scholarly journals Humidification–Dehumidification (HDH) Desalination System with Air-Cooling Condenser and Cellulose Evaporative Pad

Water ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 142 ◽  
Author(s):  
Li Xu ◽  
Yan-Ping Chen ◽  
Po-Hsien Wu ◽  
Bin-Juine Huang

This paper presents a humidification–dehumidification (HDH) desalination system with an air-cooling condenser. Seawater in copper tubes is usually used in a condenser, but it has shown the drawbacks of pipe erosion, high cost of the copper material, etc. If air could be used as the cooling medium, it could not only avoid the above drawbacks but also allow much more flexible structure design of condensers, although the challenge is whether the air-cooing condenser can provide as much cooling capability as water cooling condensers. There is no previous work that uses air as cooling medium in a condenser of a HDH desalination system to the best of our knowledge. In this paper we designed a unique air-cooling condenser that was composed of closely packed hollow polycarbonate (PC) boards. The structure was designed to create large surface area of 13.5 m2 with the volume of only 0.1 m3. The 0.2 mm thin thickness of the material helped to reduce the thermal resistance between the warm humid air and cooling air. A fan was used to suck the ambient air in and out of the condenser as an open system to the environment. Results show that the air-cooling condenser could provide high cooling capability to produce fresh water efficiently. Meanwhile, cellulous pad material was used in the humidifier to enhance the evaporative process. A maximum productivity of 129 kg/day was achieved using the humidifier with a 0.0525 m3 cellulous pad with a water temperature of 49.5 °C. The maximum gained output ratio (GOR) was 0.53, and the maximum coefficient of performance (COP) was 20.7 for waste heat recovery. It was found that the system performance was compromised as the ambient temperature increased due to the increased temperature of cooling air; however, such an effect could be compensated by increasing the volume of the condenser.

2020 ◽  
pp. 344-344
Author(s):  
Andrii Radchenko ◽  
Ionut-Cristian Scurtu ◽  
Mykola Radchenko ◽  
Serhiy Forduy ◽  
Anatoliy Zubarev

The fuel efficiency of gas engines is effected by the temperature of intake air at the suction of turbocharger. The data on dependence of fuel consumption and engine electric power on the intake air temperature were monitored for Jenbacher gas engine JMS 420 GS-N.LC to evaluate its influence. A waste heat of engine is rejected for heating water to the temperature of about 90??. The heat received is used in absorption lithium-bromide chiller to produce a cold in the form of chilled water. A cooling capacity of absorption chiller firstly is spent for technological needs and then for feeding the central air conditioner for cooling the ambient air incoming the engine room, from where the air is sucked by the engine turbocharger. The monitoring data revealed the reserves to enhance the efficiency of traditional cooling system of intake air by absorption chiller through deeper cooling. This concept can be realized in two ways: by addition cooling a chilled water from absorption chiller to about 5-7?? for feeding engine intake air cooler or by two-stage cooling with precooling ambient air by chilled water from ACh in the first stage and subsequent deep cooling air to the temperatures 7-10?? in the second stage of intake air cooler by using a refrigerant as a coolant. In both cases the ejector chiller could be applied as the most simple in design.


2019 ◽  
pp. 10-14
Author(s):  
Андрій Миколайович Радченко ◽  
Богдан Сергійович Портной ◽  
Сергій Анатолійович Кантор ◽  
Ігор Петрович Єсін

Significant fluctuations in the current temperature and relative humidity of the ambient air lead to significant changes in the heat load on the air cooling system at the inlet of the gas turbine unit, which urgently poses the problem of choosing their design heat load, as well as evaluating the efficiency of the air cooling system for a certain period of time. The efficiency of deep air cooling at the inlet of gas turbine units was studied with a change during July 2015–2018 for climatic conditions of operation at the compressor station Krasnopolie, Dnepropetrovsk region (Ukraine). For air cooling, the use of a waste heat recovery chiller, which transforms the heat of exhaust gases of gas turbine units into the cold, has been proposed. The efficiency of air cooling at the inlet of gas turbine units for different temperatures has been analyzed: down to 15 °C – an absorption lithium-bromide chiller, which is used as the first high-temperature stage for pre-cooling of ambient air, and down to 10 °C – a combined absorption-ejector chiller (with using a refrigerant low-temperature air cooler as the second stage of air cooling). The effect of air-cooling was assessed by comparing the increase in the production of mechanical energy as a result of an increase in the power of a gas turbine unit and fuel saved during the month of July for 2015-2018 in accumulating. Deeper air cooling at the inlet of the gas turbine unit to a temperature of 10 °C in a combined absorption-ejector chiller compared to its traditional cooling to 15 °C in an absorption bromine-lithium chiller provides a greater increase in net power and fuel saved. It is shown that due to a slight discrepancy between the results obtained for 2015-2018, a preliminary assessment of the efficiency of air cooling at the inlet of gas turbine plants can be carried out for one year.


2020 ◽  
pp. 18-23
Author(s):  
Роман Миколайович Радченко ◽  
Дмитро Вікторович Коновалов ◽  
Максим Андрійович Пирисунько ◽  
Чжан Цян ◽  
Луо Зевей

The efficiency of air cooling at the inlet of the main low speed engine of a transport vessel during operation in tropical climatic conditions on the Shanghai-Karachi-Shanghai route was analyzed. The peculiarity of the tropical climate is the high relative humidity of the air at the same time its high temperatures, and hence the increased thermal load on the cooling system, which requires efficient transformation of the waste heat into the cold in the case of the use of waste heat recovery refrigeration machines. The cooling of the air at the inlet of the low speed engine by absorption lithium bromide chillers, which are characterized by high efficiency of transformation of waste heat into cold – by high coefficients of performance, is investigated. A schematic-construction solution of the air cooling system at the inlet of the ship's main engine using the heat of exhaust gases by an absorption chiller is proposed and analyzed. With this the cooling potential of the inlet air cooling from the current ambient air temperature to 15 ° C and the corresponding heat consumption for the operation of the adsorption chiller, on the one hand, was compared with the available exhaust gas heat potential, on the other hand. The effect of using the exhaust gas heat to cool the air at the inlet of the engine has been analyzed taking into account the changing climatic conditions during the voyage. Enhancement of fuel efficiency of the ship's engine by reducing the inlet air temperature were evaluated by current values of the reduction in specific and total fuel consumption. It is shown that due to the high efficiency of heat conversion in absorption chillers (high coefficients of performance 0.7…0.8), a significant amount of excessive exhaust gas heat over the heat required to cool the ambient air at the inlet of the engine to 15 ° C, which reaches almost half of the available exhaust gas heat during the Shanghai-Karachi-Shanghai route. This reveals the possibility of additional cooling a scavenge air too with almost double fuel economy due to the cooling of all cycle air of the low speed engine, including the air at the inlet.


Author(s):  
Fadi A. Ghaith ◽  
Fadi J. Alsouda

This paper aims to evaluate the thermal performance and feasibility of integrating the Earth-Air Heat Exchanger (EAHE) with the building’s vapor compression air cooling system. In the proposed system, the ambient air is forced by an axial fan through an EAHE buried at a certain depth below the ground surface. EAHE uses the subsoil low temperature and soil thermal properties to reduce the air temperature. The outlet air from the EAHE was used for the purpose of cooling the condenser of the vapor compression cycle (VCC) to enhance its coefficient of performance (COP). The potential enhancement on the COP was investigated for two different refrigerants (i.e. R-22 and R410a) cooling systems. A mathematical model was developed to estimate the underground soil temperature at different depths and the corresponding outlet air temperature of EAHE was calculated. The obtained results showed that the soil temperature in Dubai at 4 meters depth is about 27°C and remains relatively constant across the year. In order to estimate the effect of using EAHE on the performance of the VCC system, a sample villa project was selected as a case study. The obtained results showed that EAHE system contributed efficiently to the COP of the VCC with an overall increase of 47 % and 49 % for R-22 and R410a cycles, respectively. Moreover, the calculated values were validated against Cycle_D simulation model and showed good agreement with a maximum deviation of 5%. The payback period for this project was found to be around two years while the expected life time is about 10 years which makes it an attractive investment.


2020 ◽  
pp. 12-16
Author(s):  
Микола Іванович Радченко ◽  
Євген Іванович Трушляков ◽  
Богдан Сергійович Портной ◽  
Сергій Анатолійович Кантор ◽  
Ян Зонмін

The efficiency of deep air cooling at the inlet of gas turbine units has been investigated for changed climatic conditions of operation during the month. For air cooling, the use of waste heat recovery chiller has been considered, which transform the heat of exhaust gases of gas turbine units into the cold. The efficiency of air cooling at the inlet of gas turbine units to different temperatures has been analysed: to 15°C – an absorption lithium-bromide chiller, which is used as the first pre-cooling stage of ambient air and down to 10°C – a combined absorption-ejector chiller, with ejector refrigerant chiller as the second stage of air cooling.The air cooling efficiency is estimated for different climatic conditions: a temperate climate on the example of Odessa (Ukraine) and a subtropical climate for Guangzhou (China). The subtropical climate peculiarity of Guangzhou is the high relative humidity of the air, respectively, and its moisture contents at the same time its high temperatures. As an indicator, when evaluating the efficiency of air cooling at the inlet of gas turbine units to 15°C in an absorption lithium-bromide chiller and deep cooling of air to 10°C in a combined absorption-ejector chiller, the specific fuel consumption reduced has been used. In this case, the needs for specific production of refrigeration capacity and specific capacity of cooling towers for cooling waste heat recovery chillers when cooling air to different temperatures are compared. It is shown that, through extremely different thermal and humidity parameters of ambient air, its cooling at the inlet of gas turbine units to 10ºС for the climatic conditions of Ukraine provides the current decrease in specific fuel consumption due to deeper cooling of the air at the inlet of the GTU in 1.6 ... 1.7 times compared with cooling to 15ºС, and for climatic conditions of the PRC - 1.4 ... 1.45 times. However, it should be noted that a deeper cooling of the air at the inlet of the gas turbine unit to a temperature of 10°C in a combined absorption-ejector chiller compared to its traditional cooling to 15°C in an absorption bromine-lithium chiller requires an increase in the required specific amount of cold by 1.7 ... 2, 0 times and the required specific capacity of cooling towers for cooling chillers by 2.6 ... 3.0 times for the climatic conditions of Ukraine, while for China - 1.25 ... 1.3 and 1.5 ... 1.6 times, respectively.


2018 ◽  
pp. 29-33
Author(s):  
Евгений Иванович Трушляков ◽  
Николай Иванович Радченко ◽  
Вениамин Сергеевич Ткаченко

It is determined that the operation of ambient air conditioning systems (AACS) has significant fluctuations in the heat load in accordance with current climatic conditions. This makes very problematic the application of refrigeration compressors with frequency converters, which are very effective for controlling the refrigeration capacity in closed air conditioning systems, in which the temperature control range and, accordingly, fluctuations in thermal load are insignificant in comparison with the ambient air cooling. For the purpose of analyzing the efficiency of controlling the refrigeration capacity of the AACS by changing the electric motor speed of the piston compressor in current climatic conditions, the entire range of changing current thermal loads is divided into two parts according to controlling the refrigeration capacity by appling a frequency converter: the part of effective cooling capacity adjustment without energy losses (without reducing the coefficient of performance) from nominal to its threshold value and the part of reduced refrigeration capacity without its controlling by a frequency converter. It is revealed that for the warmest summer month, the proportion of refrigeration capacity spent for cooling ambient air to the temperature of 10 °C with 50 % frequency controlling the refrigeration capacity is about 10 % of the total amount of that could be produced at nominal refrigeration capacity. At higher temperatures of cooled air is even less. This shows the low efficiency of controlling the refrigeration capacity of the AACS by changing the speed of rotation of the piston compressor electric motor and the need to use other methods of controlling the refrigeration capacity. The proposed approach to analyzing the efficiency of controlling the refrigeration capacity of AACS in current climatic conditions allows not only to estimate the efficiency of refrigeration capacity controlling method but also to reveal the reserves for increasing the efficiency of applying the available refrigeration capacity


Author(s):  
Michael A. Lambert ◽  
Benjamin J. Jones

The state of the art in regenerative adsorption (solid-vapor) heat pumps achieved to date is a maximum Coefficient of Performance for Cooling (COPC) of 1.1 with 70% regeneration of waste heat. A number of configurations for the heat exchanger within the adsorbent bed have been investigated, including concentric tube, shell and tube, serpentine flat pipe, spiral flat pipe, and single-pass plate type. However, to date, compact (or multiple pass plate) heat exchangers for use with adsorbent beds have not been studied. This investigation explains the challenges involved in this application, and describes the design and analysis of three configurations of a compact heat exchanger for use with solid adsorbent. The prinicipal figure of merit affecting both coefficient of performance, COPC, and specific cooling power, SCP (W cooling per kg adsorbent), is defined as NTU divided by the ratio of non-adsorbent (“dead”) to adsorbent (“live”) thermal masses. The best of the three configurations consists of thin adsorbent (zeolite) tiles epoxied to the heat exchanger plates (sheets) with screen wire pin fins in the oil passages to enhance heat transfer.


2012 ◽  
Vol 220-223 ◽  
pp. 439-442
Author(s):  
Jian Wang ◽  
Jiang Zhou Shu ◽  
Guo Hui Huang ◽  
Ai Peng Jiang

As a constant-column power generating machine, the combustion turbine has a direct proportion of its output to the quantity of input air. Therefore, when the ambient air temperature rises higher in summer, the effect of combustion turbine is decreasing. In order to enhance the efficiency of combustion turbine in summer, two sets of inlet air cooling system (IACS) were installed in PG6551(B) combustion turbines in Jinhua, Zhejiang, China. Two low-pressure evaporators were installed in the caudal flue of the waste heat boiler, therefore, the produced saturation steam drives a single-effect lithium bromide absorption chiller to cool the input air of combustion turbines to raise the output power of combustion turbine in summer; or supplies the low-pressure heater to heat the condensated water from the deaerator of the steam turbine in winter. A measurement and control system (MCS) of the new-added inlet air cooling equipments was developed. Based on the framework of DCS (Distributed Computer System), the M&C system has the IACS work correctly and easily. The structure and functions of the M&C is described in detail.


2019 ◽  
pp. 48-52
Author(s):  
Микола Іванович Радченко ◽  
Ян Зонмін ◽  
Сергій Анатолійович Кантор ◽  
Богдан Сергійович Портной

The efficiency of deep air cooling at the inlet of gas turbine units of a simple scheme has been investigated for changed climatic conditions of operation during the month. For air cooling, the application of waste heat recovery chiller has been proposed, which transform the heat of exhaust gases of gas turbine units into the cold. The efficiency of air cooling at the inlet of gas turbine units to different temperatures has been analyzed: to 15°C – an absorption lithium-bromide chiller, which is used as the first high-temperature pre-cooling stage of ambient air and down to 10°C – a combined absorption-ejector chiller, which acts as the second low-temperature stage. The air cooling efficiency is compared for different climatic conditions using the example of Yuzhnoukrainsk (Ukraine) and Shanghai (China). The climate peculiarity of Shanghai is the high relative humidity of the air, respectively, and its moisture contents at the same time its high temperatures. As indicators for assessing the effectiveness of air cooling at the inlet of gas turbine units down to 15°C in an absorption lithium-bromide chiller and deep air cooling to 10ºС, in a combined absorption-ejector chiller used an increase in useful power and a reduction in specific fuel consumption. It is shown that, through extremely different thermal and humidity parameters of ambient air, it is cooling at the inlet of gas turbine units for the climatic conditions of Ukraine provides the current increase in useful power by 10...15%, and for the climatic conditions of China – 18…22%. However, it should be noted that deeper air cooling at the inlet of the gas turbine unite to a temperature of 10°C in a combined absorption-ejector chiller compared to its traditional cooling to 15°C in an absorption lithium-bromide chiller provides an increase in useful power for a temperate climate of Ukraine (for example, Yuzhnoukrainsk) by 70...90%, whereas for tropical climatic conditions of China (Shanghai) – by 30...35%.


2019 ◽  
Vol 55 (1) ◽  
pp. 22-27
Author(s):  
R. Radchenko ◽  
M. Pyrysunko ◽  
M. Bogdanov ◽  
Yu. Shcherbak

The efficiency of integrated cooling air at the intake of Turbocharger and Scavenge air at the inlet of working cylinders of the main diesel engine of dry-cargo ship by transforming the waste heat into a cold by an Refrigerant Ejector Chiller (ECh) as the most simple in design and reliable in operation and by complex in design but more efficient Absorption Lithium-Bromide Chiller (ACh) was analyzed. A ship power plant of cogeneration type using the relatively low-grade heat of water of a heat supply system with a temperature of about 90 °C, that significantly complicates the problem of its conversion into cold were considered. Because of the insufficiently high efficiency of transformation of the heat of hot water (low coefficient of performance) as compared with steam, the resulting cooling capacity may not be enough for cooling intake air of the turbocharger and scavenge air, that raises the problem of the rational distribution of heat loads between the Turbocharger Intake Air cooling circuit (subsystem) and Scavenge air cooling circuit and the need to use chillers of various types. This takes into account the rational parameters of cooling processes of the scavenge air in the cogeneration high-temperature stage of scavenge air cooler, in the intermediate stage of traditional cooling air with seawater, and in the low-temperature stage for deep cooling of the scavenge air by using a chiller. A new approach is proposed to improve the efficiency of integrated cooling Intake Air of the turbocharger and Scavenge Air at the inlet of the working cylinders of the ship main engine of a transport ship, which consists in comparing the required cooling capacity and the corresponding heat needs during the trade route with the available heat of exhaust gases and scavenge air of the cogeneration power plant, determining the deficit and excess cooling capacity of heat utilizing cooling machines of various types, that allows to identify and realize the reserves of improving the efficiency of cooling intake air of the turbocharger and the scavenge air of the main diesel engine through the joint use of chillers of various types.


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