Optimizing a Small Ammonia Heat Pump with Accumulator Tank for Space and Hot Tap Water Heating

Abstract

The heat pump market offers a wide variety of different residential heat pumps where most of them utilize refrigerant R-410A which has high global warming potential. Considering the fact that global policy starts to focus on issues related to energy efficiency and harmful impact to the environment, it is necessary to investigate over new refrigerants. As an alternative solution is to utilize natural refrigerants, such as ammonia, which has almost zero global warming potential and zero ozone depletion potential. Since the beginning of refrigeration era, ammonia has been used in large capacity systems, whereas no attention has been paid to residential sector. In this study, small ammonia heat pump with capacity of 8,4 kW for one family house has been designed to provide heating of domestic water and space heating via floor system. Theoretical part of this study involves analysis of the present heat pump market and comparison of different heat pump applications. Previous experience in researches of small capacity ammonia systems have been summarized to highlight related problems and design futures. Practical part of this study involves calculations in the Engineering Equation Solver with estimation of the heat pump performance and evaluation of necessary storage tank volume for the heating system to provide efficient operation during variable electricity prices. Engineering part consists of principal drawing of the small ammonia heat pump with list of components. Additional drawing of a house with floor heating system is included as an example which shows possible application for the ammonia heat pump. The thesis consists of 80 pages, 73 equations, 7 tables, 44 figures, 3 drawings and 3 appendices. 24 literature sources used for this thesis. Keywords: small capacity ammonia heat pump; variable electricity prices; storage tank; heat pump operational regimes.