Cooling Water Tank Research Articles

Research on Operation Characteristics of Passive Containment Heat Removal System in Typical Accident Conditions

In order to verify the feasibility of the design of the third generation of nuclear power plant independently developed in China, this study investigated the operation characteristics of the passive containment heat removal system under five working conditions using the passive containment heat removal system general performance verification facility: the design conditions, low water level conditions, low pressure conditions in the containment, extreme accidents conditions and resistance increasing conditions are analyzed, and the thermal characteristics, power requirements and thermal parameters of the containment under different operating conditions are analyzed. The results show that the heat dissipation capacity of the passive containment heat removal system exceeds the design requirements under the design conditions. Under off-design low pressure conditions, the pressure in the system is significantly affected. The decrease in the cooling water tank’s water level not only did not adversely affect the operation of the system but instead led to a significant increase in the system’s heat dissipation power. In the case of extreme accidents, the system may initially stall, but a stable natural cycle can then be established. As the system resistance coefficient increases, the heat dissipation power of the passive containment heat removal system exhibits an approximate linear decreasing trend.

Design and application of a hemodialysis machine suitable for transporting patients

Blood purification is one of the commonly used techniques for the rescue of critically ill patients, which is used for acute and chronic kidney injury caused by various causes and renal replacement therapy (RRT) for a variety of critical diseases. Its main working principle is to drain the human blood into a variety of dialyzers through the artificial tube, exchange substances through a variety of ways, and remove harmful substances and some metabolites from patients' body. Then the purified blood is transfused back to the body, so as to maintain the patient's internal environment relatively stable. At present, there are different models of hemodialysis machines in clinical practice, but they are bulky and unable to move, and the method of heat dissipation is single, which cannot meet the needs of hemodialysis treatment in transport patients. Therefore, the medical staff of the Second Affiliated Hospital of Zunyi Medical University designed and developed a hemodialysis machine, which is suitable for patients who demand hemodialysis treatment during transport, and obtained the National Invention Patent of China (ZL 2020 1 0864737.3). The hemodialysis machine comprises a main body of the hemodialysis machine and a mobile vehicle. The main body of the hemodialysis machine is placed in the bottom of the mobile vehicle, and a protective cylinder with fixed airbags is designed around the main body of the hemodialysis machine. The fixed airbag is connected to the air storage tank through the pipeline, the air storage tank is connected to the Venturi tube through the control valve, and the throat of the Venturi tube is connected to the disinfection tank and cooling water tank. The outlet end of the Venturi tube is connected with the cooling pipe inside the main part of the hemodialysis machine and the sprinkler head placed on the top of the main body. By adding a mobile vehicle and designing an airbag and protective cylinder, the hemodialysis machine can be applied to the hemodialysis treatment during the transportation of patients. By designing the heat dissipation pipe, the main body of the hemodialysis machine can be cooled, the temperature of the hemodialysis machine can be reduced, and the hemodialysis machine can still work when the fan is damaged. By designing the sprinkler head, it is convenient to automatically disinfect the main screen and control keys of the hemodialysis machine, reduce the risk of cross infection of medical staff in the operation, and increase the safety and practicability of the hemodialysis machine. The hemodialysis machine is convenient, safe and efficient, which can be widely used in the hemodialysis treatment during transported patient, and is worthy of clinical promotion.

Radiation source terms analysis and classification of radioactive waste for the decommissioning of the first HWRR reactor in China.

Nuclear reactors will face the problem of decommissioning at the end of their operating life due to the high radioactivity of reactor components and environmental safety considerations. The Heavy Water Research Reactor (HWRR) is the first large-scale research reactor to be decommissioned in China. The second phase of HWRR decommissioning involves the main components in the reactor block, so the radiation source terms and the radioactive waste level need to be evaluated before demolition and disposal. Based on the operating history, three-dimensional geometry, materials, and other information of the HWRR, the activity of radionuclides in the main components of HWRR is calculated and analyzed, and the MCNP/ORIGEN coupling scheme is utilized for theoretical analysis. The theoretical results indicate that 14C, 54Mn, 55Fe, 60Co, 63Ni, and 152Eu are the main radioactive nuclides. The total activity of radioactive nuclides was 2.36E + 15Bq at the end of 2007, 4.27E + 13Bq at the end of 2021, and 1.83E + 13Bq at the end of 2025. Furthermore, local sampling and radiometric analyses based on the HPGe gamma-ray spectrometer are also performed to verify the theoretical results, the ratio of theoretical activity values to the measured activity of the experimental sample is within 2.5 times, so the theoretical results are conservative. According to the classification standards for radioactive waste, the inner shell, outer shell, cooling water tank, sand layer, and heavy concrete shielding layer are all low-level waste. These results and conclusions can serve as a reference for the second phase decommissioning of the HWRR and the subsequent disposal of radioactive waste.

A Study on the Simulation and Experiment of Evaporative Condensers in an R744 Air Conditioning System.

The heat transfer characteristics of evaporative condensers in an R744 air conditioning system were evaluated using the numerical and the experimental methods. Two configurations of condensers were studied: Case 1 with five layers of tubes and Case 2 with eight layers of tubes. In order to evaluate the heat transfer characteristics, the temperature field, the phase change, the pressure distribution, and thermodynamic parameters were considered. For Case 2, it indicated the capability of R744 condensation from the superheated status to the liquified status by analyzing the outlet temperature of the condenser changed from 28.7 °C to 30.3 °C with a change in condensation pressure from 72.6 bar to 68.5 bar. In this study, R744 mass flow rate increases from 14.34 kg/h to 46.08 kg/h, and the pressure drop also increases from 0.23 bar to 0.47 bar for the simulation and 0.4 bar to 0.5 bar for the experiment, respectively. The results indicate that the five-layer configuration causes a higher pressure drop and lower COP than those obtained from the eight-layer one (splitting into two sets for smaller pressure drop). Furthermore, the evaporative condensers using mini tubes that are flooded in the cooling water tank are suitable for the subcritical R744 air conditioning system. In addition, the results obtained from the experimental data are in good agreement with those obtained from the numerical results, with a deviation of less than 5%.

Experimental study on the influence of inclination on operating characteristics of secondary side passive residual heat removal system

The present work discusses the operating characteristics of the secondary side passive residual heat removal system (PRHRS) of an offshore floating nuclear plant (OFNP). A scaled experimental facility was built on a platform that can be inclined to a certain angle. Experiments were conducted in horizontal and various inclined conditions, and the transient response characteristics and steady-state operating characteristics of the PRHRS were obtained. The experimental results reveal that different inclined directions will change the potential height difference between the cold and heat sources and affect the natural circulation capacity of the system. In general, due to the small inclination of the floating platform in the ocean, the residual heat can be effectively exported by PRHRS. Thermal stratification in the cooling water tank has significant effect on the evolution process of outlet temperature of the passive residual heat removal heat exchanger, and the influence of thermal stratification on the outlet temperature of the heat exchanger decreases under inclined conditions. The research results in this paper can provide some guidance for the design of operating rules of the secondary side PRHRS.

Study of heat Energy Disposal in Hollow Roof Cooling Water Tank

Cooling tank is defined as a heat exchanger whose working fluid material is water, and air which functions to cool water by direct contact with air which causes a small portion of the water to evaporate. This water will flow in the hollow roof which is expected to absorb heat as it passes through the cavity. This study aims to obtain the value of the effectiveness of the heat transfer rate on the hollow roof, as well as to determine the amount of energy in the cooling water tank of the hollow roof that can be discharged every hour and to determine the water flow required to supply the hollow roof. During the study, the results obtained varied with the volume of water entering about 0.00064 m³ in each cavity, with a pump capacity of 5.5 LPM. From the test data obtained, if the intensity of sunlight is low, the heat will be absorbed by the environment and vice versa if the intensity of sunlight is high, the heat will be absorbed by the water. That is why the intensity of sunlight greatly affects the data collection process. From the results obtained in the field at the time of the study for 7 days, the average water temperature was 28.4ºC. This result can be categorized as safe because the water temperature does not exceed or is not far from the temperature in the water tank with an average temperature of 40.5ºC.

Experimental and Numerical Studies of AP1000 Shield Building considering Fluid-Structure Interaction

The gravity cooling water tank is a remarkable structural feature of third-generation pressurized water reactor nuclear power plant. To investigate the influence of fluid-structure interaction (FSI) on the seismic response of the structure, this study designed two 1 : 50 simplified models of the AP1000 shield building. A series of shaking table tests were conducted to study the seismic responses with and without FSI effect. The natural frequency, acceleration, strain, and hydrodynamic pressure of the two models were analyzed, and the seismic reduction effect of the water tank was evaluated. Moreover, the test data were compared with the results of numerical analysis using the ABAQUS software. The results show that the presence of water and the sloshing of water reduce the natural frequency and seismic response of the model structure. Thus, the gravity cooling water tank has a certain seismic reduction effect. The simplified model of water sloshing can be used to analyze the seismic response of the shield building.

Research on mass transfer characteristics of the flue gas dehydration using ceramic membrane transport condensers

• Building an experimental platform for flue gas dehydration with the ceramic membrane tube. • Circulating water and purge gas are used as the cooling medium. • The operating parameters are divided into flue gas and cooling medium parameters. • Correlation analysis of permeate flux and intrinsic factors influenced by operating parameters. • Excessive transmembrane pressure difference can damage the selective permeability of ceramic membranes. The direct discharge of flue gas from the coal fired boiler can result in significant water loss. Membrane separation technology is an effective means to solve the flue gas dehydration problem. Based on the permeation characteristics of porous membrane materials, ceramic membrane method flue gas dehydration is a complex mass transfer process. In this paper, the ceramic membrane transport condensers were built with circulating water, positive pressure purge gas and negative pressure purge gas as the cooling medium, respectively. Changing flue gas parameters and cooling medium parameters, the correlation coefficients of water vapor pressure difference, transmembrane pressure difference and Reynolds number with permeate flux were investigated. The results showed that the key factors that determine the permeate flux were slightly different with the different experimental conditions. Changing the flue gas temperature or the cooling medium temperature has an obvious effect on the water vapor pressure difference. There is a significant correlation between the water vapor pressure difference and the permeate flux. Changing the flue gas flow or the cooling medium flow, the water vapor pressure difference is less variable, and the transmembrane pressure difference is not the key factor affecting the permeate flux, and the Reynolds number is the key factor affecting the permeate flux. Meanwhile, the experimental process revealed that an excessive transmembrane pressure difference can cause non-condensable gases in the flue gas to enter the cooling water tank.

Experimental Investigation on Waste Heat Recovery from a Cement Factory to Enhance Thermoelectric Generation

This work investigated the potential for waste heat recovery from a cement factory using thermoelectric generation (TEG) technology. Several TEGs were placed on a secondary coaxial shell separated from the kiln shell by an air gap. The performance of the system was tested and evaluated experimentally. Two cooling methods, active water and forced air, were considered. A forced closed-loop water cooling system with a heat exchanger was considered for the active-water cooling method. A heat exchanger was inserted before the water tank to improve cooling efficiency by reducing the inlet temperature of the cooling water tank, in contrast to forced-air cooling, in which a heatsink was used. The obtained results indicated that the closed-loop water-cooled system equipped with a radiator, i.e., active water, has the highest conversion efficiency. The maximum absorbed heat for the forced-air and active-water cooling systems were 265.03 and 262.95 W, respectively. The active-water cooling method improves the power of TEG by 4.4% in comparison with forced-air cooling, while the payback periods for the proposed active-water and forced-air cooling systems are approximately 16 and 9 months, respectively.

Numerical study on long-term passive heat removal of EPRHR cooling water tank (CWT) using heat pipe heat exchanger

The EPRHR in the HPR1000 adopts natural circulation to meet the heat removal requirements of the containment for 72-hours under accident conditions. To reduce the evaporation depletion of water in CWT and enhances the passive cooling capability of the EPRHR, a long-term passive cooling scheme based on a heat pipe heat exchanger is proposed for CWT in this paper. Experimental study and numerical simulation are used to study the natural convection characteristics in the CWT. The results show that the scheme can take away 9 MW heat load as the average water temperature (Tave) is below 90 °C. The heat removal ability of the tube bundle is weakened row by row and the maximum difference of heat removal ability between tube bundles is 23%. The position of the tube bundles affects the Tave, and when the dimensionless layout factor (γ) = 3/4, Tave (346.34 K) is the smallest.

Needle shaped conductivity probes with integrated micro-thermocouple and their application in rapid condensation experiments with non-condensable gases

Abstract The present paper deals with advanced conductivity probes for local void measurements, which were equipped with a microthermocouple, which is integrated into the probe at the place of the electrode wire. These probes were used for rapid transient condensation tests in a heat exchanger pipe immersed into a cooling water tank. The experiments serve as data sources for the validation of thermal-hydraulic system codes concerning the modelling of the condensation, particularly with respect to the behaviour and effect of non-condensable gases. The present tests were carried out at the pressurizer test facility DHVA of the University for Applied Sciences in Zittau/Görlitz, IPM serving as steam source. The slightly downwards inclined condensation tube was connected to the head of the pressure vessel and supplied with steam in this way. The application of a new type of two-phase instrumentation has revealed details about the transient condensation process. Since tests were performed with and without the presence of a non-condensable gas (air), the effect of the gas could be studied. The merits of the probes lie in the ability to distinguish between steam and gas. Without the synchronous temperature and void measurement performed by the probes it would have not been possible to clarify the physical background of the temperature jumps found during the experiments with the non-condensable gas.

Experimental investigation on the heat removal capacity of secondary side passive residual heat removal system for an integrated reactor

An experimental facility named Intermediate Heat Exchange Loop (IHEL) is built to simulate the secondary side passive residual heat removal system. The IHEL mainly includes a helically coiled Once-Through Steam Generator (OTSG), a condenser, a cooling water tank, and associated piping and valves. The steam is produced by the water-to-water heat exchange method in the SG secondary side. The heat from the SG primary side is carried to the cooling water tank by the IHEL through a two-phase natural circulation method. The natural circulation characteristics of the IHEL under the low pressure (nearly atmospheric pressure) and low water inventory conditions are investigated. The result shows that the heat removal capacity of the IHEL is good at these conditions, and it is determined by the parameters of the SG primary side and IHEL together. In the present test conditions, for the parameters of the SG primary side, the heat removal rate will increase with the increase of mass flow rate or heat source temperature. For the parameters of the IHEL, the heat removal rate is not sensitive to the initial non-condensable gas content. The heat removal rate is not sensitive to the resistance level when the heat source temperature is low, while it will decrease with the increase of resistance level when the heat source temperature is high. A very meaningful conclusion is that the natural circulation has been established successfully in the very lower water inventory condition (L = 14.8% in the present study), and the heat removal rate almost remains constant with the increase of the water inventory, which indicates the IHEL is robust and is beneficial for the system design.

Case Study:Identification of Microbial Distribution and Contamination Source by PDCA Cycle at a Boiled Noodles Factory

Boiled noodles are considered to be one of the most perishable foods due to their high moisture content and high water activity. Thus, the hygiene control measures based on HACCP manuals has been recommended in the noodle manufacturing industry. However, there were several cases in which post-packaged products manufactured at the Boiled noodles factory of small-to-medium size company detected a viable cell count higher than their voluntary standards. To identify the source of microbial contamination, an investigation based on the Plan-Do-Check-Act (PDCA) cycle was conducted. The results showed that the bacteria causing the contamination were environmental bacteria. Secondary contamination occurred during the cooling process after sterilization. Airborne environmental bacteria and oxygen may have been introduced into the rinsing and cooling water tank by the strong water flow during the rinsing and cooling process, inducing growth of microorganisms in the cooling water and contaminating the final product. This is a new finding, as such occurrence was not listed in the HACCP manual and should be contributed to plan HACCP system.

Nonlinear Seismic Response Characteristics of CAP1400 Nuclear Island Structure on Soft Rock Sites

CAP1400 nuclear island structure is an advanced and novel nuclear power plant structure. In order to explore the seismic response characteristics of CAP1400 nuclear island structure on soft rock sites, a three-dimensional refined nonlinear seismic response analysis model was established for a soft rock foundation-nuclear island structure system using ABAQUS software. The influences of the input ground motion intensity and the frequency spectrum characteristics on the acceleration, relative displacement, and floor response spectrum, as well as the critical shear wave velocity of nonbedrock sites for CAP1400 nuclear island structure, were proposed. The results suggested that the increasing amplitude of the peak acceleration and relative displacement of nuclear island structure decreased as the soft rock site entered a nonlinear state, and the high-frequency components of the input ground motion became more abundant. Specifically, the earthquake response was the largest at the cooling water tank on the top of the shield building, which was the focus of the seismic research on nuclear island structure. Due to the influence of the ground motion frequency spectrum characteristics and the nonbedrock site effect, the peak acceleration, peak relative displacement, and acceleration response spectrum of the nuclear island structure showed different changing trends for the near-field and far-field ground motions. Based on the influence of the site shear wave velocity on the seismic response of nuclear island structure, it was recommended that the critical shear wave velocity of nonbedrock sites for CAP1400 nuclear island structure should be 1250 m/s, and the nuclear island structure-foundation dynamic interaction could be ignored at this time. The research conclusions could provide some technical support and theoretical basis for the construction and seismic performance research of CAP1400 and other nuclear power plants.

Analysis of the impact of rock hardness on the seismic response characteristics of CAP1400 nuclear island structure

With the rapid development of the nuclear power industry, appropriate sites for nuclear power plants have become a scarce resource. The construction of a nuclear power plant is subject to stringent requirements of site selection, and it is necessary to ensure that the plant will have sufficient seismic resistance. In this study, targeting the CAP1400 nuclear island structure as the research object, a three-dimensional finite element model of the dynamic interaction between the nuclear island structure and the foundation is established by considering the nonlinear characteristics of rocks using ABAQUS software. Our objective is to analyse the impact of rock hardness on the acceleration, displacement and floor response spectrum of the nuclear island structure caused by earthquake based on a total of 4 types of rock foundations with different degrees of hardness. The results show that, with the increase of rock hardness, the acceleration of the nuclear island structure increases, the displacement decreases, while the peak of floor response spectrum increases and moves towards the short period (high frequency band) direction. The seismic response of the nuclear island structure increases with the increase of elevation, and the greatest level of response is observed at the cooling water tank of the shield building, which therefore should be targeted as the key for seismic design. For rock foundations with high hardness, the seismic design for the nuclear island structure can follow the standard for rigid foundations so as to ignore the effect of the soil-structure dynamic interaction.

Aquadest Production System as Steam Turbine Bottom Cycle I: Influence of Pressure of Cooling Water Tank and Pinch Point Temperature Difference of Condenser

The condenser heat from the steam turbine system is discharged into the environment in a way that is likely to damage the environment. This paper simulates a system that produces aquadest with throttled 10% water of condenser output to the cooling water tank with vacuum pressure so as to produce water vapor. This water vapor is condensed in a cooling machine to produce aquadest. The cold water coming out of the cooling water tank is mixed with cooling water from the sea so the temperature is lower causing the condenser output water to be lower temperature (more environmentally friendly). This simulation varies the pressure of cooling water tanks and Pinch Points Temperature Difference (PPTD) of condenser. From the simulation it is found that the higher the pressure of the cooling water tank causes Specific Aquadest Production (SAP), and Energy Consumtion (EC) is getting smaller. The smaller PPTD leads to Specific Aquadest Production (SAP), Specific Energy Consumtion (SEC) and Energy Consumtion (EC) getting smaller. This simulation has the best result that is able to produce aquadest as much as 0.0133 [kg/s], increase the efficiency of steam power plant by 0.21%, and lower condenser water temperature by 0.9 °C.

Experimental study on transient characteristic of passive containment cooling system

Separated heat pipe is an efficient passive heat transfer device. It is widely used on chemical and aerospace industry. In this paper, the transient characteristics of the separated heat pipe which applied to a containment cooling system were studied. According to the experiment, the start-up transition characteristic of cooling system were mainly described. The influences of containment initial pressure and thermal load of separated heat pipe loop were analyzed. Based on the experimental data, it shows that the separated heat pipe is feasible for containment cooling system. It can remove the heat of containment vessel passively on design basis accident. And the separated type heat pipe cooling system has the working condition of flow instability region. The influence factors of which is relevant to cooling water tank temperature, containment pressure and system input power. The flow instability has little effects on the trend of containment pressure.

Experimental evaluation of safety performance of emergency passive residual heat removal system in HPR1000

The steam generator secondary side emergency passive residual heat removal system (EPRHR) is innovatively introduced into the Hualong Pressurized Reactor (HPR1000) to enhance its safety performance in station blackout (SBO) scenarios. The Emergency Secondary Passive Residual heat removal system Integral Test facility (ESPRIT) was constructed to obtain the safety performance of EPRHR under various initial and boundary conditions. The scaling ratio of power/volume between ESPRIT and HPR1000 is 1:62.5. The resistance matching experiments were conducted in the first place to restore the prototypical pressure drop characteristics of the EPRHR. Three transient experiments, each with the duration of 72h, were conducted under prototypical, elevated heating power and elevated resistance conditions to evaluate the safety performance of HPR1000 under SBO conditions. The experimental results reveal that the steam generator pressure decreases dramatically in the early stage after the startup of EPRHR. The safety injection rate decreases dramatically in the elevated resistance condition compared with the prototypical one. The liquid level in the cooling water tank decreases by 5.4% in the steam generator power elevation condition. The designed volume of cooling water tank satisfies the heat removal demand in SBO accident within 72h. The heat sink possesses sufficient cooling ability under elevated power condition. The system temperature remains decreasing with the decrease of residual heat in each of the transient experiment. It is also found that effective natural circulation and continuous heat exchanger cooling always remain in three experiments.

The performance of a heat pipe based solar PV/T roof collector and its potential contribution in district heating applications

Photovoltaic–thermal water collectors have the ability to convert solar energy into electricity and heat, simultaneously. Furthermore, the combination of photovoltaic–thermal solar collectors with a water cooling system can increase significantly the electrical and thermal efficiencies of the system, which can improve the total thermal efficiency of buildings. In this paper, the findings of six experimental configurations of solar-thermal collectors are presented and analyzed. Five of the solar-thermal panel configurations were implemented with a cooling cycle. Two of the solar-thermal panels were equipped with monocrystalline silicon modules, the other two collectors were equipped with polycrystalline silicone modules, one of the collectors was based on heat pipe technology and was equipped with a cooling system, while the last collector did not include any cooling cycle. The duration of the experiments was four days during the September of 2014 and they were conducted under different solar radiation conditions. The second part of the paper presents the simulation results for five of the solar-thermal panels connected with a cooling water tank (volume of 500 L), a domestic hot water tank (volume 350 L) and a water–water heat pump, in terms of covering the hot water demands of a single family dwelling. The results showed that the hybrid solar collectors would be able to cover approximately 60% of the dwelling's hot water needs for days with low levels of solar radiation, while for days with high solar radiation they could cover the hot water requirements of the family by 100%.

Measurements of Flat-Plate Milk Coolers

Measuring in laboratory conditions was performed with the aim to collect a sufficient quantity of measured data for the qualified application of flat-plate coolers in measuring under real operating conditions. The cooling water tank was filled with tap water; the second tank was filled with water at a temperature equivalent to freshly milked milk. At the same time, pumps were activated that delivered the liquids into the flat-plate cooler where heat energy was exchanged between the two media. Two containers for receiving the run-out liquid were placed on the outputs from the cooler; here, temperature was measured with electronic thermometer and volume was measured with calibrated graduated cylinder. Flow rate was regulated both on the side of the cooling fluid and on the side of the cooled liquid by means of a throttle valve. The measurements of regulated flow-rates were repeated several times and the final values were calculated using arithmetic average. To calculate the temperature coefficient and the amount of brought-in and let-out heat, the volume measured in litres was converted to weight unit. The measured values show that the volume of exchanged heat per weight unit increases with the decreasing flow-rate. With the increasing flow-rate on the throttled side, the flow-rate increases on the side without the throttle valve. This phenomenon is caused by pressure increase during throttling and by the consequent increase of the diameter of channels in the cooler at the expense of the opposite channels of the non-throttled part of the circuit. If the pressure is reduced, there is a pressure decrease on the external walls of opposite channels and the flow-rate increases again. This feature could be utilised in practice: a pressure regulator on one side could regulate the flow-rate on the other side. The operating measurement was carried out on the basis of the results of laboratory measurements. The objective was to determine to what extent the use of flat-plate coolers under specific conditions results in cost reduction and improved milk cooling process. The measurement was performed in several cycles. The first measurement took place in the existing system without the use of the flat-plate cooler. The volume of drawn milk was monitored throughout the milking process along with its temperature, temperature in the tank and electricity consumption of the cooling system. At the second stage, the flat-plate cooler was introduced into the cooling process, which was followed by monitoring the milk and cooling water volume, their temperature, temperature in the tank and electricity consumption of the cooling system. The measured data indicate considerable power cost reduction if upstream flat-plate coolers are applied.