https://docs.lib.purdue.edu/cgi/viewcontent.cgi?article=2875&context=iracc

High temperature heat pumps: Market overview, state of the art, research status, refrigerants, and application potentials

Abstract This study reviews the current state of the art and the current research activities of high temperature heat pumps (HTHPs) with heat sink temperatures in the range of 90 to 160 °C. The focus is on the analysis of the heat pump cycles and the suitable refrigerants. More than 20 HTHPs from 13 manufacturers have been identified on the market that are able to provide heat sink temperatures of at least 90 °C. Large application potentials have been recognized particularly in the food, paper, metal and chemical industries. The heating capacities range from about 20 kW to 20 MW. Most cycles are single-stage and differ primarily in the refrigerant (e.g. R245fa, R717, R744, R134a or R1234ze(E)) and compressor type used. The COPs range from 2.4 to 5.8 at a temperature lift of 95 to 40 K. Several research projects push the limits of the achievable COPs and heat sink temperatures to higher levels. COPs of about 5.7 to 6.5 (at 30 K lift) and 2.2 and 2.8 (70 K) are achieved at a sink temperature of 120 °C. The refrigerants investigated are mainly R1336mzz(Z), R718, R245fa, R1234ze(Z), R600, and R601. R1336mzz(Z) enables to achieve exceptionally high heat sink temperatures of up to 160 °C.

High Temperature Heat Pumps: Market Overview, Stateof the Art, Research Status, Refrigerants, and Application Potentials

A waste heat utilization device (2) for an internal combustion engine has a Rankine cycle (8) that recovers waste heat from an internal combustion engine (4), a generator (30) that is rotationally driven by an expander (14) and converts a rotational drive force into electric power, a converter (32) that controls the rotational speed of the expander (14) through the generator (30), refrigerant-condition detecting means (22, 24, 26, 28) that detects the pressure and temperature of a refrigerant passing through the expander (14), and a controller (34) that calculates pressure ratio Rp of the refrigerant in the immediate upstream and downstream of the expander (14) and specific heat ratio K of the refrigerant passing through the expander (14) on the basis of the pressure and temperature of the refrigerant, which have been detected by the refrigerant-condition detecting means (22, 24, 26, 28), calculates a preset pressure ratio Rps of the pressure ratio Rp by multiplying predetermined volume ratio Rv of the expander (14) by the specific heat ratio K, and specifies rotational speed N of the expander (14) to the converter (32) on the basis of the pressure ratio Rp and the preset pressure ratio Rps.

Waste Heat Utilization Device for Internal Combustion Engine

The waste heat recovery system includes a Rankine cycle device in which working fluid circulates through a pump, a boiler, an expander and then through a heat exchanging device, heat exchange occurs in the boiler between the working fluid and intake fluid that is introduced into an internal combustion engine while being cooled. The heat exchanging device includes a condenser condensing the working fluid, a receiver connected downstream of the condenser and storing liquid-phase working fluid, a subcooler connected downstream of the receiver and subcooling the liquid-phase working fluid, and a selector device serving to change the ratio of the condenser to the subcooler. The waste heat recovery system further includes a determination device for determining required cooling load for the intake fluid, and a controller for controlling the selector device depending on the required cooling load determined by the determination device.

Waste heat recovery system

The present invention relates to a system and method for cooling a combustion gas charge prior. The combustion gas charge may include compressed intake air, exhaust gas, or a mixture thereof. An evaporator is provided that may then receive a relatively high temperature combustion gas charge and discharge at a relatively lower temperature. The evaporator may be configured to operate with refrigeration cycle components and/or to receive a fluid below atmospheric pressure as the phase-change cooling medium.

System And Method For Cooling A Combustion Gas Charge

The shaft (20) of an engine (19) is coupled to a turbine (28) of an organic Rankine cycle subsystem which extracts heat (45-48, 25) from engine intake air, coolant, oil, EGR and exhaust. Bypass valves (92, 94, 96, 99) control engine temperatures. Turbine pressure drop is controlled via a bypass valve (82) or a mass flow control valve (113). A refrigeration subsystem having a compressor (107) coupled to the engine shaft uses its evaporator (45a) to cool engine intake air. The ORC evaporator (25a) may comprise a muffler including pressure pulse reducing fins (121, 122), some of which have NOx and/or particulate reducing catalysts thereon.

Organic rankine cycle mechanically and thermally coupled to an engine driving a common load

A method and system for operating a cascaded organic Rankine cycle (ORC) system (100) utilizes two waste heat sources from a positive-displacement engine (106), resulting in increased efficiency of the engine (106) and the cascaded ORC system (100). A high temperature waste heat source from the positive-displacement engine (106) is used in a first ORC system (102) to vaporize a first working fluid (118). A low temperature waste heat source from the positive-displacement engine (106) is used in a second ORC system (104) to heat a second working fluid (130) to a temperature less than the vaporization temperature. The second working fluid (130) is then vaporized using heat from the first working fluid (118). In an exemplary embodiment, the positive-displacement engine (106) is a reciprocating engine. The high temperature waste heat source may be exhaust gas and the low temperature waste heat source may be jacket cooling water.

Cascaded organic rankine cycle (orc) system using waste heat from a reciprocating engine

A cascaded Organic Rankine Cycle (ORC) system includes a bottoming cycle working fluid is first evaporated and then superheated and a topping cycle working fluid is first desuperheated and then condensed such that a percentage of total heat transfer from the topping cycle fluid that occurs during a saturated condensation is equal to or less than a percentage of total heat transfer to the bottoming cycle fluid that occurs during a saturated evaporation.

Cascaded organic rankine cycle system

A variable nozzle system can comprise a gas inlet ring, an opposing gas outlet ring, an actuation ring, guides, and vanes circumferentially spaced about and disposed between the gas inlet ring and the gas outlet ring. The gas inlet ring, the gas outlet ring, and the vanes can form nozzles, the nozzles being variable by rotation of the vanes about a pivot axis. The plurality of guides can extend from the gas inlet ring, the gas outlet ring, or the actuation ring, and the vanes can be connected to the actuation ring, so that each vane can be rotated by rotation of the actuation ring and by sliding against a respective guide from the plurality of guides. The actuation ring can have a gear rack and can be rotated by rotatable engagement of the gear rack with a pinion attached to the end of a rotatable gear shaft.

Rotatable vaned nozzle for a radial inflow turbine

Ketone C6F, which has the chemical formula: CF3CF2C(O)CF(CF3)2, has been introduced recently as a zero-ODP, zero-GWP fire extinguishing fluid. Its non-flammability and non-toxicity combined with its excellent environmental properties make it an attractive fluid for HVAC applications. Its low density limits its use to centrifugal water-cooled chiller applications. The relatively high critical temperature of the fluid promises good thermal cycle efficiency. However, the slope of the saturation dome on the temperatureentropy diagram forces the use of a vapor suction / condensed liquid heat exchanger to prevent wet compression and reduce the throttling losses. The low speed of sound of the fluid allows direct drive single stage compressor operation at relatively small tonnages. The sub-atmospheric evaporator (0.162 bar) and condenser (0.604 bar) pressures necessitate the use of a purge but eliminate the need for pressure vessel code certification.

/pdf/cycle-analysis-and-turbo-compressor-sizing-with-ketone-c6f-22mnud97o3.pdf

Lili Zhang

Papers

Organic rankine cycle mechanically and thermally coupled to an engine driving a common load

Cascaded organic rankine cycle (orc) system using waste heat from a reciprocating engine

Cascaded organic rankine cycle system

Rotatable vaned nozzle for a radial inflow turbine

Cycle analysis and turbo compressor sizing with ketone c6f as working fluid for water-cooled chiller applications