Hydronics Boiler types Flashcards
- What is a boiler, how does it use combustion and conduction and what is it used for?
- What is Latent Heat
- What is Sensible heat?
- Boiler: a container for heating liquids, that is used to heat buildings
Boilers use combustion to heat the container which inturn heats the water through Conduction (this is called sensible heat)
Hot water is moved from the boiler to heat emission units - Latent Heat: Heat the is transferred without changing the temperature of the boiler water
- Sensible Heat: When a boiler heats water through a heat exchanger, the heat is transferred as Sensible Heat
2 types of boilers:
Low Temp:
- Max temp _____
- Max PSI in a non cast iron boiler?
- Max PSI in a Cast iron boiler?
- Rated in either ____ or ____
- Usually ____ Rated
High Temp:
- Over what temp?
- Rater in either ____ or _____
- Usually _____ Rated
Low Temp:
- Max 120C/250F
- 160 psig
- 30 psig
- BTU/h or EDR
- Net Rated
High Temp:
- over 120C/250F
- MBH or BHP
- Gross Rated
- Input: BTUs are used to size what? and identify what capacity?
- Gross Rating: is the amount of BTU loss from what?
- Net Rating: is the loss of BTUs from what part of the boiler system? how much loss does this usually account for (as a percent of Gross Rating)?
- Input = _______ + _____________ + __________
- Input: BTUs used to size gas piping and to identify boiler capability, (Burner)
- Gross Rating: The Available BTU (sometimes EDR) after efficiency percentage loss are removed from the input of the boiler (Boiler Loss)
- Net Rating: Once we have the gross output of the boiler, losses must now be considered due to piping and other heat losses. Insulating pipe will help to reduce these losses
- The difference between Gross output and Net rating is often called “Piping and Pick-up” this loss number is often a factor of 1.15, but we will be using Net Rating to be 75% of the gross output rating
- Input = net rate + piping and pick up losses + boiler losses
Boiler Ratings:
- Boiler Rating: Amount of _________ on a ______ ______ that comes in contact with a product of _______
- What does a Heat Exchanger do?
- EDR: Is equivalent to the amount of heat given off by one square foot of a ______ _____ ________.
- Boiler Rating: Amount of square feet on a heat exchanger that comes in contact with a product of combustion
- Heat exchanger: a device that exchanges heat from the product of combustion in a boiler to the water
- EDR: Is equivalent to the amount of heat given off by one square foot of a cast iron radiator.
High Mass Boilers:
- What 2 types of boilers a high mass boilers?
- Advantages (list 4)
- Disadvantages (List 3)
High Mass Boiler
- Cast iron and fire tube boilers are high mass boilers
Advantages:
- Large quantity of water
- stable supply of water temperature to system
- Works well with modern controls (that monitor outside temps)
- Not very susceptible to thermal shock
Disadvantages:
- Slow recovery rate
- Risk of explosion if all safety functions fail
- Have a long heat up time (pick up load)
Low Mass Boilers:
- What 2 types of boilers are low mass boilers?
- At what point bust a Low Mass Boiler have a Flow switch? (BTU/h)
- Is it good practice to put a flow switch on all low mass boilers?
- how much space needs to be one either side of a flow switch?
- Advantages: (List 5)
- Disadvantages: (List 5)
Low Mass Boiler
- Copper tube and steel finned boilers are low mass boilers
- A.S.M.E requires all low mass boilers over 400 MBH (400,000 BTU/hr) to include a flow switch (Switch).
- However it is good practice to install one on all low mass boilers.
- Flow Switches require 5 pipe diameters of straight pipe on either side
Advantages:
- Can be used for Domestic hot water heating (drinking water)
- Heat up time is not a factor (Pick up load)
- Quick recovery rate
- Much higher velocity moving through boiler
- High velocity helps to keep boiler clean
Disadvantages:
- Small volume of water
- Build ups on heat exchanger can affect efficiency
- No flow or low flow can damage boiler
- Must be installed with a flow switch (so power will be cut off to burner when flow is to low
- Low flow would cause water to be heated to much and turn to steam which would damage boiler
What are the 3 energy sources that boilers can use?
Natural Gas, Electricity and Oil
Types of Boilers Part 1 (Material):
Cast Iron:
- Is a ____ Mass Boiler
- Describe the inner workings? (Physical attributes, How its connected and how flow moves through it)
- Naturally _____ Resistant
- Originally used in _____ Heating Systems
Cast Iron:
- High Mass Boiler
- Sections of hole cast iron plates are bolted together with tie rod
- Sections are connected together by cast iron push nipples or composition sealing rings (Gaskets)
- The water then flows between the sections
- It is naturally corrosion resistant (long life span)
- Very dense, Heavy and brittle material
Originally used in gravity heating systems (conventional flow)
Types of Boilers Part 2 (Material):
Steel:
- Used in Either ____ Tube or ____ Tube Boilers
- Describe the relationship between the product of combustion in a water tube boiler and in a Fire Tube Boiler
- Fire Tube boilers can be both vertical and horizontal Configuration, True or False?
Steel
- Used in either Water Tube or Fire tube boilers
- Water tube: water moves through a boiler in steel tubes. Product of combustion moves past the stubs exchanging heat
- Fire Tube: Product of combustion moves through steel tubes and water moves past the outside of the tubes picking up the heat
- Fire tube boilers can be of vertical or horizontal configuration
Types of Boilers Part 3 (Material):
Copper Tube:
- Only available as _____ Tube Boilers
- When used for domestic how water what materials must the pump, nipples and distribution lines be made of?
- What are the advantages of a Copper tube boiler in a domestic situation? (list 2)
- Is the water ever aloud to become still when the boiler is on?
- _____ is conducted very rapidly though a copper tube boiler
Copper Tube
- Available as water tube boilers only
- Copper tube heat exchangers may consist of coild, finned, or smooth copper tube or may be finned copper tube installed between headers, similar to a steel water tube boiler
- Copper Tube boilers may be used to heat domestic hot water lines: bronze pumps, brass nipples, and copper distribution lines are used as domestic hot water heaters
- Domestic types are used for there quick recovery time, and high capacity were required.
- Must have a constant flow of water
- Heat is conducted very rapidly though a copper tube boiler
Types of Boilers Part 4 (Material):
Stainless Steel:
- Used in _____ Boilers
- is ________ Resistant
Stainless steel
- A material of choice for condensing boilers
- Is corrosion resistant (very important for condensing boilers)
Types of Boilers Part 1 (Function):
Cast Iron Sectional Boiler:
- Is High or low Mass?
- How does it work? (Water flow, Combustion, and resalts)
- What configurations does it come as?
- What is the minimum size of a boiler drain?
Cast Iron Sectional Boiler:
- Is a High mass Boiler
- Water flows freely though cast iron sections, Burner fires, product of combustion rises and heats the water through convection, Product of combustion continuous up and exits through draft hood
Can be in two arrangements:
- Horizontal: Called “pancake Boilers” and can be expanded upon by adding more layers
Vertical:
A.S.M.E boiler drain min. Size = ¾” on boiler
Types of Boilers Part 2 (Function):
Fire Tube Boiler:
- High or Low Mass?
- How Does it work?
Fire Tube Boiler:
- Is a high mass boiler
- Product of Combustion flows through the tubes
- The tubes are surrounded by water which gets heated from conduction
Types of Boilers Part 3 Function):
Water Tube Boiler:
- High or low mass?
- How does it work?
Water Tube Boiler:
- Are Low mass Boilers
- Product of combustion flows around tubes filled with water
Types of Boilers Part 4 (Function):
Condensing Boilers:
- How efficient are they?
- What emissions do they reduce? (Name 2)
- What Material must be used for the heat exchanger and why?
- is it able to operate with a very low return tempiture
- What must be used to take out the gasses produced and why?
Condensing Boilers:
- Highly efficient up to 93% effective
- Reduces carbon dioxide and nitrous oxide emissions
- The water that condenses as a result of the combustion is acidic so SS heat exchangers must be used
- Can operate with very low return temperatures to boiler
- Gasses must be removed via a fan as temps are too low for them to exit via draft hood
