low carbon

We are currently working with Judith Evans and her team from FRPERC* at Bristol University to explore new applications of a relatively ‘old’ technology called Air Cycle.

Air cycle refrigeration systems use air as their refrigerant, compressing it and expanding it to create hot and cold air.  This technology was originally developed in the late1800’s for transporting frozen food from the antipodes or the Americas on board ships.  With the invention of CFCs in the 1930’s there was then a shift away from air cycle technology.  Currently air cycle is utilised in most passenger aircraft and in the German high speed trains, both for air-conditioning purposes.

Recent concern about the damaging environmental effects of certain chemical refrigerants, along with a desire to reduce energy use, has prompted a resurgence of interest in this low-carbon technology.  We are working with Judith and a number of food companies on a Defra funded LINK project to develop a commercially viable prototype, which can be used in the food industry. 

There are many advantages of air cycle over conventional technology for cooking and cooling/fast freezing food including:

• Creation of very high cooking temperatures (250ºC) and very low cooling temperatures (-125 ºC) with just one integrated piece of equipment
• This combined heating and cooling facility results in a highly efficient production processes and lower energy usage
• Air unlike conventional refrigerants such as HCFCs/HFCs/ammonia is free, safe and environmentally benign.
• Air cycle equipment is more reliable than vapour-compression systems, and does not leak environmentally harmful refrigerant (meaning less maintenance and down time). 
• Air cycle has the potential to make significant carbon savings if it were used efficiently by food manufacturers since it is estimated that refrigeration systems use as much as 15 percent of the total energy consumed worldwide.

Lowcarbonworks is helping Judith and the project team to identify potential barriers to the adoption of this promising new technology, and to explore ways to overcome these.  So far we have identified barriers which are not just about the performance of the technology itself, but have as much to do with the ‘human’ and organisational issues surrounding its adoption, such as:

• Communication barriers - in a project team composed of experts in the technology and non-experts it can be challenging to find a universally understood language.
• Internal competition issues can sometimes crop up for project partner - where the new technology may threaten their existing business.
• There may be competition issues between project partners which need careful handling - for example, discussions about Intellectual Property rights.
• Representatives on the project team may find it hard to ‘sell in’ the project to their own companies - particularly where it does not immediately align with management priorities or these may have changed since the start of the project.
•  Previous studies of Defra LINK projects have shown the need for a customer to champion the project in order to pull it through effectively to commercialisation.  Projects are in danger of stalling where this role is not fulfilled.

As part of the project we are also interested in how niche technologies, such as air cycle, get adopted into the mainstream market, and the process by which ‘closure’ around a particular design or application occurs.  Air Cycle is an interesting example of a technology which has not yet become ‘locked in’ to its final form, as multiple applications for this technology remain open (i.e. for cooking, refrigeration/freezing and air-conditioning). There are also inquiries coming in about this technology from industries other than food (including the building and defence industries) which may well shape its final form.  As part of the Lowcarbonworks project we will be tracking the development path that Air Cycle takes, and inquiring into the influences around this, as a way of building theory about how the transformation to low-carbon technologies can be accelerated.

*FRPERC is the Food Refrigeration and Process Engineering Research Centre, attached to the University of Bristol.

The bioreactor in a laboratory at Birmingham University 

A way to create hydrogen from sugary wastes is being pioneered by a spin-out company of Birmingham and Oxford Universities. Biowaste2energy Ltd was launched in February 2008 to commercialise a technology which can convert food waste into economic quantities of hydrogen.

The Waste and Resources Action Programme (WRAP) estimates that the UK produces about 18m tonnes of food waste per annum.  The majority of this is currently sent to landfill. Being able to convert this waste into energy makes economic sense as both the cost of waste disposal and of energy is rising.

Funding to encourage this kind of project was also announced this month.

 Hydrogen is seen as a “clean” fuel and development of the Hydrogen market (currently valued in Europe at €1.1bn and growing at 10% pa) is progressing rapidly.  Hydrogen can be utilised in a number of ways including conversion to electricity via thermal treatment or in fuel cell or as a fuel in its own right. BMW and Honda have developed hydrogen powered cars and the Greater London authority has commissioned a pilot trial of hydrogen powered buses. 

Biowaste2energy aims to develop the technology to handle a number of different waste streams including mixed food waste. It currently targets sugary food wastes using a two stage fermentation process with patented novel membrane separation technology. This  has the potential to provide a low cost, local solution for dealing with a number of wastes from commercial, industrial and municipal sources. They will initially target customers who can convert their waste into energy on-site, providing them with a dual benefit of avoiding waste disposal costs and a reduction in energy costs.

If you are interested in this story you may also like to stay in touch with action research on anaerobic digestion.

Waste to energy plant, Avonmouth. (Image: Compactpower)

Bath Action Researchers, Michelle Williams and Gill Coleman, are starting work with the Food Processing Knowledge Transfer Network on a project to help the adoption of different technologies for the conversion of food waste into energy.

Several proven technologies exist, such as, gasification and pyrolysis and anerobic digestion. Many small to medium sized companies are keen to use them but are struggling to do so. The project will look at how the barriers that stand in their way may be removed. For instance, one legislative barrier which has been suggested is the need for companies to register as “waste processors” if they use this technology. This places a huge adminnistrative burden on smaller companies.

Identifying such barriers and feeding information back about them to legislators and policy makers is expected to be a very helpful output. For instance, Defra is promoting food waste conversion as part of their “Food Industry Sustainability Strategy.” (April 2006) but needs also to create an enabling framework for this to happen more widely.

The Food Processing KTN is a government sponsored body (through the DTI and DEFRA) aimed at encouraging the transfer of knowledge between companies within the food industry and between industry and the university sector. It seeks to stimulate innovation and facilitate the introduction of new techniques and equipment, in order to improve the quality and efficiency of food manufacturing in the UK.

Another interesting project to keep an eye on is the use of sugary food wastes to create Hydrogen and a route to potential funding is described on this site..

Merton Rule Learning History

Find out more about Randolph’s role by reading the learning history above and commenting in the box below.

The Defra Climate Challenge Fund game, LogiCity, has now been formally launched and is available to play online by anyone with a reasonably fast Internet connection, or from a CD-ROM.

This game provides an entertaining introduction to Climate Change, as players explore a 3D virtual city trying to reduce their carbon emissions and discovering some of the possible effects of climate change should emissions remain unchecked.

Aimed mainly at young people under 25, the game includes five main activities (set in a house, a low-energy workplace, an energy-wasteful workplace, a car showroom - with cycle rack, bus stop and railway station nearby - and a travel agents) where players are set the task of reducing the carbon footprint of an average resident. As players work their way through the game they will pick up information about climate change, and some of the main ways in which people contribute to emissions of the main greenhouse gas (CO2). At the end of the game they are fast-forwarded to 2066 to see whether they have done enough to save LogiCity from the worst effects of Climate Change. Participants are encouraged to provide their thoughts about climate change through a simple questionnaire at the end of the game.

The project partners are the National Energy Foundation, Logicom and British Gas. This is part of Defra’s Climate Challenge programme to increase public awareness of climate change across the country.

The game can be accessed at the LogiCity site.

Walkers crisps owned by Pepsico have been attracting media attention since they started to include a carbon footprint label on their packets.

 Delving deeper in to the company’s annual report and environmental reports shows that they have been experimenting with new technologies and processes for many years in order to curb consumption of energy and water and reduce waste. This work extends across most of their brands and in N. America, Mexico, India and the UK.

Their latest initiative called “netzero” is illustrated by the refurbishment of a plant in Arizona which will allow them to come off grid but still produce Frito-Lay potato crisps.

A fuller report of the measures they are taking is available in an article in the New York Times (Nov 07) but some highlights are:

• Recycling water used in rinsing potatoes
• Burning left-over sludge and capturing the methane to run the plant’s boiler
• Installing 50 acres of PV to generate power
• Building a biomass generator

The initiative apparently has the backing of senior corporate executives at Pepsico.

Judith is based at the University of Bristol’s Food Refrigeration and Process Engineering Reserach centre (FRPERC). Among other things, Judith’s an expert in refrigeration, chilled and frozen food cabinets, and decontamination.

Her involvement in LowCarbonWorks is through a Defra funded “Link” project which aims to increase the take-up of Air Cycle technologies by the food industry.

Together with action researchers from Bath University, Judith has been exploring different ways to engage food industry representatives with new applications of an “old” technology.

Air cycle has the potential to make significant carbon savings if it were used efficiently by food manufacturers since it is estimated that refrigeration systems use as much as 15 percent of the total energy consumed worldwide.

In the UK alone, there are between 1500 to 2000 food and drink manufacturing sites that are major users of refrigeration, accounting for over 4,500 GWh of electrical energy consumption.

Air cycle is vastly more energy efficient especially if the heat produced during the chilling process is harnessed and used in another process.

The food and drink sector has a target to achieve a primary specific energy consumption of 899.6 kWh per tonne of throughput by 2010. As it is estimated that about half their electricity is consumed in refrigeration processes this leaves a target of approximately 450 kWh per tonne of refrigeration energy use, from a current base level of approximately 500 kWh per tonne.

Judith and her colleague, Tim Brown have built a prototype air cycle rig which they have been demonstrating to manufacturers.�

Business Plan 

The Carbon Trust has set up a business enterprise to broker the connection between those producing waste heat from their manufacturing processes and consumers who’d like to buy it.

Connective Energy Ltd claim that 45% of the UK’s industrial primary energy consumption is currently wasted as heat released to the environment.

40 TWh of waste heat could be recovered. This is equivalent to the heating needs of Greater Manchester.

It is worth around £1 billion per year with annual carbon savings of 7.5 million tonnes of CO2 equivalent.

Meat and Dairy products came out worst on global warming potential scores in a December 2006 report for Defra by Manchester Business School, Environmental Impacts of Food Products and Consumption.

Meat and meat products were found to have the greatest global warming potential, 4-12%, of about 35 typical products in a supermarket trolley. Next worst were dairy products with 2-4% of global warming potential (GWP)

This report is extremely thought-provoking both in terms of the comparisons between different foodstuffs and in the complexity involved in gathering and interpreting data when there are so many contingencies to consider.

For instance, the evidence gathered shows that yoghurt uses six times as much electricity to produce as the same amount of raw milk . Further impacts at the distribution stage are bound up with the size of pot and thickness of plastic used.

You may never eat another potato crisp again after you read this report. A phenomenal amount of energy is used to dry out potatoes to turn them into crisps. This struck me as particularly nonsensical because potatoes absorb a huge amount of water in their growing cycle.

An observation which seemed particularly relevant to the lowcarbonworks project was,

(p61) “product diversification in food processing tends to increase water and energy consumption because of the need to clean between production runs”

Action researchers have identified the drive to come up with new food products to remain competitive as a potential motivator or demotivator in the adoption of lower carbon technologies.

According to UK government statistics cited in The Food Industry Sustainability Strategy (1.1.12) the food industry accounts for around 126TWh of energy use per year which is equivalent to about 14% of energy consumption by UK businesses. It is a major contributor to UK carbon emissions with 7 million tonnes of carbon per year.

(2.2.4) “The Office of National Statistics has recently estimated that when the entire life cycle of goods and services is taken into account, food and drink (and tobacco) products are the largest single source of greenhouse gas emissions associated with UK household consumption.”

More hopefully perhaps, (2.2.3) post 1990s there has been a downward trend in the UK food manufacturing sector’s CO2 emissions relative to total manufacturing and the UK overall.

(4.1.8) From the late 1990s:

The food industry’s energy efficiency per tonne of production improved by 9.5% compared to the voluntary target of 7.5%

“It achieved absolute annual savings of 73,000 tonnes of carbon, despite a reported increase in production throughput of around 8%.”

(4.1.10) “Significant progress is being made in the food manufacturing sector which has reduced energy use in absolute terms by 2.8% since the 1990s and seen the carbon attached to its energy use reduced by 16% - just over half due to its own efforts, and the rest due to electricity generators” 

The Food Industry Sustainability Strategy can be downloaded from Defra online.