Reverse cycle heat pump circuit

A reversible refrigeration system adapted for heating and cooling, comprising:

• a motor compressor unit;
• an indoor heat exchanger and an outdoor heat exchanger each including a plurality of circuits;
• a valve for reversing the flow of refrigerant through said system to operate said system in a heating or cooling mode with each of said heat exchangers arranged interchangeably as a condenser or as an evaporator;
• means connecting the circuits in each of said heat exchangers in series between a heat exchanger inlet line connected to said reversing valve and an outlet line when a heat exchanger operates as a condenser;
• a conduit connecting the outlets of said heat exchangers;
• means including a pair of one way valves arranged between said heat exchanger outlet lines and said conduit to allow passage of refrigerant into said conduit from said coils when a heat exchanger is operating as a condenser and for preventing series flow of refrigerant through said circuits from said conduit when a heat exchanger is operating as an evaporator;
• a plurality of distribution means connected at one end to said conduit and at the other end to each of said circuits to arrange said circuits in parallel when a heat exchanger operates as an evaporator;
• means including valves arranged between said circuits and said heat exchanger inlet lines for permitting parallel refrigerant flow through each of said circuits between said conduit and said heat exchanger inlet line when a heat exchanger is operating as an evaporator;
• and for directing all of said refrigerant flow from said heat exchanger inlet line to said series connected circuits when a heat exchanger is operating as a condenser.