PLATE-TYPE GENERATORS FOR SUPER COMPACT ADSORPTION HEAT PUMPS

Completed

Energy Efficiency(Other)

Basic and strategic applied research

ENGINEERING AND TECHNOLOGY (Mechanical, Aeronautical and Manufacturing Engineering)

Not Cross-cutting

Professor RE Critoph
School of Engineering
University of Warwick

Standard

EPSRC

01 November 2005

28 February 2009

40 months

£242,644

Process engineering

West Midlands

Engineering science: flow -- Process Environment and Sustainability

Professor RE Critoph, School of Engineering, University of Warwick

Dr RN Thorpe, University of Warwick

Project Contact, Chart Heat Exchangers Ltd
Project Contact, Sutcliffe Speakman Carbons Ltd

Our principal aim is to develop and evaluate new types of adsorption generator that are up to two orders of magnitude more compact than existing technology, thereby enabling the introduction of a range of energy saving products.Adsorption cycles can be used in heat-driven refrigerators, air conditioners or heat pumps in which the energy source is a burning fuel, waste heat or even solar energy. The benefits of high efficiency adsorption machines include reduced running costs and, in general, areduction in the use of primary energy needed for cooling or heating and an associated reduction in CO2 emissions. They have the potential to reduce dramatically CO2 emissions compared with conventional systems e.g. half the emissions compared with gas-fired heating in heating applications and essentially zero emissions when considering waste heat or CHP (Combined Heat and Power) driven cooling applications. Achievement of their potential would result in significant savings at the national and international level. The scale of the benefit in heating is obvious but the energy used in cooling is often underestimated. In the UK 17% of total electricity consumption is used for cooling.In any sorption system there is a trade-off between the energy efficiency and the total quantity of heat that must be transferred (both internally and externally). Regenerative cycles can be made very efficient, but require more heat exchange. Reducing temperature difference is similarly beneficial,but also requires more heat transfer. This results in a compromise between efficiency and size. Efficiency and relative size are generally quantified by the COP and SCP or SHP.Coefficient of Performance (COP) = Thermal output (heating or cooling, dependent on application) / High-temperature heat inputSpecific Cooling Power (SCP) = Useful cooling per mass of adsorbentSpecific Heating Power (SHP) = Useful heating per mass of adsorbentDepending on the application, output per unit mass or unit volume of a complete system can be more appropriate, but all the alternatives give some measure of relative size.The only adsorption chillers on the market are both made in Japan and use silica gel and water as the adsorbent and refrigerant in a closed adsorption cycle. They are rated between 70 / 350 kW and are physically bulky at about 6 W cooling /litre of total volume, or 9 W cooling/ kg of total mass, not including ancillaries. We propose a radically different approach using carbon as the adsorbent and ammonia as the refrigerant in a plate-type generator that we believe can obtain in the order of 1000 W / litre. We intend to achieve process intensification of our existing ammonia - carbon adsorption technology to increase power density and to improve greatly the cost-effectiveness and application range compared with the state of the art

01/01/07