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RESEARCH INTO HEAT AND FLUID EXCHANGE IN NEW WORKING FLUID SYSTEMS FOR ABSORPTION HEAT PUMPS.

Objective

THE AIM OF EXISTING HEAT AND FLUID TRANSFER WITH SELECTED WORKING FLUID PAIRS IS TO PROVIDE FURTHER DATA FOR THE PRACTICAL APPLICATION OF NEW WORKING FLUIDS IN ABSORPTION HEAT PUMPS.

AS A RESULT OF THE THERMAL AND CALORIFIC MEASUREMENTS ALREADY MADE, THE THEORETICAL EQUILIBRIUM PROCESS OF ABSORPTION HEAT PUMPS CAN BE THERMODYNAMICALLY CALCULATED. FOR CALCULATIONS FOR THE INDIVIDUAL COMPONENTS, SUCH AS PUMP, ABSORBER AND SOLUTION HEAT EXCHANGER, HOWEVER, FURTHER RESEARCH IS REQUIRED TO BE ABLE TO PREDICT HEAT AND FLUID TRANSPORT WITH SUFFICIENT ACCURACY. THE RESEARCH IS THEREFORE INTENDED TO PROVIDE INFORMATION ABOUT THE TRANSPORT BEHAVIOUR OF THE WORKING FLUIDS.

IT HAS EMERGED FROM EARLIER RESEARCH THAT THE THERMAL STABILITY BEHAVIOUR OF WORKING FLUIDS UNDER ACTUAL WORKING CONDITIONS CAN BE LESS FAVOURABLE THAN WOULD BE EXPECTED FROM THE RESULTS OF THE STABILITY TEST IN STEEL AUTOCLAVES. WITH THIS IN MIND, THE RESEARCH IS ALSO EXPECTED TO PROVIDE INFORMATION ON STABILITY BEHAVIOUR.
The investigation, in the field of heat pump and heat transformer development, was focused on:
determination of thermophysical properties of new working fluid pairs including measurement of transport properties;
performance measurements under realistic conditions using an experimental heat pump cycle.
The results of the thermophysical properties measurements pertain mainly to trifluoroethanole (TFE) and hexafluoroisopropanole (HFIP) systems, which have proven most favourable. The marked positive influence of the addition of lithium nitrate to the ammonia water working fluid on the coefficient of performance (COP) of a heat pump is demonstrated. Further investigations on highest permissible generator temperature and long term behaviour of the system are indicated.
IN THE RESEARCH PROJECT COMING UNDER CEC CONTRACT NO EE-A4-031-D(B), A NUMBER OF NEW PAIRS OF WORKING FLUIDS FOR ABSORPTION HEAT PUMPS WILL BE STUDIED AND MEASURED. OF THESE, THE SYSTEMS :

- TRIFLUORETHANOL - N-METHYLPYRROLIDON, AND

- AMMONIA-LITHIUM NITRATE - WATER

ARE SELECTED FOR INVESTIGATION IN EXPERIMENTAL HEAT PUMP CIRCUITS. UNDER CONDITIONS TYPICAL FOR HEAT PUMP OPERATION, THE TRANSFER OF HEAT AND FLUID IN THE INDIVIDUAL STAGES OF THE EXPERIMENTAL CIRCUITS WILL BE STUDIED.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

N/A