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1 Dynamic heat pump system with capacity control Hatef Madani Dec. 2009

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2 Project goals Creating a family of models able to represent the dynamics of the real heat pump system consisting of the building, the heat pump unit, the heat source, pump, storage tank, climate, etc. A quantitatively evaluation of different techniques for capacity control and control strategies for heat pump systems.

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3 Result example: Variable capacity vs. on/off controlled heat pump system Dynamic COP of both variable speed and on/off controlled GSHP

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4 Result example: Optimum mass flow rate of secondary refrigerant Overall COP and heat capacity vs. mass flow rate of secondary refrigerant at different compressor speed

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5 Examples of conclusions Retrofitting a frequency inverter to the on/off controlled heat pump to omit the electrical auxiliary heater Finding the optimum brine mass flow rate depending on the design objective (e.g. COP or heat capacity maximization)

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6 List of publications Internal report called Capacity control in heat pump systems:methods and strategies was submitted in 2008. The paper called Variable capacity heat pump systems, modeling and simulation was published in 9 th IEA Heat pump conference, 2008. The project was presented and described in Rehva journal (the journal of federation of European HVAC association), 2009. Two papers called Ventilation heat recovery with run around coil: System analysis and a study on efficiency improvement Part I and II were published and presented in ASHRAE Region-At-Large conference, 2009. The paper called Retrofitting a variable capacity heat pump to a ventilation heat recovery system: modelling and performance analysis was submitted to the IntrenaTional Conference on Applied Energy (ICAE), 2009.

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7 List of publications The paper called Capacity control in ground source heat pump systems, Part I:modeling and simulation is ready to submit to Journal of International Institute of Refrigeration. The paper called Capacity control in ground source heat pump systems, Part II: Comparative analysis between on/off controlled and variable capacity systems is almost ready to submit to Journal of International Institute of Refrigeration. The paper called The ground source heat pump: a system analysis with a particular focus on the U-pipe borehole heat exchanger will be submitted to 14 th ASME international heat transfer conference, before Jan. 15 th 2010. A quantitatively evaluation of different techniques for capacity control and control strategies for heat pump systems.