered and the solutions developed, but also the commercial and humanitarian plans that the company has for future deployment.

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