Skip to main content

Advanced cycles and replacement working fluids in heat pumps

Objective



Objectives
This project aims at developing the use of refrigerant mixtures and the ammonia-water cycle as substitutes for CFC working fluids, in buildings and in high temperature industrial applications. Heat-pumps for buildings will be developed for increased coefficient of performance and heat pump equipment suitable for heat recovery in industrial food production and drying processes will be investigated at temperatures between 40°C and 120° C.
Technical Approach
The ammonia-water cycle is of interest because it allows higher temperatures to be achieved than are possible using ammonia alone. Problems of water migration, lubrication and materials compatibility have to be addressed. Lorenz cycles used for their wide temperature glides will be studied. New heat exchangers will be developed for Lorenz Cycles.
A major concern of the project is the properties of the working fluids and their mixtures: thermo-physical properties, flammability, chemical stability, miscibility with the lubricating oil. In order to identify methods of dynamically measuring actual refrigerant composition at key points in the cycle a "smart" control will be developed to adjust the mixture composition as to match the heat pump performance to the particular application. The safety aspects of flammable refrigerant mixtures and the implications of flammable mixtures appearing on a temporary basis at different places within the system will be investigated.
Expected Achievements and Exploitation
The outputs of the project will include:
. Design of ammonia-water absorber and desorber units to suit large temperature glides.
. Evaluation of lubricants, oil-water solubilities and influence of mixture properties on lubrication and stability of working fluids. . Methods to measure continuously ammonia-water concentrations. . Process integration aspects of heat pumps with large temperature glides. . Report on refrigerant mixture selection for operation between 40°C and 120°C, including the thermophysical and transport properties and chemical stability of the mixtures.
. Experimental investigation of split evaporator system behaviour with different refrigerant mixtures (range 40-120°C).
. Production and testing of smart controller for dynamically controlling mixture composition.
. New heat-exchanger designs to achieve counter- or pseudo-counter-current operation.
. Report on application of Lorenz cycle machines in a food processing plant and in buildings with experimental validation of performance on test facilities.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

UNIVERSITY OF ULSTER
Address
Cromore Road
BT52 1SA Coleraine
United Kingdom

Participants (11)

Ausimont SpA - Gruppo Montedison
Italy
Address
Piazza Donegani 5/6
15047 Alessanria - Spinetta Marengo
Calor Gas Northern Ireland Ltd
United Kingdom
Address
Airport Road West Sydenham
BT3 9EE Belfast
Chalmers University of Technology AB
Sweden
Address
10,Kemivagen
412 96 Göteborg
Consiglio Nazionale delle Ricerche
Italy
Address
Corso Stati Uniti 4
35127 Padova - Camin
Forschungszentrum für Kälte- und Umwelttechnik GmbH
Germany
Address
5,Rudower Chaussee
12489 Berlin
Forschungszentrum für Kältetechnik und Wärmepumpen
Germany
Address
Dorotheen Straße 1
30419 Hannover
Moy Park Ltd
United Kingdom
Address
39 Seagoe Industrial Estate
BT63 5QE Craigavon
UNIVERSITA DEGLI STUDI DI PADOVA
Italy
Address
1,Via Venezia 1
35131 Padova
Universidad de Las Palmas de Gran Canaria
Spain
Address
33,Obispo Rabadan
35003 Las Palmas De Gran Canaria
Università degli Studi di Ancona
Italy
Address
Via Delle Brecce Bianche
60131 Ancona
York International Ltd
United Kingdom
Address
Gardiners Lane South
SS14 3HE Basildon