Solar water heating system


Published on

Fabrication and analysis of passive type Solar Water Heating System.
The system is manufactured in the workshop of Quaid-e-Awam University of Engineering,Science and Technology for fulfillment of my Bachelor Engineering Degree.
The system was successful by which good results ontained in winter season through thermosiphon water heating process with 40% efficiency.

Published in: Design, Business, Technology
  • Be the first to comment

No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide

Solar water heating system

  1. 1. 2/5/2011 1
  3. 3. 1. Introduction to the Solar Water Heating2. Process of the solar water heating3. Objective of our Project4. Solar Water Heating in Pakistan5. Types of solar water heating system6. Fabrication of passive solar water heating system7. Our project (Passive solar water heating system)8. Experimental results9. Benefits of solar water heating system10.Applications of solar water heating system2/5/2011 3
  4. 4.  Solar water heating is a well establish, highly effective, pollutionfree technology for domestic water that can be used through thecountry for various applications. The solar water heater capturethe sun’s heat in the form of discrete packets of photons, that sunheat is utilised in the system for heating the water, the systemrecieves sun’s heat by the solar flat-plate collector and transfersthat heat to the water.2/5/2011 4
  5. 5.  Collection: solar radiation is captured bysolar colllector. Transfer: circulation fluids transfer thisenergy to a storage tank, circulation can benatural (thermosiphon system) or forced,using a circulator (low head pump) Storage: hot water is stored untill it isneeded at a later time in a mechanicalroom, or on the roof in case of athermosiphon system.Collection ofsolar energyCollection ofsolar energyTransferTransfer2/5/2011 5
  6. 6.  The process of solar water heating is carried out in the solarwater heaters. There are mainly two processes for water heating through solarenergy, passive water heating and active solar water heating. Passive, as the name implies, involves no moving parts (no anyexternal source required to circulate the water). Passive solarwater heaters work on the principle of convection, in which hotwater rises and cold water sinks within the tank in a continualprocess as long as there is sunlight available the process is alsocalled Thermosiphon solar water heating.2/5/2011 6
  7. 7.  Active solar water heating in this system the water is circulatedforcedly through external source (pumps are used forcirculation). The water is circulated through pump in the solarcollector and then stored in the hot water storage tank.Passive and active solar water heating systems.2/5/2011 7
  8. 8.  The principle object of designing the passive solar waterheater is to study, analysis, evaluate and fabricate a system ofwater heating by utilization of solar energy for domestic use. The project involves both economical and technical viabilityof the whole system, the theoretical evaluation were to bearrived through spot studies. The fabrication was carried out with the help of raw materialswhich are easily and cheaply available in local markets.2/5/2011 8
  9. 9. 2/5/2011 9 Solar water heating technology is quite mature but its use inPakistan has been quite limited so far mainly because of inabilityof market development and absence of governmental support andsubsidized gas price. A number of public sector organizations are actively working onthe development of solar water heaters that have now startedgaining popularity particularly in the northern mountainous regionsdue to cold weather and limited and difficult supply of natural gasin these areas.
  10. 10. Solar water heating systems represent the most common applicationof solar energy at the present time.There are basically two types of water heating systems:1.Natural circulation systems or Passive solar water heating systemDirect passive solar water heatingIndirect passive solar water heating1.Forced circulation or Active solar water heating system.Direct active solar water heating systemsIndirect active solar water heating systems2/5/2011 10
  11. 11.  The principle of natural circulationjust like boiling the water In a flatbed collector in cold water flows tothe collector. it gets warm by sunshine and flowsupward as it becomes lighter thancold water and stored in the tankwhich can be used directly.2/5/2011 11
  12. 12. Direct passive solar water heatingDirect passive solar water heating systemstake water from the household water supply tocirculate between the collector and tank.When water warms up, convection causes it torise and flow towards the storage tank.The term ‘direct’ means the water to be usedby building occupants is run directly throughthe solar collector.2/5/2011 12
  13. 13. Indirect passive solar water heatingIn indirect or closed loop systems the heat transfer fluid is treatedwater, a refrigerant, or a non-freezing liquid such as an anti-freezesolution, hydrocarbon oil, or silicone.2/5/2011 13
  14. 14.  Forced circulation or active solarwater heating system is one wherethe exchange fluid is forcedlypumped from the storage tankthrough the collectors and backinto the tank. An electric pump is used tocirculate the water from thecollector.2/5/2011 14
  15. 15. Direct active solar water heatingsystemsAn active direct solar water heater isa pump-driven system that uses solarenergy to heat potable water directly. Water from the storage tank ispumped into the solar collector underthe moderation of a controller.2/5/2011 15
  16. 16. Indirect active solar water heatingsystemsIn an active indirect system, the pumpcontrols the flow of the heat transferfluid, not the potable water itself.The heat transfer fluid is heated by thesun, then sent through a coil that eitherwraps around the bottom of the waterheater or inside the water heater.2/5/201116
  17. 17.  Passive solar water heating systems heat water using only theenergy of the sun. However these are;1. more reliable and long lasting than active solar heating systems2. lack of moving, electrical parts3. They are less expensive4. But less efficient2/5/2011 17
  18. 18. Fabrication of passive solar water heating system includes thefollowing components,Flat-plate collectorStorage tankPiping for water circulationSupporting stand2/5/2011 18Flat-plate collectorFlat-plate collectorSupporting standSupporting standStorage tankStorage tankPiping for water circulationPiping for water circulation
  19. 19.  For constructing these components, the proper materialselection is very much necessary which needs the study ofmaterial properties Flat-plate collector A solar collector is a special kind of heat exchanger thattransforms solar radiant energy into heat. Flat plate collectors easily attain temperatures of 60 to 100ºC2/5/2011 19
  20. 20.  The main components of a flat plate solar collector are:1. Absorber plate, made of any material, which will rapidly absorb heat fromsun’s rays and quickly transfer that heat to the tubes or fins attached insome manner, which produces a good thermal bond.2. Tubes or fins, for conducting or directing the heat transfer fluid from theinlet header or duct to the outlet.3. Glazing, this may be one or more sheets of glass or a diathermanous(radiation transmitting) plastic film or sheet.4. Thermal insulation, this minimizes downward heat loss from the plate.5. Cover strip, to hold the other components in position and make it all Watertight.6. Container or Casing, this surrounds the foregoing components and keepsthem free from dust, moisture, etc.2/5/2011 20
  21. 21. STORAGE TANK The storage tank is used to accumulate the hot water for serviceor end use. for designing the storage tank, a number of factors usually mustbe considered (such as the properties of the material used, theinduced stresses, elastic ability, the cost of fabrication etc.)Length Dia Ratio Most economically method of construction of cylinder is to keepthe length to diameter of vessel between 2 and 5.2/5/2011 21
  22. 22.  length-dia ratio should be kept minimum in order to haveminimum surface area so that heat losses can be prevented,hence we take length-dia ratio as;L / d = 2L = 2dSTORAGE TANK INSULATION Storage heat loss cause a significant drop in systemperformance, therefore need for thermal insulation tank isdispensable. Commonly the material used for insulation is glass wool.2/5/2011 22
  23. 23. SUPPORTING STAND / FRAMEThe supporting stand for collectorand tank is made up of iron anglesresting on legs which are also madeup of iron rods.A simple structure of mild steelsheet is fabricated so as to providethe storage tank upper height and thecollector at inclination exposed tothe sun.2/5/2011 23
  24. 24. 2/5/2011 24Passive solar water heating systemStorage tankStorage tankFlat-plate collectorFlat-plate collectorSupporting standSupporting stand
  25. 25.  This type of system will need no pump, and water will circulatethe effect of density, through the collector tubes. In this type of system collectors are placed below the level ofstorage tank, water from storage tank will flow into thecollector and on heating the density will decrease.Water having less density will lift upward and will makes room forthe colder water from the tank thus the loop will be completed.2/5/2011 25
  26. 26. Our project passive solar water heating system consists of thefollowing components;1. Flat-plate collector2. Hot water storage tank3. Supporting stand for collector and storage tank4. Controlling devices (valves and cocks)CAPACITY OF THE PROJECTThe capacity of the project is 20 U.S gallons of water which issuitable for domestic use of one person, which can be utilized forbathing, washing cloths and vessels.2/5/2011 26
  27. 27.  Capacity of solar water heating system basically involvesdetermining the total collector area and the storage volume. Collector area The collector area is 0.76 m2 Storage volume The capacity of the project is 75 liters.2/5/2011 27
  28. 28.  The passive solar water heating system was fabricated inworkshop of university, simple manufacturing processes areemployed which helps in limiting the difficulties.Components to be fabricatedFollowing components are required for passive solar water heater.1. Flat-plate collector2. Hot water storage tank3. Supporting stand2/5/2011 28
  29. 29. 1. Flat-plate collector The flat-plate collector was fabricated in the mechanicalEngineering department workshop.1. Specification of the Flat-plate collector Length of collector = 3.5 feet / 1.066 m Width of the collector = 2.5 feet / 0.76 m Length of absorber plate = 1.016 m Width od absorber plate = 0.71 m Material for absorber plate = aluminum foil2/5/2011 29
  30. 30.  Thermal conductivity of absorber plate = 237 W·m−1·K−1 Density of absorber plate material = 2.7 kg/m3 Plate thickness 18 gauges Diameter of riser tubes = 9 mm Tube center-to-center distance = 2.5 inches Number of tubes = 10 Diameter of header pipes = 0.5 inches Insulating material used = glass wool Density of insulating material = 200 kg/m32/5/2011 30
  31. 31. 1. Pictures of fabricating the collector2/5/2011 31
  32. 32.  Hot water storage tank In the fabrication of hot water storage tank steel sheet is used. The sheet is rolled by the roller machine to bring it into shellshape. Both ends of shell are sealed by a round tray shape hold to aproper size. Finally tank is placed in casing sell, the gap between the storageand casing shell is filled by the glass wool as an insulatingmedium. The capacity of the storage tank is 75 liters.2/5/2011 32
  33. 33.  Supporting stand The supporting stand for collector and tank is made up of ironangles iron rods, the legs are made by iron rods and base by theiron angles.2/5/2011 33
  34. 34.  COST OF THE FABRICATION OF PROJECTS/NO Component cost1 Flat-plate collector 9090 rupees2 Storage tank 3255 rupees3 Supporting stand 2545 rupees4 Piping and mountings 900 rupees5 Total cost 15790 Rupees2/5/2011 34
  35. 35.  Experimental study was conducted during the month ofDecember The passive solar water heating system tested to investigate itsperformance in terms of the water heating through solarenergy. We took twenty readings in five corresponding different daysand different timings in a day from morning to noon.2/5/2011 35
  36. 36.  The experimental results include following parameters.1. Solar radiation in W/m22. Humidity in percentage3. Atmospheric temperature in centigrade4. Inlet cold water temperature in centigrade5. Outlet hot water temperature in centigrade6. Difference in temperature in centigrade2/5/2011 36
  37. 37.  INSTRUMENTS USED FOR RESULTS Following instruments were used for getting the readings ofthe result parameters:1. Light meter HD2302.02. Digital Thermometer KT2013. Humidity Temperature meter MS 65032/5/2011 37
  38. 38. 2/5/2011 38Light meter HD2302.0
  39. 39. 2/5/2011 39Digital thermometer KT201
  40. 40. 2/5/2011 40Humidity temperature meter MS 6503
  41. 41.  RESULTS AND DISCUSSION 1st day results on 13thDec 20102/5/2011 41Time InletTemp:T 1˚COutletTemp:T 2 ˚CDiff: inTemp:T ˚CAtm.Temp:T ˚CHumidityMax:% RHSolarRadiationW/m29:30 am 16.4 38.7 22.3 21.4 41% 700 W/m211:00am20 75 55 25 39% 846 W/m212:30pm22.5 79 56.5 22.5 41% 980 W/m22:00 pm 23.5 87.7 64.2 27.3 35.1% 773 W/m2Totalaverage20.6 ˚C 70.1 ˚C 49.5 ˚C 24.05 ˚C 39.025%RH824.75W/m2
  42. 42.  Graph of the Dec 13th2010 results2/5/2011 42
  43. 43.  TOTALAVERAGE RESULTS OF THE PROJECTDAY InletTemp:T 1˚COutletTemp:T 2 ˚CDiff: inTemp:T ˚CAtm.Temp:T ˚CHumidityMax:% RHSolarRadiationW/m213 Dec201020.6 70.1 49.5 24.05 39 824.7514 Dec201024.075 75.35 51.2 26.3 37.05 787.7515 Dec201023.6 76.675 53.07 22.3 44.5 76620 Dec201024.6 77.45 52.85 24.55 43.4 77521 Dec201027.75 74.5 51.75 24.55 42.75 793.75Totalaverage24.125 ˚C 74.815 ˚C 51.674 ˚C 24.35 ˚C 41.245%RH789.45W/m22/5/2011 43
  45. 45. We can save over 50% on our energy bill for domestic hotwater.The fuel we use to heat our water (the sun) is free.We are protected from future fuel shortages and priceincreases.Solar water heaters do not pollute the environment.We avoid carbon dioxide, nitrogen oxides, sulphur dioxide andother air pollutants created when electricity or solid fuel isused to heat water.2/5/2011 45
  46. 46. Solar energy is extremely safe and clean.(It is ideal for allergy sufferers and those with chemicalsensitivity.)We avoid storing tanks of highly flammable material in ourhouse.We avoid fuel odors and reduce electromagnetic fields in oraround our home.Virtually no maintenance, repair work or cleaning is required.• We are choosing a socially aware and environmentallyresponsible energy source2/5/2011 46
  47. 47.  Following are the applications of solar water heating;A.Domestic applicationsB. Commercial applicationsC. Industrial applications2/5/2011 47
  48. 48.  From the practical of fabrication and analysis of passive solarwater heating system, we have learned that how to design thesolar water heater for domestic use and other purposes wherethe hot water is required. The system works on the solar energy which is free of cost andis a renewable source of energy. the use of renewable energy is the need of today’s world dueto increasing the environmental concerns by the use of nonrenewable energy resources such as natural gas, oil and coal.• On the basis of above mentioned experimental observation itis concluded that: Fabricated passive solar water heating system was satisfactory. From the practical of system we achieved good experimentalresults.2/5/2011 48
  49. 49. 2/5/2011 49Any Queries / Questions