40 Questions
According to the text, how often should climatic data be measured for energy model calculations?
Every hour
What is the ratio of ground reflectance with and without snow cover?
30% without snow cover and 70% with snow cover
In the energy model calculations, which building envelope assemblies and components need to be addressed?
All of the above
For locations with multiple climatic data sets, what should be used for energy model calculations?
The data set that best represents the climate at the building site
What should the energy model calculations account for in terms of heat transfer?
Heat transfer through various building envelope assemblies and components
Which of the following values is used for the solar heat gain coefficient of fenestration?
0.26
What is the value for the thermal mass?
0.06
What is the value for the solar absorptance of the exterior walls, roofs, and exposed floors?
0.4
What is the value for the airtightness in terms of air changes per hour at 50 Pa pressure differential?
2.5
How should the effective thermal resistance and overall thermal transmittance values be determined for the energy model calculations of the reference house?
By using Table 9.36.2.6.-A for walls, ceilings below attics
Which of the following is true about the energy model calculations for service water heating use in residential buildings?
The calculations shall take into account the hourly draws on service water heating presented in Table 9.36.5.8.
Which of the following is NOT required for the energy model calculations of a proposed house?
Consistency with proposed construction specifications for solar heat gain coefficient and overall thermal transmittance of fenestration.
What is the default value for thermal mass in the energy model calculations for a proposed house?
A default value of 0.060 MJ/m2·°C.
What is the required solar absorptance for exterior walls, roofs, and exposed floors?
0.4
What is the maximum allowable orientation of the foundation of a proposed house?
22°
Which of the following factors are accounted for in the energy model calculations for each wall assembly, fenestration component, roof-ceiling assembly, and exposed floor assembly?
d) All of the above
Which of the following factors are accounted for in the energy model calculations for the effect of each assembly in contact with the ground on below-grade heat transfer?
d) All of the above
What factors are accounted for in the energy model calculations for heat transfer through fenestration separating conditioned spaces from the outdoors, including skylights?
e) All of the above
What does the energy model calculations exclude when accounting for the effect of thermal mass?
b) Contents of the house
What does the energy model calculations account for in the presence of thermally active walls, floors, and ceilings with embedded conditioning systems that form part of the building envelope?
a) Solar heat gain
Which of the following is true about the airtightness value used in the energy model calculations for the proposed house?
It must be determined through a specific testing method.
Which of the following is true about the design airtightness used in the energy model calculations for the proposed house?
It is determined using air changes per hour at 50 Pa pressure differential.
Which of the following is true about determining airtightness in accordance with CAN/CGSB-149.10-M for the energy model calculations?
It must exclude Clause 6.1.6 related to intentional openings for mechanical equipment.
Which of the following is true about the modeling of HVAC systems in the energy model calculations for the proposed house?
Multiple HVAC systems should be called in a specific order.
Which of the following is true about the performance characteristics of the heat-recovery ventilation system in the energy model calculations for the proposed house?
The required principal ventilation rate should be determined based on the number of bedrooms.
According to the text, how should the circulation fan power be calculated if the proposed house contains multiple HVAC systems?
The circulation fan power shall be the sum of the circulation fan power capacity of each system.
According to the text, how should the ventilation fan power consumption be modeled?
2.32 W/L/s for each ventilation fan on the exhaust side and, where applicable, on the supply side
According to the text, how should the flow rate of the circulation fan in the reference house be determined for a forced-air system in the proposed house?
Multiply the capacity of the heating system in the proposed house by 0.0604 for heat pumps and 0.0251 for all other types of heating systems.
According to the text, how should the minimum electricity requirement of the circulation fan be determined for a forced-air system in the proposed house?
Multiply the flow rate of the circulation fan in the reference house, determined in accordance with Sentence (15), by a factor of 2.30.
According to the text, how should the power capacity of the circulation fan be modeled for a forced-air system in the proposed house?
Model the power capacity as specified in the design for the proposed house.
The thermal mass of the reference house is 060 MJ/m2·°C.
True
The solar absorptance of the exterior walls, roofs, and exposed floors is 0.4.
True
The solar heat gain coefficient of fenestration is 0.26.
True
The airtightness of the reference house is 2.5 air changes per hour at 50 Pa pressure differential.
True
The effective thermal resistance and overall thermal transmittance values used in the energy model calculations for the reference house are determined according to Table 9.36.2.6.-A for walls and ceilings below attics.
True
The design airtightness used in the energy model calculations for the proposed house is not specified in the text.
False
The energy model calculations for service water heating use in residential buildings are not mentioned in the text.
False
The flow rate of the circulation fan in the reference house for a forced-air system in the proposed house should be determined according to the text.
True
The energy model calculations account for the presence of thermally active walls, floors, and ceilings with embedded conditioning systems that form part of the building envelope.
True
The climatic data should be measured at least once every 10 years for energy model calculations.
False
Study Notes
Climatic Data
- Climatic data for energy model calculations should be based on measurements at time intervals no greater than 1 hour for 1 year (8760 hours)
- Data should be averaged over at least 10 years, collected from the nearest weather station to the building site
- For urban regions with multiple climatic data sets, the data set that best represents the climate at the building site should be used
Building Envelope Calculations
- Energy model calculations should account for heat transfer through:
- Wall assemblies
- Roof-ceiling assemblies (including attics)
- Exposed floor assemblies
- Calculations should consider:
- Thermal characteristics of each assembly
- Thermal bridging
- Area of interior side of insulated surfaces
- Emissivity
- Effective thermal resistance or overall thermal transmittance
- Below-grade heat transfer should be accounted for, considering:
- Foundation geometry
- Soil conditions
- Insulation configuration
HVAC System Calculations
- Energy model calculations should account for energy consumption of each HVAC system for each hour of the year
- Each heating and cooling system should be modeled separately
- Conditioned spaces should be modeled as:
- Heated
- Cooled
- Heated and cooled
- Performance requirements from Table 9.36.3.10 should be used
- Duct and piping losses should be included for both proposed and reference houses
Service Water Heating System Calculations
- Energy model calculations should account for energy consumption of all service water heating systems
- Performance requirements from Table 9.36.4.2 should be used
- Piping and standby losses should be included for both proposed and reference houses
- Supply cold water temperature should be calculated based on HDD (heating degree-days)
- Service water delivery temperature should be 55°C
- Service water heating use schedule from Table 9.36.5.8 should be used
General Requirements for Modeling the Proposed House
- Energy model calculations should be consistent with proposed construction specifications
- Modeling should include:
- Building envelope assemblies
- HVAC system types and capacities
- Service water heating system types and capacities
- Airtightness value should be:
- 3.2 air changes per hour at 50 Pa pressure differential
- 2.5 air changes per hour at 50 Pa pressure differential with airtightness testing
- Measured airtightness value
- Exterior walls, roofs, and exposed floors should have a solar absorptance of 0.4
Modeling HVAC System of Proposed House
- Energy model calculations should include:
- Heat pump efficiency and shut-down temperature
- Permanent supplementary heating systems
- Heat-recovery ventilation system characteristics
- Part-load performance of equipment
- Duct and piping losses
Modeling Service Water Heating System of Proposed House
- Energy model calculations should include:
- Piping losses
- Drain-water heat recovery
- Service water heating system size and type
General Requirements for Modeling the Reference House
- Energy model calculations should be consistent with prescriptive requirements of Subsections 9.36.2 to 9.36.4
- Modeling should include:
- Building envelope assemblies
- HVAC system types and capacities
- Service water heating system types and capacities
- Values used for the reference house should be the same as those used for the proposed house, including:
- Floor area
- Heated volume
- Number and types of rooms
Test your knowledge on energy model calculations for house orientation and airtightness values. Determine the correct 5° orientation and choose the accurate airtightness value for the proposed house.
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