DEVELOPMENT OF RIVERBANK FILTRATION WATER SUPPLY AND RETURN SYSTEM FOR SUSTAINABLE GREEN HOUSE HEATING AND COOLING

Transcription

1 DEVELOPMENT OF RIVERBANK FILTRATION WATER SUPPLY AND RETURN SYSTEM FOR SUSTAINABLE GREEN HOUSE HEATING AND COOLING Yon Cho 1, Dae Geun Km 1, Jsook Seo 1, Jon-Pl Moon 2, and Hyoun-Soo Km 3 1 Green Technoloy Research Center, K-water Insttute, Daejeon, Korea 2 Department of Arcultural Enneern, Natonal Academy of Arcultural Scence, Suwon, Korea 3 Enneern of Enery and Resources, Junwon Unversty, Choonbuk, Korea ycho@kwater.or.kr Keywords: Rverbank Fltraton, Alluvum Aqufer, Temperature Dfference Enery, Water-Source Heat Pump, Green House, Heat Source ABSTRACT The reen house on the waterfront s ar-condtoned by a water-source heat pump system wth rverbank fltraton water. In order to supply rverbank fltraton water n alluvum aqufer, the rverbank fltraton faclty for water ntake and njecton, two pumpn wells and one rechare well, has been constructed. The research ste n Jnju, Korea was chosen as a ood ste for rverbank fltraton water supply amon four prelmnary stes by the surface eolocal survey, electrcal resstvty soundns, and borehole surveys. In the results of two boreholes drlln at the ste, t was revealed that the roundwater table s about 3 m under the round, and that the sandy ravel aqufer layer n the thckness of 6.5 m and 3.5 m occurs at 5 m and 7 m n depth below the round level respectvely. To prevent the rechare water from affectn the pumped water whch mht be used as heat source or snk, the dstance between pumpn and rechare wells s desned at least 70 m wth a quarter of rechared flow rate. It s predcted that the transfer term, the rechare water affects the pumpn well, s over 6 months of heatn season. Hydroeolocal smulaton and underround water temperature measurement have been carred out for the pumpn and rechare well postons. 1. INTRODUCTION The area of protected cultvaton n Korea 2008 reaches to 53,408ha, and heatn system for wnter s operated to cultvate hortcultural crops n 13,329ha whch occupy about 25% of that. In the end of the 2008, t s estmated that about 60% of supply quantty of tax-free ol for arculture s used for heatn of protected cultvaton. A sudden rse of ol prce recently caused weht of heatn cost amon protected cultvaton producton costs to sharply o up and added a lare dffculty to arcultural manaement. In response to t, development of enery savn technoloy s essental and the eothermal heat pump s very excellent n terms of effcency and applcablty. However, the eothermal heat pump has lmt of heat source volume, and sea water and round fltraton water may be used as substtute heat source to settle nsuffcent heat source. Snce most arcultural facltes n Korea s far away from sea, t s very realstc to use round fltraton water heat source from rver/dam-reservor water. Rverbank Fltraton water s typcally used as round fltraton water from rver/dam-reservor. Ths method has been used n Amerca, Europe and other reons before about 150 years but 1 feasblty survey for rverbank fltraton water ncludn 5 rvers n Korea; Han Rver, Nadon Rver, Keum Rver, Younsan Rver and Sumjn Rver has been started from the 1990s to use rverbank fltraton water. In Chanwon located at the downstream of Nadon Rver, domestc water s currently suppled by the rverbank fltraton method. As the result of analyzn water pumpn rate of the water purfcaton staton at Daesan-myon n Chanwon, water pumpn rate shows dfference of approxmate 2,000 m 3 /day and t showed a tendency that water pumpn volume s ncreased especally n a hh water season (June, July and Auust). Water-source heat pump s enerally used for heatn and cooln of a buldn, and rverbank fltraton water, round water, and raw water s used for the heat sources of the system. Hwan et al.(2006) developed the cooln and heatn system wth bank-fltraton water whch s transferred to the water treatment works for drnkn water. Water volume for heat source s less than 400 m 3, whle the fltraton water of 60,000 m 3 s pumped a day. Therefore the pumpn well ddn t need to be consdered n the well desn. It was confrmed that the system wth the temperature of fltraton water s 17~19 n February could be practcal n only 6 days test. Nam and Ooka(2010) nvestated the performance of a round water source heat pump. The system depends on the temperature and depth of the water, and ts effcency s much hher than that of an ar source heat pump. In another study, Nam et al.(2010) developed the dual-source hybrd heat pump system usn roundwater and ar. In sprn and autumn, the round water heat pump system s not more effcent than an ar source heat pump based on the temperature comparson between the roundwater and the ambent temperature. Accordn to ther experments, the developed hybrd system showed an mprovement of 2~7% compared to a water cooln system, and 4~18% compared to an ar source heat pump. Cho and Yun(2011) studed the heat pump system usn raw water whch s taken from a reservor and suppled to a water treatment works. It was showed that the cooln and heatn load rato and water temperature affect the performance of the system. In ths study, pumpn well and recharn well are developed for sustanable heatn and cooln of a reen house. The wells are desned and tested to have an approprate rverbank fltraton water pumpn rate for the heat pump capacty. 2. MATERIALS AND METHODS To use fltraton water heat source, we selected the optmum reon throuh survey a reenhouse away 300m from the rver bank, and performed a ste applcaton test to New Zealand Geothermal Workshop 2009 Proceedns November 2009 Rotorua, New Zealand

2 the paprka cultvaton reenhouse of about 3,300 m 2 throuh optmum desn of the heatn system usn round fltraton water source heat. 2.1 Expermental reon We performed electrcal resstvty and born survey to select the optmum applcaton reon for takn fltraton water from a rver, and performed a feasblty study for thckness of the water aqufer and heatn of the expermental reenhouse and the optmum pumpn water volume of 1,000 m 3 /day for the Gum and the Jnju reon. It was found that the Jnju reon s optmal place for pumpn water volume, and as the result of the statc water level pumpn test that was performed n course of a born survey at the Jnju reon, the hydraulc transmsson deree of the sand/ravel layer whch s man aqufer was ood as about cm/sec and the BH-1 hole forms the sand/ravel layer of 3.5m, the BH-1 forms the sand/ravel layer of 6.5m, and t was found that collectable water volume of 1,000 m 3 /day could be developed. 2.2 Basc desn of heatn system for round fltraton water source heat pump. A concept drawn of the heatn system usn round fltraton water s as F. 1 and the ntal faclty expenses are very low snce depth of pumpn and recharn well s not deep and heat source flux s suffcent as a heat pump system usn round fltraton water whch s underround water not subject to pressure around a rver or lake. Water temperature of round fltraton water has very smlar characterstcs to underround water but operaton and manaement of the system s requred consdern that chane of flowrate s affected by the rver. The system developed n ths study was desned to reduce water resources and acheve a sustanable crculaton to ensure that recovery to the underround aqufer are acheved and that exceedn flux can return to the rver throuh the surface dschare by nstalln both recharn water and surface dschare ppe, and so that heat exchane effcency can be mproved by nstalln a flter and removn ron and mananese. F.1 Conceptual Scheme of Ground Fltraton Water Source Heat Pump. 2.3 Development of thermal storae tank usn a separaton plate F. 2 Temperature separaton phenomena experment of thermal tank throuh separaton plate. We developed a temperature separaton type of thermal storae tank for mprovn performance of the heat pump usn a separaton plate and tested temperature separaton by a heat nsulaton separaton plate by manufacturn an expermental tank by usn an acryl plate as n F. 2. In addton, we tested temperature separaton effect of both hh temperature part and low temperature part by ncreasn the quantty and made a hole at the bottom part of the separaton plate for heat storae tank to pass the separaton plate wthn the experment tank. As the result of experment, the more number of separaton plate ncrease, the better temperature separaton, and larer temperature dfference. It was found that nstalln the separaton plate n front sde as shown n 4 was effectve and that temperature separaton was acheved better f lenthenn a flow lne by born the top and bottom part of the separaton plate. Flowrate was desned so that t s same as crculaton flowrate or s somewhat larer than t. 2.4 Devce for removn ron or mananese The most effcent method to treat ron and mananese contann a lot of flow s a method to use oxdaton sand. We also desned a devce to remove foren materal from fltraton water by usn the method. Desn condtons were provded to treat round fltraton water of maxmum 500 m 3 per day to ensure that the fltraton effcency s calculated. In addton, the system was composed to compare dfference by placn a heat pump passn throuh the flter and a heat pump not passn throuh t. The oxdaton sand s remnant materal for water treatment developed n Japan and the oxdaton sand contactn wth mananese covern. It was selected snce the materal was sutable for the fltraton water heat source type of heatn system snce ts use was smple, and treatment speed and effcency were ood. Desn was done to ensure that Ferox oxdaton power would be dstrbuted by aeraton wth treatment capacty of 1.5 Fe/l. A cyclone type of sand flter was nstalled as pre-treatment devce. 2.5 Ste applcaton test Development of pumpn and recharn well We developed a recharn well to supply round fltraton water as heat source of the heat pump of 60RT for supplyn heatn for the expermental reenhouse. We also frstly selected poston of a recharn well throuh the electrc resstvty and born survey, and performed a

3 hydraulc eolocal smulaton on underround water by usn a 3D FEFLOW model to verfy t. We fnally selected poston of both water pumpn hole and recharn hole on the base of the smulaton result and theolocal formula for well hydraulc of the aqufer, and performed the desn aanst remnant materal and screen, and fnally completed development of water pumpn holes at 2 places and recharn hole at a place as n Fure.3 We contracted water collecton holes and lftn holes at the ste on the fnal desn drawn but partal modfcaton was performed dependn on eolocal status at the ste and results of the fnal constructon are same as n Table Determnaton of maxmum heatn load We determned the maxmum heatn load by usn calculaton formula of the maxmum heatn load of a reenhouse suested n a ude book for faclty hortculture enery savn, and used standard weathern data and temperature n the round whch was measured from the recent 5 years. Locaton: Jun Myun-whan s farm at Daeok, Jnju, Gyeonsannam-do, Korea (paprka) Type of reenhouse: 1-2W type, contnuous 7 span plastc reenhouses Sze of reenhouse: Wdth 7m x Sde heht 4m x heht 6m x Lenth 65m, 0.3ha Insulaton: Snle vnyle cover and double alumnum screen Desn temperature: Lowest outdoor temperature: C, Temperature n the round: 1.3 C, Heatn setup temperature: 20 C F. 3 Research ste and ts surroundn Classfcaton Vertcal depth Water pumpn hole 1 (m) Water pumpn hole 2 (m) hole (m) D500 secton 0.0 ~ ~ ~ 11.5 D400 secton 13.0 ~ ~ ~ 22.0 Installaton secton of outsde casn Processn secton of outsde casn roove Screen nstallaton secton 0.0 ~ ~ ~ ~ ~ ~ Table.1 Constructon result of water pumpn and recharn holes Calculaton formula of maxmum heatn load: Q ht q q q v f w f w h f h T T A h T T A 1 5,067 3,185 r v o b b ,000kcal / h 372kW Maxmum heatn load: 372kW, Applcable heatn load: 260KW(70% of maxmum load) We determned 70% of maxmum heatn load as heat pump capacty to save enery by usn thermal storae tank and prevent excessve desn of heat pump capacty, and substtuted the remann 30% wth capacty of a thermal storae tank n order to respond to the maxmum heatn load. We also nstalled 2 separaton plates nsde and nstalled wth classfcaton nto hh, mddle and low temperature parts Capacty determnaton of heat storae tank - Possble tme of heat storae: 09:00~16: h/day (heat storae for 5 hours a day) - Capacty of heat pump: kw = 228Mcal/h - Temperature of heat storae water use; 50.0 C 40 C, 10.0 C - Storae heat quantty of heat storae tank: Capacty of heat pump Heat storae tme for a day = Mcal/h 5.0h/day = 1,144 Mcal/day - Capacty of heat storae tank: Storae capacty of heat storae tank/ Use temperature = 1,144 Mcal/day/ 10.0 C 110 m 3 ( ) Mcal/h 13hr (heatn tme at nht) 229Mcal/h 5hr(heat storae tme n daytme)

4 2.5.4 Proper desn of heat pump system We selected a heat pump as n Table 2 usn R407 refrerant that satsfed desn capacty whle coeffcent of performance s beyond 4.0 and that was envronmentfrendly. We also determned crculaton flow n the round sde and the load sde dependn on capacty of heat pump and desn temperature of cold/warm temperature as n Table 3. We fnally nstalled the fltraton water heat source type of heatn system at the ste as n F. 4, performed a heatn test n the paprka reenhouse at Waryon-r, Daeok-myon, Jnju cty from February 2011 to Aprl 2011, and measured and analyzed coeffcent of performance for heat pump, coeffcent of performance for system and chane of temperature wthn reenhouse, etc. Table 2 Capacty of heat pump and coeffcent of performance Model (refre rant) Capacty of heat pump (kw) Heatn Quantty Cooln Power consumpton (kw) Heatn Cooln COP F. 4 Desn drawn for ste applcaton of round fltraton water heat source heat pump 2.6 Rversde fltraton water recharn test The purpose of ths study, an mportant factor to prevent the depleton of rversde fltraton water farmers need the people always meet the water requrements, to protect the natural envronment nature and compulson recharn were tested. Natural recharn experments are summarzed n Table 4, and the rechare well for the test s shown n F. 5. For natural recharn test at atmospherc pressure, 63% of ntake water from a pumpn well can be rechared n the busy season for farmers, whle the recharn rate falls down to 19% n the lesure season for farmers. Perod Table 4 Natural recharn test results Intakn water volume (l/mn) volume (l/mn) rate (%) Note HP030 0WW (R407) March- May Busy season for farmers Total June Lesure season for farmers Table 3 Desn flow n the round sde and the load sde dependn on performance of heat pump, Desn Temperature of cold/warm water Ground sde Load sde Desn tem EWT ( LWT ( Flow (lpm) EWT ( LWT ( Flow (lpm) Heatn Cooln HP- 0300W W Heatn Cooln F. 5 Natural recharn test at atmospherc pressure Table 5 Artfcal recharn test results Perod March- May volume (l/mn) pressure rate (%) Note Requre proloned test (one pump)

5 June Sure around a tube well (two pumps) F.7 Study area and 3-D fnte elements mesh F. 6 Artfcal recharn test and ts montorn Compulson recharn test results, recharn rate ncreased amount, but recharn well dent and underround eolocal chane can be seen that concern. F. 8 Detaled map of study area wth wells and observaton ponts * Compulson recharn test : In the state seal wth the compulson pressure test. Therefore, n order to ncrease recharn volume the follown mprovements seem necessary. well addton development (lare tube well development, small tube well many development) Accordn to water demand recharn tme control (Busy season for farmers recharn, Lesure season for farmers bleedn) Control for ntake water volume mprove recharn rate 2.7 Effect analyss of sol temperature For a lon tme, round water level varaton of heatncooln enery supply ste and round temperature varaton predcton have been carred out usn heat source of Rverbank fltraton water for controlled hortculture cultvaton. Consequently, Hydroeolocal smulaton test have been carred out for best manaement practces for the future and wthdrawal well and njecton well are redesn of expanded facltes. F. 9 Results of temperature modeln n aqufer (z = GL -12m) accordn to njecton and tme (a-1) 119 days (b-1) 117days (a-2) 177 days (b-2) 177days (a-3) 242 days (b-4) 239days (a-4) 301 days (b-4) 301days

6 (a-5) 481 days (b-5) 481days ncreasnly n the latter may be an adverse operatn condtons. Revewed by heatn up to stop a second aun well, frst aun well ood to drve economcally. F. 10 Temperature chanes n observaton ponts 1 (sold lnes) and 2 (dashed lnes). Thck lne represents the case of njecton 1,000 ton/day and thn lne 500 ton/day Hydroeolocal smulaton results are as follows : 1. At the tme of 1000 ton njecton, second aun well s after the start of heatn 60 days (Injecton of cold water) ben nfluenced, At the tme of 500 ton njecton, ths effect s somewhat delayed, but t s affected. 2. Gaun well n the frst case, not drectly affected by the njected water (10-deree), but heatn the water s pumped 1,000 tons at the end of njecton, 2-deree nsde and outsde, njecton of 500 tons, could fall to about 1- deree. 3. When stops heatn and cooln, njecton water s under the nfluence of roundwater flow Some n the drecton of the rver flows. but when you start re-condtonn cooln or heatn s the amnotc flud aan. 4. After stoppn work, the temperature condtons durn the ntal heatn, before heatn under the nfluence of cold water njected, Durn heatn of hot water prevously njected under the nfluence when cooln s relatvely economcal heatn and cooln wll help. 5. Overall, a relatvely lon perod of heatn, so Slowly n aqufers, the water temperature radually falln (reference for 2 observatonal statons of Fure 4) but the phenomena observed, Falln temperatures after 10 years t s estmated that not more than 1 deree. 3. RESULTS AND DISCUSSION We nstalled the round fltraton water heat source Heat pump n the paprka reenhouse at Waryon-r, Daeokmyon, Jnju cty and performed a heatn test. Averae heatn performance coeffcent of performance for heat pump and system measured by month s suested as n Table 4. It was found that temperature of round fltraton water was lowest n Aprl and the coeffcent of performance was reduced as water temperature became low. The results showed that the averae coeffcent of performance for heat pump rane wthn , and the total system coeffcent of performance were wthn , whch ndcated that the effcency of the heat pump was ood. In addton, as the analyss of heat test result, temperature dfference between hh temperature part and low temperature part showed 5.5, when heat supply s performed n a reenhouse due to separaton of partton plate and temperature separaton phenomena of the thermal storae tank. But temperature dfference of 3.0 and coeffcent of performance for heat pump was mproved as F. 5 when no heat supply s performed n a reenhouse and when temperature separaton phenomena of the heat storae tank were dstnct by heat supply. Table 6 Performance coeffcent of heat pump and system heatn by month Month Temperature of fltraton water n rver ( Performance coeffcent of heat pump (COP unt ) Performance coeffcent of system (COP sys ) Feb Mar Apr Multple wells njecton rather than ndependent well njecton s recommended. It s advantaeous n terms of effectveness and effcency of heatn and cooln. 7. Injected frst aun well at a lon dstance njecton well annual ntake of the water temperature s around 2-deree. however, near second aun well s 8-deree. therefore, second aun well as ntal, relatvely economcal operaton s possble, but

7 F. 11 Improvement effect of coeffcent of performance by temperature separaton of the thermal storae tank 4. CONCLUSION We developed a heatn system for protected cultvaton reenhouse over the mddle sze usn round fltraton water heat source n ths study, and the system may be called as a system to maxmze enery use effcency by usn a heat pump. In addton, we could construct a contnual and stable system throuh a thermal storae tank usn a separaton plate, a devce to remove sand, ron and mananese, optmum desn of both water pumpn well and recharn well, and selecton of well nstallaton poston, etc. We performed a ste applcaton test by selectn the paprka cultvaton reenhouse located at downstream of Nam Rver, Daeok-myon, Jnju cty, Korea for verfcaton of ths system. The reenhouse area was 3,300m 2. It was desned wth a snle fold of vnyl cover and 2 layers of horzontal thermal curtan were nstalled so that 320,000kcal/h can be suppled. A reenhouse heatn test was performed from Feb. 1, 2011 to Apr. 30, As the result, COP unt of the heat pump was measured n the rane of 3.7~4.7, whle COP sys of the system was represented as 2.9 ~ 3.3. The coeffcent of performance (COP) measured of ths system was very ood. It was found that coeffcent of performance of the heat pump was mproved by 20%~30% due to the separaton phenomena of a thermal storae tank ACKNOWLEDGEMENTS Ths study was carred out wth the support of "Cooperatve Research Proram for Arcultural Scence & Technoloy Development (PJ006508)", Rural Development Admnstraton, Republc of Korea. REFERENCES Cho, Y. and Yun, R.: A raw water source heat pump arcondtonn system, Enery and Buldns, Vol. 43, Issue 11, pp (2011) Hwan, K.S., Jun, W.S., and Ahn, Y.S.: The feld test of bankfltraton(ncludn alluval and rverbed deposts) source heat pump cooln & heatn system, Proc. SAREK 2006 Summer Annual Conference, Pyeonchan, Korea, pp (2006). Nam, Y. and Ooka, R.: Numercal smulaton of round heat and water transfer for roundwater heat pump system based on real-scale experment, Enery and Buldns, Vol. 42, Issue 1, pp (2010). Nam, Y., Ooka, R., and Shba, Y.: Development of dualsource hybrd heat pump system usn roundwater and ar, Enery and Buldns, Vol. 42, Issue 6, pp (2010).