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# Central steam heating system report

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Central steam heating system Central Heating is a heating system in which air or water is heated at a central point and sent through the whole interior of a building via vents or pipes and radiators to provide warmth in multiple rooms or parts of a building. Central heat sources can be boilers for oil, gas, biomass or solar heating systems. Depending on the size of the building and available energy sources, a central heating solution might have multiple shapes.

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### Central steam heating system report

1. 1. CENTRAL STEAM HEATING SYSTEM Presented by: Maaz Khan Zavain Rehman Usman Pervez H.M Immad Tariq Awais Iqbal HP By Group B REG # 234 REG # 236 REG# 245 REG# 233 REG # 230
2. 2. By Group B [CENTRAL STEAM HEATING SYSTEM] ABSTRACT In this report we discuss thoroughly about the central heating system, it provides some recommendation to upgrade and improve the efficiency of central heating system in houses, For that first a basic view of the heat load and heat load calculation. Secondly the perimeters used to overcome the heat losses which can effects the energy efficiency of the heating system. Third case, we discuss about the boiler and the types of boiler used normally and the basic importance of using them. In fourth case we discuss bout the radiator used and there types. Heat load, radiator, boiler, pipes calculation 2
3. 3. By Group B [CENTRAL STEAM HEATING SYSTEM] TABLE OF CONTENT Abstract Main Text: CENTRAL HEATING SYSTEM 5 1. Introduction_______________________________________________________________________5 1.1 How central heating system works___________________________________________________5 SECTIONS: 2. HEAT LOAD 6 2.1 What is Heat Load______________________________________________________________6 2.2 Factors Affecting Comfort in winter______________________________________________6 2.3 Mathematical Calculation_______________________________________________________7 2.3.1 Calculation ________________________________________________________________9 2.3.1.1 Apartment#1 ___________________________________________________________9 2.3.1.2 Apartment#2___________________________________________________________11 2.4 Table____________________________________________________________________15 2.5 assumption_______________________________________________________________15 3. INSULATION OF WALLS/ROOF/BOILER AND CONNECTING PIPES 16 3. What is Insulation_________________________________________________________________ 16 3.1 Types of Insulation______________________________________________________________17 3.1.1 Insulation Used________________________________________________________________17 3.2 4. table___________________________________________________________________________17 BOILER SELECTION 4.1 What is Boiler_____________________________________________________________________18 4.2 Types of Boiler___________________________________________________________________18 4.3 Selection of Boiler________________________________________________________________18 4.3.1 Fire tube boiler_______________________________________________________________18 3
4. 4. By Group B [CENTRAL STEAM HEATING SYSTEM] 4.3.2 Our boiler specification __________________________________________________18 4.3.3 Types of Fuel Used in Boiler_______________________________________________19 4.3.4 Benefits are ____________________________________________________________19 4.3.5 Combustion energy______________________________________________________19 4.4 Boiler Losses and Measure of Efficiency__________________________________________20 4.5 Boiler Accessories___________________________________________________________ 21_ 4.6 Calculations__________________________________________________________________22 5 T-S DIAGRAM 6 PLUMBING 23 24 6 What is Plumbing__________________________________________________________________24 6.1. Types of Piping_______________________________________________________________24 6.1.1 One pipe ___________________________________________________________________24 6.1.2 Two pipe ___________________________________________________________________24 6.2 Selection of Piping______________________________________________________________25 6.3 Steam Mains for gravity flow______________________________________________________25 7 RADIATOR SELECTION 26 7.1 What is Radiator_______________________________________________________________26 7.2 Types of Radiator______________________________________________________________26 7.3 Working ______________________________________________________________________29 7.4 Material _____________________________________________________________________29 7.5 Radiator selection_____________________________________________________________29 7.5.1 Material selection _________________________________________________________29 7.6 Sizing _______________________________________________________________________30 7.6.1 for apartment #2, 3, ______________________________________________________30 7.6.2 for apartment # 1_________________________________________________________30 8 BIOGRAPHY AND REFERENCE 31 4
6. 6. By Group B [CENTRAL STEAM HEATING SYSTEM] the radiators there. 6. A thermostat mounted in one room monitors the temperature and switches the boiler off when it's hot enough, switching the boiler back on again when the room gets too cold. 7. Waste gases from the boiler leave through a small smokestack called a flue and disperse in the air. 2 HEAT LOAD: 2.1 WHA T IS HEA T LOAD? Heat load (including heat loss, or heat gain) is the term for the amount of heating (heat loss) or cooling (heat gain) needed to maintain desired temperature and humidity in controlled air (e.g., in a structure). Regardless of how wellinsulated and sealed a building is, buildings gain heat from warm air or sunlight or lose heat to cold air and by radiation. Engineers use heat load calculations to determine the HVAC needs of the space being cooled or heated. 2.2 FACTORS AFFECTING COMFORT IN WINTER 1. TEMPERATURE difference between the inside and outside of the building is the primary cause of heat loss in the winter months. The greater this difference, the higher the rate of heat loss. Since most buildings are controlled to a constant inside temperature by the occupants, higher heat loss occurs when it is colder outside. 2. WIND is the second greatest source of heat loss during the winter. High winds can occur on the cold nights and when they do, heat loss can be higher because of air scrubbing the outside of the space covering. Winds can also force their way through cracks in the structure, causing infiltration and drafts. In fact, up to one-third of the annual heating energy goes to heat this moving infiltration air many times each winter day. 3. HUMIDITY levels can also affect the comfort within a structure. Very low humidity levels (less than 20% relative humidity) cause scratchy throats and dry noses in most people. 6
7. 7. By Group B [CENTRAL STEAM HEATING SYSTEM] 4. RADIATION sources can also affect comfort in a structure. The sun shining through a window will make a room very comfortable in winter; that same sun could make it unbearable in summer. Walls and windows also release and absorb radiation. A Trobe wall heated by the sun will keep a room feeling warm with an air temperature less than 60°F. A large expanse of cold glass windows can also make a room feel chilly 2.3 MA THEMA TICAL CALCULA TION The heat loss is divided into two groups: 1) The conductive heat losses through the building walls, floor, ceiling, glass, or other surfaces, 2) The convective infiltration losses through cracks and openings, or heat required to warm outdoor air used for ventilation. We neglect the infiltration and ventilation losses across the walls of apartments. Q = A * U * (Ti – To) Where Q = Total hourly rate of heat loss through walls, roof, glass, etc in Btu/hr U = Overall heat-transfer coefficient of walls, roof, ceiling, floor, or glass in Btu/hr ft2 F A = Net area of walls, roof, ceiling, floor, or glass in ft2 Ti = Inside design temperature in °F To = Outside design temperature in °F 7
8. 8. By Group B [CENTRAL STEAM HEATING SYSTEM] Heat loads of the Apartments is equal to Heat load across wall + Across Windows+ across Roof Ceiling + Across Floor Resistivity value of different materials used is as follows: R(brick) per inch 0.2 9 * 0.2 = 1.8 U= R (gypsum) per 5/8 inch R(Cellulose) per inch 0.45 3 2.5*3=7.5 𝟏 𝑹𝟏+𝑹𝟐+𝑹𝟑 U=0.102 8
9. 9. By Group B 2.3.1 [CENTRAL STEAM HEATING SYSTEM] CALCULATION 2.3.1.1 APARTMENT # 1 Bedroom # 2 Walls: A= 188 ft sq U= 0.102 ∆T= 56.7 U= 188 * 57.6 * 0.102 Q=1104.5 Btu/hr Window: A=16 ft sq Double Pane with 1/4" air space R=1.69 width= 0.5” R=1.69 U= 0.5 Q=0.5*57.6*16= 460 BTU/hr Q=920 Btu.hr (for 2 windows) Roof: A=120 ft sq R=7.05 U=0.1233 Polyutheren 1” 6.25 9
10. 10. By Group B [CENTRAL STEAM HEATING SYSTEM] Q= 120 * 57.6 * 0.1233 Q=967.68 Btu/hr Total Room 2 Q= 2991.68 Btu/hr BEDROOM #1 Walls Q=0.102*57.6*204 =1198.5 Btu/hr Windows: Q= 460 Btu/hr Roof: Q= 0.14*57.6*120=967.6 Btu/hr Total Room # 1 Q= 2627 Btu/hr TV ROOM: Walls A=344 ft sq Q= 344*0.102*57.6=2021.1Btu/hr Windows: Q=460 Btu/hr Roof: Q=0.14*57.6*186=1500 BTU/hr 10
11. 11. By Group B [CENTRAL STEAM HEATING SYSTEM] Total Q= 3981 BTU/hr TOTAL APT # 1 Q= 9600 BTU/hr 2.3.1.2 APARTMENT # 2 Bedroom 2 For the wall which are exposed to outside environment. Ti= 89.6 F To =32 F U= 1/R (where R is the resistance) Walls: R(brick) per inch R (gypsum) per 5/8 inch R(Cellulose) per inch 0.2 0.45 3 so for wall R= 9.75 ( 9” brick wall) + ( 2.5” cellulose)+(5/8” gypsum) U=0.102 Area = 213 feet sq ∆T= 57.6 F Q= U* ∆ T * A 11
12. 12. By Group B [CENTRAL STEAM HEATING SYSTEM] Q= 0.102*57.6*213 = 1226.88 BTU/hr WINDOWS: A=16 ft sq Double Pane with 1/4" air space R=1.69 width= 0.5” R=1.69 U= 0.5 Q=0.5*57.6*16= 460 BTU/hr For 2 windows Q= 920 BTU/hr ROOF/FLOOR: A=151.2 ft sq R=7.05 U=0.1233 Polyutheren 1” R= 0.80 6.25 4” concrete Q=151.2*57.6*0.14 =1235.3 BTU/hr TOTAL H.L BEDROOM # 2: = 3383.7 BTU/hr Bedroom # 1 WALLS: 12
13. 13. By Group B [CENTRAL STEAM HEATING SYSTEM] A= 229 ft sq R=9.75 U = 0.102 Q = 229 * 0.102 * 57.6 Q= 1345.4 Btu/hr Window: Q= 460 BTU/hr Roof: Q= 1235.3 Btu/hr TOTAL BEDROOM # 1 Q= 3040.7 BTU/hr TV ROOM: Walls: A=104 ft sq Q= 104*57.6*0.102 Q= 611.02 BTU/hr Windows: Q=460 BTU/hr Roof: Q=187.2 * 57.6 * 0.14 Q=1509.5BTU/hr 13
14. 14. By Group B [CENTRAL STEAM HEATING SYSTEM] TOTAL TV ROOM Q= 2580 BTU/hr HALL: Walls: A=60 ft sq R=9.75 U=0.102 Q=350 * 57.6 * 0.102 Q=2056.32 BTU/hr ROOF: A= 143 ft sq Q= 143*57.6 * 0.14 Q= 1153.15 BTU/hr Total Q= 3209.47 BTU/hr TOTAL APT # 2 Q=12213.87 BTU/hr 14
15. 15. By Group B 2.4 Apartment [CENTRAL STEAM HEATING SYSTEM] TABLE Apartment Apartment Apartment Apartment #1 #2 #3 #4 Bedroom #1 (BTU/hr) 2627 3040.7 3040.7 3040.7 Bedroom #2 (BTU/hr) 2991.68 3383.7 3383.7 3383.7 TV Room 3981 2580 2580 2580 3209.47 3209.47 12213.87 12213.87 BTU/hr) Hall (BTU/hr) _ Total 9600 2.5 3209.47 12213.87 ASSUMP TION : The heat losses of Apartment 2 is equal to the heat losses of Apartment 3 and 4 because of the same dimensions of the apartments and it is also assume that the heat loss from the floor of Apartment 2 is equal to the heat loss from the floor of Apartment 3 and 4. 15
16. 16. By Group B 3 [CENTRAL STEAM HEATING SYSTEM] INSULATION Insulation is the reduction of heat transfer (the transfer of thermal energy between objects of differing temperature) between objects in thermal contact or in range of radioactive influence. Reducing the heat load can save energy and cut your running costs. It can also reduce the capital cost of a system. 16
17. 17. By Group B [CENTRAL STEAM HEATING SYSTEM] 3.1 TYPES OF INSULA TION: There are basically four different types of insulation you can use in your home: Blankets of Insulation - Fiberglass and Rockwool Blown In Insulation - Cellulose and Fiberglass Spray Foam Insulation - Open and Closed Cell Foam Board Insulation - EPS, XPS and ISO 3.1.1 INSULA TION USED: The insulation which is used to insulate the walls of the are cellulose and gypsum while in windows, we have use double glazed window which helps to lessen the amount of heat loss, on the other hand, we use polyutheren as insulation which also helps to lower the heat losses. R(brick) per inch 0.2 9 * 0.2 = 1.8 R (gypsum) per 5/8 inch 0.45 R(Cellulose) per inch 3 2.5*3=7.5 17
18. 18. By Group B 4 [CENTRAL STEAM HEATING SYSTEM] BOILER 4.1 WHA T IS BOILER? A boiler is a closed vessel in which water or other fluid is heated. The heated or vaporized fluid exits the boiler for use in various processes or heating applications, including central heating. 4.2 TYPES OF BOLILER Fire tube boilers Watertube boilers Electric boilers etc 4.3 SELECTION OF BOILER We selected fire tube boiler because: 4.3.1 FIRE TUBE BOILER where the hot combustion gases pass down a tube and into subsequent bundles of tubes immersed below water level. The heat from these gases is then transferred to heat the water. Most steam and hot water boilers in the UK are derivatives of the shell type, which are also referred to as ‘fire tube’. 4.3.2 OUR BOILER SPECIFICA TION Specification Vertical Fire Tube Boiler Efficiency Medium Floor Space Required Very Low Maintenance Low Initial Cost Low Pressure Range 15 psi Typical Applications Heating System Temperature Up to 240 F or 100 C power 1.2 ton for APT #1 & 1.5 ton for APT #2, 3, 4 18
19. 19. By Group B 4.3.3 [CENTRAL STEAM HEATING SYSTEM] TYPES OF FUEL USED IN BOILERS There are a wide range of fuels used. Boilers commonly burn standard hydrocarbon fuels, such as natural gas, oil and coal, but some burn tallow or waste materials. Some boilers, known as dual-fuel boilers, can burn gas or oil. This is useful in the rare cases where an interruptible gas supply contract is held. Coal burners can be a variety of designs mainly centring on how the coal is fed to the boiler and burnt. Currently, gas boilers are the most popular type of steamraising or hot-water-producing equipment. So we are using natural gas 4.3.4 BENEFITS ARE:  Natural gas is convenient. The energy source is piped directly to the customer's facility through the safe, efficient pipeline system. There's no need to store oil on site in tanks, or schedule oil deliveries .  There is an abundant supply of domestic natural gas. Over half of the oil used in this country is imported. The price and supply of oil is susceptible to international events .  Natural gas is reliable. The pipeline system can't be easily damaged by weather or affected by weather conditions. In contrast, oil must be trucked to the customer's location, and truck deliveries are susceptible to weather conditions.  Natural gas is the cleanest burning fossil fuel. Because the combustion process for natural gas is almost perfect, very few byproducts are emitted into the atmosphere as pollutants. 4.3.5 COMBUSTION ENERGY  Flame thermal power (thermal load) Mixture composition, gas velocity, heat of combustion of a fuel  Heat of combustion higher heating value (HHV) (or higher calorific value lower heating value (LHV) (or lower calorific value) Fuel HHV MJ/kg LHV MJ/kg Methane Fuel + oxidizer 55.5 50 products + energy Combustion is an exothermic reaction between fuel and oxidizer. 19
20. 20. By Group B 4.4 [CENTRAL STEAM HEATING SYSTEM] BOILER LOSSES AND MEASURES OF EFFICIENCY The operational efficiency of a boiler is measured by the percentage of the fuel input energy that is eventually delivered as useful heat output. Not all of the heat released when the fuel is combusted can be used and some potential heat is never released due to incomplete combustion. Major sources of heat loss from steam boilers are through the flue gas, blow down and radiation to the boiler’s surroundings. See Figure for a diagram of major losses; note that losses in the flue gas are the most significant. Many measures of performance can be used to define efficiency. Two common ones are combustion efficiency and boiler efficiency, the calculations of which are shown in the example. The box, right, shows how efficiencies can be quoted. Bear in mind that figures may be expressed as either gross efficiency or net efficiency, depending on whether the gross or the net calorific value of the fuel is used when calculating the energy content of the fuel. Gross calorific value includes the energy (heat) that is held in the water vapour formed during combustion of the fuel. This energy is not included in the net calorific value of a fuel. 20
21. 21. By Group B 4.4.1 [CENTRAL STEAM HEATING SYSTEM] CALCULA TIONS OF EFFICIENCY –A T A GLANCE Calculations of efficiency – at a glance Combustion efficiency is defined as the percentage of energy in the fuel that is released after combustion within the boiler. Some of the energy contained in the fuel is lost due to incomplete combustion. Combustion efficiency (%) = (Actual energy released during combustion x 100)/Total energy content of the fuel. 4.5 BOILER ACCESSORIES LOW WATER CUT OFF SENSES water level in a steam boiler it will stop burner when water level falls below a safe level. A WATER COLUMN with a gauge glass when mounted on the side of the steam boiler allows the operator to see water level. A PRESSURE GAUGE AND THERMOMETER mounted or near the boiler outlet to check the performance. VENT is use for the exhaust of fuel gases SAFETY RELIEF VALVE : 4.5.1 A Safety Relief Valve opens if boiler pressure is excessive. An automatic system that relieves by static pressure on both gas and liquid 4.5.2 THERMOSTA T:  A Thermostat is a component of a control system which senses the temperature of a system so that the system's temperature is maintained near a desired set point  A room thermostat constantly measures the air temperature of a space and can be set to whatever temperature you like. This prevents your home getting warmer than it needs to be. 21
22. 22. By Group B [CENTRAL STEAM HEATING SYSTEM] When the temperature falls below the setting, it switches on the central heating. Once the room reaches the set temperature, the thermostat switches the heating off. 4.6 4.6.1 CALCULA TION ASSUMTION We assuming that the steam dryness factor x = 0.10 at temperature 115℃ and at 1.71 bar So specific volume v=0.104 The volume of the combustion chamber V=3ft³ or 0.044m³ And the volume of pipes an radiators is 6.9 ft³ When Pipes diameter =2.5 inch So total volume of the system = 0.27m³ Mass of water to be added in system is 2.5 kg 22
23. 23. By Group B 5 5.1.1 [CENTRAL STEAM HEATING SYSTEM] T-S DIAGRAM IN THIS DIAGRAM: Process 1 to 2: water boil and convert in to steam (constant pressure ). Process 2 to 3: steam works and passes through pipes Process 3 to 4 : steam transfer its heat and get condens. (constant pressure ). Process 4 to 1: work done on the system (pump) or gravitational work 23
24. 24. By Group B 6 [CENTRAL STEAM HEATING SYSTEM] PLUMBING 6.1 6.1.1 BASIC STEAM HEATING SYSTEMS ONE-PIPE In a one-pipe, gravity-flow system, each heating unit has a single pipe connection through which it receives steam and releases condensate at the same time. All heating units and the end of the supply main are sufficiently above the boiler water line so that condensate flows back to the boiler by gravity. 6.1.2 TWO-PIPE In a two-pipe system, steam supply to the heating units and condensate return from heating units are through separate pipes. Air accumulation in piping and heating units discharges from the system through the open vent on the condensate pump receiver. Piping and heating units must be installed with proper pitch to provide gravity flow of all condensate to the pump receiver. 6.2 SELECTION OF PIPE We are using one pipe gravity flow system return. And copper tubing Water circulation in a gravity system is achieved by the change in the density of the water as it is heated by the boiler, which is normally situated at the lowest part of system. A column of hot water weighs less than a column of cold water of the same volume and height, and the heated water will therefore rise from the boiler and the colder water will fall back via the pipe work system to the boiler. The addition to the pipe work of radiators and a heating coil within a storage cylinder utilizes the circulating steam to provide heating and domestic steam Copper tubing advantages  Frictional resistance is less than steel resulting in the possibility of smaller pump and less power consumption.  It is not subject to oxidizing and scaling 24
25. 25. By Group B APT # [CENTRAL STEAM HEATING SYSTEM] Length Diameter Volume Ground Floor 95‘ 2.5” 6.83 cubic feet First Floor 105’ 2.5” 6.9 cubic feet 6.3 STEAM MAINS FOR GRAVITY FLOW Correct pitch for horizontal supply mains and dry returns must be 1/4" min. in 10' in the direction of steam and condensate flow. Arrows indicate direction of pipe pitch. 25
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