The Development and Calculation of an Energy-saving Plant for Obtaining Water from Atmospheric Air

Transcription

1 IOP Conferene Series: Materials Siene and Engineering PAPER OPEN ACCESS The Development and Calulation of an Energy-saving Plant for Obtaining Water from Atmospheri Air To ite this artile: D A Uglanov et al 2018 IOP Conf. Ser.: Mater. Si. Eng View the artile online for updates and enhanements. This ontent was downloaded from IP address on 12/07/2018 at 05:53

2 The Development and Calulation of an Energy-saving Plant for Obtaining Water from Atmospheri Air D A Uglanov 1, K E Zheleznyak 2 and P A Chertykovsev 3 1 Samara National Researh University, Russia 2 Samara National Researh University, Russia 3 Samara National Researh University, Russia 1 dmitry.uglanov@mail.ru, 2 zheleznyak999@yandex.ru, 3 p.a.hert@mail.ru Abstrat. The artile shows the alulation of harateristis of energy-effiient water generator from atmospheri air. This installation or the atmospheri water generator is the unique mehanism whih produes safe drinking water by extration it from air. The existing atmospheri generators allow to reeive safe drinking water by means of proess of ondensation at air humidity at least equal to 35% and are apable to give to 25 liters of water in per day, and work from eletriity. Authors offer to use instead of the ondenser in the sheme of installation for inrease volume of produed water by generator in per day, the following refrigerating mahines: the vapor ompression refrigerating mahines (VCRM), the thermoeletri refrigerating mahines (TRM) and the Stirling-yle refrigerating mahines (SRM). The paper desribes alulation methods for eah of refrigerating systems. Calulation of tehnial-and-eonomi indexes for the atmospheri water generator was arried out and the optimum system with the maximum volume of reeived water in per day was piked up. The atmospheri water generator whih is onsidered in artile will work from autonomous solar power station. 1. Introdution At present, there are problems of energy saving in various areas of human life and in power omplexes of industrial plants [1, 2, 3]. Aording to the World U.N. report about development of water resoures, many ountries already ahieved limit opportunities of water use: onsumption of fresh water for the last half a entury inreased triply. In extensive regions of developing world unequal aess to safe drinking water, water purifiation for prodution of provisions and proessing of drainage water remains. Nearly five billion people will be left without drinking water to 2030 if people will not undertake nothing, and it is about 67% of the population of the planet. Problems with drinking water and water resoures have led to reation of atmospheri water generators. The atmospheri water generator is the unique mehanism whih produes safe drinking water by extration it from air. For the first time the atmospheri water generators were developed in the 1990th. They were similar to system whih is used for dehydration air in refrigerators. In this artile the analysis is made of the energy-effiient installation working from the photoeletri onverter (installation power W = 200V) with use of refrigeration installations, suh as the VCRM, the TRM and the SRM. The analysis allowed to estimate fully overall operational effiieny Content from this work may be used under the terms of the Creative Commons Attribution 3.0 liene. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal itation and DOI. Published under liene by Ltd 1

3 of the generator and quality of water, and also promoted adoption of the design solutions inreasing the volume of reeived water by installation in per day. 2. The atmospheri water generator working at VCRM basis Ahievable temperatures in installations, refrigerating apaity and expenses of mehanial work signifiantly depend of kind and properties of refrigerant oolants. Refrigerant oolants need to have ability to absorb a large amount of warmth at evaporation, to have small speifi volumes of steam, low ritial temperatures, visosity and density, high oeffiient of heat dissipation and heat transfer, to be harmless, fireproof, available and inexpensive. Therefore, for work two refrigerant oolants were hosen: R134A and R502. In this work for alulation and analysis of a yle of the VCRM the CoolPak [4] program was used. It is the program for design, alulation, analysis and optimization of refrigerating systems. We will onsider the return Rankine yle for eah refrigerant oolant in autumn, spring, summer and winter seasons. Example is shown on the figure 1. Values of average temperatures and humidity in the Samara region for every season, and also the onsumed power by installation from the photoeletri onverter are presented in table 1. Table 1. Initial data for alulation of the VCRM winter spring summer autumn С ) Moisture ontent(%) Power onsumption plant N (W) 200 Suh levels of temperature of evaporation at alulation are aused by need of hoie of the optimum mode whih orresponds to the maximum quantity of the reeived water. All values reeived in the program are tabulated for eah refrigerant oolant and season. For definition of moisture ontent at eah mode we will use I-d diagram of humid air [5]. Shedules of dependenes of moisture ontent d, mass and volume onsumption (m and V) of refrigerant oolant, refrigerating oeffiient COP, heat input Qe and heat output Q from temperature T for eah refrigerant oolant were onstruted. We will onsider dependenes for refrigerant oolant R134A on the figures

4 Figure 1. Addition of moisture ontent d from temperature T for refrigerant oolant R134a Figure 2. Addition of mass onsumption from temperature T for refrigerant oolant R134a 3

5 Figure 3. Addition of refrigerating oeffiient COP from temperature T for refrigerant oolant R134a Figure 4. Addition of volume onsumptionv, heat input Qe and heat output Q from temperature T for refrigerant oolant R134a The analysis of reeived values showed that during the summer period at temperature of evaporation -30 C in the VCRM on refrigerant oolant R134a the maximum quantity of moisture 4

6 ontent is developed. But for further alulation we hoose the autumn period whih orresponds to average value of reeived moisture ontent. Further by known methods [6], main elements of the VCRM were alulated: ompressor, ondenser and evaporator. Values of oeffiients of heat transfer are defined kev=39,1 W/m^2*K and kond=23 W/m^2*K, heat dissipation α=41,31 W/m^2*K and α=23 W/m^2*K, effetive refrigerating oeffiients ε=2,24, Qe=0,942 kw, Q=1,122 kw and geometrial parameters of evaporator F=0,27 m^2, ondenser F=0,18 m^2 and ompressor Ne=0,309 kw. 3. Calulation of the Stirling-yle refrigerating mahine Calulation was arried out by Shmidt's method [7]. For alulation the following main equations were used: - Equations of motion Vh 0,5 VОХ (1 os ) (1) V 0,5 K VОХ (1 sin ) (2) 0,5 K VОХ (1 sin ) 0,5 VОХ (1 os ) X V (3) ОХ VР X V (4) ОХ - Energy balane equations L Q1 Q (5) 2 Q1 Q2 (6) Q2 (7) L - Material balane equations - Gas equation mz mh m mм (8) Тh Т (9) Vh K V (10) 2X S k 2 k os k 2 S Рh Vh mh RT h Р V m RT РМ VМ mм RT М Calulation of the regenerative heat exhanger was arried out. Parameter found N1 1 Р 1 2 N1 1 CHm H 9 Cm P З (11) (12) (13) (14) (15) (16) 5

7 and losses for approah, the hydrauli resistane and total losses from ratio l/d, hot and old heat exhangers, external loading. 4. Calulation of the thermoeletri refrigerating mahines Calulation of parameters of the thermoeletri refrigerating mahines was arried out by method [8]. Calulation of the refrigerating thermobattery in mode of the maximum refrigerating oeffiient. Further the software produt «KRYOTHERM» [9] was used for alulation and hoie of standard modules. Initial data for alulation in program are Tг = 283 К, Tх= 243 К, Qо = 25 W. The module TВ 127 2,0 1,65 was piked up for initial data and harateristis of hosen module were onstruted (figure 5, 6). Figure 5. Standard performane Q = f(dt),u = f(dt), COP = f(dt), U = f(i) module TВ 127 2,0 1,65 6

8 Figure 6. Detailed performane Q = f(dt),u = f(dt),cop = f(dt), U = f(i) module TВ 127 2,0 1,65 5. Determination of effiieny of installation The produed quantity of water in per day by the atmospheri generator with various refrigerating mahines was determined by the following method: Ga d24 mw (17) 1000 where G a - air-mass flow through automati ventilating mahine; d - humidity. Air-mass flow through automati ventilating mahine is equal: G V n (18) a fan a where V fan - air-quantity flow through automati ventilating mahine; a - density of air; n - quantity of automati ventilating mahines. Fout We will define the neessary quantity of automati ventilating mahines: n and air-quantity F flow through automati ventilating mahine V fan, knowing F out and F fan. 6. Results The produed quantity of water in per day by the atmospheri generator with refrigerating systems table 2. Table 2. The produed quantity of water in per day by the atmospheri generator with refrigerating systems N, W n, ps. Nn, W d, g/kg mw, l/d VCRM ,08 5,3 84 SRM ,88 5,3 48 TRM ,84 4,8 2 fan 7

9 Number of tehnial-and-eonomi indexes was entered for determination of effiieny, total power onsumption, energy and monetary ost 1 l/days of water table 3. Table 3. Tehnial-and-eonomi omparison of installation with various refrigerating systems N, NΣ, Nn, m, mw, Qс, Кq0, Кm, P, К, WΣ, C, W W W kg l/d W l/d*kw l/d*kg rub l/d*rub kw*h rub/l VCRM ,1 10,08 13, ,09 6, ,002 4,6 0,13 SRM ,9 5, ,04 4, ,001 4,46 0,23 TRM ,8 0,84 1, ,08 1, ,0001 4,34 5,58 For tehnial-and-eonomi omparison we offer to use the following oeffiients: - oeffiient of effiieny depending on its refrigerating apaity, mass, prie, and also energy and monetary ost 1 l/days of water. mw l Кq0, (19) Q d kw - oeffiient of effiieny depending on mass and prie of refrigerating system is determined by the following formulas mw l Кm, (20) m d kg К m l, P d rub - the total power onsumed by installation N W 24, kw h 1000 (22) - We will use the following formulas for determination of energy and monetary ost 1 l/days W kw h Сen, (23) m l / d Eletri rate is i 2,57 rub. kw h w (21) rub С Сen i, (24) l / d 7. Conlusion This artile desribes methods of alulation and seletion of main elements of refrigerating systems used in the atmospheri generator for inrease of volume of reeived water. As refrigerating system the vapor ompression refrigerating mahines, the thermoeletri refrigerating mahines and the Stirling-yle refrigerating mahines are onsidered. The return Rankine yles were onstruted in the program CoolPak for the vapor ompression refrigerating mahine. Calulation of yle parameters is arried out for autumn, spring, summer and winter seasons for refrigerant oolants R134a and R502. On the basis of reeived results the optimum mode - the autumn season was hosen ( tи 30 С, tк 10 С, Qe 0,942kW, Q 1,122 kw, d 5,3 g / kg ) whih is used in further alulations. Calulation was arried out for evaporator 2 2 ( F 0,27m ), ondenser ( F 0,18m ) and ompressor ( N 0,309kW ). e 8

10 In the program Kryotherm the thermoeletri module ТВ-127-2,0-1,65 (n = 2 ps) was piked up and was alulated for the thermoeletri refrigerating system. Calulation was arried out for regenerator ( р 0,98, Q 115,63W ), heat exhangers of external loading of ompressor and expander avities, volumes of hot and old avities ( Q1 78,3J, Q2 67,5J ) for the Stirling-yle refrigerating mahine. The automati ventilating mahine DEEPCOOL XFAN 120 was piked up 3 ( V 44 m / h, N 0,84W ). The neessary quantity of automati ventilating mahines for the VCRM is n=12 ps, for the SRM is n=7 ps, for the TRM is n=1 ps. The quantity of reeived water in per day was alulated. So, the atmospheri generator with the VCRM an generate mw 84 l / d, with the SRM - mw 48 l / d, with the TRM - mw 6 l / d Coeffiients of effiieny were alulated for eah system depending on its refrigerating apaity К q0, mass К, prie m К, and also energy С and monetary en C ost 1 l/days of water. Monetary ost 1 l/days of water reeived by the atmospheri generator with the VCRM is C 0,13 rub l / d., by the atmospheri generator with the SRM is C 0,23 rub, by the atmospheri l / d. generator with the TRM is C 5,58 rub l / d.. The optimum refrigerating mahine with the maximum effiieny of water in per day is the vapor ompression refrigerating mahine for work in fixed onditions. Referenes [1] Kerdphol, T., Qudaih, Y., Mitani, Y.Optimum battery energy storage system using PSO onsidering dynami demand response for mirogrids.(2016) International Journal of Eletrial Power and Energy Systems, 83, pp [2] Kakumoto, Y., Koyamatsu, Y., Shiota, A., Qudaih, Y., Mitani, Y. Appliation of Geographi Information System to Power Distribution System Analysis (2016) Energy Proedia, 100, pp [3] Burtsev, S.A., Karpenko, A.P., Leontiev, A.I. A method for distributed prodution of liquefied natural gas at gas-distribution stations. (2016) High Temperature, 54 (4), pp [4] [5] Sokolov E Y, Brodyansky V M Energy basis of heat transformation and ooling proesses. -M.: p. [6] Mysin V M, Tatarenko Y V Seletion and alulation of the main elements of a single-stage vapor ompression refrigerating mahine. - SPb.: University of ITMO, p. [7] Walker G Stirling Engines / Clarendon Press, Oxford, p. [8] Shostakovskii P P Thermoeletri soures of alternative power supply. Components & Tehnologies, 2010, no. 12, pp [9] 9