Abstract: A method of gas generation resides in transformation of a cryogenic agent, capable of passing to the supercritical state, from the liquid state to the gaseous state thereof by way of thermoinversion in an isochoric process with enhancement of the potential energy of pressure of the gaseous medium thus obtained, and reducing the shaped gas stream, this being followed by gasdynamic ejection of the ambient medium. A plant for effecting the method comprises a source of a working medium (a cryogenic agent), at least one chamber (1,2), a gas reducer (29) and a gas ejector (24), arranged in succession downstream and communicating with each other.

Abstract: A refrigeration system comprises an evaporator overfed with liquid refrigerant and discharging a mixture of vapor refrigerant and liquid refrigerant; a compressor for compressing vapor refrigerant discharged from the evaporator; a condenser receiving compressed vapor refrigerant from the compressor for transforming it into liquid refrigerant; and a receiver receiving the liquid refrigerant from the condenser and supplying it to the evaporator. A separator receiving the refrigerant discharged from the evaporator separates the-vapor refrigerant for the compressor from the liquid refrigerant for recirculation. A feeder stores the pressurized liquid refrigerant and overfeeds the evaporator therewith. An educer feeds liquid refrigerant from the separator to the feeder using liquid refrigerant from the receiver as pressurizing agent.

Abstract: A closed loop refrigeration system utilizing an expansion device in the evaporation system is disclosed. In one embodiment, an expansion engine is connected to the evaporator inlet while a compressor is connected to the evaporator outlet. Liquid refrigerant flows through the expansion engine wherein it expands and drives the expansion engine. The compressor may be driven by the expansion engine or by a separate motor. A control circuit adjusts the refrigerant through the control valve in a manner which maintains a desired degree of superheat of the refrigerant leaving the compressor. In an alternate embodiment, the evaporator system has two evaporators. An expansion device is disposed between the inlet of the first evaporator and the outlet of the second evaporator. Partially subcooled liquid refrigerant from the first evaporator is passed into the second evaporator through an expansion valve wherein it evaporates into gas a refrigerant.

Abstract: A closed loop vapor cycle refrigeration system an expander-compressor is disclosed. A portion of the liquid refrigerant in the system is expanded into gas. This gas is used to operate a compressor. The compressor compresses the low pressure gas from the evaporator and discharges the compressed gas either to a primary compressor or the condenser. A novel expander-compressor device is also disclosed for use in the refrigeration system.

Abstract: A method of reducing flow metastability in a liquid refrigerant in an ejector nozzle by generating dispersed bubbles in the flow entering the nozzle by first forming relatively large bubbles and then breaking them down into small finely dispersed bubbles, so as to reduce the density of the flowing mixture and provide nucleation sites allowing control of flow rate and causing the mixture to expand in substantial thermodynamic equilibrium with maximum nozzle velocity.

Abstract: The invention concerns a process for extraction of a liquefiable substance from a gaseous carrier fluid. According to that process on one hand, we force the fluid to flow across a convergent-divergent nozzle such as that in that nozzle, the fluid is submitted to a fast expansion and, on the other hand, we define the cross sections (A(x)/Ao) along the axis (x) of the nozzle such as that the pressure diagram and the velocity diagram exhibit in the neighbourhood of the throat one landing section at least. Within those conditions, the liquefiable substance condenses and forms a cloud of drops of larger diameter and reduced concentration.

Abstract: A method and apparatus is provided for improving the performance of vapor turbine diffusers by preventing flow separation from the diffuser walls. Such separation from the diffuser walls is decreased or eliminated herein by chilling the diffuser walls below the saturation temperature, causing some condensation to occur and insuring vapor flow toward the walls to eliminate the natural tendency toward separation in diffusing vapor passages.

Abstract: A refrigeration system is disclosed which utilizes an expansion engine in the condensate line of the condenser. The liquid leaving the condenser drives the expansion engine when it passes therethrough. The expansion engine, in turn, drives a compressor which compresses gas from the reservoir to the condenser. The discharge of the liquid refrigerant from the condenser is controlled by a micro-controller circuit. The micro-controller circuit increases the flow when the temperature difference between the liquid refrigerant and the ambient air flowing across the condenser is below a predetermined value and decreases the flow when the temperature difference is above a predetermined value. A liquid pump is used to elevate the pressure of the liquid refrigerant leaving the receiver.

Abstract: Centrifugal gas compressor - expander for use in refrigeration system where low temperature level energy rejected from the condenser is recovered and used to produce kinetic energy to assist driving the compressor, and thus reducing the electric power required for refrigeration.

Abstract: A thermodynamic constant volume vapor compression heat pump system including method and apparatus wherein a closed fluid loop having first, intermediate and second treatment stations, is employed. A liquid refrigerant fluid under low pumping pressure is introduced to a first treatment station following initial expansion, accelerating propulsion, and atomization thereof, precedent to evaporation of the refrigerant fluid through a divisive containment of the accelerated refrigerant fluid.

Abstract: A refrigeration system and cycle are disclosed. The system includes a compressor, condenser, injector nozzle, evaporator, and refrigerant separator tank connected in series in a primary refrigerant path. The compressor overfeeds the condenser with refrigerant which therefore condenses only partially to a wet vapor in the condenser. The injector nozzle completes condensation, drawing liquid refrigerant from the separator tank to inject it into the evaporator. The evaporator is a shell and tube heat exchanger, the tubes being product fluid conduits. The shell side of the evaporator is overfed with liquid refrigerant so that most of it does not evaporate. A liquid/vapor refrigerant emulsion is thus produced, maintaining a constant phase transition temperature in the evaporator. The high flow rate of this emulsion within the evaporator creates a turbulence preventing boundary layers from forming on heat exchange surfaces.

Abstract: A thermally powered heat transfer system employing a boiler for producing a refrigerant in vaporized form at relatively high pressure, the output of the boiler being connected to a pump, aspirator or compressor which may comprise a single cylinder, double piston structure functioning as a power source for moving the refrigerant and a pumping source for creating a low pressure for drawing refrigerant vapor form from an evaporator and into the condenser where the refrigerant vapor gives up its heat. The condenser is coupled in circuit with receiver means which holds liquid refrigerant and delivers same to the boiler and evaporator under control of suitable valving means.

Abstract: A cooling system which uses a jet or ejector pump in place of a mechanically driven compressor includes a working fluid composed of two or possibly more different refrigerants. One has a low saturation temperature while the other has a higher one. The mixture of the two refrigerants is subject to a distillation or separation. Following the separation the low saturation temperature refrigerant (vapor) is condensed in an auxiliary condenser and inducted through the evaporator while the higher saturation temperature refrigerant (liquid) is returned to a boiler for vaporization and subsequent used in the jet pump which produces the pressure reduction via which the low saturation temperature refrigerant is inducted into the evaporator.

Abstract: A method for the production of microfine frozen particles comprises filling a vessel with a cold gas which may be a cooled gas or mixed gas obtainable by mechanical refrigeration of a refrigerant gas, air, or the like, atomizing a material to be frozen, such as water, into the cold gas so that the atomized particles become frozen by heat exchange with the cold gas, and collecting the fine frozen particles thus produced.

Abstract: A cryopump is regenerated by means of an ejector pump which draws gas from the cryopump as the pump is warmed. The ejector is actuated by an inert gas. The same inert gas may also be used to purge the pump during evacuation.

Abstract: A thermally powered engine has a pair of power cylinders with each power cylinder defining a closed interior space. A power pistin is reciprocally mounted in the interior space of each power cylinder with each piston dividing the interior of its cylinder into upper and lower portions. A liquid piston interconnects the upper portions of the two power cylinders. First mechanically powered valves having two states control the flow of the working fluid of a heat transfer loop through the lower portions of each power cylinder. A second mechanically powered valve causes the first mechanically powered valve to change state so that movement of the power pistons in the pair of power cylinders is substantially 180.degree. out of phase.

Abstract: The invention is a method of returning process generated warm vapors of a cryogen such as hydrogen, helium and neon, to the main liquefier by contacting the warm vapors with process liquefied cryogen in order to generate saturated, essentially constant enthalpy vapors that can be readily processed by the main liquefier. Three example methods are described. In the first two methods, the warm vapor is recycled through the main storage tank associated with the process back to the main liquefier. In the third method, the warm vapor is washed with liquid in a contactor before being recycled to the main liquefier.

Abstract: Process for producing cold and/or heat by using a non-azeotropic mixture of fluids in a cycle with ejector. The working fluid is condensed (C), then separated in two fractions (2 and 7); the first fraction (2) is evaporated (EV) at relatively low temperature, the second fraction (7) is evaporated (B) at a relatively high temperature, and then the two vaporized fractions pass through an ejector (E) and are fed back to condenser (C). This process can be used for domestic heating or for refrigeration.

Abstract: A thermally powered engine which obtains energy from a closed heat transfer loop. The engine has two power cylinders. A piston is reciprocally mounted within each cylinder and divides the interior space of each cylinder into two portions. A piston rod is affixed to each piston and extends through the upper closed end of each cylinder. A flexible diaphragm is mounted in the lower portion of each cylinder and with the lower closed end of the cylinder forms a power chamber. A fluid fills the upper portion of both cylinders. A passageway between the cylinders permits the fluid to act as a free piston causing the piston of the cylinder in its exhaust stroke to force refrigerant from its power chamber to the condenser of the heat transfer loop. Refrigerant from the evaporator of the transfer loop flowing into a power chamber forces the piston upward during the pistons power stroke. Valves regulate the flow of refrigerant into and out of the power chambers of each of the power cylinders.

Abstract: A refrigeration or air-conditioner circuit has an ejector through which refrigerant is driven from a heated supply reservoir to an unheated collecting reservoir. The ejector sucks refrigerant from a branch circuit containing an expansion valve and an evaporative heat-exchanger providing cooling. Valving interchanges the functions of the two reservoirs when the refrigerant supply reservoir is empty so that operation of the circuit is uninterrupted.

Abstract: A method and apparatus are disclosed for increasing the production of liquid natural gas and conserving energy and reducing vapor production, while reducing equipment cost, in a liquid natural gas manufacturing installation. A liquid gas stream from a main exchanger is fed to a bi-phase rotary separator, which separates a vapor phase from the liquid phase without requiring an expansion valve and flash device, or liquid pump, as is commonly used. Optionally, work can also be extracted from the stream by the separator.

Abstract: A thermally powered heat transfer system which sequentially displaces thermal energy from the highest temperature heat source through two or more high temperature heat transfer loops to a heat sink. The system includes two or more two chamber compressors, with the high temperature chamber of each compressor being included in a high temperature heat transfer loop, there being a high temperature heat transfer loop for each compressor. The low temperature chamber of each compressor is included in one or more low temperature heat transfer loops. The source of heat for the evaporator heat exchanger of each high temperature heat transfer loop except one being heat from the condenser heat exchanger of another high temperature loop. The heat exchangers for the low temperature heat transfer loops being interchangeable depending on the mode of operation at any given time.

Abstract: A thermally powered heat transfer system consisting of two closed heat transfer loops which share a compressor which is powered alternately by the refrigerants of the two loops. This system is powered by a single heat source with a portion of the heat from that heat source being transferred at a higher temperature to a structure to be heated, the balance being transferred to a low temperature external heat sink. The first loop includes an evaporator and the condenser within the structure to be heated, and is charged with a first refrigerant. The second loop includes an evaporator and a condenser located so as to transfer heat to an external heat sink. The second loop is charged with a refrigerant having a lower boiling point than the refrigerant in the first loop.

Abstract: An air ventilator for ventilating indoor air to the environment comprising a motor provided with a shaft, a rotor mounted on said shaft, a plurality of fan blades pivotally attached to the rotor, a rotating circular plate having a plurality of sliding slots and a plurality of connecting holes mounted on said shaft of the motor, a fixed circular plate connected to the rotating circular plate with pins and mounted on the shaft of said motor, centrifugal weight members disposed between the fixed circular plate and the rotating circular plate, and a torsion coil spring connecting the centrifugal weight member with the rotating circular plate for elastically supporting the weight member, whereby when the motor is operating, the centrifugal weight members engage the rotating circular plate, apply a circumferential directional force thereto, and angularly displace the circular plate, said displacement being transmitted to the fan blades for ventilating the inside air to the environment; and when the motor is not ope

Abstract: This disclosure relates to a heat pump including a plurality of interconnected elements, each of said elements comprising a piston body having an evaporator section at one end thereof and a condenser section at the other end thereof, each condenser section being connected to a vapor condenser. Each element has its evaporator section connected by a vapor bridge to the condenser of an adjacent element. Each piston body contains a working fluid having a liquid phase and a vapor phase, the liquid phase forming a liquid piston which oscillates during operation and the pistons of the elements oscillating with a phase displacement. The evaporator sections are located in relatively warm areas and the condensers are located in another cooler area. Portions of the liquid in the evaporator sections vaporize and the vapor is heated, and the heated vapor is condensed in the condensers thereby transferring heat from the warm areas to the cooler areas.

Abstract: In a vacuum generating system having a liquid ring vacuum pump preceded in a gas flow path by a precompressor and followed by a liquid separator, the precompressor is driven by steam produced in a heat exchanger in contact with the working fluid of the vacuum pump. The working fluid is kept at a temperature exceeding the boiling point of water.

Abstract: Buildings are advantageously heated or heat-conditioned with a heat pump operated with a non-azeotropic mixture of two working fluids. The mixture comprises 99 to 70% by mole of dichlorodifluoromethane (R 12), monochlorodifluoromethane (R 22) or one of the halohydrocarbon azeotropes R 500, R 501 or R 502 with 1 to 30% by mole of trifluoromethane (R 23) or the halohydrocarbon azeotrope R 503.

Abstract: Method and apparatus for transferring heat. A pair of closed loop heat transfer loops each includes a refrigerant, a condenser to remove heat from the refrigerant, and an evaporator which adds heat to the refrigerant from its associated heat source. Each loop also includes a chamber of a compressor which has a free piston common to both chambers. One of the chambers is located above the other so that in one of the two cycles of operation, thermal energy from a heat source of the loop including the upper chamber evaporates liquified refrigerant collected in a collector of the loop in the previous cycle of operation which vapor together with gravity acting on the free piston cause the piston to compress vaporized refrigerant of the other loop in the lower chamber. This compressed refrigerant is condensed by loss of heat to an associated heat sink and is collected in the collector of its loop.

Abstract: A method and apparatus for utilizing low grade thermal energy is shown to reduce the energy required to drive the compressor of a refrigeration or air conditioning system. The thermal energy is used to vaporize a fluid which is used as a motive fluid to drive a thermal compressor, such as a jet compressor or a vapor compression cycle compressor. In a normal air conditioning system including a condenser, expansion valve, evaporator and compressor, the jet compressor is inserted between the discharge of a compressor and the inlet for the condenser when there is sufficient thermal energy to drive a thermal compressor. This produces a two-stage compressor which improves the efficiency of the overall system. If separate fluids are utilized, a thermal evaporator is located in a heat exchange relationship with the condenser to cool the refrigerant fluid within the condenser tube, a tube-in-tube arrangement being such a heat exchange relationship.

Abstract: Buildings are advantageously heated or heat-conditioned with a heat pump operated with a non-azeotropic mixture of two working fluids. The mixture comprises 99 to 70% by mole of dichlorodifluoromethane (R 12), monochlorodifluoromethane (R 22) or one of the halohydrocarbon azeotropes R 500, R 501 or R 502 with 1 to 30% by mole of trifluoromethane (R 23) or the halohydrocarbon azeotrope R 503.

Abstract: A thermally powered heat transfer system consisting of two closed heat transfer loops which share a compressor which is alternately powered by the refrigerants of the two loops. This system is powered by two heat sources having different temperatures of which the lower temperature heat source may be the heat within a structure to be cooled. An evaporator of the first loop located within the structure to be cooled is charged with a low boiling point refrigerant while an evaporator of the second loop is heated by a higher temperature heat source and is charged with a higher boiling point refrigerant. The heat sinks of the loops are at temperatures between those of the two heat sources. Controls are activated at the completion of each compressor stroke, or cycle, to alternately open and close valves which regulate vapor and liquid flows to cause the compressor to act with compressive force upon one or the other refrigerant vapor during each cycle of operation of the system to effect useful heat transfer.

Abstract: The expander-compressor transducer of this invention is for expanding refrigerant fluid from a high pressure source into a low pressure heat absorber while simultaneously precompressing the same fluid stream derived from the low pressure heat absorber.The device includes a body enclosing a chamber for confinement of refrigerant fluid; motor driven, a fluid-responsive piston arranged to oscillate in the chamber and dividing the chamber into an expansion chamber at one end and a compression chamber at the other end, a motor drive for oscillating the piston; a fluid control regulator for permitting flow of fluid into and out of the expansion chamber and into the compression chamber; and a check valve for permitting the refrigerant to flow out of the compression chamber whenever the pressure in the compression chamber overcomes the check valve.

Abstract: A closed refrigeration system in which a fluid refrigerated can be circulated includes a heater for converting the fluid to gas at a high pressure, an expansion chamber downstream of the heater, the expansion chamber including a cylindrical chamber with an inlet adapted for introducing the gas tangentially into the chamber, and an outlet coaxial with the chamber but of smaller diameter so that conservation of angular momentum increases the tangential velocity of the gas as it flows through the expansion chamber, producing an approximately isentropic expansion. A compression chamber is connected to the outlet of the expansion chamber, the compression chamber being approximately a mirror image of the expansion chamber so that the fluid undergoes approximately isentropic compression in passing through the compression chamber. A condenser condenses the fluid from the compression chamber to a liquid, which is circulated back to the heater.

Abstract: A refrigeration system employing an adiabatic expansion and an impulse generating means for the oscillatory compression and pumping of the working fluid. The impulse generating means is a venturi having a liquid inlet downstream of the throat with means for applying heat by a heat source, typically the waste heat of an automobile engine to the working fluid. The working fluid may be used to cool air through an evaporation in an automobile passenger compartment.

Abstract: A reaction turbine is used in a refrigeration (or heat pump) process, to improve efficiency.

Abstract: In a water chilling plant and method, normally with two or more stages of vacuum chilling, the vapor from the chilling stage or stages is presented to an air cooled heat exchanger for condensation in two different flow streams at different stages of compression, so that the cooler air nearer the air inlet works on vapor at a lower stage of compression.

Abstract: A process and apparatus for exchanging heat with condensable fluid are disclosed. In the process, a two-phase fluid is passed through the tubes of a heat exchanger under conditions of temperature and pressure such that the quality of the two-phase flow lies in the range of 0.03 to 0.97. The two-phase fluid is in a state of thermodynamic saturation at both the entry and exit of the heat exchanger. The change in quality of the two-phase mixture passing through the heat exchanger is distributed over the entire heat exchanger. The apparatus according to the invention includes a plurality of connected modular stages, each stage including a heat exchanger, a vapor-liquid separator, a compressor, an ejector and the suitable conduits to establish fluid communication between adjacent stages.

Abstract: A vapor compression refrigeration and/or heat pump system employing a particular type of expansion motor replacing the expansion valve of a conventional system.

Abstract: This invention embodies improvements in evaporative type refrigeration and space cooling units, both as to energy conservation and efficiency and economy of operation. It utilizes the new abentropic principle as set forth in my U.S. Pat. No. 4,109,470, which demonstrates that the energy of the latent heat of vapor is potential energy and need not be discarded as is done in present practice but can be converted to mechanical energy by taking advantage of the fact that the vapor pressure exuded by boiling hot condensate is the same as that of the vapor itself. The difference between this vapor pressure and that of a hard vacuum is sufficient to drive an engine. The energy necessary for the work done is extracted from the latent heat of the incoming vapor causing some of the vapor to condense at its boiling point proportionately as the work proceeds.

Abstract: A heating and air conditioning system and method involves the use of turbomachinery and a working fluid capable of changing phase at specific temperature and pressure and powered by an external heat source. The pressure of a portion of the working fluid in liquid form is increased and thereafter heated to change phase to a gas for use as a high energy working fluid component which is flowed through the turbo-drive. Another portion of the working fluid, at an intermediate pressure is expanded to a lower pressure and then passed through an evaporator, whose output forms a low energy working fluid component in gas form. The low energy working fluid is flowed into the turbo-device for admixture with the high energy working fluid, to effect an energy exchange therebetween. The turbo-device includes an output which is condensed and at an intermediate pressure. Various systems, turbo-devices and working fluids are described.

Abstract: The expander-compressor transducer of this invention is for expanding refrigerant fluid from a high pressure source into a low pressure heat absorbing heat exchanger while simultaneously precompressing the same fluid stream derived from the low pressure heat absorbing heat exchanger for delivery through suitable conduit heat exchangers to the suction side of the high pressure source.

Abstract: The invention relates to apparatus and a method for production of cold by the use of waste heat, more particularly to production of cold with use of refrigerating equipment with a steam jet apparatus which operates with a one-component refrigerant.

Abstract: In a refrigerant system having a liquid trapping suction accumulator between the evaporator exit and the compressor entrance and a very short bore capillary as an expansion tube to replace the thermostatic expansion valve, a recirculating ejector is added to recirculate any liquid that may be trapped by the accumulator back into the evaporator inlet where it can be used to provide desired refrigerating effect without requiring additional work in the compressor. The expansion tube is positioned so that it functions as the primary nozzle of the ejector. Thus the high-pressure liquid refrigerant being expanded through the expansion tube becomes the prime mover that is needed to drive the liquid from the accumulator into the evaporator. Because the high-pressure liquid refrigerant must be expanded to the relatively lower evaporator pressure in any vapor cycle refrigeration system, the recirculating function is accomplished without using additional energy or penalizing system capacity.

Abstract: A continuous method and closed cycle system for converting thermal energy to mechanical energy comprises vaporizing means, including an energy conversion tube comprising at least one nozzle section, for converting a liquid working fluid stream to a predominantly, by volume, vapor or an all vapor stream, turbine means operated by the stream for converting a portion of the vapor stream energy to mechanical shaft work; means for increasing the thermal and potential energy of the turbine exhaust stream and for condensing it to a substantially liquid stream; and means for recycling the liquid stream to the vaporizing means. The system has particular application to conventional refrigeration/heat pump cycles wherein the conventional throttling valve is replaced by a non-throttling nozzle and a turbine for capturing and using the work of expansion. Energy conversion tubes of the present system also find application in high flow rate, two phase flow applications, such as pressure vessel safety relief valves.

Abstract: A first mass of driving vapor is admitted into a single chamber of variable volume and permitted to perform isobaric then polytropic work in an expansion which increases the chamber volume. A second mass of vapor derived from the refrigeration cycle is then admitted at constant pressure in order to attain maximum volume. The work performed by the driving vapor is utilized in a polytropic process for compressing the vapor masses which are then discharged to the condenser in an isobaric process when the chamber approaches minimum volume.

Abstract: A separation system is disclosed for obtaining pure components from a fluid mixture employing a minimum amount of energy. A rectification column is utilized in which the fluid mixture is separated into its components whereby the heat addition and cooling required is accomplished by means of a heat pump transfer system. The system transfers heat energy to a working fluid to power a compressor structure in a heat pump cycle by supplying heat to the liquid phase. Compressor structure is disclosed in the forms of an ejector and a turbine-powered compressor. As disclosed, the same working fluid is employed in the power cycle and the heat pump cycle. Specific structures are disclosed for obtaining greater efficiency including an arrangement for heat regeneration in the power loop of the heat pump cycle and also disclosed is an arrangement whereby individual systems are staged for the separation of multicomponent mixtures.

Abstract: A heat pump system including an evaporator with an inlet and an outlet, a condenser with an inlet and an outlet, a boiler with an inlet and an outlet, an expansion valve connecting the condenser outlet to the evaporator inlet, a liquid pump connecting the condenser outlet to the boiler inlet, and a system working fluid in combination with an expansion-compression device defining a chamber therein and including a free-piston slidably carried in the chamber for linear movement therein, and dividing the chamber into a first subchamber of varying size as said free piston moves and a second subchamber of varying size as said free piston moves along with boiler valve means for selectively introducing working fluid from the boiler outlet into the first subchamber; valve means for selectively introducing working fluid from the evaporator outlet into the first subchamber; condenser valve means for selectively introducing working fluid from said first subchamber into the condenser inlet; means for pressurizing the seco

Abstract: A dual loop, heat driven, heat pump system including an expansion-compression device with a linearly movable operating mass such as a free piston assembly; a Rankine cycle power loop with a working fluid operatively connected to the expansion-compression device to drive same; a vapor compression heat pump loop with a working fluid operatively connected to the expansion-compression device to be driven thereby; and control means for selectively associating the working fluid of the power loop with the linearly movable mass of the expansion-compression device to cause the power loop working fluid to drive the movable mass linearly and induce linear kinetic energy in the movable mass, and for selectively associating the working fluid of the heat pump loop with the mass while the linear kinetic energy is stored therein to cause at least a portion of the kinetic energy of the mass to be transferred to the heat pump loop working fluid as compression work.