Refrigeration system for transcritical operation with economizer and low-pressure receiver

Abstract

A refrigeration apparatus for transcritical operation includes a gas cooler, an aftercooler, an evaporator with a low-pressure liquid separator, a compressor, a first controllable throttling device and interconnecting piping between the mentioned components and in addition a second controllable throttling device and an intercooler that comprises two flow paths separated by heat exchanging surfaces. A first flow path inlet of the intercooler is connected to the gas cooler outlet. A first flow path outlet of the intercooler is connected to the aftercooler inlet. A second flow path inlet of the intercooler is connected to the outlet of the second throttling device. A second flow path outlet of the intercooler is connected to the economizer port of the compressor. The second throttling device inlet is connected to the piping either upstream or downstream of the aftercooler. The second throttling device outlet is connected to the second flow path inlet of the intercooler.

1 . A refrigeration apparatus for transcritical operation comprising a screw compressor featuring inlet and outlet ports geometrically controlled by rotation of male and female rotors operating at least on three pressure levels: suction pressure on the compressor suction side, intermediate pressure at the economizer port and discharge pressure at the compressor discharge side, a gas cooler, a low-pressure liquid separator, an aftercooler communicating with said low-pressure liquid separator, a first controllable throttling device and an evaporator, wherein there is a second controllable throttling device and an intercooler that comprises a first and a second flow path separated by heat-exchanging surfaces. 
   
   
       2 . A refrigeration apparatus according to  claim 1  wherein a first flow path inlet of said intercooler is connected to the gas cooler outlet, a first flow path outlet of said intercooler is connected to the aftercooler inlet, a second flow pass inlet of said intercooler is connected to the outlet of said second controllable throttling device and a second flow pass outlet of said intercooler is connected to the economizer port of the compressor. 
   
   
       3 . A refrigeration apparatus according to  claim 1  wherein the inlet of said second controllable throttling device is connected to the piping either upstream or downstream of the aftercooler and the outlet of said second controllable throttling device is connected to said second flow pass inlet of said intercooler.