Fluid Mechanical Design of a Dry-Cooling System Thermal Storage Reservoir, or Stratification Minimization in Horizontal Channel Flow

1983 ◽  
Vol 105 (2) ◽  
pp. 174-180 ◽  
Author(s):  
E. C. Guyer ◽  
M. W. Golay
Keyword(s):  
Cold Water ◽  
Cooling System ◽  
Plug Flow ◽  
Cooling Water ◽  
Thermal Storage ◽  
The United States ◽  
Hot Water ◽  
Flow Mode ◽  
Storage Reservoir ◽  
Dry Cooling

The use of a capacitive Thermal Storage Reservoir (TSR) initially filled with cold water as part of a dry cooling system for a central power station is attractive economically if the reservoir can be designed to operate in an approximate “plug-flow” mode—discharging cold water to the condenser and filling with hot water from the cooling tower. Such a system would avoid the loss of station capacity associated with dry cooling at high dry-bulb temperatures, and the economic penalties due to such losses when they are coincident with electrical demand peaks (as is common in the United States). The initial employment of this concept is most likely to occur in solar-powered thermal electric power stations in arid climates in view of the likely low thermal efficiency and limited cooling water access of such plants. Buoyant flow stratification hinders attaining this goal since it can cause “short circuiting” of the TSR. For adequate flow control, a long narrow reservoir configuration is desirable. In investigating the behavior of such a TSR experimentally, it was found over the range of cases examined that injection of water into a long narrow reservoir which is initially at a different temperature always results in a stratified flow superimposed upon the gross plug flow of the TSR, and it was found that acceptable performance could be obtained inexpensively by placing flow-constricting barriers at regular intervals along the reservoir length. Experimental investigation of barrier design and spacing has permitted definition of a practical prototype TSR design which provides approximately 87 percent of the thermal capacity of a plug flow TSR.

scholarly journals STUDY ON BOTTOM WATER INTAKE FOR CONDENSER COOLING SYSTEM OF POWER STATION SITED ON A BAY

1966 ◽  
Vol 1 (10) ◽  
pp. 83
Author(s):  
Shin-ichi Senshu ◽  
Akira Wada
Keyword(s):  
Cold Water ◽  
Sea Water ◽  
Cooling System ◽  
Lower Layer ◽  
Thermal Power ◽  
Cooling Water ◽  
Hot Water ◽  
Power Station ◽  
Reclaimed Land ◽  
Intake Structure

This report concerns study on a method of taking the cold water from bottom layer with relation to the design of the intake structure of cooling water for the power station sited on a bay. The quantity of cooling water used for condenser system increases year by year along with the construction of thermal power stations of large capacity. If the bottom sea water of low temperature is taken into the condenser cooling system, remarkable saving of fuel expenses can be expected due to the improvement of heat efficiency of turbine. Especially, in case that the location of intake structure of cooling water is chosen at the interior of the reclaimed land or the bay, it is absolutely necessary to take the colder water from the lower layer of the sea, in order to prevent taking hot water over the sea basin where the water temperature of the surface layer is raised by the evacuation of heat of released industrial water. Various hydraulic problems concerning thermal density flow phenomena were examined aiming to obtain the design method of the most effective intake works of cooling water, and the authors proposed a curtain-wall type intake structure. Some results of analysis are described in this paper.

Simulation and Experimental Analysis of a Solar Driven Absorption Chiller With Partially Wetted Evaporator

2008 ◽  
Author(s):  
Jan Albers ◽  
Giovanni Nurzia ◽  
Felix Ziegler
Keyword(s):  
Cooling System ◽  
Cooling Water ◽  
Hot Water ◽  
Absorption Chiller ◽  
Efficient Operation ◽  
Part Load ◽  
Solar Cooling ◽  
Wetted Area ◽  
Solar Cooling System ◽  
Load Conditions

The efficient operation of a solar cooling system strongly depends on the chiller behaviour under part-load conditions since driving energy and cooling load are never constant. For this reason the performance of a single stage, hot water driven 30 kW H2O/LiBr-absorption chiller employed in a solar cooling system with a field of 350 m2 evacuated tube collectors has been analysed under part-load conditions with both simulations and experiments. A simulation model has been developed for the whole absorption chiller (Type Yazaki WFC-10), where all internal mass and energy balances are solved. The connection to the external heat reservoirs of hot, chilled and cooling water is done by lumped and distributed UA-values for the main heat exchangers. In addition to an analytical evaporator model — which is described in detail — experimental correlations for UA-values have been used for condenser, generator and solution heat exchanger. For the absorber a basic model based on Nusselt theory has been employed. The evaporator model was developed taking into account the distribution of refrigerant on the tube bundle as well as the change in operation from a partially dry to an overflowing evaporator. A linear model is derived to calculate the wetted area. The influence of these effects on cooling capacity and COP is calculated for three different combinations of hot and cooling water temperature. The comparison to experimental data shows a good agreement in the various operational modes of the evaporator. The model is able to predict the transition from partially dry to an overflowing evaporator quite well. The present deviations in the domain with high refrigerant overflow can be attributed to the simple absorber model and the linear wetted area model. Nevertheless the results of this investigation can be used to improve control strategies for new and existing solar cooling systems.

Vacuum Cooling of Cooked Mussels (Perna perna)

2006 ◽  
Vol 12 (1) ◽  
pp. 19-25 ◽  
Author(s):  
E. Huber ◽  
L. P. Soares ◽  
B. A. M. Carciofi ◽  
H. Hense ◽  
J. B. Laurindo
Keyword(s):  
Weight Loss ◽  
Cold Water ◽  
Temperature Drop ◽  
Relative Weight ◽  
Cooling Water ◽  
Hot Water ◽  
Process Time ◽  
Promising Alternative ◽  
Industrial Processing ◽  
Vacuum Cooling

Mussels pass through a thermal treatment during industrial processing with hot water or steam and then are pre-cooled before the manual extraction of the meat. This pre-cooling is classically accomplished by the immersion of the cooked mussels in cold water. In this work, vacuum cooling of mussels after the cooking stage was used as a technique to quickly decrease the product temperature and to avoid a possible microbial contamination by the cooling water or by manipulation. In about 3 minutes, mussels were cooled from about 90 °C to 20 °C. The relative weight loss during the vacuum cooling of the whole sample (meat and shell) was about 8% of the initial sample’s weight, for temperatures drop cited above. In this way, there was a 8.7 0.26 °C temperature drop for each 1% of weight loss. For separated meat (without shell), the ratio was 7.5 0.30 ºC per 1% weight loss, which agreed with the literature for vacuum cooling of meats in general. A simple numerical simulation was able to determine weight loss during the vacuum cooling process, providing data that agreed very well with experimental results. The vacuum cooling technique is a promising alternative for processing pre-cooked mussels, because process time is shortened and cross-contamination risk is significantly reduced in the cooling stage. The water loss is not a serious problem when the cooled mussels are canned in brine.

Analysis on Affecting Factors of Slab Surface Transversal Corner Crack for Medium-Carbon Steel with Boron in Continuous Casting

2013 ◽  
Vol 275-277 ◽  
pp. 1890-1895
Author(s):  
Qi Chun Peng ◽  
Zhi Bo Tong ◽  
Dan Ping Fan
Keyword(s):  
Carbon Steel ◽  
Cold Water ◽  
Cooling System ◽  
Cooling Water ◽  
Medium Carbon Steel ◽  
Control Measures ◽  
Affecting Factors ◽  
Corner Crack ◽  
Medium Carbon ◽  
Degradation Ratio

Based on the production practice of boron microalloyed medium-carbon steel, oscillating curve, cooling water flow in mould, secondary cooling system and arc alignment precision, rolling gap precision on transversal corner crack in slab was analyzed, and the corresponding control measures were put forward. Such as: Stabilizing the [S] and making w(S） less than 0.015%; Increasing Mn/S, and making the Mn/S was not less than 37.6 in A36-LB; Strictly controlling the w(Ca)/w(Als) was more than 0.09. Decreasing stroke 1mm and improving frequency to reduce negative sliding time 32%; Stabilizing cooling water around 4000/380 L/min, less cooling, reduce the total water cold water and 50% Side water; Testing rolling gap termly, strengthening maintenance and Replacing bad roller column to make sure precision in the reasonable scope, the measures above suppressed the corner crack in slab effectively, and it’s degradation ratio and quality disputes were below that of Q235B in the mouth production level.

scholarly journals Numerical Simulation Study for the Performance of a Large Solar Hot Water System With Horizontal Storage Tank

2015 ◽  
Author(s):  
Ru Yang ◽  
Geng-Yi Lin
Keyword(s):  
Numerical Simulation ◽  
System Performance ◽  
Storage Tank ◽  
Large Scale ◽  
Cooling System ◽  
Water System ◽  
Thermal Storage ◽  
Hot Water ◽  
Design Parameters ◽  
Total Load

A large solar hot water system can be utilized to provide driving energy for heating system, heat-driven cooling system, as well as to provide hot water. This research addresses the effects of the storage tank design parameters on the performance of a large-scale solar hot water system with a horizontal storage tank. Most literatures only considered the stratification performance of the thermal storage tank itself instead of considering the overall system performance. Also, there is lack of experimental research data available for the design purpose. Therefore, this study employs a numerical simulation technique to study the design parameters effect of a horizontal thermal storage tank on the performance of a large-scale solar hot water system. In this study, the ANSYS-CFX program is employed to calculate the flow and temperature distributions inside horizontal thermal storage tank. Then the inlets and outlets of the tank are combined with the TRNSYS program to simulate the entire system performance under the weather of three representative cities of Taiwan, (Taipei, Taichung and, Kaohsiung). The results of the present study indicate that the vertical stratification baffles in the tank have important effects on system performance improvement. Quantitative increase of solar fraction of the total load is obtained. The comparison with the system with vertical storage tank is provided. The results of the present study can provide important reference for the large solar hot water system design in improving system efficiency.

Simulation and performance study of a two-bed adsorption cooling system operated with activated carbon-ethanol

2021 ◽  
pp. 095440622110420
Author(s):  
V Baiju ◽  
A Asif Sha ◽  
NK Mohammed Sajid ◽  
K Muhammedali Shafeeque
Keyword(s):  
Water Temperature ◽  
Performance Optimization ◽  
Cooling System ◽  
Cooling Water ◽  
Hot Water ◽  
Coefficient Of Performance ◽  
Cooling Power ◽  
Performance Study ◽  
Evaporator Temperature ◽  
Adsorption Cooling System

This paper presents the transient model of a two-bed adsorption cooling system performed in the SIMULINK platform. The inlet chilled water temperature in the evaporator, temperature of cooling water and hot water temperature of the adsorbent bed and its effect on systems coefficient of performance, refrigeration effect and specific cooling power have been studied and presented. It is observed that the systems coefficient of performance is 0.57 when the inlet hot water temperature about 80 °C. In this study, the optimum cooling power and systems coefficient of performance are also determined in terms of the phase time, shifting duration and hot water inflow temperature. The results indicates that the cooling water and hot water inlet temperatures significantly affects the coefficient of performance, specific cooling power and cooling power of the system. The effect of mass flow rate on the cooler efficiency is also presented. A two bed adsorption system of capacity 13.5 kW having an evaporator and condenser temperatures of 6°C and 28°C, respectively, are considered for the present investigation. The adsorbent mass considered is 45 kg with a shifting duration of 20 sec. The result of this study gives the basis for performance optimization of a practical continuous operating vapour adsorption cooler.

scholarly journals CFD Simulation of Silica Gel as an Adsorbent on Finned Tube Adsorbent Bed

2018 ◽  
Vol 67 ◽  
pp. 01014 ◽  
Author(s):  
Andre Kurniawan ◽  
Nasruddin ◽  
Asep Rachmat
Keyword(s):  
Silica Gel ◽  
Outer Surface ◽  
Cooling System ◽  
Cooling Water ◽  
Momentum Conservation ◽  
Hot Water ◽  
Adsorption Rate ◽  
Conservation Equations ◽  
Absolute Adsorption ◽  
Adsorption Technology

The adsorption technology is becoming the more expected solution by today’s researchers for fix the energy and environmental issues. The main part of the cooling system adsorption is adsorbent and adsorbate. One of the most widely used adsorbents in research of adsorption technology is silica gel. A new silica gel-water adsorption chiller design was developed that composed of two sorption chambers with compact fin tube heat exchangers as adsorber, condenser, and evaporator. Energy, mass, and momentum conservation equations of the adsorption systems have been used for the CFD two and three dimensional models. The geometry of simulation is simply made within silica gel layer between two fins. The simulation is also implemented using a finite volume method through the CFD software Fluent. User defined functions are given to modify the energy, mass, and momentum conservation equations. The simulation of adsorption process is adjusted at unsteady condition. Adsorption and desorption processes are simulated with room temperature for cooling water inlet at temperature 305.15 °K, hot water inlet at temperature 353.15 °K, mass flow rate cooling water inlet at 0.3 kg/s and pressure 32 KPa. For the whole adsorbent bed area, the result shows that the highest absolute adsorption rate at the outer surface, while the lowest rate is at the center. After adsorption was finished, the condition is reversed. The highest absolute adsorption rate is achieved at center, while the lowest rate is achieved at the outer surface.

FREEZE PROTECTION METHOD USING HOT WATER FOR PASSIVE SOLAR WATER HEATING SYSTEM

2012 ◽  
Vol 20 (04) ◽  
pp. 1250021 ◽  
Author(s):  
HIKI HONG ◽  
JONG HYUN KIM ◽  
JAE DONG CHUNG ◽  
HIROYUKI KUMANO ◽  
DOUGLAS REINDL
Keyword(s):  
Storage Tank ◽  
Cold Water ◽  
Thermal Storage ◽  
Heating System ◽  
Hot Water ◽  
Water Pipe ◽  
Solar Water ◽  
Protection Method ◽  
Passive Solar ◽  
Freeze Protection

In the present work, a new freeze protection method is introduced with intended applications for passive solar water heaters. Though electro-thermal wire heat tracing is popularly used to prevent freezing with subsequent risk of burst, this approach is problematic due to resistance heater failure and excessive electric power consumption. In the experimental device, hot water in thermal storage tank is used to heat the outlet pipe from the tank when the surface temperature of the pipe falls lower than a pre-determined set point. The cold water pipe to the thermal storage tank is installed in direct contact with the hot water pipe, controlling its temperature by conduction with the hot water pipe.

Solar Assisted Desiccant Cooling Simulation for Different Climate Zones

2011 ◽  
Author(s):  
Wendell Concina ◽  
Suresh Sadineni ◽  
Robert Boehm
Keyword(s):  
Air Conditioning ◽  
Cooling System ◽  
Evaporative Cooling ◽  
The United States ◽  
Economic Benefits ◽  
Climatic Conditions ◽  
Hot Water ◽  
Low Grade ◽  
Cooling Systems ◽  
Climate Zones

Evaporative cooling is among the most cost effective methods of air conditioning, but is less efficient in humid climates. An evaporative system coupled with a desiccant wheel can operate effectively in broader climatic conditions. These cooling systems can substitute traditional vapor compression air conditioning systems as they involve environmentally friendly cooling processes with reduced electricity demand (which is commonly generated from fossil fuels) along with no harmful CFC based refrigerant usage. Furthermore, direct utilization of low grade energy sources such as solar thermal energy or flue gas heat can drive the desiccant regeneration process, thus providing economic benefits. This study presents the results of simulations of desiccant cooling system performance for different climate zones of the United States. Solar assisted desiccant air conditioning is particularly useful where there are abundant solar resources with high temperature and humidity levels. Building energy simulations determined cooling energy requirements for the building. Simulation of an evacuated solar hot water collector model provided the heat energy available for regeneration of the desiccant. Solid desiccant of common material such as silica gel used in a rotary wheel is simulated using established validated computer models; this is coupled with evaporative cooling. Transients of the overall system for different cooling loads and solar radiation levels are presented. Finally, feasibility studies of the desiccant cooling systems are presented in comparison with traditional cooling system. Further analysis of the data presents optimization opportunities. Energy savings were achieved in all climatic conditions with decreased effectiveness in more humid conditions.

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