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11 mn01 review 3

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solar absorption cooling

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11 mn01 review 3

  1. 1. Project Phase – I Review -IIIDesign and Analysis of Solar Absorption Chiller - Phase Change Material Integrated Technology (SAPIT) for cooling telecommunication shelters in India Undertaken by: Anirudh B Mentored by: Dr.R.Velavan 11MN01 Associate Professor School of Energy PG Scholar PSG College of Technology ME Energy Engineering School of Energy PSG College of Technology
  2. 2. Transient analysis of telecom shelter using TRNSYS 16Building simulation wizard
  3. 3. Theoretical model of SACThermal energy required by the absorption chiller, 𝑄𝑐 𝑄 𝑐ℎ = 𝐶𝑂𝑃 𝑐ℎWhere, 𝐶𝑂𝑃 𝑐ℎ is the coefficient of performance of the absorption chillerwhich varies with demand is given in a fourth order polynomial for partialload efficiency of absorption chiller, 4 3 2 𝐶𝑂𝑃 𝑐ℎ = 𝑎𝑓𝑐ℎ + 𝑏𝑓𝑐ℎ + 𝑐𝑓𝑐ℎ + 𝑑𝑓𝑐ℎ + 𝑒Where, a=-2.0821,b=6.2385,c=-7.2852,d=3.8055,e=0.023Where, 𝑓𝑐ℎ is the ratio of the cooling load and the chiller nominal capacityand given by 𝑄𝑐 𝑓𝑐ℎ = 𝐶𝐻 𝑐𝑎𝑝Courtesy: N. Fumo, V. Bortone, J. C. Zambrano, “Solar Thermal Driven Cooling System for a DataCenter in Albuquerque New Mexico”, Journal of Solar Energy Engineering, ASME(2011)
  4. 4. Building simulation wizard- Time vs. Cooling load_W
  5. 5. Building simulation wizard- Time vs. Zone temperature
  6. 6. Building simulation wizard- Time vs. PLF
  7. 7. Building simulation wizard- Time vs. COP
  8. 8. Building simulation wizard- Time vs. Required thermal energy
  9. 9. PCM properties and specificationsTypes Properties Value Application Phase change temperature 27 – 29 deg C Operating range 22 – 34 deg C Density 1550 kg/𝑚3 Latent heat 190 kJ/kg Maximum operating 80 deg C temperature HS 29 Quantity per kWh 20 kg Telecom HDPE profile size 840X200X20 mm shelter cooling Maximum amount of heat to 5000 W application be removed Operating hours of PCM 16 hrs Quantity of PCM required 1515 kg No. of panels required 379 panelsCourtesy: Pluss polymers Ltd., www.thermalenergystorage.in
  10. 10. Evacuated tube collector- thermal analysisSolar radiation incident on the tube, 𝐸 𝑖𝑛𝑐𝑖𝑑𝑒𝑛𝑡 = 𝐺𝐴 𝑝𝑜Where, 𝐺 is the Global horizontal solar radiation on a typical day and𝐴 𝑝𝑜 is the aperture area of the outer borosilicate tubeSolar radiation transmitted through the tube, 𝐸 𝑡𝑟𝑎𝑛𝑠𝑚𝑖𝑡𝑡𝑒𝑑 = 𝐸 𝑖𝑛𝑐𝑖𝑑𝑒𝑛𝑡 𝜏Where, 𝜏 = 0.92Useful heat gained by the collector, 𝐸 𝑢 = 𝐸 𝑡𝑟𝑎𝑛𝑠𝑚𝑖𝑡𝑡𝑒𝑑 𝑁 𝑡Where, 𝑁 𝑡 is the number of tubes in the collectorOutlet hot water from the collector is given by, 𝐸 𝑢 = 𝑚ℎ,𝑐𝑜𝑙 𝑐ℎ,𝑐𝑜𝑙 (𝑇ℎ,𝑐𝑜𝑙 − 𝑇 𝑎𝑣𝑔 )Where, 𝑇 𝑎𝑣𝑔 is the average temperature of the storage tankCourtesy: Siddharth Arora, Shobhit Chitkara, R. Udayakumar, Muhammad Ali, “Thermal analysisof evacuated tube solar collectors”, Journal of Petroleum and Gas Engineering, Vol. 2(4), pg: 74-82, April 2011
  11. 11. Transient analysis of SAC model using TRNSYS 16TRNSYS Simulation Studio
  12. 12. Inputs to the Simulation – Evacuated tube solar thermal circuitParameters ValueNumber of collectors in series 6Collector Area 8𝑚2Transmissivity of the tube 0.92Absorptivity of the tube 0.04Outer borosilicate tube diameter 47 mmLength of the evacuated tube 1500 mmIntercept efficiency 0.7Negative Ist order efficiency coefficient 𝑘𝐽 10 ℎ𝑟.𝑚2 𝐾Negative 2nd order efficiency coefficient 𝑘𝐽 0.03 ℎ𝑟.𝑚2 𝐾Hot water pump maximum flow rate 200 kg/hrMaximum power 0.2kWInlet mass flow rate 120 kg/hrThermal storage tank volume 1.2 𝑚3Tank loss coefficient 𝑘𝐽 3 ℎ𝑟.𝑚2 𝐾Temperature levels used in the tank 6
  13. 13. Inputs to the Simulation – Chiller hot watercircuit componentsParameters ValueChiller rated capacity 4TR (14kW)Rated COP 0.8Hot fluid, chilled water fluid, cooling 4.19 kJ/kg.Kwater fluid specific heatChilled water inlet temperature 15.5 deg CChiller water mass flow rate 2173 kg/hrCooling water inlet temperature 28 deg CCooling water mass flow rate 2613 kg/hrHot water inlet temperature 90 deg CHot water mass flow rate 3456 kg/hrChiller set point temperature 10 degCAuxiliary heater maximum capacity 0.5 kWOverall loss coefficient 𝑘𝐽 10 ℎ𝑟.𝑚2 𝐾Efficiency 0.8Set point temperature 90 deg C
  14. 14. Inputs to the Simulation – Chiller coolingwater circuit componentsParameters ValueCooling tower rated capacity 5TR (17.5kW)Fan power at maximum capacity 0.5 kWSump volume 1 𝑚3Initial sump temperature 26 deg CSump make up temperature 26 deg CWet bulb temperature 25 deg CDry bulb temperature 28 deg CRated flow rate for variable speed pump 700 kg/hrRated power 0.5 kWPower coefficient 1Pump efficiency 0.6Motor efficiency 0.9
  15. 15. TRNSYS simulation studio – Time vs. Total horizontal globalradiation
  16. 16. TRNSYS simulation studio – Time vs. Total global radiation on thecollector surface
  17. 17. TRNSYS simulation studio – Time vs. global radiation on collectorsurface on a typical day of January month
  18. 18. TRNSYS simulation studio – Time vs. global radiation on collectorsurface on a typical day of April month
  19. 19. TRNSYS simulation studio – Time vs. global radiation on collectorsurface on a typical day of July month
  20. 20. TRNSYS simulation studio – Time vs. global radiation on collectorsurface on a typical day of December month
  21. 21. TRNSYS simulation studio – Time vs. Hot water inlet to thecollector and tank average temperature
  22. 22. TRNSYS simulation studio – Time vs. Hot water outlettemperature from the collector
  23. 23. TRNSYS simulation studio – Time vs. Hot water outlettemperature from the chiller
  24. 24. Economic Analysis – Equipment and utility costParameters ValueConventional air-conditioner 30000 Rs./TRAuxiliary heater 3000 Rs./kWDG set cost (20kVA) 2,15,000 Rs.Hot water fired absorption chiller 50000 Rs./TR(inclusive of cooling tower)Evacuated tube solar collector 12000 Rs./𝑚2PCM cost 50 Rs./kgThermal storage tank 7500 Rs./𝑚3Electricity rate 7.5 Rs./kWhDiesel rate 50 Rs./ltr
  25. 25. Economic Analysis – Annual energy and cost savingsParameters ValueOperating hours per day (air – conditioner) 24hrsElectrical energy consumed by a telecom shelter 5 kWPercentage of energy consumed by AC from both grid and DG set 60%Electricity consumed by the air-conditioner of capacity (2.5 TR min) 26,280 kWhElectricity cost per year Rs. 98,550DG set operating hours per day 12hrsDiesel cost per year Rs. 2,62,800Total cost per year Rs. 6,15,350SAC investment and operational cost (inclusive of PCM cost) Rs. 4,60,537Operational hours of the AH per day 10hrsElectricity consumed by AH per year 1460 kWhTotal energy savings 24,820 kWhTotal cost savings Rs.1,54,812Payback period 9 months
  26. 26. Environmental BenefitsParameters ValueCarbon Emission factor of lignite coal 101.2 kg/TJCarbon Emission factor of diesel 74.1 kg/TJDiesel consumption per hour 2 ltrCalorific value of Lignite coal 15000 kJ/kgCalorific value of diesel 45000 kJ/kgEnergy supplied by lignite coal 0.147825 TJEnergy supplied by diesel 0.1963116 TJ𝐶𝑂2 emission by coal 14.95 tons𝐶𝑂2 emission by diesel 14.54 tonsTotal 𝐶𝑂2 emissions per year 29.506 tons𝐶𝑂2 emission by AH per year 2.07 tonsTotal 𝐶𝑂2 mitigated per annum 27.42 tons
  27. 27. ConclusionSolar driven absorption chiller has been designed and analyzed for part load condition using TRNSYS 16The cooling load profile for a typical telecom shelter has been generated for a year and has been used for further analysisSimulation results showed that to achieve a solar thermal efficiency of 65%, the mass flow rate was to be maintained at 120kg/hr in a total collector area of 8𝑚2The hot fluid temperature at the outlet of each collector must be maintained between 90 deg C to 130 deg C to achieve the average temperature of the tank between 75 deg C to 85 deg C and in order to maintain the COP of the chiller between 0.68 to 0.76The chilled water and cooling water temperature difference was found to be around 5 deg C and 4 deg C respectivelyThe economic analysis shows that the total energy savings potential per year as 24,820kWh and the total cost savings potential as Rs.1,54,812The environmental analysis shows us there is a potential of mitigating 27.8 tons of CO2 per annum if the SAPIT cooling system replaces the conventional cooling system

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