Development of centrifugal chiller and heat pump using …hpc2017.org/wp-content/uploads/2017/06/o341.pdf · Development of centrifugal chiller and heat pump using low ... Development
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The shell & tube type heat exchanger, and flooded type evaporator Since the specific gas volume is larger, and the differential pressure between the condenser and evaporator is smaller than R-134a, pressure drop should be carefully considered.
We analyzed the actual chiller and measured the verification test
The volume of the evaporator and condenser reduce to 120%.
The outside heat-transfer coefficient of evaporator registers no more than 10% decrease, and the coefficient of condenser registers no more than 20% decrease at the rated condition.
Test results of evaporator Test result of condenser
Industrial customers have required us heat pumps to use high temperature heat.
We have been developing a high temperature heat pump
heating pressurized water to the temperature from 160°C to 200°C
The target COP is 3.5 with the aim of boiler replacement.
Refrigerant
The operational temperature must be considered. This requires the following;
Stability at high temperature: Prevention of isomerization and decomposition.
Standard boiling point: The size of compressor should not be too small for the adiabatic efficiency. The design pressure should not be too high for the manufacturing.
Critical point: The critical temperature should be higher than the operating temperature to improve the efficiency of the cycle.
Lubricant oil
The lubricant oil must maintain the stability at high temperature, requiring the temperature-dependent viscosity and solubility in the refrigerant.
Stability of R-1233zd(E): Thermal stability for 90°C applications
Enough solubility and viscosity: Kinetic viscosity and solubility are 125% and 112%, compared with requirements for the bearings of up to 160°C applications.
Refrigerant and lubricant oil First step; We investigated the replacement with a low GWP refrigerant in a 90°C application.
Accelerated thermal stability testing for 90°C applications
Comparison of R-134a and olefins for 90°C applications
The heat pumps operating at high temperature using low GWP refrigerants are going to be developed through the stages, 90°C, 160°C, 200°C.
The development of refrigerants and lubricant oil are being conducted in parallel with that of the heat pump.
We focus to introduce a model to heat pressurized water to 200°C in practical applications by 2023.
Application
Heat pumps heating water to the temperature from 160°C to 200°C are suitable for industrial applications, for example, chemical reaction and dried processes.
We have been investigating the details to propose a heat system for industrial processes. ex) heat and energy balance operating time temporal axis of thermal demand and heat source
A centrifugal chiller using low GWP refrigerant have been developed.
A R-1234ze(E) type have been developed for the capacity from 300 to 5000 USRt.
A R-1233zd(E) type have been developed for the capacity from 150 to 700 USRt.
A centrifugal heat pump using a low GWP refrigerant is being developed.
In the experiments, R-1233zd(E) was selected for a heat pump heating water to 90°C. The design have been completed and we are preparing for drop-in testing.
The developments of heat pumps heating water to 90°C, and higher temperatures are going to be carried out, with a final goal of operation at 200°C.
This work is supported by New Energy and Industrial Technology Development