Lecture 9 HVAC Systems PDF

Building Services (Small Buildings) 221-370-VA – A2024 Roger Bartosh, ing. [email protected] Vanier College Department of Architectural Technology - Building Services (Smal...

Building Services (Small Buildings) 221-370-VA – A2024 Roger Bartosh, ing. [email protected] Vanier College Department of Architectural Technology - Building Services (Small Buildings) - Roger Bartosh 1 LECTURE 9 1. Review Lecture 8 2. Continue with HVAC 3. Assignment 6 Vanier College Department of Architectural Technology - 2 Building Services (Small Buildings) - Roger Bartosh HVAC Basics Heating Ventilation Air Conditioning Vanier College Department of Architectural Technology - 3 Building Services (Small Buildings) - Roger Bartosh Heating Heat is a form of energy that is transferred between objects of different temperature, flowing from high temperature to low Heat is measured in BTU (British Thermal Units), Calories, or Joules BTU = The amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit Calorie = The amount of heat required to raise the temperature of of 1 gram of water by one degree Celsius Joule = The amount of energy required to move one Newton a distance of one metre (Force x Distance) Vanier College Department of Architectural Technology - 4 Building Services (Small Buildings) - Roger Bartosh Question??? What is the difference between heat and temperature? Vanier College Department of Architectural Technology - 5 Building Services (Small Buildings) - Roger Bartosh Answer Heat is the transfer of thermal energy between molecules within a system. Heat measures how much energy moves or flows, whereas Temperature indicates the average kinetic energy of molecules within a material or system. Temperature is an indication of the existing thermal energy and Heat is the energy required to increase the temperature. Vanier College Department of Architectural Technology - 6 Building Services (Small Buildings) - Roger Bartosh Heating 1 Calorie = 4.2 Joules 1 BTU = 1,055 Joules = 252 Calories The ability to deliver heat is measured in heat per unit time One ton = approx. 12,000 (11,917) BTU/hr The term “ton” was originally based on the amount of heat required to melt one ton (2,000 lbs.) of ice in 24 hours Important: A four ton furnace, or a four ton air conditioner does not weight four tons! It is the amount of heat they can generate in one hour! Vanier College Department of Architectural Technology - 7 Building Services (Small Buildings) - Roger Bartosh Heating Vanier College Department of Architectural Technology - 8 Building Services (Small Buildings) - Roger Bartosh Heating Systems Central Furnace + ducts (forced air) In-floor radiant heating (glycol closed-loop with heat exchanger + pump) Circulated steam or hot water (geothermal or boiler + radiators) Non-central Electric baseboards or space heaters Electric in-floor heating cables Vanier College Department of Architectural Technology - 9 Building Services (Small Buildings) - Roger Bartosh Furnace and Ducts Vanier College Department of Architectural Technology - 10 Building Services (Small Buildings) - Roger Bartosh Gas Furnace Electric Furnace Vanier College Department of Architectural Technology - 11 Building Services (Small Buildings) - Roger Bartosh In-floor Radiant Heating Vanier College Department of Architectural Technology - 12 Building Services (Small Buildings) - Roger Bartosh Steam Vanier College Department of Architectural Technology - 13 Building Services (Small Buildings) - Roger Bartosh Electric Baseboard Vanier College Department of Architectural Technology - 14 Building Services (Small Buildings) - Roger Bartosh Electric In-floor Vanier College Department of Architectural Technology - 15 Building Services (Small Buildings) - Roger Bartosh Ventilation Ventilation is the provision of fresh air Ventilation is the mechanical system in a building that brings in fresh outdoor air and removes the contaminated indoor air In a residential home, ventilation can be provided as part of the heating or air conditioning system, or by natural means. Vanier College Department of Architectural Technology - 16 Building Services (Small Buildings) - Roger Bartosh Ventilation Vanier College Department of Architectural Technology - 17 Building Services (Small Buildings) - Roger Bartosh Ventilation Vanier College Department of Architectural Technology - 18 Building Services (Small Buildings) - Roger Bartosh Air Conditioning Heat is a form of energy that is transferred between objects of different temperature, flowing from high temperature to low Cold is not an entity, it is the absence or removal of heat Thermodynamics is the branch of physics that deals with the relationships between heat and other forms of energy Vanier College Department of Architectural Technology - 19 Building Services (Small Buildings) - Roger Bartosh Air Conditioning – Refrigeration Cycle Vanier College Department of Architectural Technology - 20 Building Services (Small Buildings) - Roger Bartosh Air Conditioning – Refrigeration Cycle Note that the refrigeration cycle also produces heat, therefore, the reverse process of Air Conditioning can be used to heat – this is a Heat Pump All Air conditioners produce heat which must be evacuated in a suitable location, usually outdoors, or in the case of a refrigerator, into a large space so that the ambient air temperature is not noticeably effected. Most residential air conditioning systems are either Packaged units, Split Systems, or Heat Pump Systems Vanier College Department of Architectural Technology - 21 Building Services (Small Buildings) - Roger Bartosh Air Conditioning – Packaged Unit Vanier College Department of Architectural Technology - 22 Building Services (Small Buildings) - Roger Bartosh Packaged Units (Commercial): 3-5 Ton Vanier College Department of Architectural Technology - 23 Building Services (Small Buildings) - Roger Bartosh Air Conditioning – Split System Also known as a “ductless” system Vanier College Department of Architectural Technology - 24 Building Services (Small Buildings) - Roger Bartosh Split System – Added After Original Construction Vanier College Department of Architectural Technology - 25 Building Services (Small Buildings) - Roger Bartosh Air Conditioning – Heat Pump System Vanier College Department of Architectural Technology - 26 Building Services (Small Buildings) - Roger Bartosh Air Conditioning – Window Unit Vanier College Department of Architectural Technology - 27 Building Services (Small Buildings) - Roger Bartosh Air Conditioning – Window Unit Vanier College Department of Architectural Technology - 28 Building Services (Small Buildings) - Roger Bartosh HVAC - General Notes A Central system with ducts (forced air) is usually preferable because: It will heat the home quicker than a radiant system Air Conditioning can be easily combined with the heating system Air is filtered Air can be humidified or dehumidified from central loacation Compatible with smart thermostats Generally more efficient = lower energy bills Overall comfort Adds value to home Vanier College Department of Architectural Technology - 29 Building Services (Small Buildings) - Roger Bartosh HVAC - General Notes Non-central system may have lower up-front cost Non- central is often easy to Install – no ductwork Non-central may be convenient for a renovation project, or to supplement existing system In the Montreal area, the generally preferred system for new house construction is an electric-powered forced air furnace and heat pump The heat pump can cool during the summer and heat during the winter The furnace will usually have to supplement heating when the temperature gets below -15 degrees Celsius Vanier College Department of Architectural Technology - 30 Building Services (Small Buildings) - Roger Bartosh  Play News Video regarding Heat Pumps Vanier College Department of Architectural Technology - 31 Building Services (Small Buildings) - Roger Bartosh Lecture 9 – New Stuff Vanier College Department of Architectural Technology - 32 Building Services (Small Buildings) - Roger Bartosh Heat Content of Fuel Heat Content is the theoretical maximum amount of heat that can be delivered by a unit of fuel Vanier College Department of Architectural Technology - 33 Building Services (Small Buildings) - Roger Bartosh  U.S. Home Heating Residential Fuel Prices 2021 Fuel Type Recent Price (USD) Units Source & comments as of 2020 Natural gas prices 10.84 K CuFt U.S. E.I.A. 49% of homes use natural gas Cost of Fuel No. 2 home heating oil $2.86 US Gallon as of 09/21/2021 U.S. E.I.A. 6% of homes use NO. 2 oil 10/22/2021 price was $3.372 as of 03/29/2021 U.S. E.I.A. 6% of homes LPG/Propane Price $2.295 US Gallon use propane Propane gas prices vary considerably by U.S. State as of 2015 Electricity prices $0.1246 (12.46 cents) KWH U.S. E.I.A. 4% of homes heat with electricity as of Feb 5 2015. Web survey of vendors Firewood price $230 Full Cord 2% of U.S. homes heat primarily by wood 1% of homes use other heating methods like those below as of 5 Feb 2015. Walmart Price Pellet Fuel $5.22 40 Lb Bag U.S. Tractor Supply price: $5.29 2015 U.S. E.I.A., Coal prices range by area and coal type, including coal SO2 levels. Coal $53. -> $11.55 Ton BTUs per ton also varied from 12.5K BTU/pound to 8.8K BTU/pound where prices roughly also track BTU differences. Vanier College Department of Architectural Technology - 34 Building Services (Small Buildings) - Roger Bartosh Heating Equipment Efficiency The efficiency of a heating unit is the actual amount of heat delivered compared to the Heat Content of the consumed fuel A furnace with 70% Efficiency delivers 70 units of heat for every 100 units of heat available in the fuel The efficiency is a function of the equipment, not the fuel A furnace with a higher efficiency rating has a higher initial cost Actual Fuel Cost = Fuel Consumed Efficiency Vanier College Department of Architectural Technology - 35 Building Services (Small Buildings) - Roger Bartosh Heating Equipment Efficiency Vanier College Department of Architectural Technology - 36 Building Services (Small Buildings) - Roger Bartosh Conventional Gas Furnace High-Efficiency Gas Furnace Vanier College Department of Architectural Technology - 37 Building Services (Small Buildings) - Roger Bartosh Humidifiers Vanier College Department of Architectural Technology - 38 Building Services (Small Buildings) - Roger Bartosh Vanier College Department of Architectural Technology - 39 Building Services (Small Buildings) - Roger Bartosh  HRVs and ERVs Heat Recovery Ventilators Energy Recovery Ventilators Vanier College Department of Architectural Technology - 40 Building Services (Small Buildings) - Roger Bartosh HVAC System Design Considerations The following applies to a central forced air system: A well-designed system should deliver maximum interior comfort at the lowest cost while also preserving indoor air quality It should convey specified rates of air flow to prescribed locations It should be economical in combined initial cost and operating cost It should not transmit or generate objectionable noise. Vanier College Department of Architectural Technology - 41 Building Services (Small Buildings) - Roger Bartosh HVAC System Design Considerations Geographic Location? Building Construction Information, such as R-value Size and types of rooms, number of levels (layout) Vanier College Department of Architectural Technology - 42 Building Services (Small Buildings) - Roger Bartosh HVAC System Design Considerations Vanier College Department of Architectural Technology - 43 Building Services (Small Buildings) - Roger Bartosh HVAC System Design Considerations Air Flow must be circular: allowing supply air to circulate in the intended space before being returned the AHU (Air Handling Unit). Return grilles should NOT be located next to supply registers. Vanier College Department of Architectural Technology - 44 Building Services (Small Buildings) - Roger Bartosh HVAC System Design Considerations Air Flow Principles: Flow of air is caused as a result of pressure differential between two points. Flow will originate from an area of high energy (or pressure) and proceed to area(s) of lower energy. Vanier College Department of Architectural Technology - 45 Building Services (Small Buildings) - Roger Bartosh HVAC System Design Considerations cfm: volume of air flow; cubic feet/minute fpm: velocity or speed of air flow; feet/minute sq.ft: duct size or cross-sectional area; square feet Given any two of these three quantities, the third can be readily determined: Vanier College Department of Architectural Technology - 46 Building Services (Small Buildings) - Roger Bartosh HVAC System Design Considerations cfm = fpm x Area fpm = cfm/area Area = cfm/fpm A smaller duct can deliver the same volume of air as a larger duct, but the air velocity will be higher. High velocity = Noise. Low velocity = large ducts ($$$). Vanier College Department of Architectural Technology - 47 Building Services (Small Buildings) - Roger Bartosh HVAC System Design Considerations Once the overall system requirements have been calculated, a distribution system must be designed Vanier College Department of Architectural Technology - 48 Building Services (Small Buildings) - Roger Bartosh Vanier College Department of Architectural Technology - 49 Building Services (Small Buildings) - Roger Bartosh HVAC System Design Considerations Once the overall system requirements have been calculated, a distribution system must be designed Vanier College Department of Architectural Technology - 50 Building Services (Small Buildings) - Roger Bartosh HVAC Distribution System The air distribution system will have a designation depending on the function of the duct. Broadly, there are five designations of ducts: 1. Supply air ductwork Main Consideration for most Home Applications 2. Return air ductwork 3. Fresh air ductwork 4. Exhaust (relief) air 5. Mixed air ductwork mixes air from the outdoor air and the return air then supplies this mixed air to the air handling unit. Vanier College Department of Architectural Technology - 51 Building Services (Small Buildings) - Roger Bartosh HVAC Distribution System Plenum or Main Trunk: The plenum is the main part of the supply and return duct system that goes directly from the air handler to the “Trunk Duct”. Trunk Duct: A duct that is split into more than one duct is called a “trunk”, just like a tree. Ducts that are on the end of a trunk and terminate in a register are called branches. Take Off: Branch ducts are fastened to the main trunk by a takeoff- fitting. The takeoff encourages the air moving the duct to enter the takeoff to the branch duct. Air Terminals Devices: Air terminals are the supply air outlets and return or exhaust air inlets. For supply, diffusers and registers are most common. Grilles are usually for return air and do not have a damper. Vanier College Department of Architectural Technology - 52 Building Services (Small Buildings) - Roger Bartosh HVAC Distribution System Vanier College Department of Architectural Technology - 53 Building Services (Small Buildings) - Roger Bartosh Zones Vanier College Department of Architectural Technology - 54 Building Services (Small Buildings) - Roger Bartosh Vanier College Department of Architectural Technology - 55 Building Services (Small Buildings) - Roger Bartosh HVAC Distribution System Diffusers are the terminal devices that supply air in various directions through the use of their deflecting vanes. Vanier College Department of Architectural Technology - 56 Building Services (Small Buildings) - Roger Bartosh HVAC Distribution System Registers look like grilles but are comprised of one-way or two- way adjustable air stream deflectors and dampers to restrict the amount of air flow required to be returned, supplied or exhausted. Vanier College Department of Architectural Technology - 57 Building Services (Small Buildings) - Roger Bartosh HVAC Distribution System Grilles are defined as air devices that are typically used to return air back to the fan or to exhaust air from a space. Grilles are generally not used in supply distribution due to their inability to control the air. Vanier College Department of Architectural Technology - 58 Building Services (Small Buildings) - Roger Bartosh Metal Duct Materials 1. Galvanized Steel: This is the standard, most common material used in fabricating ductwork 2. Aluminium: Used in clean room applications. These are also preferred systems for moisture laden air, special exhaust systems and ornamental duct systems. 3. Stainless Steel: Used in duct systems for commercial kitchen exhaust, moisture laden air, and fume exhaust. 4. Carbon Steel (Black Iron): It is widely used in applications involving flues, stacks, hoods, other high temperature and special coating requirements for industrial use. 5. Copper: It is mainly used for certain chemical exhaust and ornamental ductwork. Vanier College Department of Architectural Technology - 59 Building Services (Small Buildings) - Roger Bartosh  Non-Metal Duct Materials 1. Flex Duct: Flex ducts are very common and consist of a duct inner liner supported on the inside by a helix wire coil and covered by blanket insulation with a flexible vapor barrier jacket on the outside. Flex ducts are often used for runouts, as well as with metal collars used to connect the flexible ducts to supply plenums, trunks and branches constructed from sheet metal or duct board. Flex ducts provide convenience of installation as these can be easily adapted to avoid clashes but has certain disadvantages. These have more friction loss inside them than metal ducting. Flex duct runs should be as short as possible (5 to 6 ft. max.) and should be stretched as tight as possible. 2. Polyvinyl Chloride (PVC): Used for exhaust systems for chemical fumes and underground duct systems. Advantages include resistance to corrosion, light weight, and ease of modification. Limiting characteristics include cost, fabrication, code acceptance, thermal shock, and weight. 3. Fabric: Fabric ducting, also known as textile ducts, is usually made of special permeable polyester material and is normally used where even air distribution is essential 4. Fibreglass Reinforced Plastic (FRP): It is used mainly for chemical exhaust, scrubbers, and underground duct systems. Advantages are resistance to corrosion, self-insulation, excellent sound attenuation and high quality sealing. Limiting characteristics include cost, weight, range of chemical and physical properties, and code acceptance. Vanier College Department of Architectural Technology - 60 Building Services (Small Buildings) - Roger Bartosh Flex Duct Vanier College Department of Architectural Technology - 61 Building Services (Small Buildings) - Roger Bartosh Non-Metal Duct Materials The main drawback of this type of ducting is its fire classification. Even if it complies with local standards, when exposed to fire, since it is combustible, it will propagate the fire. Vanier College Department of Architectural Technology - 62 Building Services (Small Buildings) - Roger Bartosh HVAC Distribution System Much like friction loss in supply plumbing, there is also a loss in ductwork, dependant on the shape and the inner surface of the duct work Round metal ducts will have less loss than flex ducts The length of the ductwork, and the number and type of connections will increase the friction loss Vanier College Department of Architectural Technology - 63 Building Services (Small Buildings) - Roger Bartosh HVAC Distribution System Vanier College Department of Architectural Technology - 64 Building Services (Small Buildings) - Roger Bartosh HVAC Distribution System Vanier College Department of Architectural Technology - 65 Building Services (Small Buildings) - Roger Bartosh HVAC Distribution System Vanier College Department of Architectural Technology - 66 Building Services (Small Buildings) - Roger Bartosh Duct Shape Most practical to hide between Most Efficient Compromise joists and inside walls Vanier College Department of Architectural Technology - 67 Building Services (Small Buildings) - Roger Bartosh Supply Ductwork Systems Vanier College Department of Architectural Technology - 68 Building Services (Small Buildings) - Roger Bartosh Supply Ductwork Systems Vanier College Department of Architectural Technology - 69 Building Services (Small Buildings) - Roger Bartosh Supply Ductwork Systems Reduced Trunk System Vanier College Department of Architectural Technology - 70 Building Services (Small Buildings) - Roger Bartosh Supply Ductwork Systems Vanier College Department of Architectural Technology - 71 Building Services (Small Buildings) - Roger Bartosh Supply Ductwork Systems Vanier College Department of Architectural Technology - 72 Building Services (Small Buildings) - Roger Bartosh Supply Ductwork Systems Vanier College Department of Architectural Technology - 73 Building Services (Small Buildings) - Roger Bartosh Return Ductwork Systems Return systems pull the air out of the rooms back to the AHU The return must be balanced with the supply to maintain neutral pressure Therefore, an adequate number of properly placed return grilles and ducts are required Return duct systems are generally Distributed Return, or Central Return Vanier College Department of Architectural Technology - 74 Building Services (Small Buildings) - Roger Bartosh Return Ductwork Systems In a distributed return, each room has a return duct that provides a pathway for air to flow back to the air handler. The scheme ensures that the air flow is returned from all rooms, avoids too much positive pressurization, minimizes pressure imbalances, improves privacy, and is quiet. However, design and installation costs are generally higher than for a central return system, and higher friction losses can increase blower requirements. Vanier College Department of Architectural Technology - 75 Building Services (Small Buildings) - Roger Bartosh Return Ductwork Systems In a central return duct system, return grilles are located in central locations on the common plenum, usually close to the air handler. To ensure proper air flow from all rooms, especially when doors are closed, transfer grilles or jumper ducts must be installed in each room. Vanier College Department of Architectural Technology - 76 Building Services (Small Buildings) - Roger Bartosh Return Ductwork Systems 1. Transfer Grilles: They allow air to move from one space to another to alleviate pressure differences. For example, a transfer grille installed above a bedroom door enables air to move between the bedroom and the hallway, regardless of whether the door is open or closed 2. Jump ducts: Are short ducts that connect adjacent rooms and help balance air flow between rooms in cases where there’s one shared return grille serving the whole floor Vanier College Department of Architectural Technology - 77 Building Services (Small Buildings) - Roger Bartosh Return Ductwork Systems Vanier College Department of Architectural Technology - 78 Building Services (Small Buildings) - Roger Bartosh Return Ductwork Systems Vanier College Department of Architectural Technology - 79 Building Services (Small Buildings) - Roger Bartosh Dampers Dampers are used to control air flow. They may be required to fully shut off air flow or regulate flow. Two main types are in use: parallel blades where the blades rotate in one direction, or opposed blades where the adjacent blades rotate in opposite directions A fire damper is a device installed in ducts and air transfer openings to interrupt the passage of flame and maintain the integrity of the fire rated separation. Fire dampers are equipped with a fusible link (rated for 165°F up to 286°F) that holds the blades open until it the link melts. Upon reaching the melting point, the blades then close and stop the flame from moving into an adjoining compartment. Vanier College Department of Architectural Technology - 80 Building Services (Small Buildings) - Roger Bartosh Dampers Air Flow Vanier College Department of Architectural Technology - 81 Building Services (Small Buildings) - Roger Bartosh Standard Duct Sizes (General Example) Air Flow Duct Diameter Duct Size (1) Duct Size (2) Tonnage 50 cfm 4” round 3” x 4” 2” x 6” 100 cfm 6” round 5” x 6” 4” x 8” 200 cfm 8” round 6” x 8” 4” x 12” ½ ton 300 cfm 9” round 10” x 7” 5” x 14” ¾ ton 400 cfm 10” round 8” x 10” 6” x 14” 1 ton 600 cfm 12” round 10” x 12” 8” x 14” 1½ tons 800 cfm 13” round 10” x 14” 8” x 18” 2 tons 1000 cfm 14” round 10” x 16” 12” x 14” 2½ tons 1200 cfm 16” round 10” x 20” 12” x 16” 3 tons Vanier College Department of Architectural Technology - 82 Building Services (Small Buildings) - Roger Bartosh Energy Conservation Typical duct systems lose 25 to 40 percent of the heating or cooling energy Some friction loss is unavoidable Insulation can be applied to ductwork to minimize the rate of thermal loss through the thin sheet metal Faulty duct systems lose additional energy in two ways: heat transfer through the duct walls air leakage through accidental holes or through open spaces between poorly connected sections of ductwork Vanier College Department of Architectural Technology - 83 Building Services (Small Buildings) - Roger Bartosh System Noise 1. Duct borne noise: Caused by the flow of air and directly dependent on the velocity of air. 2. Radiated equipment noise: Caused by vibration of equipment and inherent sound pressure of the equipment. Can be either direct from the equipment or propagated along the ductwork. Vanier College Department of Architectural Technology - 84 Building Services (Small Buildings) - Roger Bartosh Vanier College Department of Architectural Technology - 85 Building Services (Small Buildings) - Roger Bartosh Typical Duct Fittings and Transitions Vanier College Department of Architectural Technology - 86 Building Services (Small Buildings) - Roger Bartosh Vanier College Department of Architectural Technology - 87 Building Services (Small Buildings) - Roger Bartosh  Assignment 6 Submit via Omnivox - Lea in pdf format (all other formats will not be accepted) and hand in a paper copy before the start of next class. Late submissions will not be accepted (mark = 0). Create a provisional but comprehensive list of plumbing and electrical requirements for your Project 1 building, including but not limited to: 1. location and brief description of building (assume city water supply, sanitary, storm, and Hydro are available); 2. Provide a list of rooms by building level (basement, ground floor, etc.); 3. Using the above list of rooms, define the type and or quantity of the following: a. All plumbing fixtures (toilets, sinks, bathtubs, showers, etc.), appliances, etc.; b. Lighting (number and type of fixtures); c. Other requirements (garage, swimming pool, Utility shed, lawn sprinklers, spa, etc.). 4. Consider future requirements, for example, the basement. The list should be organized into a table and occupy at least one full page. Ensure that your submission is clear and legible, or you will lose marks. Rectify any problems from previous assignments. Always check plot. Make sure to add your name, Assignment number, course name and number, section number, and date. Vanier College Department of Architectural Technology - 88 Building Services (Small Buildings) - Roger Bartosh Assignment 6 Sample Vanier College Department of Architectural Technology - 89 Building Services (Small Buildings) - Roger Bartosh Homework: Review Today’s Lecture Notes Assignment 6 Vanier College Department of Architectural Technology - 90 Building Services (Small Buildings) - Roger Bartosh