STUDY STATE SIMULATION OF ABSORPTION TYPE HEAT PUMP -FUNDAMENTAL MODELS CONSIDERING HEAT AND MASS TRANSFER IN DETAILD

摘要

In these days, energy problems and environmental problems like global warming and destructionrnof ozone layer became more and more serious. So, we are demanded to restrict consumptionrnof energy resources and improvement of equipment performance. The countermeasurerntechnology of these problems, an absorption type heat pump attracts attention. Unlike a compressionrntype heat pump, absorption type heat pump does not need much electric power and itrncan be driven by waste heat sources. So, an absorption type heat pump can contribute energyrnsavings. Additionally, the absorption type heat pump uses natural refrigerant, like water orrnammonia. Unlike CFCs, they don't cause global warming or ozone depletion.rnIn the absorption heat pump, as the mass and heat transfer phenomena of the absorber andrngenerator is very complex, so general designing method of this type heat pump has not beenrnestablished and design of the system still relies on the designers experience.rnThe purpose of this study is to construct the high precision general mathematical model thatrncan be applied for the design of the absorption type heat pump. In this study, the static modelrnof the absorption type heat pump that considers the heat and mass transfer phenomena in detailrnis constructed. This model is applied to the single effect absorption type heat pump that isrnthe most basic cycle of the absorption type heat pump. This system consists of an absorber,rnevaporator, generator, condenser and solution heat exchanger. The working fluid is water (refrigerant)rnand lithium bromide (absorption solution).rnTo investigate the validity of the simulation model, we develop the single-effect absorptionrnchiller. The feature of this system is that this system uses very accurate measurement system -rnmass flow meter, platinum resistance temperature detector and pressure gage- for each element.rnAnd this has very big sight glass from which we can see the flow pattern of each element.rnAnd also this system uses only flat tubes for each element because fundamental heatrnand mass transfer correlation can be adopted without any modification. We don't use octanol.rnIn the simulation, the absorber, generator, evaporator, and condenser are discretized as tworndimensions model for longitudinal coordinate and vertical coordinate. With this method, it isrnenable to simulate the temperature and concentration profiles with high accuracy.rnAs a result, simulation results agree with experimental ones well. The error of almost everyrnparameter – COP, cooling capacity, temperature and concentration are within approximatelyrn10%. Therefore, we confirmed the validity of the mathematical model. So, The model we developedrncan be applied to the actual system design.