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Office spaces shall have maximum lighting power

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Unformatted text preview: ents using a “componentbased” approach. For example: • Exterior walls shall have a minimum thermal resistance of R-15. • Office spaces shall have maximum lighting power density of 10 W/m2. • Washroom faucets in public building shall have automatic shut-off (e.g. to conserve hot water). Note: The above are only examples of the types of requirements. (The actual requirements for each component are listed within the code/standard.) Aside: Code requirements are typically based on cost-effective good-practice for “typical” building conditions. However, for some specialized building types, application of the code requirements may not be suitable/practical. (End of Aside.) Both codes used two basic types of requirements: “Mandatory Requirements” • A minimum level of performance that must be met by all designs. “Prescriptive Requirements” • Define a “reference level” of performance. • Comply either by meeting each individual prescriptive requirement, or by demonstrating the design will not use more energy than a design that did meet each individual prescriptive requirement. • Provides some flexibility in design (“trade-offs”). STRUCTURE OF MNECB 1997 Mandatory Provisions Building Envelope Lighting Service Water Htg HVAC Prescriptive Path Electrical & Power Performance Path Building Envelope Trade-Offs Trade-Offs Prescriptive (simple) (computer) Building Energy Performance (Simulation) Lighting HVAC NO Service Water Heating REDESIGN Compliance? YES Example of Application of Mandatory and Prescriptive Code Provisions: Imagine an extremely simple building where applicable code provisions are only as follows: Mandatory Provisions 1. Maximum allowable flow-rate of shower-heads is 9.0 L/min. Prescriptive Provisions 1. Maximum thermal transmittance (U-value) of exterior walls = 0.38 W/m2-°C. 2. Minimum efficiency of furnace = 85%. outdoors flue Furnace Heated Space fuel heat loss through exterior wall with thermal transmittance = heat input from heating device with efficiency = Mandatory Provisions… Shower-head flowrate must be 9.0 L/min or less. (Cannot “trade-off” versus other provisions.) Any design with showerhead flowrate higher than 9.0 L/min would not comply—no matter how “efficient” the other components of the building were made. Prescriptive Provisions… Characteristic Design A Design B Design C Design D Wall U-value (W/m2-°C) 0.38 0.30 0.30 0.50 Furnace Efficiency 85% 85% 80% 95% Complies? Yes. Yes. ? ? Prescriptive Performance Path (simulation) Performance Path (simulation) Compliance Method? Prescriptive “Reference Design” Compare to performance of “Reference Design” (i.e. design that exactly meets prescriptive provisions) Sample Requirements from MNECB 1997: BUILDING ENVELOPE Mandatory Requirement: Vestibules are required at exterior doors. (Some doors are exempted from this requirement—as described in the Code). Prescriptive Requirement: Maximum Overall Thermal Transmittance (U-value), W/m2-°C “Ontario Region A” (Southern Ontario) Component Above Ground Walls Heating Source Electricity Natural Gas 0.330 0.550 Sample Requirements from MNECB 1997: LIGHTING Mandatory Requirement: Exterior lights shall be controlled by a lighting schedule controller (timer) or by a photocell (daylight sensor). Prescriptive Requirement: Maximum Allowable Lighting Power Density (W/m2) by Space-Type Space Type LPD (W/m2) Laboratory 24.8 Classrooms 21.5 Gymnasium 10.8 Jail Cell 8.6 Sample Requirements from MNECB 1997: HVAC Mandatory Requirement: Systems shall have controls capable of reducing energy use through temperature set-back or equipment shut-down during periods of non-use (with some exceptions). Prescriptive Requirement: HVAC systems shall utilize outside-air economizers (with some exceptions). Sample Requirements from MNECB 1997: SERVICE WATER HEATING Mandatory Requirement: Faucets in public access washroom shall have a device capable of automatically shutting off the flow of water when the faucet is not in use (e.g. motion sensor or spring-return valve). ELECTRICAL POWER Mandatory Requirement: Electrical transformers shall conform to CAN/CSA-C802 “Maximum Losses for Distribution, Power, and Dry-Type Transfomers” where the installed transformer falls within the scope of the standard. (CAN/CSA-C802 includes minimum requirements for transformer efficiency.) Typical Procedures for “Performance Compliance Analysis” • Usually hour-by-hour simulations are performed to compare performance of “proposed design” vs the code “reference design” (i.e. prescriptive design) • In general, any characteristics not covered by Prescriptive Requirements are treated identically – – – – Size and use of building Operating schedules (occupants, lighting, plug loads, etc) Minimum fresh air rates (ventilation) Area and orientation of exterior envelope components (with some exceptions) For Example: “EE4” Software • Hour-by-hour simulation tool intended comparing “Proposed Design” to MNECB for • Simulator describes characteristics of the “Proposed Design” – Software performs simulation of the “Proposed Design” – Software automatically creates a second simulation file – the “Reference Design” simulation, which is identical to the proposed design, except that it uses the relevant pre...
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