Enhanced refrigerant system

Abstract

A refrigerant system providing enhanced performance over a wider range of operating conditions than traditional economized refrigerant systems. The system includes an economizer branch that connects a liquid outlet from a suction accumulator to an economizer inlet port of a compressor unit. The economizer branch includes a liquid refrigerant pump that delivers a non-evaporated liquid refrigerant portion from the suction accumulator into the economizer heat exchanger, where the liquid refrigerant portion evaporates, increasing thermodynamic potential of the main circuit refrigerant also flowing in through the economizer heat exchanger, and a formed vapor stream is delivered into the economizer inlet port of the compressor unit.

1 . An enhanced refrigerant system comprising:
 a refrigerant closed-loop circuit including a compressor unit, a heat rejection unit, an economizer heat exchanger, an expansion device, an evaporator unit, and a suction accumulator, said suction accumulator including an inlet, a vapor outlet, and a liquid outlet, said compressor unit including a suction inlet port, an economizer inlet port, and a discharge outlet port;   an economizer branch providing passage for a refrigerant stream flowing between said liquid outlet of said suction accumulator and said economizer inlet port of said compressor unit, said economizer branch including a liquid refrigerant pump and an economizer heat exchanger;   said economizer heat exchanger providing heat transfer interaction between said refrigerant stream in said economizer branch and said refrigerant stream in said refrigerant circuit;   said evaporator unit being configured and operated to provide refrigerant at its exit such that at least a portion of this refrigerant is a liquid and non-evaporated phase; and   wherein said liquid refrigerant pump of said economizer branch pumps said liquid refrigerant from the exit of said evaporator unit through said economizer branch and said economizer heat exchanger, and where at least a portion of said liquid refrigerant evaporates and forms a vapor refrigerant stream in said economizer branch that flows into said economizer inlet port of said compressor unit.   
   
   
       2 . An enhanced refrigerant system of  claim 1  wherein said enhanced refrigerant system operates in a sub-critical cycle and said heat rejection unit functions as a condenser. 
   
   
       3 . An enhanced refrigerant system of  claim 1  wherein said enhanced refrigerant system operates in a trans-critical cycle and said heat rejection unit functions as a gas cooler. 
   
   
       4 . An enhanced refrigerant system of  claim 1  that includes at least one of:
 (a) said heat rejection unit including a plurality of individual heat rejection units.   (b) said expansion device including a plurality of individual expansion devices.   (c) said evaporator unit including a plurality of individual evaporators.   (d) said suction accumulator including a plurality of individual suction accumulators.   (e) said liquid refrigerant pump includes a plurality of individual pumps; and   (f) said economizer heat exchanger including a plurality of individual heat exchangers.   
   
   
       5 . An enhanced refrigerant system as recited in  claim 1  wherein said economizer heat exchanger includes a plurality of channels. 
   
   
       6 . An enhanced refrigerant system as recited in  claim 1  wherein said heat rejection unit is an outdoor unit and said evaporator unit is an indoor unit. 
   
   
       7 . An enhanced refrigerant system of  claim 1  wherein said heat rejection unit is an indoor unit and said evaporator unit is an outdoor unit. 
   
   
       8 . An enhanced refrigerant system of  claim 6  wherein said refrigerant closed-loop circuit includes a four-way reversing valve, said four-way reversing valve includes a vapor inlet port, a vapor outlet port, a first bi-flow port, and a second bi-flow port, said vapor inlet port is connected to said discharge port of said compressor unit, said vapor outlet port is connected to said vapor inlet port and to said suction accumulator, said first bi-flow port is connected to said refrigerant closed-loop circuit at a location upstream of said outdoor unit, and said second bi-flow port is connected to said refrigerant closed-loop circuit at a location downstream of said indoor unit. 
   
   
       9 . An enhanced refrigerant system of  claim 1  wherein said compressor unit and said heat rejection unit are combined into a single unit assembly. 
   
   
       10 . An enhanced refrigerant system of  claim 1  wherein said expansion device is combined with said evaporator unit. 
   
   
       11 . An enhanced refrigerant system of  claim 1  wherein said liquid refrigerant pump and said suction accumulator are combined into a single unit assembly. 
   
   
       12 . An enhanced refrigerant system as recited in  claim 1  wherein said compressor unit includes a low-pressure compressor, a high-pressure compressor, and said economizer inlet port that is located between said low-pressure and said high-pressure compressor; each of said compressors including at least one compression stage. 
   
   
       13 . An enhanced refrigerant system as recited in  claim 12  wherein at least one of said at least one compression stage includes a plurality of parallel compressors. 
   
   
       14 . An enhanced refrigerant system of  claim 12  wherein said low-pressure compressor and said high-pressure compressor are separate compressor units. 
   
   
       15 . An enhanced refrigerant system as recited in  claim 1  wherein said compressor unit includes two parallel compressors, a first compressor provides a refrigerant passage between said economizer inlet port and said discharge outlet port, and a second compressor provides a refrigerant passage between said suction inlet port and said discharge outlet port; each of said compressors includes at least one compression stage. 
   
   
       16 . An enhanced refrigerant system as recited in  claim 15  wherein said first compressor includes a plurality of parallel compressors. 
   
   
       17 . An enhanced refrigerant system as recited in  claim 15  wherein said second compressor includes a plurality of parallel compressors. 
   
   
       18 . An enhanced refrigerant system of  claim 15  wherein said first compressor and said second compressor are separate compressor units. 
   
   
       19 . An enhanced refrigerant system of  claim 1  wherein said economizer heat exchanger is a counterflow heat exchanger in a primary operational mode. 
   
   
       20 . An enhanced refrigerant system of  claim 1  wherein said economizer heat exchanger is a parallel flow heat exchanger in a primary operational mode. 
   
   
       21 . An enhanced refrigerant system of  claim 1  wherein said economizer heat exchanger is a crossflow heat exchanger. 
   
   
       22 . An enhanced refrigerant system of  claim 1  wherein said economizer heat exchanger is a flash tank having a vapor inlet port, a vapor outlet port, and two liquid ports and providing a direct thermal contact between refrigerant stream in said refrigerant closed-loop circuit and refrigerant stream in said economizer branch. 
   
   
       23 . An enhanced refrigerant system of  claim 22  wherein at least one of two said liquid ports has an expansion device for said refrigerant closed-loop circuit upstream of said flash tank. 
   
   
       24 . An enhanced refrigerant system of  claim 23  wherein at least one of two said liquid ports and said flash tank are combined into a single unit. 
   
   
       25 . An enhanced refrigerant system of  claim 1  wherein said enhanced refrigerant system operates in a trans-critical cycle and said economizer inlet port of said compressor unit is combined with said discharge port of said compressor unit. 
   
   
       26 . An enhanced refrigerant system of  claim 1  wherein said enhanced refrigerant system operates in a trans-critical state and said economizer inlet port of said compressor unit is a separate device located downstream of said heat rejection unit and upstream of said economizer heat exchanger. 
   
   
       27 . An enhanced refrigerant system of  claim 1  wherein said compressor is a variable speed compressor. 
   
   
       28 . An enhanced refrigerant system of  claim 1  wherein said compressor is a multi-speed compressor. 
   
   
       29 . An enhanced refrigerant system of  claim 1  wherein said liquid refrigerant pump is a variable speed pump. 
   
   
       30 . An enhanced refrigerant system of  claim 1  wherein said liquid refrigerant pump is a multi-speed pump. 
   
   
       31 . An enhanced refrigerant system of  claim 2  wherein a liquid refrigerant receiver is installed at a location downstream said heat rejection unit. 
   
   
       32 . An enhanced refrigerant system comprising:
 an economizer branch providing passage of a refrigerant stream flowing between a liquid outlet of a suction accumulator and an economizer inlet port of a compressor unit, said economizer branch including a liquid refrigerant pump and configured to pass through an economizer heat exchanger that provides for heat transfer interaction between said refrigerant stream in said economizer branch and a refrigerant stream in a main refrigerant closed-loop circuit; and   wherein said main refrigerant closed-loop circuit also passes through said economizer heat exchanger and includes a compressor unit including a suction inlet port that is located downstream of said suction accumulator.   
   
   
       33 . The enhanced refrigerant system of  claim 32  wherein said main refrigerant closed-loop circuit further includes an evaporator unit being configured and operated to provide refrigerant at its exit such that at least a portion of this refrigerant is in a liquid and non-evaporated phase and wherein said liquid refrigerant pump of said economizer branch pumps said liquid refrigerant through said economizer branch and into said economizer heat exchanger in heat transfer interaction with the refrigerant flowing through said main closed-loop refrigerant circuit, and where at least a portion of said liquid refrigerant evaporates and forms a vapor refrigerant stream in said economizer branch that flows into said economizer inlet port of said compressor unit. 
   
   
       34 . An enhanced refrigerant system as recited in  claim 33  wherein said compressor is a variable speed compressor. 
   
   
       35 . An enhanced refrigerant system as recited in  claim 33  wherein said compressor is a multi-speed compressor. 
   
   
       36 . An enhanced refrigerant system as recited in  claim 33  wherein said liquid refrigerant pump is a variable speed pump. 
   
   
       37 . An enhanced refrigerant system as recited in  claim 33  wherein said liquid refrigerant pump is a multi-speed pump. 
   
   
       38 . An enhanced refrigerant system as recited in  claim 11  wherein said liquid refrigerant pump is located below said suction accumulator. 
   
   
       39 . An enhanced refrigerant system as recited in  claim 11  wherein said liquid refrigerant pump is located above said suction accumulator. 
   
   
       40 . An enhanced refrigerant system as recited in  claim 11  wherein said liquid refrigerant pump is located inside said suction accumulator. 
   
   
       41 . An enhanced refrigerant system as recited in  claim 11  wherein said liquid refrigerant pump is located below, above or inside of said accumulator. 
   
   
       42 . An enhanced refrigerant system of  claim 8  wherein said compressor unit, said four-way reversing valve, and said heat rejection unit are combined into a single unit. 
   
   
       43 . An enhanced refrigerant system of  claim 1  wherein said compressor unit is equipped with an oil separator returning oil to said compressor. 
   
   
       44 . An enhanced refrigerant system as recited in  claim 1  wherein said heat rejection unit is a mini-channel heat exchanger. 
   
   
       45 . An enhanced refrigerant system as recited in  claim 1  wherein said heat absorption unit is a mini-channel heat exchanger.