Environmental Technology Shortlist

RENEWABLE HYDROGEN RESEARCH AND DEVELOPMENT CENTRE

UPS Systems and University of Glamorgan

The University of Glamorgan’s Hydrogen Centre is part of a plan to create a hydrogen economy for Wales, and was the first in the country to use renewable energy sources to produce hydrogen for use in fuel cells. It’s the result of a collaboration between the university and UPS Systems, which provided a 10kW fuel cell along with associated systems, including a bespoke control system, to the centre.

Costing £2.2m, the Hydrogen Centre was funded by the university and a grant from the European Regional Development Fund, and aims to link together intermittent renewables, such as wind and solar, with fuel-cell systems. Evaluating whether hydrogen generation could be a viable energy-storage medium, providing a flow of energy when the sunshine or wind aren’t strong enough to generate power, is a major goal of the centre, but it wouldn’t have been possible without the fuel cell itself.

UPS Systems’ equipment for the centre includes the fuel cell, its inverters and a controller running supervisory software. The fuel cell charges a battery that provides the actual power to run the centre and its facilities; the controller constantly checks the state of charge on the battery and, if it falls below a specified point, starts up the fuel cell and keeps it running until charge is restored.

The centre acts as a showcase for hybrid renewable/fuel cell systems and has already started gathering attention since its opening last October.

Subsequent projects have included a telemetry application at nPower Renewables and a prime power application at the Environmental Energy Technology Centre in Rotherham.

SORPTION ENERGY
Sorption Energy and University of Warwick

Air conditioning systems use electricity to cool air, and tend to do it fairly inefficiently. A team led by Prof Bob Critoph of the University of Warwick has been working on a more efficient form of cooling system, which works by the process of chemical adsorption. The team has beenworking on the technology for around 10 years and has now commercialised it through Sorption Energy.

The technology uses activated carbon beds to adsorb and desorb ammonia, the system’s refrigerant. The beds replace the electrically driven compressor used in standard air conditioning systems, driving the refrigerant between the expansion valve, evaporator and condenser.

Critoph’s technology has already been the subject of much research: an EU-funded project, led by Fiat, looked at using the waste heat of a car engine to drive an air conditioning unit; another, funded by EPSRC and E.ON, uses adsorption as part of an air-sourced gas-fired heat pump, which works as a 130 per cent efficient gas boiler. Sorption Energy claims that such systems could replace any gasfired electric boiler, of which some 1.7 million are sold each year in the UK alone.

FLOWTOOL

Rolls-Royce and University of Cambridge

Designing jet engines and gas turbines is a series of tricky balancing acts; every parameter has to be carefully considered to ensure that the engine works efficiently and that any harmful emissions, such as nitrous oxide and particulates, are minimised.

To do this, designers ensure that there is a high proportion of air to fuel in the combustion chamber, which ensures that combustion is as clean as possible.

However, this also means that the engine operates close to its stability limits. To tackle this problem, Rolls-Royce set up a project with Matthew Juniper of Cambridge University’s engineering department to look at the design of the fuel injectors, which dictate how fuel and air mix in the engine.

Each jet engine contains 20 fuel injectors, which feed fuel into the combustion chamber. These injectors are affected by the acoustic vibrations of the engine, and the flames resulting from the mixing of air and fuel can be disrupted if the injector vibrates at a resonant frequency, where the oscillations become selfsustaining. Juniper’s team developed a numerical system for predicting the resonant frequency of an injector and packaged this within a graphical user interface called FlowTool.

The system uses computational fluid dynamics (CFD) data from an injector, and from these it derives the injector’s stability characteristics including its resonant frequencies.

This is a highly complex calculation and without the FlowTool packaging it’s impossible to do without an understanding of the theory of combustion stability. Juniper’s system allows design engineers to work out their injectors’ stability profiles by looking at the flow through the design in slices and building up a picture of its stability section by section. The team is also working on modules for the system; the first of these, FlowTweak, allows designers to make small changes to the velocity of fuel through the injector to see the effect this will have.