Internal Heat Exchanger Application in Heat Pumps: Evaluation and testing of different internal heat exchangers for efficiency improvement
Typ
Examensarbete för masterexamen
Program
Sustainable energy systems (MPSES), MSc
Publicerad
2021
Författare
Amperayani, Hemanth Kumar
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
A heat pump is a device which is an effective means of producing heat to satisfy heating and cooling demands for a building following the refrigeration cycle through transferring thermal energy from a colder region to a warmer region. This thesis is limited to explore options available in efficiency improvements of heat pumps focusing on cost reduction. Achieved through conducting an extensive study on efficiency improvement collecting relevant information within the scope of heat pumps. Internal heat exchanger has been selected from the conducted literature review diving deep into this due to its adaptability to different product variants. Various options for internal heat exchanger have been formulated which has been then designed and verified. The options included are plate heat exchangers, parallel contact and concentric tube arrangement of pipes within the refrigeration circuit where there is a high possibility of heat exchange. Parallel contact and concentric tube heat exchangers are evaluated by assessing their potential of heat transfer between the media by performing a steady state thermal analysis. The changes observed in the performance of heat pump among these op- tions are compared by developing a simulation model. Furthermore, a conceptual design of components has been carried out covering all operating conditions and simulating it for an existing system. A sensitivity analysis has been carried out to obtain in-depth understanding of the model for their reliability. Testing of parallel contact heat exchanger is performed on a real product for the same operating conditions followed in the theoretical simulations to conform the improvements in coefficient of performance. The results from simulations show that among the options evaluated for internal heat exchangers, concentric tube heat exchangers have the highest potential for heat transfer. Whereas the alternative of plate heat exchanger is the best it is not preferrable due to the costs. Practically a maximum of 5% increase in coefficient of performance can be observed from testing and theoretically a 4.5% increase in coefficient of performance from theoretical simulations.
Beskrivning
Ämne/nyckelord
Heat Pumps, COP improvement, Internal Heat Exchangers, Plate Heat Exchanger, Concentric Tube Heat Exchanger, Parallel Contact Heat Exchanger