Study on Performance Verification and Evaluation of District Heating and Cooling System Using Thermal Energy of River Water

Transcription

1 Study on Performance Verification and Evaluation of District Heating and Cooling System Using Thermal Energy of River Water September 16, 214 NIKKEN SEKKEI Research Institute Naoki Takahashi

2 Abstract The heating and cooling system used in Osaka s Nakanoshima district uses heat pumps and river water to achieve the efficient use of the heat source and mitigate the heat island effect. The system is properly operated and maintained continuously. This presentation outlines the performance verifications and evaluations that have been conducted, operational results, plant performance, and heat source equipment performance since the operation was launched. Also, secular changes in river water heat exchangers are analyzed and the effect of cleaning heat exchangers are evaluated. (1) Overview of the heating and cooling facilities (2) Operational results since launch (3) Secular changes in plant performance (4) Secular changes in facilities using river water 1

3 (1) Overview of the heating and cooling facilities 2

4 Overview of Nakanoshima, Osaka Osaka Ｎakanoshima - Nestled between the Dojima and Tosabori rivers, Nakanoshima is a sandbank stretching roughly 3 km in an east-west direction. - As well as Osaka City Hall, the island is home to a number of leading Japanese companies and other public and business facilities. - Pathways and other amenities help create an attractive riverside environment. Nakanoshima-3chome Tosabori river Dojima river - Area space: about 5 ha - Floor space: about 1 million m2 - Daytime population: about 35, (As of 26) 3

5 District heating and cooling system in Nakanoshima Characteristics of heat supply plant in Nakanoshima district -River water is utilized as heat source and cooling water overall (in comparison with normal system 15% of energy saving) -Adopt large-scale ice heat storage system and realize equalization of electricity load -Adopt turbo chiller and heat recovery facilities as high efficiency heat source -Utilize waste heat discharged from substation, and supply in large difference of temperature Water intake Heat exchangers Water discharge Turbo chiller Screw heat pump pumps 4

6 Heat supply area(1st stage : 25-28) N 5

7 Heat Supply Area(From 1st to 2nd Stage : ) N 6

8 Heat Supply Area(From 1st to 3rd Stage : 213-) N 7

9 Heat supply system(1st stage25-28) [ 1st Stage ] Heat source equipment Cooling Heating Number HP/Water source screw heat pump - 838MJ/h 1 Cool water Cool water: heat recovery: IHP/Water source 3,8MJ/h 3,66MJ/h 8Unit screw heat pump Ice Storage: Ice storage (16) (Ice storage and heat recovery) 1,936MJ/h heat recovery: 2,448MJ/h TR1 Water cooling turbo chiller 5,63MJ/h - 1 Ice storage tank Storage capacity Number Dynamic type 139,44MJ 87m 3 8 [ Facilities using river water ] Intake : Dojima river Water intake and discharge place Discharge : Tosabori river Quantity of water intake Summer :.426m 3 /s Winter :.348m 3 /s Proceedings Use difference of temperature Summer : 5 C of the Winter 14th International : - 3 C Conference for Enhanced Building Operations, Beijing, China, September 14-17, 214 River water dependence rate 1% 8

10 Heat supply system(from 1st to 2nd stage : ) [ 1st Stage ] Heat source equipment Cooling Heating Number HP/Water source screw heat pump - 838MJ/h 1 Cool water Cool water: heat recovery: IHP/Water source 3,8MJ/h 3,66MJ/h 8Unit screw heat pump Ice Storage: Ice storage (16) (Ice storage and heat recovery) 1,936MJ/h heat recovery: 2,448MJ/h TR1 Water cooling turbo chiller 5,63MJ/h - 1 Ice storage tank Storage capacity Number Dynamic type 139,44MJ 87m 3 8 [ 2nd stage ] Heat source equipment Cooling Heating Number SR1/HP/Water source screw heat pump (Ice storage, change of cool and warm water mode) SR2/HP/Water source screw heat pump (Ice storage, change of cool and warm water mode) TR2/water cooling turbo chiller(inverter) Cool water: 5,62MJ/h Ice Storage: 4,44MJ/h Cool water: 8,64MJ/h Ice Storage: 8,478MJ/h 4,187MJ/h 1 13,86MJ/h 1 7,595MJ/h - 1 Ice storage tank Storage capacity Number Static type 78,23MJ 545m 3 8Unit [ Facilities using river water ] Intake : Dojima river Water intake and discharge place Discharge : Tosabori river Quantity of water intake Summer :.66m 3 /s Winter :.382m 3 /s Use difference of temperature Summer : 5 C Winter : - 3 C River water dependence rate 1% 9

11 Heat supply system(from 1st to 3rd stage : 213-) [ 1st Stage ] Heat source equipment Cooling Heating Number HP/Water source screw heat pump - 838MJ/h 1 Cool water Cool water: heat recovery: IHP/Water source 3,8MJ/h 3,66MJ/h 8Unit screw heat pump Ice Storage: Ice storage (16) (Ice storage and heat recovery) 1,936MJ/h heat recovery: 2,448MJ/h TR1 Water cooling turbo chiller 5,63MJ/h - 1 Ice storage tank Storage capacity Number Dynamic type 139,44MJ 87m 3 8 [ 2nd stage ] Heat source equipment Cooling Heating Number SR1/HP/Water source screw heat pump (Ice storage, change of cool and warm water mode) SR2/HP/Water source screw heat pump (Ice storage, change of cool and warm water mode) TR2/water cooling turbo chiller(inverter) Cool water: 5,62MJ/h Ice Storage: 4,44MJ/h Cool water: 8,64MJ/h Ice Storage: 8,478MJ/h 4,187MJ/h 1 13,86MJ/h 1 7,595MJ/h - 1 Ice storage tank Storage capacity Number Static type 78,23MJ 545m 3 8Unit [ 3rd Stage ] Heat source equipment Cooling Heating Number R31 R32/HP/Water source screw heat pump (change of cool and warm water mode) 8,561MJ/h 8,91MJ/h 2 Heat source equipment Cooling Hot water Number HWR41 HWR42 Scroll heat pump(high temp.) - 464MJ/h 2 HSR43 Scroll heat pump(high temp.) HSR44 Scroll heat pump (High temp.and heat recovery) [ Facilities using river water ] - 184MJ/h 1 113MJ/h 184MJ/h 1 Intake : Dojima river Water intake and discharge place Discharge : Tosabori river Quantity of water intake Summer : 1.24m 3 /s Winter :.88m 3 /s Use difference of temperature Proceedings Summer : 5 C of the Winter 14th International : - 3 C Conference for Enhanced Building Operations, Beijing, China, September 14-17, 214 River water dependence rate 1% 1

12 Developments in heat supply plant since operation started Performance has been continuously verified and evaluated to ensure proper operation and maintenance since the operation was first launched. Year Performance verification and evaluation phase Topics Supply status Performance verification framework 1st year 2nd year 3rd year 4th year 5th year 6th year 7th year 8th year 9th year 1th year Phase-1 Phase-2 Phase-3 Initial performance verification and evaluation 1st stage started operation Mild winter Early performance verification and evaluation Hot summer 2nd stage started operation Started operation for Office2 in 29/4 Started operation for Office1 in 25/1 Started operation for Station in 28/1 Initial performance verification and evaluation meeting Continual performance verification and evaluation meeting Performance verification of 2nd stage system Late performance verification and evaluation Requested electricity saving The Great East Japan Earthquake Verification of saving effect Installed additional substations Electricity-saving target 3rd stage started operation Started operation for Office3 in 213/3 Started operation for Hotel in 214/1 Continual performance verification and evaluation meeting Performance verification of 3rd stage system Verification and evaluation items Efforts on demand side and plant side Efforts on plant side Cooling Heating Performance verification of heat source system Performance verification of conveyance system Verification of effectiveness of using river water Verification of effectiveness of leveling load Initial performance evaluation (first COP) Created system simulator Considered operation improvement 3-year performance evaluation Optimized thermal storage in the building The ratio of cool water follow-up cooling operation was increased due to increased cooling load in summer Adjusted bypass flow Increased TR operation Performance verification of 2nd stage system Considered heat source operation map 6-year performance evaluation Prioritized IHP cool water heat recovery operation Adapted IHP (Enabled separated operation) The ratio of cool water heat recovery operation was increased due to decreased heating load in winter Reviewed power-saving methods Performance verification of 3rd and effect stage system Evaluated secular changes of heat source performance Evaluated secular changes of river water utilization system Power-saving operation Optimized IHP and SR operation 1-year performance evaluation Optimized thermal storage in the building Considered supply temperature mitigation Others Adjusted plant ventilating fan Proceedings of the 14th International Secured Conference temperature for Enhanced difference Building of river water Operations, Beijing, China, Reviewed September temperature 14-17, difference 214 of river water 11

13 Example of efforts on plant side : Adjusted bypass flow -Because setting of the bypass differential pressure was excessive, in the first half of 25, bypass flow quantity increased, and the consumption electricity of the second pump increased. -As a result of having lowered setting of the differential pressure after the latter half of 25, bypass flow quantity decreased. Return Cool water first pumps 冷水ヘッダーバイパス流量 Bypass flow quantity [m [ m3 3 / /day] 日 ] 5, 4, 3, 2, 1, Change setting of differential pressure (25/6-) 年 年 Bypass Supply Heat source Cool water second pumps Bypass 冷水ヘッダーバイパス差圧 differential pressure [kpa] [kpa] 月 Change setting of differential pressure 25 年差圧 (25/6-) 25 Differential 26 年差圧 pressure 26 Differential 25 年設定値 pressure 25 set 26 point 年設定値 26 set point 月 12

14 (2) Operational results since launch 13

15 Outdoor air temperature and river water temperature - Though affected by outdoor air temperature, river water temperature fluctuates less than outdoor air temperature. - In summer, river water is advantageous as cooling water because it is.1 to 1 C cooler than outdoor air temperature. - In winter, conversely, river water is advantageous as heat source water because it is 1 to 2.8 C warmer than outdoor air temperature. Monthly Average Outdoor Temp.[ C] Monthly Average River Water Temp.[ C] Proceedings of 5the 7 14th 9 11International Conference for 7 Enhanced Building 5 7 9Operations, Beijing, China, 1 3 5September ,

16 15 Hourly temperature fluctuations of outdoor air and river water In terms of temperature, river water is more advantageous than outdoor air as a cooling agent. <Outdoor air temperature (August)> - The temperature differential between a hot summer (21) and cool summer (29) is about 2 C. - The temperature differential between daytime and nighttime is about 4 to 5 C. Mean Hourly Outdoor Temp.[ C] Hour <River water temperature (August)> - The temperature differential between a hot summer (21) and cool summer (29) is about 1.5 C. - The temperature differential between daytime and nighttime is maintained at a lower temperature than the air. Mean Hourly Rier Water Temp.[ C] Hour

17 Amount of heat sold by the plant (Total) - Cooling demand was on the increase and heating demand on the decrease until 28. Due to more internal heat generation caused by the use of more large computers as well as a higher occupancy rate - In 21, cooling demand increased in summer due to a heat wave. - Since 211, the power-saving effect has become noticeable as an effect of power-saving measures on the demand side. 8, Sales Heat Amount [GJ/year] 7, 6, 5, 4, 3, 2, 1, Cooling Heating 32,833 27,942 29,815 3,293 8,912 7,997 5,441 6,651 59,48 9,324 68,722 56,481 53,339 17,431 18,23 19,27 64,135 2,979 Sales Heat Amount [GJ/month] 35, 3, 25, 2, 15, 1, 5, 5, 1, Station Open(28/9) Great Erathquake(211/3) Office3 Open Proceedings of the 14th International Conference for Enhanced Office2 Building Open(29/3) Operations, Beijing, China, September 14-17, 214 (213/5) Monthly Average Outdoor Air Temp.[ C] 16

18 Amount of heat sold by the plant (per consumer, cooling) When the 2 nd stage work was completed in 29, the amount of heat significantly increased. However, after the 211 earthquake it decreased. Since then, the 21 record (hot summer) has not been broken, even following the completion of 3 rd stage work in 213. Sales Cooling[GJ/year] 8, 7, 6, 5, 4, 3, 2, 1, Office3 Station 5,93 Office2 4,351 Office1 27,979 21,496 27,942 29,815 3,293 32,363 33,56 35,65 3,864 23,464 9,694 3,715 3,837 22,586 23,534 29,153 27,38 27,7 Sales Cooling[GJ/month] 25, 2, 15, 1, 5, Station Open(28/9) Great Erathquake(211/3) Outdoor Air Temp Monthly Average Outdoor Air Temp.[ C] Proceedings of the 14th International Conference for Enhanced Office2 Building Open(29/3) Operations, Beijing, China, September 14-17, 214 Office3 Open (213/5) 17

19 Amount of heat sold by the plant (per consumer, heating) Since the 2 nd stage work was completed in 21, the amount of heat has significantly increased. After the 211 earthquake it increased slightly. After the earthquake, power-saving by consumers caused a decrease in internal heat generation. Sales Heat Amount[GJ/year] Sales Heat Amount[GJ/month] 25, 2, 15, 1, 5, 8, 6, 4, 2, Office1 Office2 Station Office3 2, ,57 1,438 11,95 1, ,27 8,912 7,997 5,441 6,526 5,791 6,477 7,219 7,494 7,217 Station Open(28/9) Great Erathquake(211/3) Outdoor Air Temp Monthly Average Outdoor Air Temp.[ C] Office3 Open Office2 Open(29/3) (213/5) 18

20 19 Changes to heat source operation policy since launch of operation Mainly in order to cut down on power demand with heat storage utilizing nighttime electric power, heat source operation has been optimized considering heat load, installations of heat source equipment, and external factors such as earthquakes. Year Performance verification and evaluation phase Topics Situation of the heat load Policy of heat source operation 1st year 2nd year 3rd year 4th year 5th year 6th year 7th year 8th year 9th year 1th year Phase-1 Phase-2 Phase-3 Initial performance verification and evaluation 1st stage started operation Mild winter Utilizing nighttime electric power Heat storage use and heat recovery operation Early performance verification and evaluation Hot summer 2nd stage started operation Incerasing load Increasing due to 2nd stage cooling load due started operation to hot summer Utilizing nighttime electric power High efficiency of follow-up heat source Heat storage use, heat recovery operation and increasing of followup operation Late performance verification and evaluation Requested electricity saving The Great East Japan Earthquake Decreasing cooling load Restraint of demand electricity Electricity saving Keeping of heat storage use Electricity-saving target 3rd stage started operation Incerasing load due to 3rd stage started operation Restraint of demand electricity Electricity saving Priority driving of high efficiency heat source Driving order of heat sources Cooling Daytime Nighttime 1)IHP Melting ice 2)TR-1 3)IHP Cool water 1)TR-1 2)TR-2 3)IHP Melting ice 4)SR Melting ice 5)IHP Cooling 6)SR-1 or 2 1)IHP Melting ice 1)TR-1 or 2 2)IHP Melting ice 1)TR-1 2)TR-2 3)IHP Melting ice 4)SR Melting ice 5)IHP Cooling 6)SR-1 or 2 1)TR-2 2)IHP Melting ice 1)TR-1 2)TR-2 3)R-31 4)R-32 5)IHP Melting ice 6)SR Melting ice 7)IHP Cool water 8)SR-1 or 2 1)TR-2 2)IHP Melting ice Heating Daytime 1)HP 2)IHP Ice storage heat recovery 1)HP 2)IHP Cool water heat recovery 3)IHP Ice storage heat recovery 4)SR-1 1)HP 2)IHP Cool water heat recovery 3)IHP Ice storage heat recovery 4)SR-1 1)HP 2)IHP Cool water heat recovery 3)SR-2 4)R-31 or 32 Nighttime 1)HP 1)HP 2)IHP Cool water heat recovery 1)HP 2)IHP Cool water heat recovery 1)HP 2)IHP Cool water heat recovery

21 Amount of heat produced by the plant (per operation mode, cooling) - During 1 st stage, heat storage operation using nighttime electric power and highly efficient ice storage heat recovery operation were implemented. - During 2 nd stage, heat storage operation was increased and the operation of highly efficient follow-up heat source equipment was implemented. - After the earthquake, heat demand decreased and heat storage was maintained to cut down on power demand. - During 3 rd stage, the operations of highly efficient equipment were prioritized to save power. Annual Product Heat Amount[GJ/year] 8, 7, 6, 5, 4, 3, 2, 1, Ice Storage Ice Storage(Heat Recovery) Cool water(heat Recovery) 37,811 Cool water 29,175 29,52 26,397 42,763 3,694 6,723 1,52 12,163 13,571 13,451 6,471 6,229 5,91 4,11 2,551 3,594 6,187 3,677 29,41 25,623 19,489 2,4 18,899 2,115 24,361 18,

22 Amount of heat produced by the plant (per operation mode, heating) - During 1 st stage, highly efficient ice storage and cool water heat recovery operation were implemented. - During 2 nd stage and later, highly efficient ice storage and cool water heat recovery operation has mainly been used, along with highly efficient follow-up heat source equipment. Annual Product Heat Amount[GJ/year] 25, 2, 15, 1, 5, Ice Storage Heat Recovery Cool water Heat Recovery Warm water 8,7 5,889 6,164 6,852 1,67 1,899 1,972 1, , , , ,26 6,18 6,175 4,381 11,438 1,991 1,736 11,

23 Amount of power consumption by the plant (daytime and nighttime) and nighttime electric power ratio - During 1 st stage, the nighttime electric power ratio was 55% and higher. This contributed to leveling the electric load. - During 2 nd stage, the nighttime electric power decreased to 44% due to increased cooling and heating demand. After the earthquake, cooling demand decreased and the ratio relatively recovered to 49%. Electric Power Consumption[MWh/year] 16, 14, 12, 1, 8, 6, 4, 2, Night Daytime Nighttime Electric Power Ratio 55% 57% 57% 56% 54% 2,128 1,94 1,738 1,95 2,557 2,544 2,323 2,465 3,243 44% 47% 49% 4,89 41% 3,932 3,736 4,83 3,745 3,781 3,455 3,63 3, % 8% 6% 4% 2% % Nighttime Electric Power Ratio 3, 1% Electric Power Consumption[MWh/month] 2,5 2, 1,5 1, 5 Nighttime Electric Power Ratio Station Open(28/9) Office2 Open(29/3) Great Erathquake(211/3) 8% 6% 4% 2% % Office3 Open (213/5) Nighttime Electric Power Ratio

24 (3) Secular changes in plant performance 23

25 Annual average COP of IHP Annual Average COP [-] , 4, 35, 3, 25, 2, 15, 1, Product Heat Amount[GJ/year] <Ice storage heat recovery> In 213, the downward trend was remarkable. <Ice storage> A downward trend has been noticeable for these two years Product Heat : IHP Ice Storage Product Heat : IHP Ice Storage(heat recovery) COP : IHP Ice Storage COP : IHP Ice Storage(heat recovery) 5, Normal rate COP (Ice storage) 3.3 (Ice storage heat recovery) 5.43 Annual Average COP [-] Product Heat : IHP Cool water Product Heat : IHP Cool water(heat recovery) COP : IHP Cool water COP : IHP Cool water(heat recovery) , 25, 2, 15, 1, 5, Product Heat Amount[GJ/year] <Cool water heat recovery> In 213, the downward trend was remarkable. <Cool water> There is a slight downward trend. Normal rate COP (cool water) 4.23 (cool water heat recovery)

26 Annual average COP of TR-1,2 and HP Annual Average COP [-] TR-1 5,747 6,95 Normal Rate COP 5.6 7,828 7,996 9,784 1,26 8,738 5,745 7, , 1, 5, Product Heat Amount[GJ/year] <TR-1> There is a slight downward trend and it is within secular deterioration. Product Heat : TR-1 Cool water COP : TR-1 Cool water Annual Average COP [-] TR-2 Normal Rate COP ,446 12,827 12,72 13,328 19, , 3, 25, 2, 15, 1, 5, Product Heat Amount[GJ/year] <TR-2> An upward trend is observed due to the increased amount of heat. Product Heat : TR-2 Cool water COP : TR-2 Cool water Annual Average COP [-] HP Normal Rate COP ,12 1,124 1, , ,488 3, 2,5 2, 1,5 1, 5 Product Heat Amount[GJ/year] <HP> There is a slight downward trend and it is within secular deterioration Product Heat : HP Hot water COP : HP Hot water 25

27 Annual plant COP Since operation started, COP has steadily been increased and 213 saw a record high of 1.1. Annual Plant COP [-] Annual Plant COP [-] /1~25/12 25/7~26/6 26/1~26/12 26/7~27/6 27/1~27/12 27/7~28/6 28/1~28/12 28/7~29/6 29/1~29/12 29/7~21/6 21/1~21/12 21/7~211/6 211/1~211/12 211/7~212/6 212/1~212/12 212/7~213/6 213/1~213/12 26

28 (4) Secular changes in facilities using river water 27

29 Maintenance history of river water heat exchangers From work completion to 29: Inspection and cleaning (by blown air only) was conducted every April. In 21: Eddy current testing (ECT) was conducted for the first time. - Since 21, cleaning with a brush has been conducted. In 211: Flaw detection was performed on No.3 HEX, which had the worst pipe wall thinning, and its corrosion over one year was confirmed. In 212: No.1 HEX: 141 No.3 HEX: 49 thin tubes were replaced. In 213: Flaw detection In 214: Thin tubes will be replaced depending on the inspection results. 28

30 Performance evaluation of river water heat exchangers (RHEX1 to 4) Tci Tco DOJIMA River TOSABORI River 3 rd stage plant Tho Thi Heat Exchange Coefficient KF S= Qt / MTD MTD=(ΔT1-ΔT2)/ln(ΔT1/ΔT2) ΔT1 = Tho - Tci ΔT2 = Thi - Tco MTD:Mean Temperature Difference Qt:Heat Exchange Calorimetry [MW] S:Heat Exchange Area[ m2 ] By checking the change in the heat exchange coefficient, the efficiency of maintenance such as cleaning and secular changes in heat exchangers are confirmed. 29

31 Evaluation of secular changes in heat exchangers - Comparing the coefficients of each August since 27, large secular change is not observed. The planned maintenance has helped maintain initial performance. - The effect of replacing thin tubes in 212 has not been confirmed. Heat Exchange Codfficient(KFS)[MW/K] 5, 4, 3, 2, 1, - Aug-213 Aug-212 Aug-211 Aug-21 Aug-29 Aug-28 Aug-27 1, 2, 3, 4, 5, 6, 7, 8, Exchange Heat Amount(Qt)[MW] Heat Exchange Coefficient(KFS)[MW/K] 4, 3,5 3, 2,5 2, 1,5 1, , 2, 3, 4, 5, 6, 7, Exchange Heat Amount[MW] 3

32 Effect of cleaning river water heat exchangers Comparing coefficients after cleaning (in May) to those before cleaning (in April), the improvement is apparent. The effect of annual cleaning is confirmed. Heat Exchange Coefficient (KFS)[MW/K] 4, 3,5 3, 2,5 2, 1,5 1, 5 - Just After Cleaning(213.5) Just After Cleaning Just Before Cleaning(213.4) Just Before Cleaning 1, 2, 3, 4, 5, 6, 7, Exchanged Heat Amount [MW] 31

33 Conclusion We have seen the performance verification and evaluation of the heating and cooling system in Osaka's Nakanoshima 3-chome district, which utilizes river water. -Performance of this heating and cooling system has been continuously verified and evaluated to ensure proper operation and maintenance since the operation started. We have shown one example of efforts to ensure proper operation on the plant. -We looked at the nine-year operational results since the plant was launched. Heat source operation has been optimized considering the change of heat demand, heat source arrangement, and external factors such as earthquakes. -We have also seen the results of plant performance. Some heat source facilities indicate a slight downward trend, but since the operation started, the plant COP has steadily been increased and 213 saw a record high of We have seen the secular changes in facilities using river water. The planned maintenance Proceedings of the 14th International has helped Conference for Enhanced maintain Building Operations, the Beijing, initial China, September performance ,

34 Thank you for your attention. 33