To improve heating performance and running stability of high temperature heat pump
the structure of the heat pump should be rebuilt and optimized. Setting an internal heating exchanger economizer into the heat pump system
the experiments are conducted to validate the function of vapor injection technique in twin screw high temperature heat pump system. It is indicated that vapor injection facilitates increasing the total heating capacity of the heat pump with condenser outlet water temperature of 88 ℃
and the heating capacity increases up to 9.28 kW while vapor injection ratio rises from 9.88% to 22.61%. There exists an optimal vapor injection pressure or vapor injection ratio
with which the heating COP gets the maximum in running process. The economizer also provides higher degree of supercooling for the refrigerant from the condenser to ensure working safety of the throttling structure of high temperature heat pump.
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references
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